Dernière mise à jour : août 28, 2026
Radiotherapy to the pelvis — for prostate, cervical, rectal or bladder cancer — cannot spare everything in its path. The bladder sits in the middle of that field, and in a minority of patients the radiation leaves behind fragile, poorly-supplied tissue with abnormal blood vessels that bleed.
It affects roughly one in twenty people treated, and the timing is characteristic: sometimes within three to six months, but frequently years later — often around a decade after treatment finished, by which time the connection is easily missed.
- Centre d'urologie Hôpital de Bangkok Thaïlande Réservation en ligne 02-310-3009 bhquro@bdms.co.th
- Hôpital Samitivej Sriracha Chonburi 088-022-1445
The most important point on this page
The earlier version of this article moved from a history of radiotherapy straight to treating radiation cystitis. That step must not be skipped, because radiotherapy is itself a risk factor for a later bladder cancer.
Someone bleeding ten years after pelvic radiation has three possible explanations, not one: radiation damage to the bladder, a new cancer caused by the radiation, or the original cancer returning. They cannot be told apart by the history.
So the assessment is the same one anybody with visible blood in the urine receives — imaging of the kidneys and ureters, and a look inside the bladder — before the bleeding is attributed to radiation. Radiation cystitis is a diagnosis reached by exclusion, not one assumed from the history. See blood in the urine et cystoscopie flexible.

Controlling active bleeding
- Bladder washout and continuous irrigation through a wide catheter, where clots are forming and blocking the flow.
- Correcting what can be corrected — treating infection, reviewing blood-thinning medication with the prescriber, and correcting anaemia or clotting problems.
- Admission and transfusion where blood loss is significant.
- Cystoscopy to stop bleeding points directly, which also provides the look inside that the diagnosis requires. Treating irradiated bladder tissue has to be done sparingly, since aggressive cautery damages already-fragile tissue and can make matters worse.
One caution worth knowing: drugs that promote clotting are sometimes used, and they carry a real risk of forming clots inside the bladder that then cannot be passed. This is a decision for the treating team rather than something to request.
Treating the underlying damage
Hyperbaric oxygen
The problem is essentially that irradiated tissue is starved of oxygen and cannot repair itself. Breathing oxygen at increased pressure raises the amount dissolved in the tissue enough to allow new blood vessels to form and healing to occur. It has the best evidence of anything on this list, with high response rates reported and better results the earlier it is started.
What the earlier version did not say is what it asks of the patient. This is not a single treatment: it is typically thirty to forty sessions, each lasting about two hours, on consecutive weekdays over several weeks. It requires a chamber, which not every city has. There are ear pressure problems, temporary short-sightedness that reverses, and it is unsuitable for some lung conditions and for people who cannot tolerate enclosed spaces.
Reported success figures of the order of nine in ten come from relatively small series in selected patients. The direction is reliable; the decimal place is not, and the commitment is real.

