[Breast-conserving treatment for early invasive lobular breast cancer: 15 years results].

BACKGROUND: Infiltrating lobular cancer is biologically different from invasive ductal cancer and there is disagreement regarding appropriate local management of this disease.

PURPOSE: To examine treatment outcomes after breast-saving surgery for patients with invasive lobular breast cancer.

MATERIAL AND METHODS: Between 1983 and 1987, 77 women with early, stage I-II invasive lobular breast cancer were treated with complete gross excision of the tumour and axillary dissection. Fifty-eight of these patients were treated with 50 Gy ipsilateral breast irradiation, and 19 did not receive radiotherapy. During 176 month median follow-up local-regional recurrences, distant metastases, contralateral breast cancers, breast cancer deaths and deaths caused by other disease were scored. The probability of survival was estimated by Kaplan-Meier method. In uni- and multivariate analysis the Cox-model was used. Relative risk (RR) and associated confidence intervals (CI) were calculated from the regression coefficients. Statistical differences in proportions and means were assessed by log rank and Fisher exact-tests.

RESULTS: In the saved breast, the actual rate of local recurrence at 15 years was 13% for irradiated and 53% for non-irradiated patients (RR: 0.1; 95% CI: 0.03-0.31; p: < 0.0001). The incidence of total breast cancer relapses (local-regional recurrences and distant metastases) was also higher for non-irradiated than for irradiated patients (74% vs. 40%; p: 0.0168). In multivariate analysis irradiation (no vs. yes) showed a significant effect on local tumour control (RR: 0.08: 95% CI: 0.02-0.28; p: 0.0001), but menopausal (pre vs. post), T-(T1 vs. T2) and N-(N0 vs. N1) status did not. The breast cancer specific survival at 15 years was 74% without and 62% with local recurrence (RR: 1.45; 95% CI: 0.53-3.96; p: 0.4697). The majority of local recurrences (9 of 14) were curable by salvage surgery. For all patients the rate of contralateral breast cancer was 6.5%.

CONCLUSION: Results of long-term follow-up confirmed that breast-conserving surgery and radiotherapy is a reasonable treatment for patients with early invasive lobular breast cancer. The majority of local recurrences are curable by salvage surgery.