RISK FACTORS FOR CONTRALATERAL MASTECTOMY

Risk Factors Warranting Contralateral Prophylactic Mastectomy for Breast Cancer Identified

January 29, 2009 — Risk factors that may warrant contralateral prophylactic mastectomy (CPM) for breast cancer have been identified, according to the results of a study reported in the January 26 Online First issue of Cancer.

"Although...CPM reduced the risk of contralateral breast cancer in unilateral breast cancer patients, it was difficult to predict which patients were most likely to benefit from the procedure," write Min Yi, MD, from The University of Texas M. D. Anderson Cancer Center in Houston, and colleagues. "The objective of this study was to identify the clinicopathologic factors that predict contralateral breast cancer and thereby inform decisions regarding performing CPM in unilateral breast cancer patients."

The study sample consisted of 542 patients with unilateral breast cancer who underwent CPM at The University of Texas M. D. Anderson Cancer Center from January 2000 to April 2007. Clinicopathologic factors predicting contralateral breast cancer were determined from logistic regression analysis.

Occult malignant tumor was present in the contralateral breast in 25 (5%) of patients. At final pathologic evaluation of the contralateral breast, 82 patients (15%) had moderate-risk to high-risk histologic findings.

Three independent factors predicting malignant tumor in the contralateral breast, based on multivariate analysis, were ipsilateral invasive lobular histologic findings, ipsilateral multicentric tumor, and 5-year Gail risk of 1.67% or greater. Independent predictors of moderate-risk to high-risk histologic findings in the contralateral breast were age 50 years or older at the time of the initial cancer diagnosis and an additional ipsilateral moderate-risk to high-risk pathologic finding.

Limitations of this study include single-institutional, retrospective design and relatively short follow-up time.

"CPM may be a rational choice for breast cancer patients who have a 5-year Gail risk ≥1.67%, an additional ipsilateral moderate-risk to high-risk pathology, an ipsilateral multicentric tumor, or an ipsilateral tumor of invasive lobular histology," the study authors write. "Evaluating 5-year Gail risk and histologic findings in the ipsilateral breast in unilateral breast cancer patients may help predict the likelihood of contralateral breast cancer and assist in stratifying risk and counseling patients."