Contralateral cancerous breast lesions in women with clinical invasive breast carcinoma

Eighty‐four consecutive autopsies of women with a clinical diagnosis of invasive breast carcinoma (BC) were examined by extensive histopathologic methods for malignant changes of the contralateral breast. Sixty‐eight percent of the women were found to have primary contralateral BC, of which 33% were invasive and 35% in situ lesions. Another 16% had metastases to the breast. Only two women had had treatment for their contralateral BC. In eight cases a malignant lesion was diagnosed or suspected clinically, but in the remaining cases, the malignancies were identified only by histopathologic examination. No clinical data or histologic characteristics of the first BC had any predictive value for the risk of contralateral BC. In the contralateral breast, a significant coincidence was found between fibrocystic disease and the occurrence of primary malignant BC. The majority of the BC on both sides were of ductal type. Seventy‐nine percent of the invasive contralateral BC were tumefacient, and 71% had axillary lymph node metastases. The mean survival time was comparable for women with and without contralateral primaries, but a significantly higher proportion of women with contralateral invasive BC died of disseminated BC. The frequency of contralateral malignancies is thus much higher than previously reported. The consequence of these findings may implicate a reevaluation of the treatment and control schedule regarding the contralateral breast in women with invasive BC.