Breast conservation treatment of early stage breast cancer: patterns of failure

This study retrospectively assesses the patterns of failure in conservatively treated early stage breast cancer patients by correlating various clinical, pathologic, and treated-related factors with local, axillary, and distant relapse.

Between 1973 and 1990, 796 patients (817 breasts) received breast conservation surgery followed by radiotherapy. Local recurrences were counted as events even if they occurred simultaneously or after the appearance of axillary or distant metastases.

The 10-year actuarial relative disease-free survival (DFS) rate for T1N0, T2N0, and T1-2N1 was 82%, 71%, and 54%, respectively. Stage N0 patients had a significant DFS advantage over N1 patients (p = 0.02). The 15-year actuarial local recurrence-free rate for T1 and T2 tumors was 82% and 87%, respectively (p = nonsignificant). Univariate analysis identified three significant risk factors for local relapse: (a) 48 breasts with tumors showing an extensive intraductal component had a crude local recurrence rate of 23% compared to 8% for 769 breasts without intraductal component (p = 0.0016); (b) the actuarial 10-year local recurrence-free rate for patients under age 40 years was 64% compared to 88% for patients over 40 years (p < 0.0001); (c) the 10-year actuarial local recurrence-free rate for 416 postmenopausal women without adjuvant tamoxifen was 83% compared to 97% for 107 postmenopausal women with tamoxifen (p = 0.0479). Salvage therapy for operable local recurrent patients resulted in a 8-year actuarial DFS rate of 47%, significantly lower than that obtained with primary treatment. The incidence of axillary relapse as the first sign of recurrence was 2%, and could be correlated with the lack of axillary dissection (p < 0.0000005) and primary tumor size (p = 0.03). Radiotherapy to the axilla did not influence axillary relapse. Actuarial 5-year DFS rate after treatment of isolated axillary recurrence was 27%. Axillary failure was a marker for distant failure. Contralateral breast cancer occurred in 8% of patients and did not have a detrimental effect on survival. Adjuvant tamoxifen decreased the 9-year actuarial incidence of contralateral breast cancer from 10% to 4% (p = 0.053).

Tumors with extensive intraductal component, age under 40 years, and the omission of adjuvant tamoxifen in postmenopausal women increased local recurrence rate. Stage T2 and the lack of axillary dissection increased axillary recurrence rate. Stage N+ and local or axillary relapse increased distant failure rate. Axillary irradiation did not influence locoregional control nor survival. Improved therapy is needed for relapsing patients.