Tag Archive for: radiation effects

Tranexamic Acid for Radiation Cystitis: Benefits, Duration and Important Risks

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Blood in the urine after pelvic radiotherapy can be frightening. It may appear months or even many years after treatment for prostate, bladder, rectal or gynaecological cancer. One possible cause is radiation cystitis: delayed injury to the bladder lining and its small blood vessels.

Tranexamic acid is sometimes considered when bleeding is troublesome. It can help stabilise blood clots, but it does not repair the radiation injury itself and it is not suitable for every patient. In urinary tract bleeding, preventing a clot from dissolving may reduce bleeding but may also allow a larger clot to obstruct the bladder or ureter. Careful patient selection and medical supervision are therefore essential.

Seek urgent medical attention if you cannot pass urine, are passing large clots, feel faint or breathless, develop fever or flank pain, or the bleeding is heavy or worsening.

What is radiation cystitis?

Radiotherapy can cause progressive damage to the bladder’s small blood vessels. These vessels may become fragile and bleed easily. Patients may experience visible haematuria, urinary frequency, urgency, pain or recurrent clot retention.

Radiation cystitis should not be assumed simply because a patient has previously received radiotherapy. Infection, urinary stones, recurrent or new cancer, kidney disease and medication-related bleeding must also be considered. Assessment may include urine testing and culture, a full blood count, renal function, imaging of the upper urinary tract and cystoscopy. Biopsy is used selectively because irradiated tissue heals poorly.

How does tranexamic acid work?

The body normally breaks down blood clots through a process called fibrinolysis. Tranexamic acid blocks the binding of plasminogen and plasmin to fibrin, slowing this breakdown. It is therefore an antifibrinolytic medicine: it helps a clot remain in place rather than acting as a blood-clotting factor itself.

For radiation cystitis, tranexamic acid is intended to control active bleeding. It does not remove abnormal radiation-induced blood vessels, reverse fibrosis or prevent future bleeding once the medicine is stopped.

How effective is it for radiation cystitis?

The evidence is limited. Tranexamic acid has been used for haematuria from several causes, and a small randomised emergency-department study found that intravenous treatment reduced the amount of bladder irrigation required to clear the urine. However, it did not significantly reduce haemoglobin loss or transfusion requirements. Importantly, this study included mixed causes of haematuria and was not designed specifically for radiation cystitis.

The Canadian Urological Association best-practice report concluded that evidence was insufficient to make a formal recommendation for tranexamic acid in radiation-induced haemorrhagic cystitis. Later narrative reviews have reached a similar conclusion. Intravesical tranexamic acid, placed directly into the bladder, has shown encouraging results in small emergency-department studies of gross haematuria, but evidence specific to radiation cystitis is still inadequate and this remains a specialist, non-standard use.

In practice, tranexamic acid may be considered as a temporary adjunct in selected patients while the cause and severity of bleeding are assessed, or while more definitive treatment is arranged. It should not delay bladder washout, clot evacuation, cystoscopic treatment, hyperbaric oxygen therapy, embolisation or other appropriate care when these are required.

How long can tranexamic acid be used?

There is no well-supported universal duration for radiation cystitis. The Australian product information for oral tranexamic acid describes treatment of haematuria while blood remains macroscopically visible, but radiation cystitis is a recurrent condition and that instruction should not be interpreted as approval for indefinite therapy.

For this indication, treatment is generally best regarded as a short, medically supervised course for an active bleeding episode. The exact dose and duration depend on:

  • whether bleeding is mild, ongoing or causing clot retention;
  • whether the source is the bladder or upper urinary tract;
  • kidney function, because tranexamic acid is largely eliminated in the urine;
  • previous blood clots, cardiovascular risk and pro-thrombotic medicines;
  • anticoagulant or antiplatelet therapy; and
  • the response to treatment and need for definitive therapy.

There is no good evidence supporting continuous long-term tranexamic acid as prophylaxis for recurrent radiation cystitis. If bleeding has not clearly improved within a short course, recurs promptly after treatment, or requires repeated courses, the diagnosis and management plan should be reassessed. Longer or repeated use should occur only under specialist supervision, with renal function and thrombotic risk reviewed.

