Purpose: The aim of this study was to evaluate the effects of hyperbaric oxygen therapy (HBO) on the enhancement of hyperthermic chemosensitisation to carboplatin at mild temperatures in experimental tumours.
Methods: SCCVII carcinoma in C3H/He mice was used to assess tumour growth delay. The mice received intraperitoneal injections of carboplatin. For HBO treatment, the mice were exposed to HBO at 2.0 atmospheres of absolute oxygen for 60 min. For mild hyperthermia (HT), treatment at 41.5 °C for 30 min was performed. The tumour tissue pO2 levels were measured with a digital pO2 monitor during and immediately after treatment.
Results: The average time taken to reach a threefold relative tumour size was significantly longer after treatment with carboplatin combined with mild HT and HBO than after treatment with carboplatin and mild HT. The relative sizes of the tumours after the combined treatment were smallest when the treatment sequence was carboplatin, mild HT, and HBO. The tumour tissue pO2 values were significantly higher immediately after mild HT followed by HBO than immediately after HBO followed by mild HT. The tumour tissue pO2 levels during mild HT and HBO generally increased, although the patterns of the increases varied.
Conclusion: The administration of HBO increased the effects of hyperthermic chemosensitisation to carboplatin at mild temperatures on experimental tumours, particularly when given in the sequence of carboplatin, mild HT, and HBO, a finding that supports previous clinical outcomes for a novel combined therapy using carboplatin plus HT and HBO.
Keywords: Carboplatin; chemotherapy; hyperbaric oxygen; hyperthermia.