Pathologic Characteristics of Breast Cancer that Predict for Local Recurrence After Lumpectomy Alone

Breast conservation surgery (BCS) plus irradiation has been shown to be equivalent to mastectomy in controlling ipsilateral breast cancer recurrence. The purpose of this study is to evaluate the factors that determine the rate of local recurrence in a group of patients treated with partial mastectomy without postoperative radiation, adjuvant hormonal therapy, or chemotherapy. We also assess the role of standard pathologic features, specifically lymphovascular invasion (LVI) in identifying high- and low-risk subsets of patients. We have a cohort of 293 patients treated with partial mastectomy followed prospectively for a median of 8 years. Data collected included patient's age, tumor size, tumor morphology, tumor grade, the extent of ductal carcinoma in situ (DCIS), the presence of LVI, lymph node status, and hormone receptors. Statistical analyses carried out were Kaplan-Meier plots with Wilcoxon (Peto-Prentice) test statistics for univariate analysis and Cox stepwise regression for multivariate analysis; the end point was local recurrence. The relapse rate in this cohort was 26%. In univariate analysis the significant factors associated with prolonged disease-free survival included older age, negative nodes, positive estrogen receptor (ER) status, and absence of LVI. Small tumor size was significant only in the univariate analysis. In the multivariate analysis, absence of comedocarcinoma entered the model in addition to the other variables. If the variables are stratified, a group of 66 patients with 6% local recurrence rate was identified. These were node-negative women >/=50 years of age with no LVI, no comedo DCIS, and ER-positive tumors. This study clearly indicates the important role of pathologic parameters in assessing the risk of recurrence.