Patients should not start, extend, repeat or stop prescribed tranexamic acid without discussing it with their treating clinician.

Important side effects

Common or less serious adverse effects may include:

  • nausea, vomiting, diarrhoea or abdominal discomfort;
  • headache, dizziness or fatigue; and
  • muscle or joint discomfort.

Potentially serious adverse effects include:

Blood clots

Deep-vein thrombosis, pulmonary embolism, stroke, heart attack and other arterial or venous thromboses are uncommon but potentially serious. Risk assessment is particularly important in patients with an active or previous clot, known thrombophilia, active malignancy, prolonged immobility or concurrent pro-thrombotic medication.

Urgent assessment is required for new unilateral leg pain or swelling, sudden chest pain, shortness of breath, coughing blood, weakness on one side, difficulty speaking or sudden severe headache.

Clot retention and urinary obstruction

Tranexamic acid may stabilise clots within the urinary tract. This can contribute to painful bladder clot retention. It is particularly concerning when bleeding arises from a kidney or ureter, because a clot may obstruct the ureter and cause flank pain, hydronephrosis or loss of kidney function. Upper-tract haematuria therefore warrants particular caution and specialist assessment.

Kidney impairment

Most tranexamic acid is excreted unchanged through the kidneys. The dose must be reduced when renal function is impaired; accumulation increases the risk of toxicity, including neurological adverse effects. Significant renal impairment may make treatment inappropriate or require a substantially altered regimen.

Seizures

Seizures are a recognised, dose-related risk, reported particularly with high intravenous doses and when the medicine accumulates in renal impairment. A history of seizures requires careful consideration.

Visual disturbance

Rare visual effects, including altered colour vision, have been reported. New visual symptoms require prompt review and usually discontinuation pending medical advice. Ophthalmic monitoring may be considered when prolonged treatment is unavoidable.

Severe allergy

Facial or throat swelling, wheeze, breathing difficulty or a widespread blistering rash requires emergency care.

Who may not be suitable for treatment?

Tranexamic acid may be contraindicated or require particular caution in people with:

  • active thromboembolic disease or a substantial history or risk of thrombosis;
  • significant kidney impairment;
  • upper urinary tract bleeding or suspected ureteric obstruction;
  • a history of seizures;
  • acquired disturbances of colour vision;
  • disseminated intravascular coagulation unless managed by an experienced clinician; or
  • hypersensitivity to tranexamic acid.

Medication review is essential. Anticoagulants and antiplatelet agents can worsen bleeding, but stopping them may cause stroke, pulmonary embolism, heart attack or coronary-stent thrombosis. They should not be stopped merely because haematuria develops without an individual risk assessment involving the prescribing clinician. Likewise, combining tranexamic acid with pro-thrombotic medicines requires caution.

Where does it fit in the management pathway?

Management is guided by severity. Initial care may include resuscitation, correction of significant anaemia or coagulopathy, a large-bore catheter, manual washout and continuous bladder irrigation. Cystoscopy permits clot evacuation, exclusion of tumour and cautery or laser treatment of bleeding areas.

For persistent or recurrent radiation cystitis, options may include intravesical agents, hyperbaric oxygen therapy, selective arterial embolisation and, rarely, urinary diversion or cystectomy. Hyperbaric oxygen is one of the better-studied treatments because it aims to improve tissue oxygenation and new blood-vessel formation rather than merely suppressing an episode of bleeding.

Tranexamic acid may have a role as a bridge or adjunct in a carefully selected patient. Its value must always be balanced against the danger of thrombosis and urinary tract obstruction.

The take-home message

Tranexamic acid can reduce haematuria in some patients, but evidence specifically for radiation cystitis is weak. It is not a cure and should usually be used only for a short, active bleeding episode under medical supervision. There is no established safe or effective duration for continuous long-term use in radiation cystitis. Kidney function, clotting history, the anatomical source of bleeding and concurrent medication must be reviewed before treatment.

Visible haematuria after radiotherapy always deserves proper investigation, particularly if it is recurrent, contains clots or is accompanied by difficulty passing urine.

