Hyperbaric oxygenation for experimental bladder tumor. II. Hyperbaric oxygenation in combination with chemotherapy in N-butyl-N-(4-hydroxybutyl)nitrosamine-induced bladder tumors.

Two series of experiments were conducted to ascertain whether hyperbaric oxygenation (HBO) treatment with or without antineoplastic chemotherapy can really suppress tumor development in N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN)-induced bladder tumor in rats. HBO treatment of 2 ATA of air saturating with 30-35% of oxygen for 90 min daily plus 0.5 mg/100 g body weight of 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU) administration for 5 times suppressed the neoplastic spread of the bladder for 9 weeks and reduced the bladder weight in BBN-treated rats. Similar effects were also obtained in ACNU-treated rats, but to a lesser extent. HBO treatment associated with or without doxorubicin failed to suppress tumor growth in BBN-treated animals. Based on these findings combined with the previous study (part I), HBO treatment associated with ACNU might be available for the treatment of some cases of bladder tumors.