Oral and bladder treatments
- Pentosan polysulfate, which supplements the protective layer lining the bladder. It takes one to eight weeks to have an effect. An important caution was missing: long-term use has been associated with a form of retinal damage affecting central vision, which may not fully reverse on stopping. Anyone taking it for an extended period should have their eyes checked and report any change in vision.
- Hyaluronic acid or similar instillations into the bladder, which replace that lining layer directly and are well tolerated.
- Formalin instillation — effective for bleeding that resists everything else, and genuinely a last-resort option. The earlier version listed kidney injury and respiratory failure as its risks; the more relevant hazards are severe pain requiring anaesthesia, scarring that permanently shrinks the bladder, and damage to the ureters — reflux must be excluded first, or the formalin reaches the kidneys. It trades bleeding for a smaller, stiffer bladder, which is sometimes the right trade and never a small one.
Surgery, and a correction
Where everything fails and bleeding is life-limiting, the bladder is removed and the urine diverted. The earlier version described this as creating a neobladder connected to the abdominal wall. Those are two different operations and the description has been corrected: a neobladder is an internal reservoir joined to the urethra, with no stoma, while a diversion to the abdominal wall is a conduit or a continent cutaneous reservoir.
Either is major surgery, and it is more difficult and carries a higher complication rate than usual because it is performed in tissue that has been irradiated and heals poorly. It is genuinely a last resort — which is why the earlier options are worth persisting with.
Two further things that help throughout: stopping smoking, which impairs the healing of irradiated tissue and independently raises bladder cancer risk, and keeping fluid intake up so that clots are less likely to form.
Symptoms that need attention the same day
In an emergency in Thailand, call 1669.
- Clots in the urine, or inability to pass urine with a painful full bladder — clot retention needs draining and washing out, not waiting.
- Heavy bleeding, or bleeding with dizziness, breathlessness or a racing pulse — signs of significant blood loss.
- Fever or shaking chills.
- Douleur au flanc, which may mean the ureters are obstructed.
- Any visible bleeding after pelvic radiotherapy that has never been fully investigated. Not urgent today, and the item on this list most likely to matter.
Foire Aux Questions Sur la Cystite Radique
I had radiotherapy years ago and now there is blood in my urine. Is that radiation cystitis?
It may be, and it must not be assumed. Radiotherapy itself raises the risk of a later bladder cancer, and the original cancer can also return, so bleeding is investigated with imaging of the kidneys and ureters and a look inside the bladder before it is attributed to radiation damage. Radiation cystitis is a diagnosis of exclusion.
How long after radiotherapy can it appear?
Sometimes within three to six months, but often much later — commonly around a decade afterwards, which is long enough that patients and doctors may not connect the two.
What does hyperbaric oxygen involve?
Breathing oxygen at increased pressure to raise oxygen delivery to tissue that radiation has left poorly supplied, allowing repair. It has the best evidence of the available treatments and works better the earlier it is started — but it typically means thirty to forty sessions of about two hours each over several weeks, needs a chamber, and is unsuitable for some lung conditions or for those who cannot tolerate enclosed spaces.
Are there risks with the oral medication?
Pentosan polysulfate has been associated with a form of retinal damage affecting central vision after prolonged use, which may not fully reverse. Anyone taking it long term should have eye checks and report any change in vision. This was not mentioned in the earlier version of this article.
Will I need my bladder removed?
Very unlikely. It is reserved for bleeding that resists everything else, and it is more difficult and riskier than usual because irradiated tissue heals poorly — which is why the earlier treatments are worth persisting with even when progress is slow.
Arranging a consultation
Dr. Soarawee Weerasopone sees patients at Hôpital de Bangkok Siège social and at Samitivej Sriracha Hospital in Chonburi on 088-022-1445. Bring the details of your radiotherapy — what was treated, when, and where — together with any previous cystoscopy or imaging, and a list of your medicines including any blood thinner.
La télémédecine de Bangkok Hospital est disponible pour les patients qui ne peuvent pas se déplacer en personne, y compris les patients internationaux — organisez-la à l'avance par e-mail auprès du service d'urologie à bhquro@bdms.co.th. Samitivej Sriracha is in-person only. Enquiries about cost and about hyperbaric chamber availability are answered by the hospital, not by this website. Heavy bleeding or clot retention goes to an emergency department, not to email.
Avis de non-responsabilité : This content is written and reviewed by Dr. Soarawee Weerasopone, a board-certified urologist at Bangkok Hospital Headquarters, and is intended for education only. It is not medical advice, diagnosis or a prescription for any individual, and no advice, diagnosis or prescription is given through personal messaging channels or social media. Dr. Soarawee operates no public social media account; any account offering private consultation in his name is fraudulent. In an emergency in Thailand, call 1669.
Rédigé et révisé par des médecins : Dr Soarawee Weerasopone (Dr Pom) — Urologue certifié, siège social de l'hôpital de Bangkok, en pratique urologique depuis 2016. Fellowship : Chirurgie robotique, Chang Gung Memorial Hospital, Taïwan (2019) · Stage d'observation : Endourologie, Hôpital universitaire Juntendo, Tokyo (2022) · Chercheur et observateur clinique, Département d'urologie Scott, Baylor College of Medicine, États-Unis (2025-2026).

Le Dr Soarawee Weerasopone (Dr Pom) est urologue certifié au Bangkok Hospital Headquarters, spécialisé en santé masculine, chirurgie robotique (da Vinci Xi) et traitement des calculs rénaux. Il est actuellement chercheur et observateur clinique au département d'urologie Scott du Baylor College of Medicine (2025-2026), sous la direction du Pr Mohit Khera. Il a effectué un fellowship en chirurgie robotique au Chang Gung Memorial Hospital de Taïwan (2019) et un stage d'observation en endourologie au Juntendo University Hospital de Tokyo (2022).

