CONSEQUENCES OF WALKER-256 TUMOR-GROWTH FOR THE PLACENTAL FETAL DEVELOPMENT IN RATS/

The association between pregnancy and cancer occurs in a small but cli nically important group of patients. Studies about the influence of pr egnancy on cancer prognosis have yielded conflicting results. Pregnanc y has been reported to improve, worsen or not affect cancer prognosis. Metabolic adaptations to pregnancy are directed to ensure satisfactor y growth and development of the fetus and to store energy for the new born and mother for immediate neonatal and lactation use. The effects of Walker 256 tumor growth and Walker 256 ascitic fluid intraperitonea l injection in adult pregnant Wistar rats and its consequences for fet al development were investigated. After mating, females were followed during 23 days. In non-pregnant and pregnant rats, the tumor implantat ion decreased daily food intake, nitrogen balance (NB) and carcass wei ght. Tumor weight was lower in pregnant than in the non-pregnant group . In addition, we observed that due to tumor growth there was a reduct ion of the fetal and placental weights. Fetal reabsorption was higher in pregnant tumor-bearing (25%) and in pregnant rats injected with asc itic fluid (25,3%) when compared with pregnant control group. Therefor e, both tumour development and tumor ascitic fluid injected during pre gnancy promote similar damaging effects in the placenta and fetal. The se alterations were probably induced by substances produced by the hos t and cancer cells, which would directly or indirectly act on placenta l and/or fetal tissues.