This article provides general information and does not replace individual medical advice. Tranexamic acid is a prescription medicine in Australia; its use for radiation cystitis must be individualised by the treating clinician.

References

  1. Goucher G, Saad F, Lukka H, Kapoor A. Canadian Urological Association Best Practice Report: Diagnosis and management of radiation-induced hemorrhagic cystitis. Can Urol Assoc J. 2019;13(2):15–23. doi:10.5489/cuaj.5788
  2. Moharamzadeh P, Ojaghihaghighi S, Amjadi M, Rahmani F, Farjamnia A. Effect of tranexamic acid on gross hematuria: a pilot randomized clinical trial study. Am J Emerg Med. 2017;35(12):1922–1925. doi:10.1016/j.ajem.2017.09.012
  3. Abramowitz D, et al. Clinical management of radiation cystitis: a narrative review. AME Med J. 2021;6:30. Clinical management of radiation cystitis
  4. Choi H, et al. Impact of intravesical administration of tranexamic acid on gross hematuria in the emergency department: a before-and-after study. Am J Emerg Med. 2023;68:118–122. doi:10.1016/j.ajem.2023.03.010
  5. Pfizer Australia. Cyklokapron (tranexamic acid) Australian Product Information. Current product information should be checked through the Therapeutic Goods Administration or the sponsor before prescribing. Australian product information
  6. DailyMed. Tranexamic acid injection—prescribing information. US National Library of Medicine. DailyMed drug labelling
  7. Chauncey JM, Wieters JS. Tranexamic Acid. In: StatPearls. Updated 2025. NCBI Bookshelf

 

Blood in the Urine After Radiotherapy: Understanding Radiation Cystitis

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Pelvic radiotherapy is an important and often highly effective treatment for prostate, bladder, rectal and gynaecological cancers. However, radiation can leave the small blood vessels and lining of the bladder fragile. Months or even many years later, this may cause urinary symptoms or bleeding known as radiation cystitis. When bleeding is prominent, the condition is also called radiation-induced haemorrhagic cystitis.

Most episodes can be controlled, but visible blood in the urine must never simply be attributed to previous radiotherapy. Infection, urinary stones, recurrent cancer and a new bladder or upper urinary tract cancer must first be considered.

Seek urgent medical care if you cannot pass urine, are passing large clots, feel faint or short of breath, develop fever or severe pain, or have heavy ongoing bleeding.

What causes radiation cystitis?

Radiotherapy damages cancer cells, but the bladder may receive some radiation because it lies close to the treatment area. Early inflammation can make the bladder lining swollen and irritable. Late injury is different: progressive damage to small blood vessels causes reduced oxygen supply, scarring and fragile abnormal vessels called telangiectasia. These vessels may bleed with little provocation.

Radiation damage can also reduce bladder capacity and elasticity. In severe cases, ulceration, fibrosis, fistula formation or obstruction may occur.

When does it present?

Radiation-related bladder problems have two broad patterns:

  • Acute radiation cystitis occurs during radiotherapy or within the first few weeks or months. Frequency, urgency, burning and pelvic discomfort are common; substantial bleeding is less usual. Symptoms often settle after treatment finishes.
  • Late radiation cystitis generally begins more than six months after radiotherapy and may appear years or even decades later. The Canadian Urological Association review notes pathological vascular changes from about 6–12 months, with new symptoms reported as long as 20 years after treatment.

The risk varies with radiation dose and field, treatment technique, previous pelvic surgery, smoking, vascular disease, diabetes and combined cancer treatments.

How can it present?

Presentation ranges from microscopic blood found on a urine test to recurrent heavy bleeding with clots. Symptoms may include:

  • pink, red or cola-coloured urine;
  • small or large blood clots;
  • urinary frequency, urgency, burning or bladder pain;
  • interrupted flow or complete retention when clots obstruct the outlet;
  • tiredness, dizziness or breathlessness from anaemia; and
  • a small, painful or poorly compliant bladder in advanced disease.

Bleeding may be intermittent. A clear urine sample between episodes does not exclude radiation cystitis.

Does anticoagulant or antiplatelet therapy matter?

