title: A contribution to the natural history of breast cancer. V. Bilateral primary breast cancer: incidence, risks and diagnosis of simultaneous primary cancer in the opposite breast.
abstract: Tissue from contralateral breast was taken from 505 patients with invasive breast cancer. Every 5th patient had simultaneous carcinoma in the opposite breast, 7.7% (39/505) had invasive cancer, and 13.1% (66/505) had carcinoma in situ. Invasive cancers in the opposite breast were diagnosed at an earlier stage as compared with the neoplasm of the primary breast. However, 26% of the patients already had positive axillary nodes. The following risk indicators of the bilateral disease were found: age at time of diagnosis, histologic type of tumours, familial breast cancer, suspicious mammography, P2/DY-breast parenchymal pattern (Wolfe) and multicentric cancer of primary breast. Our findings support the proposal to consider bilaterality of breast cancer as a sign of systemic disease of the breasts, involving the ductal and lobular system within eight quadrants of a paired organ (Ober).
mesh_terms: D000367:Age Factors; D001943:Breast Neoplasms / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology; D002278:Carcinoma in Situ / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology; D005260:Female; D005860:Germany, West; D006801:Humans; D008207:Lymphatic Metastasis; D008875:Middle Aged; D009378:Neoplasms, Multiple Primary / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology; D012306:Risk