[Effects of parenteral nutrition on tumor growth: experimental aspects]

There still exist controversies about the effect of parenteral nutrition on cancer growth. For elucidation of this question the development of Walker 256 carcinosarcoma in rats submitted to parenteral nutrition (PN) was studied. Thirty-five Wistar rats were randomly distributed in three groups: OT group (11), tumor-bearing animals always under oral feeding for 14 days; PC group (14), tumor free animals under PN for 7 days; PT group (10), tumor-bearing rats under PT for 7 days. PT solution contained 15% glucose, 3% aminoacids and essential micronutrients. Body and tumor weight (in OT and PT groups) were evaluated daily. Carcass weight was obtained by the difference between the body and tumor weight. The rats of the PC group had an initial body weight loss that became stabilized afterwards at a lower plateau level. The rats of the PT group also presented an initial body weight loss recovered progressively afterwards. This difference is probably due to tumor mass expansion in PT animals, since PT rats carcass weight remained similar to that of body weight in PC group. The tumor growth has shown no difference between the oral and parenteral feeding groups, particularly when tumor weight/carcass weight ratio was considered. It is concluded that parenteral nutrition does not favor tumor growth in detriment to carcass weight development.