Survival and hematologic outcomes in prostate cancer patients with radiation cystitis receiving hyperbaric oxygen therapy: A propensity-matched analysis.

Abstract

e17138 Background: Radiation cystitis is a common complication in prostate cancer patients receiving radiotherapy. Hyperbaric oxygen therapy (HBOT) is used to manage radiation-induced bladder injury, but its impact on hematologic parameters and survival outcomes is unclear. A prospective study in patients receiving HBOT reported no changes in hematological indices but called for more robust evidence. Given its effects on angiogenesis and tissue oxygenation, there has been theoretical concern that HBOT could influence tumor biology and cancer progression, although clinical data remains limited and inconclusive. We evaluated survival and hematologic outcomes in patients receiving HBOT versus matched controls. Methods: We conducted a multi-center retrospective cohort study using the TriNetX Global Collaborative Network. Adult patients with prostate cancer receiving HBOT within one month of diagnosis of radiation cystitis were compared to those not receiving HBOT. Propensity score matching was done using demographics, co-morbidities, prior prostate cancer therapies including radiotherapy and hormonal therapy, metastases, gross hematuria, baseline labs and prior blood transfusion. Outcomes were compared up to one year at 3 monthly intervals. Significance was set at p < 0.05. Results: After matching, 1,068 patients were included in each cohort. There was no difference in survival at 1-3, 3-6, 6-9 or 9-12 months (Hazard ratio, p values- 0.8,0.65; 0.59,0.33; 0.76,0.2; 1.14,0.7). Baseline hematologic indices were comparable between the matched cohorts with a standard mean difference of < 0.1. No differences were observed at 1–12 months. HBOT was associated with significant gross hematuria at 1–3, 3–6, and 9–12 months. Blood transfusion was infrequent post index event precluding meaningful analysis. Subgroup analysis was done based on metastases. Metastatic and non-metastatic sub-groups included 207 and 854 patients resepctively. Survival could not be assessed for sub-groups because of insufficient event counts before and after propensity matching, however there were no differences in labs between cohorts. In metastatic patients, gross hematuria did not significantly differ at any interval (all p > 0.05). In non-metastatic patients, HBOT was associated with significant gross hematuria at 1–3, 3–6 months and 9-12 months. Conclusions: HBOT does not affect survival or hematologic parameters up to one year. It is associated with higher gross hematuria at several intervals, whereas some intervals, including all in the metastatic subgroup, were not significant. This may indicate that HBOT is being chosen for patients with significant gross hematuria (sicker population). Overall, these findings support similar survival and the hematologic safety of HBOT in prostate cancer patients with radiation cystitis.