Nonobesity at the time of mastectomy is highly predictive of 10-year disease-free survival in women with breast cancer.

25 unselected women with operable breast cancer were followed after radical mastectomy until they died of recurrent cancer (non-survivors), or for 10 years if there was no recurrence (survivors): all the women still alive at 10 years were clinically and radiographically disease-free. Survivors and non-survivors were compared with respect to premastectomy height, and deviation from ideal weight. There were 16 women in the survivor group; at the time of mastectomy, they averaged 11% above ideal weight and only 4 of them (25%) were obese (20% or more above ideal weight). There were 9 women in the non-survival group; they averaged 51% above ideal weight at the time of mastectomy and all of them were obese, as defined. The intergroup difference in mean deviation from ideal weight was very highly significant (P less than 0.0001). Of the 13 women who were obese at mastectomy, only 4 (31%) became survivors, while 100% of the 12 women who were non-obese at mastectomy became survivors; the difference in percent survival was very highly significant (P less than 0.005). Separate evaluation of the roles of height and weight showed that height was not a factor and weight accounted entirely for the observed differences. It appears that maintenance of nonobesity may be a more effective way of decreasing mortality from breast cancer than any other measure proposed to date.