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Late Radiation Damage to the Bladder, Bowel or Jaw: What Research Says About Hyperbaric Oxygen 11/3/26
Radiation is one of the most important tools in cancer care. For some people, though, side effects show up months or years after treatment ends. Doctors call this late radiation tissue injury. At HyOx in Marietta, we evaluate people from across metro Atlanta for it.
This article covers three of the most common kinds: radiation cystitis in the bladder, radiation proctitis in the bowel, and osteoradionecrosis of the jaw. We'll explain the warning signs, where hyperbaric oxygen therapy (HBOT) fits, and what the research actually shows, including the studies that did not find a benefit. Future posts will go deeper on each of these three conditions.
Why radiation damage can show up years later
Radiation can slowly damage the tiny blood vessels in the area that was treated. Over time, that tissue gets less blood and oxygen. It can become thin, scarred and fragile. It may bleed easily or have trouble healing after an injury, surgery or dental work.
Because it happens slowly, people often don't connect a new problem to radiation they had years ago.
Signs to tell your doctor about
Bladder (after pelvic radiation for prostate, cervical, uterine, rectal or bladder cancer):
Blood in your urine, or blood clots
Needing to urinate often or urgently, or pain when you urinate
Bowel (after pelvic radiation):
Bleeding from the rectum, or mucus in your stool
Sudden urges to have a bowel movement, or rectal pain
Jaw (after head and neck radiation):
Exposed bone in the mouth, or a sore that won't close
Jaw pain, swelling or drainage
A tooth socket that won't heal after an extraction
These symptoms can have other causes, including a return of cancer, so see your doctor. If you have heavy bleeding, dizziness or can't pass urine, go to the emergency room.
How HBOT fits in
During HBOT you breathe 100% oxygen inside a pressurized chamber. This raises the amount of oxygen carried in your blood. Researchers think a series of sessions may help damaged tissue grow new small blood vessels, which is why HBOT has been studied for late radiation injury.
HBOT is not usually the first treatment, and it's used alongside other care, not instead of it. A hyperbaric physician reviews your records to decide whether it makes sense for you.
The bladder: radiation cystitis
The main randomized trial here is RICH-ART, run at five hospitals in Sweden, Norway, Denmark and Finland. It compared HBOT plus standard care with standard care alone in 79 people with late radiation cystitis. People who had HBOT reported a bigger improvement in urinary symptoms six to eight months later.
A five-year follow-up published in 2025 found that the improvement lasted for many people who responded to HBOT. It also found that about 3 in 10 patients did not improve. By the five-year point most of the comparison group had also had HBOT, so there was no comparison group. One limit is that patients knew which group they were in, because there was no sham (pretend) treatment.
The bowel: radiation proctitis
For the bowel, the results are mixed.
A double-blind trial called HORTIS-IV (Clarke and colleagues, 2008) included 120 people with radiation proctitis that hadn't responded to other care. Some had HBOT and some had a sham treatment. The HBOT group improved more on a standard symptom scale.
A later UK trial called HOT2 (Glover and colleagues, 2016) studied 84 people with ongoing bowel problems after pelvic radiation, also against a sham treatment. It found no clear benefit from HBOT at 12 months.
The jaw: osteoradionecrosis and dental extractions
Osteoradionecrosis (ORN) means jawbone in the radiation field has broken down and is exposed or not healing. It often follows a tooth extraction.
Preventing ORN before dental work. For years, many centers gave HBOT before and after extractions in an irradiated jaw. A large UK trial called HOPON (Shaw and colleagues, 2019) tested this. It found no clear difference in ORN between people who had HBOT and people who didn't, and ORN was uncommon in both groups. If you need dental work after head and neck radiation, your dentist, oncologist and hyperbaric physician can talk through your own risk.
Treating ORN that has already developed. The research here is mixed too. A French trial published in 2004 (Annane and colleagues) was stopped early because patients with ORN who had HBOT were doing no better, and possibly worse, than those who had a placebo. The difference between the groups was not statistically significant. Two later trials in Europe, combined in a 2022 report (Forner and colleagues), found that more people healed after surgery plus HBOT than after surgery alone. But the trials enrolled too few patients, so the difference could have been due to chance.
A 2024 international guideline on jaw ORN from cancer and oral care societies (ISOO, MASCC and ASCO) said the use of HBOT to prevent or treat ORN "remains largely unjustified, with limited evidence to support its practice." It does not recommend routine HBOT before dental extractions, but says HBOT may be offered before invasive dental work where a large area of jawbone received high-dose radiation, and may be used together with surgery for established ORN. These were weak recommendations based on low-quality evidence. That is why decisions about HBOT for the jaw are made case by case, usually together with an oral surgeon.
In short
Bladder: encouraging evidence from a randomized trial, but not everyone improves.
Bowel: mixed, with one positive and one negative sham-controlled trial.
Jaw: routine HBOT before extractions is not supported by the largest trial, and the evidence for treating established ORN is mixed.
A 2016 Cochrane review, published before HOPON, concluded that HBOT may be justified for selected patients and that more research is needed.
Does Medicare cover HBOT for these conditions?
