We studied the relation of certain endocrine-related variables among 23 cases of male breast cancer and 76 apparently healthy male controls. There were significant inverse associations with smoking (P = 0.03), birth order (P = 0.02) and reported frequency of orgasms in later life (P = 0.0004). The study provides strong indirect evidence that endocrine factors are important in the aetiology of male breast cancer.
Copyright 2000 Cancer Research Campaign.