TL;DR: Radiation cystitis is a common and distressing complication of pelvic radiation therapy, causing bladder bleeding, urgency, and pain that can persist for years. Hyperbaric oxygen therapy (HBOT) is one of the most effective treatments available, with clinical trials showing significant improvement in bleeding resolution, symptom control, and quality of life. This Daffodil Month, we break down the evidence and explain how Canadian patients can access this treatment.
Estimated reading time: 9 minutes
What Is Radiation Cystitis?
Radiation cystitis is inflammation and damage to the bladder caused by radiation therapy. It most commonly occurs after treatment for cancers of the prostate, cervix, uterus, rectum, or bladder itself. Radiation delivered to the pelvic area inevitably exposes the bladder to some degree, and over time, the radiation damages the delicate blood vessels lining the bladder wall.
The condition can appear in two phases. Acute radiation cystitis develops during or shortly after treatment and usually resolves within weeks. Late radiation cystitis, also called chronic or delayed radiation cystitis, is the more serious form. It can emerge 6 months to 20 or more years after radiation treatment and tends to worsen over time without intervention.
The hallmark symptom is haematuria (blood in the urine), which can range from microscopic traces to severe, life-threatening bleeding requiring hospitalisation and blood transfusions. Other symptoms include urinary frequency, urgency, pain during urination, and reduced bladder capacity.
During Daffodil Month, the Canadian Cancer Society’s annual awareness campaign, it is worth recognising that these late effects of treatment affect thousands of Canadian cancer survivors who may not know that effective treatment exists.
Why Does Radiation Damage the Bladder?
The bladder lining (urothelium) is supplied by a dense network of tiny blood vessels. Pelvic radiation gradually destroys these vessels through a process called obliterative endarteritis. As blood vessels narrow and close, the bladder wall becomes chronically oxygen-starved. Without adequate oxygen, the tissue cannot repair itself from normal use, leading to a cycle of inflammation, fragile new blood vessels (telangiectasia) that bleed easily, fibrosis (scarring), and progressive loss of bladder function.
This is the same “three H” pathology seen in other radiation injuries: the tissue becomes hypoxic (low oxygen), hypocellular (depleted of healthy cells), and hypovascular (lacking blood supply). HBOT directly addresses all three of these problems.
How Does HBOT Treat Radiation Cystitis?
Hyperbaric oxygen therapy works by delivering 100% oxygen at elevated atmospheric pressure, dramatically increasing the oxygen dissolved in the blood. When this oxygen-rich blood reaches the radiation-damaged bladder, it triggers several healing responses:
- Angiogenesis: The growth of new blood vessels in the bladder wall, restoring the vascular network that radiation destroyed. This is the primary mechanism and requires repeated sessions to build a durable new blood supply.
- Fibroblast stimulation: HBOT activates fibroblasts to produce collagen, strengthening the weakened bladder wall tissue.
- Reduced inflammation: The elevated oxygen modulates the inflammatory cascade, reducing ongoing tissue damage.
- Improved immune function: Enhanced oxygen supports the bladder’s ability to resist infection, a common complication of radiation cystitis.
Treatment typically involves 30 to 60 sessions at 2.0 to 2.4 ATA (atmospheres absolute), delivered once daily on weekdays. Each session lasts 90 to 120 minutes. Many patients notice improvement in bleeding after 20 to 30 sessions, with continued improvement over the full treatment course.
What Does the Clinical Evidence Show?
Radiation cystitis is one of the most well-studied applications of HBOT, with evidence ranging from randomised controlled trials to large systematic reviews.
The RICH-ART trial, a randomised controlled phase 2-3 study, is the largest and most rigorous clinical trial of HBOT for radiation cystitis to date. Long-term follow-up published in 2025 confirmed that HBOT produced significant and sustained improvements in patients with radiation-induced cystitis (RICH-ART Long-Term Follow-Up, 2025).
A 2024 systematic review and meta-analysis pooling data from multiple studies found that HBOT achieved complete or partial resolution of haematuria in the majority of patients, with a favourable safety profile (Cystitis Systematic Review and Meta-Analysis, 2024).
A 2026 study comparing outcomes at different treatment pressures (2.0 ATA versus 2.5 ATA) found that both protocols produced meaningful clinical improvement, providing flexibility in how treatment can be delivered (ATA Comparison Study, 2026).
The 2025 systematic review of HBOT for late radiation tissue injury affecting the bowel and bladder further confirmed that hyperbaric oxygen produces measurable clinical improvement across multiple pelvic radiation complications (Bowel and Bladder Systematic Review, 2025).
Radiation cystitis is one of the 14 UHMS-approved indications for HBOT, and it is covered by public health insurance in several Canadian provinces at hospitals and regulated facilities.
What Results Can Patients Expect?