Medicare's national policy, NCD 20.29, lists osteoradionecrosis and soft tissue radionecrosis among the conditions it may cover, both "as an adjunct to conventional treatment." Late radiation injury of the bladder or rectum may fall under soft tissue radionecrosis when your records show the diagnosis and the other treatments you've tried. Whether it is covered depends on your records and Medicare's criteria. Medicare Advantage and private plans set their own rules and often require approval first. Our team can check your coverage with your plan before you begin.
What treatment is like at HyOx
Sessions are usually once a day on weekdays for several weeks. In RICH-ART, patients had 30 to 40 sessions. Your hyperbaric physician sets your plan.
The most common side effect is pressure in the ears, similar to flying. Some people notice temporary changes in their vision during a course of treatment. Your care team will go over the risks before you start.
Treatment takes place in a 31 x 9 ft walk-in multiplace chamber that seats up to 12 patients. A trained attendant is in the chamber with patients during every session.
For referring physicians
We welcome referrals from urology, gynecologic oncology, radiation oncology, colorectal surgery, GI, head and neck surgery, oral and maxillofacial surgery and dentistry for late radiation tissue injury. Helpful records include radiation dates, site and dose; evaluation for recurrence; cystoscopy, endoscopy or dental imaging as relevant; transfusion history; prior therapies; and anticoagulant use. For dental cases, include the planned procedure and timing. Our hyperbaric physicians screen for contraindications and confirm whether HBOT is appropriate. In light of HOPON, we review requests for HBOT before dental extractions case by case. Records can be faxed to 678.303.3205.
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Next step
If you're having bladder, bowel or jaw problems after radiation, talk with your doctor or dentist and ask whether a hyperbaric evaluation makes sense. You can also reach out to us directly.
Request an appointment → or call 678.303.3200.
Contact HyOx Medical Treatment Center
2550 Windy Hill Road SE, Suite 110, Marietta, GA 30067
Phone: 678.303.3200 | Fax: 678.303.3205 | Email: office@hyox.com
This article is for general education and is not medical advice. Hyperbaric oxygen therapy (HBOT) is used together with standard medical care, not in place of it, and it is not right for everyone. A physician evaluation is required before treatment, and results vary from person to person. HBOT has risks, including ear and sinus pressure injury (barotrauma), anxiety from being in an enclosed space, temporary changes in vision and, rarely, a seizure caused by oxygen toxicity. Medicare and other insurance may cover HBOT only when specific medical criteria are met and documented, and individual plans vary. If you have a medical emergency, call 911.
References
Centers for Medicare & Medicaid Services. National Coverage Determination 20.29: Hyperbaric Oxygen Therapy. Medicare National Coverage Determinations Manual, Pub. 100-03. https://www.cms.gov/medicare-coverage-database/view/ncd.aspx?NCDId=12
Huang ET, ed. UHMS Hyperbaric Medicine Indications Manual. 15th ed. North Palm Beach, FL: Best Publishing Company; 2023. (Chapter: Delayed Radiation Injuries, Soft Tissue and Bony Necrosis.)
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 Oncol. 2019;20(11):1602-1614. doi:10.1016/S1470-2045(19)30494-2
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
Clarke RE, Tenorio LM, Hussey JR, et al. Hyperbaric oxygen treatment of chronic refractory radiation proctitis: a randomized and controlled double-blind crossover trial with long-term follow-up. Int J Radiat Oncol Biol Phys. 2008;72(1):134-143. doi:10.1016/j.ijrobp.2007.12.048
Glover M, Smerdon GR, Andreyev HJ, et al. Hyperbaric oxygen for patients with chronic bowel dysfunction after pelvic radiotherapy (HOT2): a randomised, double-blind, sham-controlled phase 3 trial. Lancet Oncol. 2016;17(2):224-233. doi:10.1016/S1470-2045(15)00461-1
Shaw RJ, Butterworth CJ, Silcocks P, et al. HOPON (Hyperbaric Oxygen for the Prevention of Osteoradionecrosis): a randomized controlled trial of hyperbaric oxygen to prevent osteoradionecrosis of the irradiated mandible after dentoalveolar surgery. Int J Radiat Oncol Biol Phys. 2019;104(3):530-539. doi:10.1016/j.ijrobp.2019.02.044
Annane D, Depondt J, Aubert P, et al. Hyperbaric oxygen therapy for radionecrosis of the jaw: a randomized, placebo-controlled, double-blind trial from the ORN96 study group. J Clin Oncol. 2004;22(24):4893-4900. doi:10.1200/JCO.2004.09.006
Forner LE, Dieleman FJ, Shaw RJ, et al. Hyperbaric oxygen treatment of mandibular osteoradionecrosis: combined data from the two randomized clinical trials DAHANCA-21 and NWHHT2009-1. Radiother Oncol. 2022;166:137-144. doi:10.1016/j.radonc.2021.11.021
Peterson DE, Koyfman SA, Yarom N, et al. Prevention and management of osteoradionecrosis in patients with head and neck cancer treated with radiation therapy: ISOO-MASCC-ASCO guideline. J Clin Oncol. 2024;42(16):1975-1996. doi:10.1200/JCO.23.02750
Bennett MH, Feldmeier J, Hampson NB, Smee R, Milross C. Hyperbaric oxygen therapy for late radiation tissue injury. Cochrane Database Syst Rev. 2016;4:CD005005. doi:10.1002/14651858.CD005005.pub4
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