OBJECTIVETo assess the safety of hyperbaric oxygen in the treatment of radiation-induced hemorrhagic cystitis in patients with prostate cancer, and to investigate its effect on the growth of indolent prostate cancer in vivo.

METHODSThirty severe combined-immunodeficient mice received subcutaneous injection of human prostate cancer LNCaP cells. Then they were randomized to an experimental and a control group and exposed to 20 sessions of hyperbaric oxygen and normobaric air, respectively, followed by a 4-week observation on the growth of the transplanted tumors and analyses of their histopathological features at 28 days, including the volume, microvessel density (CD34), apoptosis markers (p53 and p27 proteins) and the proliferation index (Ki-67) of the LNCaP tumors.

RESULTSOn the 28th day after tumor vaccination, the tumor volume was (120 +/- 7.9) mm3 in the HBO and (122 +/- 8.2) mm3 in the control group; the microvessel density and the expressions of Ki-67, p53 and p27 were 39.3 +/- 5.2, (78.1 +/- 7.6)%, (40.4 +/- 6.2)% and (63.7 +/- 5.1)% in the former, and 36.2 +/- 4.9, (75.3 +/- 8.4)%, (44.2 +/- 5.7)% and (61.5 +/- 5.5)% in the latter. There were no significant differences in all the indexes above between the two groups (P > 0.05).

CONCLUSIONHyperbaric oxygen did not promote the growth of indolent prostate cancer in the murine model, nor did it have any significant effect on the new vessels.