Routine Contralateral Breast Biopsy: Helpful or Irrelevant?

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Abstract
Is routine contralateral biopsy in the breast cancer patient justified, and by which parameters can the result be predicted in advance? Routine contralateral biopsy remains controversial, and with the possible exception of an invasive lobular primary, little used by most surgeons. Previous series are biased by small sample size, by interpreting lobular carcinoma in situ (LCIS) as a positive result, by selection on the basis of tumor type, and by the inclusion of patients with clinical or mammographic abnormalities. Among 1113 consecutive patients with breast cancer treated in the author'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 biopsy. Invasive cancers were found in 1.6%, duct carcinoma in situ in 1.4%, LCIS in 3.2%, and atypical hyperplasia in 6.9% of all random biopsies. If LCIS was excluded as a positive result, invasive lobular 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 biopsy 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 history of breast cancer (6.3% vs. 2.2%, p = 0.004). The following conclusions can be made: 1. If LCIS was excluded as a positive biopsy result, invasive lobular was not significantly more bilateral than invasive duct cancer. 2. Family history and older age significantly predicted a positive biopsy, whereas young age, tumor size, and axillary node status did not. 3. Routine contralateral biopsy identified conditions (invasive cancer or duct carcinoma in situ) requiring immediate 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, with low cost and little morbidity, contralateral biopsy deserves wider consideration in an era of ever-earlier breast cancer diagnosis.