Anticoagulants such as warfarin, apixaban, rivaroxaban or dabigatran, and antiplatelet drugs such as aspirin or clopidogrel, do not create radiation cystitis. They can, however, make bleeding from its fragile vessels more prolonged or severe. Excess anticoagulation, impaired kidney function, drug interactions and combined anticoagulant–antiplatelet therapy can further increase bleeding risk.

These medicines may be preventing a stroke, heart attack, pulmonary embolus or thrombosis of a coronary stent. Do not stop them yourself. During significant bleeding, the urologist, emergency team and the clinician responsible for the medication should jointly balance:

  • the severity of bleeding and haemoglobin fall;
  • the reason for treatment and the risk of thrombosis if it is interrupted;
  • the last dose, kidney function and, for warfarin, the INR;
  • whether a temporary hold, reversal or dose adjustment is justified; and
  • when and how treatment should safely restart.

Importantly, anticoagulant or antiplatelet use does not remove the need to investigate haematuria. It may reveal bleeding from an otherwise silent bladder or upper-tract tumour.

How is haematuria investigated after radiotherapy?

Assessment is tailored to the patient and severity, but commonly includes:

  1. History and examination: radiation site, dose and timing; cancer history; smoking; infection symptoms; bleeding pattern; and all medicines.
  2. Urine testing: urinalysis and culture. Urine cytology may be appropriate in selected patients, but it does not replace cystoscopy.
  3. Blood tests: full blood count, kidney function and coagulation studies. Severe or ongoing bleeding may require group-and-screen or crossmatch.
  4. Imaging of the upper urinary tracts: usually CT urography when appropriate; ultrasound or alternative imaging may be chosen when contrast or radiation exposure is unsuitable.
  5. Cystoscopy: inspection of the urethra and bladder to identify typical diffuse telangiectasia, exclude a tumour, evacuate clots and sometimes cauterise bleeding vessels. Suspicious areas require biopsy, performed carefully because irradiated tissue heals poorly.

A stepwise approach to treatment

Treatment depends on the rate of bleeding, clot retention, anaemia, bladder function, medical fitness and local expertise. No single treatment suits every patient.

1. Stabilisation and bladder drainage

Heavy bleeding may require hospital admission, intravenous fluids, correction of anaemia or clotting abnormalities, and blood transfusion when clinically necessary. A large three-way catheter permits manual clot washout and continuous bladder irrigation with saline. Persistent clots may require cystoscopic evacuation under anaesthesia.

Treat a proven urinary infection, but antibiotics do not treat sterile radiation injury. Medication contributing to bleeding should be reviewed collaboratively rather than stopped automatically.

2. Cystoscopy and endoscopic haemostasis

Cystoscopy can confirm the diagnosis and exclude malignancy. Focal bleeding may be treated with diathermy, laser or another endoscopic coagulation technique. This is often effective initially, although diffuse disease may recur and repeated aggressive cautery can worsen scarring or perforation risk.

3. Intravesical and systemic options

Options used for persistent or recurrent bleeding include:

  • Alum bladder irrigation: may control bleeding relatively quickly, but recurrence is possible. It requires caution in substantial kidney impairment because aluminium toxicity can occur.
  • Hyaluronic acid, sometimes combined with chondroitin sulphate: aims to restore the bladder’s protective lining. Evidence suggests benefit for haematuria and urinary symptoms, but treatment is gradual and is not suitable for an unstable major bleed.
  • Oral sodium pentosan polysulphate: has limited, slower-onset evidence. Long-term exposure also requires discussion of pigmentary maculopathy and eye monitoring.
  • Other agents have been reported, but supporting evidence is generally limited.

Formalin can rapidly seal bleeding vessels but may cause severe pain, bladder contraction, reflux, ureteric damage, fistula or systemic complications. It is therefore reserved for life-threatening or otherwise uncontrollable bleeding, used at the lowest effective concentration by experienced teams after the upper tracts have been assessed and protected.

4. Hyperbaric oxygen therapy

Hyperbaric oxygen therapy (HBOT) is one of the best-studied treatments for persistent late radiation cystitis. The patient breathes 100% oxygen in a pressurised chamber. This increases tissue oxygen levels and encourages new blood-vessel growth and healing in chronically oxygen-deprived bladder tissue; it is not simply a short-lived attempt to “oxygenate the blood.”

