Factors influencing outcomes for breast conservation therapy of mammographically detected malignancies

OBJECTIVE: To evaluate the importance of surgeon caseload, lesion type, and biopsy type on outcomes in breast conservation therapy (BCT). BACKGROUND: Breast conservation therapy has low rates of morbidity and mortality and is being performed with increasing frequency. Its primary advantage is cosmetic, and the amount of breast tissue resected is the main determinant of cosmetic outcomes. STUDY DESIGN: Two hundred seventeen consecutive patients undergoing breast conservation therapy at Northwestern Memorial Hospital for mammographically detected breast cancer were evaluated. The volume of tissue excised was compared with the volume of the tumor as a ratio. Univariate and multivariate analyses of the relationships between the specimen-to-tumor-volume ratio (STVR) and histologic diagnosis, biopsy type, surgeon caseload, and lesion type were examined. RESULTS: The mean (log scale) STVR was significantly lower when the mammographic lesion was identified as a mass or architectural distortion versus calcifications (p < 0.001 in multivariate analysis). Mean log (STVR) was also decreased for higher-caseload surgeons (p = 0.02). Core biopsy before lumpectomy was associated with significantly increased mean log (STVR) (83 versus 50, p = 0.05) without significantly increasing the rate of negative margins. CONCLUSIONS: Mammographic lesion type and biopsy method were associated with the amount of tissue excised relative to tumor size as measured by STVR. In addition, surgeons with higher caseloads were better able to perform needle localization lumpectomy to negative margins while limiting the volume of normal breast tissue excised.