Nonpalpable versus palpable invasive breast tumors treated with breast-conserving surgical management

Most mammographically detected breast cancers are small, nonpalpable malignancies that should be amenable to cure by definitive breast-conserving therapy (BCT) consisting of tumor excision and postoperative radiation. We examined this hypothesis by retrospectively comparing the incidence of local recurrence and the rate of survival in breast cancer patients undergoing BCT for nonpalpable versus palpable lesions. Between 1982 and 1991, 345 patients at the John Wayne Cancer Institute, a large referral center for breast diseases, underwent BCT for invasive ductal and/or invasive lobular breast carcinomas: 120 (35%) had nonpalpable lesions detected by mammography (MG group), and 225 (65%) had palpable lesions detected by physical exam (PE group). The clinical and pathologic tumor status and the clinical outcome were recorded in each case. Median tumor size was significantly larger in PE than MG patients (2 cm versus 1 cm, P < 0.001). Only 29 percent of MG patients were premenopausal, compared with 51 percent of PE patients (P < 0.05). Axillary node involvement was more frequent in PE than MG patients (46% versus 19%, P < 0.01). Over a median follow-up of 58 months, local recurrence rates were 8 per cent for both MG and PE patients. In both groups, the incidence of local recurrence increased significantly when tumor was found in the margins of the resected breast specimen. In the MG group, the risk of local recurrence was significantly higher in premenopausal patients (P < 0.05). Survival was similar in both groups. The rate of local recurrence after BCT is the same for nonpalpable and palpable breast tumors. However, nonpalpable lesions have a lower rate of regional node metastases, which may improve survival. Both local recurrence and metastases seem to be related to tumor size. Tumor-free operative margins are the best predictor of local control.