How effective is it?

The evidence is encouraging, although success definitions and patient populations vary:

  • A meta-analysis cited by the Canadian Urological Association included 602 patients with at least one year of follow-up; 84% achieved partial or complete resolution of haematuria.
  • The multicentre randomised RICH-ART trial found a clinically meaningful improvement in patient-reported urinary symptoms after HBOT compared with standard care. At five years, 48 of 70 followed patients (68.6%) met the study’s responder definition, and the mean improvement among responders remained substantial. This supports durability for many—but not all—patients.
  • HBOT is not guaranteed. Some patients have incomplete improvement, relapse, or still require endoscopic or more invasive treatment. Earlier referral after recurrent bleeding may be preferable to waiting until the bladder is severely fibrotic or the patient has needed repeated transfusions.

How long does it take?

A usual course is 30–40 weekday sessions, sometimes more. Each treatment commonly involves approximately 80–90 minutes breathing oxygen at pressure, although total chamber time is longer. In practical terms, treatment usually takes six to eight weeks. Benefit may develop during the course and continue over subsequent weeks or months as tissue healing progresses.

HBOT is unsuitable or requires specialist assessment in some circumstances. An untreated pneumothorax is an absolute contraindication. Ear or sinus pressure injury, temporary visual change, claustrophobia and, rarely, oxygen-related seizure can occur. Lung disease, certain chemotherapy drugs, implanted devices and difficulty equalising ear pressure require individual review. Availability and daily travel are practical limitations.

5. Arterial embolisation

For ongoing significant bleeding despite less invasive measures, selective or super-selective embolisation can block the bleeding arterial supply. Modern targeted techniques reduce, but do not eliminate, risks such as pelvic pain, tissue ischaemia and non-target embolisation. It can be valuable in frail patients who are poor candidates for major surgery.

When should urinary diversion be considered?

Urinary diversion is a last-resort, potentially life-saving strategy, not an early treatment for uncomplicated bleeding. It should be discussed in a multidisciplinary setting at an experienced centre when there is:

  • life-threatening, transfusion-dependent or recurrent clotting haematuria despite endoscopic treatment, HBOT, appropriate intravesical therapy and/or embolisation;
  • a severely contracted, painful, non-functional bladder with intolerable frequency or poor storage;
  • fistula, necrosis, major outlet or ureteric damage, or progressive upper-tract deterioration;
  • repeated admissions and unacceptable loss of quality of life; or
  • inability to control bleeding safely by less invasive means.

Options include nephrostomy tubes or ureteric occlusion as temporary or palliative measures; cutaneous ureterostomy; or an ileal conduit. Diversion without removing the bladder may be considered in a very high-risk patient, but the retained irradiated bladder can continue to bleed, become infected or painful, and may later require surgery. Cystectomy with diversion provides definitive removal of the diseased bladder but is a major operation. Previous radiation makes tissue planes, healing and bowel surgery more difficult, so complication and mortality rates are substantially higher than for routine cystectomy.

The decision should incorporate the patient’s cancer status, cardiovascular and respiratory fitness, frailty, kidney and bowel function, previous operations, goals of care and willingness to manage a stoma or external drainage.

The practical message

Radiation cystitis may appear long after the original cancer treatment and can range from mild intermittent haematuria to a medical emergency. Blood-thinning medication may worsen the episode, but it should neither be blamed as the sole cause nor stopped without a coordinated medical plan. A careful evaluation to exclude malignancy and other treatable causes comes first.

Management is progressive: stabilisation and irrigation, cystoscopic treatment, selected bladder therapies, HBOT and embolisation before major diversion surgery. HBOT offers worthwhile, durable improvement for many appropriately selected patients, but requires a substantial weekday treatment commitment. Diversion is reserved for a devastated bladder or bleeding that remains dangerous despite comprehensive treatment.

