Body weight and vascular invasion in post-menopausal women with breast cancer.

To examine the relationship between body weight and vascular invasion (VI) around tumours in post-menopausal women with operable breast cancer, a retrospective study was conducted of 393 patients treated in a breast unit between 1987 and 1991. Weight was measured at the time of diagnosis. Vascular invasion was recorded as being present or absent. Vascular invasion was seen in slightly more of the 50 perimenopausal patients than in the 343 post-menopausal women (44% vs 36%). In the tumour specimens from post-menopausal patients weighing <50 kg, VI was observed in 11% compared with 45% of those weighing more than 80 kg (P= 0.02). Furthermore, the 5-year survival of those with VI was 74% compared with 91% for those without (P < 0.0001). Menopausal status and body weight may influence survival in patients with breast cancer, possibly as a result of the presence of unopposed circulating oestrogens at the time of surgery. Oestrogens may alter cohesiveness of breast cancer cells and modulate secretion of proteases, thereby influencing invasive potential. Excision of tumours in such an environment may have a deleterious impact on survival.