ROUTINE CONTRALATERAL BREAST BIOPSY - HELPFUL OR IRRELEVANT - EXPERIENCE IN 871 PATIENTS, 1979-1993

Objective Is routine contralateral biopsy in the breast cancer patient justified, and by which parameters can the result be predicted in adv ance? Summary Background Data Routine contralateral biopsy remains con troversial, and with the possible exception of an invasive lobular pri mary, little used by most surgeons. Previous series are biased by smal l sample size, by interpreting lobular carcinoma in situ (LCIS) as a p ositive result, by selection on the basis of tumor type, and by the in clusion oi patients with clinical or mammographic abnormalities. Metho ds Among 1113 consecutive patients with breast cancer treated in the a uthor's practice between 1979 and 1993 (excluding 77 patients who had a previous mastectomy, 131 who declined biopsy, and 34 with suspicious clinical or mammographic findings), 871 had a routine contralateral b iopsy. Results Invasive cancers were found in 1.6%, duct carcinoma in situ in 1.4%, LCIS in 3.2% and atypical hyperplasia in 6.9% oi all ran dom biopsies, ii LCIS was excluded as a positive result, invasive lobu lar carcinoma was not significantly more bilateral than invasive duct (5.2% vs, 2.9%, p = 0.32), nor were in situ tumors more bilateral than invasive (2.5% vs. 3.0%, p = 0.76). Tumor size, axillary node status, and young age were not predictive of a positive result. A positive bi opsy result was significantly more frequent in patients older than 50 years of age (4% vs, 1%, p = 0.016), and with a first-degree family hi story of breast cancer (6.3% vs. 2.2%, p = 0.004). Conclusions The fol lowing conclusions can he made: 1. If LCIS was excluded as a positive biopsy result, invasive lobular was not significantly more bilateral t han invasive duct cancer. 2. Family history and older age significantl y predicted a positive biopsy, whereas young age, tumor size, and axil lary node status did not. 3. Routine contralateral biopsy identified c onditions (invasive cancer or duct carcinoma in situ) requiring immedi ate further management in 3.0% of patients, and markers of risk (LCIS or atypia) with the potential to influence future decisions in another 10.1%. 4. As a screening device applied in a high-risk population, wi th low cost and little morbidity, contralateral biopsy deserves wider consideration in an era of ever-earlier breast cancer diagnosis.