References

  1. Goucher G, Saad F, Lukka H, Kapoor A. Canadian Urological Association Best Practice Report: Diagnosis and management of radiation-induced hemorrhagic cystitis. Can Urol Assoc J. 2019;13(2):15–23. doi:10.5489/cuaj.5788
  2. Oscarsson N, Müller B, Rosén A, et al. Radiation-induced cystitis treated with hyperbaric oxygen therapy (RICH-ART): a randomised, controlled, phase 2–3 trial. Lancet Oncology. 2019;20(11):1602–1614. doi:10.1016/S1470-2045(19)30494-2
  3. Abramowitz DJ, Warner JN. Clinical management of radiation cystitis: a narrative review. AME Med J. 2021;6:9. doi:10.21037/amj-20-62
  4. Liem X, Saad F, Delouya G. A practical approach to the management of radiation-induced hemorrhagic cystitis. Drugs. 2015;75:1471–1482. doi:10.1007/s40265-015-0443-5
  5. Smit SG, Heyns CF. Management of radiation cystitis. Nat Rev Urol. 2010;7:206–214. doi:10.1038/nrurol.2010.23
  6. AUA/SUFU. Microhematuria Guideline (2020; amended 2025). American Urological Association. AUA guideline
  7. Oscarsson N, Rosén A, Müller B, et al. Radiation-induced cystitis treated with hyperbaric oxygen therapy (RICH-ART): long-term follow-up of a randomised controlled, phase 2–3 trial. EClinicalMedicine. 2025;83:103214. doi:10.1016/j.eclinm.2025.103214
  8. Yang TK, Wang YJ, Li HJ, et al. Efficacy and safety of hyperbaric oxygen therapy for radiation-induced hemorrhagic cystitis: a systematic review and meta-analysis. J Clin Med. 2024;13(16):4724. doi:10.3390/jcm13164724

This article provides general information and does not replace individual medical advice. Treatment availability and suitability vary. Visible haematuria, particularly with clots or difficulty passing urine, requires prompt medical assessment.

Protecting the Rectum During Prostate Radiotherapy: A Patient Guide

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Radiotherapy is an established treatment for many men with prostate cancer. Modern planning and image-guidance techniques can direct radiation accurately, but the prostate lies immediately in front of the rectum. Because the two organs are so close, part of the rectal wall may receive radiation during treatment.

Radiation teams use several methods to limit exposure to surrounding healthy tissue. For selected patients, one option is to place a temporary biodegradable material between the prostate and rectum before radiotherapy planning.

This article explains why bowel effects occur, how rectal spacing works, its possible benefits and limitations, and the questions patients should discuss with their treating team. It does not recommend a particular product, device or brand.

Why can prostate radiotherapy affect the bowel?

The front wall of the rectum normally sits very close to the back of the prostate. Radiation directed at the prostate may therefore also reach a small amount of nearby rectal tissue.

Possible bowel effects during or after radiotherapy include:

  • increased bowel frequency
  • urgency
  • loose stools or diarrhoea
  • mucus discharge
  • rectal discomfort
  • bleeding
  • inflammation known as radiation proctitis

Many bowel symptoms are mild and settle after treatment, but some develop later or persist. Risk varies with the radiation technique, dose, fractionation schedule, individual anatomy, bowel health, medicines and previous pelvic treatment.

Rectal bleeding after radiotherapy should not automatically be attributed to radiation. Other causes, including haemorrhoids, polyps, inflammatory bowel disease and bowel cancer, may require investigation.

How is the rectum protected?

Protection begins with careful radiotherapy planning rather than with a spacer alone. Strategies may include:

  • intensity-modulated or volumetric-modulated radiotherapy
  • image guidance before and during treatment
  • accurate bladder and bowel preparation
  • management of rectal gas or stool
  • individualised dose constraints
  • limiting movement of the prostate
  • selecting an appropriate radiation schedule
  • a temporary rectal spacer in selected patients

A spacer is therefore an additional planning tool, not a substitute for high-quality radiation oncology.

What is a rectal spacer?

A rectal spacer is a temporary biodegradable material placed into the tissue plane between the prostate and the anterior rectal wall. Increasing this distance may reduce the radiation dose received by the rectum.

Materials used in currently available spacer systems include:

  • polyethylene-glycol hydrogel
  • stabilised hyaluronic-acid gel

These materials have different handling and imaging characteristics. They should not be assumed to have identical evidence, contraindications or safety profiles.

