Hyperbaric Oxygen Therapy for Radiation Cystitis: Evaluation of Treatment Efficacy Seen During Post-treatment Follow-Up

Abstract

Hyperbaric oxygen therapy has been reported to be effective in the treatment of delayed soft tissue radiation injuries. HBOT stimulates angiogenesis, improves tissue oxygenation, stimulates stem cell activity, and decreases fibrosis. However, few follow-up data are available. This study assesses follow-up outcomes at one clinical center for patients with radiation cystitis receiving HBOT. Patients with radiation cystitis receiving HBOT at our facility between January 2006 and December 2014 were included. HBOT involved patients breathing nearly 100% oxygen for 90 minutes in a hyperbaric chamber pressurized to 2.4 atmospheres absolute (ATA). Data recorded included patient characteristics, type of cancer, dose of radiotherapy (RT) received, time between RT and diagnosis of cystitis, time between diagnosis of cystitis and HBOT, and the number of HBOT sessions completed. Hyperbaric physicians evaluated patients’ symptoms before, during, and upon completion of HBOT. After HBOT, radio-oncologists and urologists conducted follow-up evaluations. Treatment was considered effective if symptoms were resolved or improved. Unimproved or worsening symptoms were classified as failure of treatment. A bivariate analysis was made for the number of exposures and the effectiveness of HBOT. Data are presented as mean±SD with range or percentage as appropriate. Significance was accepted at P<0.05. Thirty-five patients (67±10 [29-84] years of age at start of HBOT) received 43±9 (29-60) hyperbaric treatments. The majority of patients had hematuria as the principal symptom (n=34; 97%), were male (n=30; 86%), non-smoking (n=32; 91%), and had prostate cancer (n=30; 86%). The radiation dose received was 67±17 (33-120) Gy (EQD2). Post-HBOT follow-up ran for 29±21 (1-60) months. The time between RT and diagnosis was 42±39 (1-146) months. The time between diagnosis of cystitis and HBOT was 21±50 (0-298) months. Twenty-three patients had tried pentosan polysulfate, 18 electrofulguration, and 8 needed transfusions. There was no difference in symptom resolution if patients had 40 or 50 HBO exposures. At 6 months, 91% (n=32) had improved or resolved symptoms. Overall, treatment was effective in 71% (n=25) of cases. Conversely, 29% (n=10) of patients had a failure of treatment, four at ≤3 months of follow-up, and 6 at 22±9 (12-36) months. Six patients with failure of treatment returned to their pre-HBOT condition, and 4 had worsening symptoms. Seven patients (20%) with failure of treatment needed surgery post-HBOT: 5 had cystectomy, 1 cystoprostatectomy, and 1 pelvic exenteration. HBOT was effective in the majority of patients with radiation cystitis as evidenced through a mean 2.5-year follow-up period. Patients that needed surgical management presented an early failure to HBOT. Studies with longer follow-up periods are still required.