Reversed cerebral asymmetry in women with breast cancer.

Altered intrauterine hormonal environment might predispose to both atypical cerebral asymmetry and breast cancer. We therefore investigated computed tomographic scans of 79 right-handed, white patients with breast cancer and 97 controls to assess the pattern of cerebral asymmetry. Women with breast cancer had a reversed pattern of cerebral asymmetry significantly more often than did controls (p less than 0.0001 for both frontal and occipital width. Our findings suggest that an intrauterine or early life factor, probably hormonal, could predispose to breast cancer in adulthood.