A spacer does not treat prostate cancer. Its role is to alter the anatomy temporarily while radiation treats the cancer.

Do all men having prostate radiotherapy need a spacer?

No. Many patients can receive carefully planned radiotherapy without one.

Potential benefit depends on factors such as:

  • the natural distance between the prostate and rectum
  • prostate size and shape
  • tumour position and extent
  • radiation dose and treatment schedule
  • the ability to meet rectal dose constraints without a spacer
  • previous prostate or pelvic procedures
  • bowel disease
  • bleeding risk and relevant medicines
  • whether pelvic lymph nodes are also being treated
  • local expertise and access

For some patients, the predicted reduction in rectal dose may be clinically meaningful. For others, the benefit may be small, uncertain or outweighed by the insertion risk.

The decision is usually made with the radiation oncologist. A urologist or another trained proceduralist may also be involved.

What does the evidence show?

Clinical studies of biodegradable rectal spacers generally show that increasing the distance between the prostate and rectum can reduce the radiation dose delivered to parts of the rectal wall.

A multicentre randomised trial involving 201 men receiving hypofractionated prostate radiotherapy evaluated a hyaluronic-acid spacer. The study reported improved rectal dosimetry and fewer acute grade 2 or worse gastrointestinal adverse events in the spacer group than in the control group.

These findings are relevant but require context:

  • dosimetric improvement does not guarantee that an individual patient will avoid bowel symptoms
  • trial participants and treatment protocols may differ from patients treated in routine practice
  • evidence for short-term bowel outcomes is stronger than evidence for some long-term outcomes
  • results for one spacer material or insertion technique should not automatically be applied to another
  • operator experience and correct placement affect both benefit and risk

Patients should ask how the published evidence applies to their planned radiotherapy technique and personal anatomy.

How is a spacer inserted?

The procedure is generally performed before radiotherapy planning.

Under ultrasound guidance, a needle is passed through the perineum—the skin between the scrotum and anus—into the potential space between the prostate and rectum. The tissue plane is checked carefully, and the spacer material is then introduced while its position is monitored.

Depending on the patient and treating centre, the procedure may use:

  • local anaesthesia
  • sedation
  • general anaesthesia

Fiducial markers used to help target radiotherapy may sometimes be inserted during the same procedure.

The exact preparation, antibiotic policy, management of anticoagulants and post-procedure care vary. Patients should follow the instructions given by their treating team.

Why does correct placement matter?

The spacer needs to create suitable separation along the part of the rectum closest to the planned radiation target. Too little separation, marked asymmetry or injection into the wrong tissue plane may reduce the expected dosimetric benefit.

Incorrect placement may also injure the rectal wall, prostate, urethra, bladder or nearby blood vessels. Training, real-time imaging, careful patient selection and recognition of abnormal anatomy are therefore important.

Some hyaluronic-acid materials can be broken down with an enzyme if significant malposition is recognised. This does not make incorrect placement harmless or remove the need for prevention, prompt assessment and appropriate management.

Who may be unsuitable?

Suitability depends on the particular device instructions, the patient’s anatomy and the clinical situation. Reasons to avoid or reconsider insertion may include:

  • infection or inflammation near the proposed injection site
  • inability to identify a safe tissue plane
  • tumour extending into the space behind the prostate
  • extensive scarring from previous surgery or treatment
  • significant rectal or anorectal disease
  • uncorrected bleeding disorder
  • anticoagulant or antiplatelet therapy that cannot be managed safely
  • allergy or hypersensitivity relevant to the proposed material
  • significant immunosuppression
  • a situation in which the expected dosimetric benefit is minimal

The approved Australian instructions for use for the exact device should be checked by the treating clinician.

Anticoagulant and antiplatelet medicines must not be stopped without advice from the clinician who manages them. Interrupting these medicines can cause stroke, heart attack, thrombosis or other serious harm.

Possible short-term effects

Temporary effects may include:

  • perineal discomfort or bruising
  • minor bleeding
  • a sensation of rectal fullness
  • discomfort when opening the bowels
  • urinary frequency or burning
  • a weaker urinary stream
  • constipation

The pattern and duration vary. New, severe or worsening symptoms require clinical review.

