Local recurrence after breast conserving surgery: risk factors and prognostic relevance in 503 consecutive patients

Background: Breast-conserving surgery and axillary dissection followed by external beam radiation therapy has become the standard of care for women with early-stage breast cancer. Local recurrence occurs in 10-20% of patients treated with breast conserving surgery for stage I-II breast cancer. The aim of the present study is to investigate breast cancer local recurrence, potential risk factors and its prognostic impact. Methods: A total of 503 patients with invasive breast cancer treated with breast conserving surgery were included in the study. All patients underwent axillary dissection and postoperative radiotherapy and had negative margins at pathological examination. Median follow-up was 82 months. Local recurrence was classified as early when occurred within 2 years from surgery. The risk factors for local recurrence and overall survival were estimated by univariate and multivariate analyses. Results: Forty-six cases (9.1%) of local recurrence were observed, of which 11 within 24 months from surgery and 35 later. Mean time to local recurrence was 74.6 months (range 11-154). The majority of local recurrences appeared in the same quadrant of the index tumor (67.4%). Statistically significant risk factors for local recurrence were premenopausal status, peritumoral vascular invasion, multifocality and absence of estrogen receptors. Independent negative prognostic factors for overall survival at 5 and 10 years were N stage, absence of estrogen receptors and early time to recurrence. Overall survival at 10 years was 10.0% for patients with early recurrence, 87.5% for patients with late recurrence and 87.9% for patients without recurrence. In order to establish the different risk factors for early and late recurrences, univariate and multivariate analyses were performed comparing these subgroups with the patients without local recurrence. LVI resulted an independent risk factor for both early and late recurrence, absence of estrogen receptors resulted an independent risk factor for late recurrence only and age <45 years for early recurrence only. Conclusions: None of the studied clinico-pathological characteristics alone is determinant for the choice of surgical treatment. Younger patients treated with breast conserving surgery should receive an aggressive post-surgical treatment and should be followed with an intensive follow-up program when metastatic axillary lymph nodes, negative estrogen receptors or peritumoral vascular invasion are present.