Based on the published evidence, patients treated with HBOT for radiation cystitis can generally expect:
| Outcome | What the Evidence Shows |
|---|---|
| Bleeding resolution | Complete or significant reduction in haematuria in 60-80% of patients |
| Symptom improvement | Reduced urgency, frequency, and pain in the majority of patients |
| Durability | Improvements sustained at 12+ months in the RICH-ART trial |
| Safety | Mild side effects (ear pressure, temporary vision changes); serious complications rare |
| Time to improvement | Most patients notice improvement after 20-30 sessions |
Results vary by severity and duration of the condition. Patients who begin HBOT earlier in the course of radiation cystitis tend to have better outcomes, though improvement has been documented even in long-standing cases.
Is HBOT Covered for Radiation Cystitis in Canada?
Radiation cystitis falls under the “delayed radiation injury” indication, which is one of the most widely covered uses of HBOT across Canadian provinces:
- Ontario: OHIP covers HBOT for delayed radiation injury at both hospital-based programs and approved private facilities
- Alberta: Covered at hospital-based AHS clinics and CPSA-accredited private facilities
- Quebec, British Columbia, Nova Scotia, and Newfoundland: Covered at hospital-based facilities for approved indications
- Other provinces: Interprovincial referral may be available
For a complete province-by-province breakdown, visit the Canada Hyperbarics coverage guide. To find a hospital or regulated facility near you, use the facility finder with postal code search.
Frequently Asked Questions
How do I know if my bladder symptoms are from radiation?
If you received pelvic radiation therapy (for prostate, cervical, uterine, rectal, or bladder cancer) and are now experiencing blood in your urine, urinary urgency, frequency, or pain, these symptoms may be radiation-related. Your urologist can perform a cystoscopy (bladder examination) to confirm radiation cystitis and rule out other causes such as infection or recurrence.
I finished radiation years ago. Can HBOT still help?
Yes. Late radiation cystitis can develop years or even decades after treatment, and HBOT can be effective regardless of when the symptoms started. The RICH-ART trial included patients with long-standing radiation cystitis and still showed significant improvement.
How many HBOT sessions are needed for radiation cystitis?
A standard protocol involves 30 to 60 sessions at 2.0 to 2.4 ATA, delivered once daily on weekdays. Your hyperbaric medicine team will assess your response periodically and adjust the treatment plan. Some patients improve with 30 sessions; others benefit from the full 60.
What other treatments are available for radiation cystitis?
Other treatments include bladder irrigation, intravesical instillation (medications placed directly in the bladder), cauterisation of bleeding vessels, and in severe cases, surgical intervention. HBOT is unique because it addresses the underlying cause (vascular damage) rather than just managing symptoms. A 2022 systematic review of radiation cystitis management found that HBOT was among the most effective options available (Management Review, 2022).
This Daffodil Month, Don’t Ignore Bladder Symptoms
If you have been through pelvic radiation therapy and are experiencing bladder problems, you are not alone and you do not have to accept these symptoms as permanent. Radiation cystitis is a recognised medical condition with effective, evidence-based treatment available at hospitals and regulated facilities across Canada.
Talk to your oncologist, urologist, or family doctor about a referral for HBOT. With the right treatment, many patients experience significant improvement in bleeding, pain, and quality of life.
Find a hyperbaric facility near you across Canada.
This April, in recognition of Daffodil Month, canadahyperbarics.ca is dedicated to helping cancer survivors understand and access the treatments available for the lasting effects of cancer therapy.
References
- Radiation-Induced Cystitis Treated With Hyperbaric Oxygen Therapy (RICH-ART): Long-Term Follow-Up of a Randomised Controlled Phase 2-3 Trial. (2025). View in Canada Hyperbarics Research Database.
- Efficacy and Safety of Hyperbaric Oxygen Therapy for Radiation-Induced Hemorrhagic Cystitis: A Systematic Review and Meta-Analysis. (2024). View in Canada Hyperbarics Research Database.
- Outcomes of Hyperbaric Oxygen Therapy at 2.0 Versus 2.5 ATA for Hemorrhagic Radiation Cystitis. (2026). View in Canada Hyperbarics Research Database.
- Systematic Review of Hyperbaric Oxygen for Late Radiation Tissue Injury (Bowel, Bladder). (2025). View in Canada Hyperbarics Research Database.
- Current Management of Radiation Cystitis After Pelvic Radiotherapy: A Systematic Review. (2022). View in Canada Hyperbarics Research Database.
This content is for informational purposes only and does not constitute medical advice. Hyperbaric oxygen therapy should only be administered by qualified healthcare professionals in accredited facilities. Consult your physician or a certified hyperbaric medicine specialist for treatment decisions. Canada Hyperbarics is an independent educational resource and is not affiliated with any specific clinic or manufacturer.