Uncommon but important complications

Spacer insertion is invasive and can cause serious complications, even when performed carefully.

Reported or plausible complications include:

  • infection, prostatitis or pelvic abscess
  • bleeding or haematoma
  • urinary retention
  • significant rectal or pelvic pain
  • spacer malposition or migration
  • injection into the rectal wall, prostate or another unintended site
  • injury to the urethra, bladder, rectum or blood vessel
  • rectal ulceration or tissue necrosis
  • embolic or vascular complications
  • fistula formation
  • need for further treatment, hospital admission or surgery

Severe pain, fever, difficulty passing urine, heavy bleeding, worsening bowel symptoms or feeling systemically unwell after the procedure should be assessed promptly.

What happens to the spacer?

Biodegradable spacers are intended to remain during the radiotherapy period and then gradually break down and be absorbed.

The expected duration and degradation process depend on the material. A second operation is not normally required solely to remove an appropriately placed biodegradable spacer.

Different spacer materials

The choice should not be reduced to a promotional comparison between brand names. Relevant clinical differences may include:

Consideration Hyaluronic-acid gel Polyethylene-glycol hydrogel
Primary purpose Temporary prostate–rectum separation Temporary prostate–rectum separation
Typical placement Transperineal, image-guided Transperineal, image-guided
Biodegradable Yes Yes
Handling Deposited and shaped during injection Forms a hydrogel after delivery
Imaging Visibility depends on material and imaging method Some formulations are designed for greater CT visibility
Evidence Randomised and observational studies are available Randomised, prospective and observational studies are available
Key limitation Insertion-related risk and dependence on correct placement Insertion-related risk and dependence on correct placement

This table is descriptive, not a claim that one material is safer or more effective. Head-to-head observational comparisons may be affected by patient selection, injected volume, operator technique, learning curve and treatment planning. They cannot by themselves establish universal superiority.

What about previous surgery or salvage radiotherapy?

Previous prostate procedures, pelvic surgery, focal therapy, radiotherapy or inflammation may alter the tissue plane behind the prostate. This can make placement more difficult or unsuitable.

The evidence for spacers in salvage or re-irradiation settings is less established than for primary prostate radiotherapy. These cases require individual assessment in an experienced multidisciplinary setting.

Questions to ask before deciding

  • What bowel risks are associated with my proposed radiotherapy plan?
  • Can the required rectal dose limits be met without a spacer?
  • What additional benefit is expected in my anatomy?
  • What spacer material is proposed, and is the exact device included in the ARTG for this intended use?
  • What evidence supports it for my radiation schedule?
  • Who will perform the procedure, and what is their experience?
  • What are the recognised contraindications and complications?
  • How will my anticoagulant or antiplatelet medicines be managed?
  • What symptoms after insertion require urgent review?
  • What are the alternatives if I choose not to have a spacer?
  • Are there additional costs or gaps?

Australian regulatory considerations

The Australian Register of Therapeutic Goods (ARTG) is the public database of therapeutic goods that may be legally supplied in Australia, unless an exemption or another authorised access pathway applies. An ARTG entry records the particular sponsor and intended purpose; it is not a general recommendation that the product is best for an individual patient.

Device inclusion, instructions for use, contraindications, availability and reimbursement can change. The treating team should confirm the current ARTG entry and approved instructions for the exact device proposed.

The bottom line

The rectum lies close to the prostate and may receive some radiation during prostate-cancer treatment. Modern planning and image guidance are the foundation of rectal protection.

A biodegradable rectal spacer can create temporary separation and may reduce rectal radiation exposure in selected patients. It does not treat the cancer, cannot guarantee freedom from bowel effects and introduces procedural risks of its own.

The decision should be individualised according to anatomy, the proposed radiation plan, expected dosimetric benefit, medical history, bleeding risk and local expertise. It should be made before radiotherapy planning through an informed discussion with the treating radiation oncology team.

This article provides general disease education and does not replace individual medical advice. It does not promote or recommend a particular therapeutic device, spacer material, brand, clinician or health service.

References and further reading