Omega-3 fatty acids inhibit tumor growth in a rat model of bladder cancer.

Omega-3 (omega-3) fatty acids have been tested on prevention and treatment of several cancer types, but the efficacy on "in vivo" bladder cancer has not been analyzed yet. This study aimed at evaluating the chemopreventive efficacy of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) mixture in an animal model of bladder cancer. Forty-four male Wistar rats were divided into 4 groups during a 20-week protocol: control; carcinogen-N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN); omega-3 (DHA + EPA); and omega-3 + BBN. BBN and omega-3 were given during the initial 8 weeks. At week 20 blood and bladder were collected and checked for the presence of urothelium lesions and tumors, markers of inflammation, proliferation, and redox status. Incidence of bladder carcinoma was, control (0%), omega-3 (0%), BBN (65%), and omega-3 + BBN (62.5%). The omega-3 + BBN group had no infiltrative tumors or carcinoma in situ, and tumor volume was significantly reduced compared to the BBN (0.9 +/- 0.1 mm(3) versus 112.5 +/- 6.4 mm(3)). Also, it showed a reduced MDA/TAS ratio and BBN-induced serum CRP, TGF-beta 1, and CD31 were prevented. In conclusion, omega-3 fatty acids inhibit the development of premalignant and malignant lesions in a rat model of bladder cancer, which might be due to anti-inflammatory, antioxidant, anti-proliferative, and anti-angiogenic properties.