Radiation cystitis is a known complication of pelvic radiotherapy, characterized by hematuria due to chronic ischemic injury and neovascular fragility of the bladder mucosa. Severe cases can be challenging to manage, leading to significant morbidity, recurrent hospitalizations, and impaired quality of life [1]. Conventional treatments, including bladder irrigation, intravesical therapy, and coagulation techniques, often provide only temporary relief and do not address the underlying tissue damage [2].

Hyperbaric oxygen therapy (HBOT) has emerged as an effective treatment for radiation-induced soft tissue injuries by enhancing oxygen delivery to hypoxic tissues, promoting angiogenesis, and facilitating tissue repair [3]. Studies have demonstrated that HBOT can significantly reduce hematuria, improve bladder function, and enhance overall quality of life in patients with radiation cystitis [4][5].

A 77-year-old man with a known history of prostate adenocarcinoma, diagnosed in 2016, who completed a course of radiotherapy in 2018. He presented with a two-week history of frank hematuria, which was painless but persistent and associated with the passage of blood clots. The patient denied any recent trauma, strenuous physical activity, or history of urinary tract infections. He also reported no significant weight loss, fever, or lower urinary tract symptoms such as dysuria, urgency, or frequency. His medical history was otherwise unremarkable, and he was not on any anticoagulant or antiplatelet therapy.

The patient presented to the Emergency Department of Hospital Universiti Sains Malaysia. His laboratory investigations revealed a hemoglobin level of 9.6 g/dL, with a platelet count of 302,000/μL and a normal coagulation profile, INR of 1.06. Renal function tests were within normal limits, with no evidence of acute kidney injury. An immediate abdominal and pelvic computed tomography (CT) scans were performed revealing no evidence of malignancy or other structural abnormalities.

During initial evaluation, a flexible cystoscopy was performed, which revealed diffuse mucosal hyperemia, telangiectasia, and areas of ulceration. With the prior history of radiotherapy, hence a diagnosis of radiation-induced cystitis was made. Bladder irrigation was initiated to manage the hematuria; however, the bleeding persisted despite these measures (Fig. 1).

Given the refractory nature of his hematuria and the failure of conventional therapies, the patient was referred for HBOT. He underwent a total of 10 HBOT sessions, during which he experienced transient episodes of nausea and vomiting, which were effectively managed with anti-emetic therapy. By the completion of the HBOT course, the hematuria had completely resolved (Fig. 2), and the patient reported significant improvement in his overall condition. He was discharged in stable condition with close outpatient follow-up. At subsequent follow-up visits over the next six months, there were no recurrent episodes of gross hematuria, and his hemoglobin levels remained stable.

A chronic side effect of pelvic radiation therapy, radiation cystitis is brought on by gradual ischemic damage to the bladder mucosa [6]. Patients are at risk for chronic hematuria due to endothelial damage, which causes fibrosis, neovascularisation, and increased fragility of the bladder vasculature [4]. Bladder irrigation, intravesical instillations, and coagulation therapy are examples of conventional treatments that often provide only short-term relief and fail to address the underlying ischemic pathology [7][8].

By improving oxygen transport to hypoxic areas, encouraging angiogenesis, and aiding in tissue repair, HBOT has become a successful therapeutic approach. According to T.K. Yang et al. (2024), 55% of patients experience total remission after HBOT, dramatically lowers hematuria [5]. Furthermore, HBOT was observed to relieve symptoms more than control therapies in a randomized controlled trial [9].

Table 1 summarizes articles demonstrating the efficacy of HBOT in treating chronic hemorrhagic cystitis. These articles include prospective and retrospective analyses, as well as case reports, with patients presenting symptoms such as hematuria, dysuria, and urinary frequency following radiation therapy or other treatments. The majority of patients experienced significant improvement or complete resolution of symptoms after HBOT, with session numbers ranging from 6 to 196. These findings align with the outcome of the current case, in which the patient achieved complete resolution of hematuria following 10 HBOT sessions.

This case highlights the efficacy of HBOT in managing refractory radiation cystitis. HBOT offers a non-invasive and effective alternative when conventional therapies fail, promoting angiogenesis and tissue repair to address the underlying ischemic pathology. However, further research is essential to refine treatment protocols, establish standardized guidelines, and optimize long-term outcomes for patients with this challenging condition.