Locoregional failure 15 years after mastectomy in women with one to three positive axillary nodes with or without irradiation the significance of tumor size.

BACKGROUND: There is insufficient evidence to suggest the routine use of postmastectomy radiotherapy (PMRT) in patients with one to three positive axillary nodes and T1/2 tumors. We have assessed the risk of locoregional recurrence (LRR) with or without RT in this group of patients, and focused on the results in subgroups defined by tumor size.

PATIENTS AND METHODS: 249 women with T1/2 tumors and one to three positive nodes underwent mastectomy and axillary dissection between 1983 and 1987. Locoregional RT of 50 Gy was given to 175 patients. Chemotherapy or hormonal therapy was administered to 41 and 71 women, respectively. The median follow-up time of survivors was 189 months (range, 167-227 months).

RESULTS: The rates of isolated LRR without or with RT were 16% (12/74) and 8% (14/175), respectively (p = 0.05), and the total (with or without distant relapse) LRR rates 23% and 12%, respectively (p = 0.03). 15-year overall survival amounted to 41% without RT and to 52% with RT (p = 0.2). The rates of isolated LRR for patients treated with chemotherapy or hormonal therapy only were 25% and 12%, respectively. In the absence of RT, age (> 45 vs = 45 years; p = 0.06), tumor size (T1 vs T2; p = 0.07), and extranodal invasion (ENI; absent vs present; p = 0.09) were related to the risk of developing an isolated LRR. On multivariate analysis, only tumor size (relative risk [RR], 3.92; 95% confidence interval [CI], 1.11-15.14) and age (RR, 3.37; 95% CI, 1.03-11.09) emerged as independent significant predictors, whereas ENI (RR, 1.50; 95% CI, 0.81-2.77) did not. In the T1 subgroup, the estimated 15-year isolated LRR rate was 9% (3/36) without and 9% (8/99) with RT (p = 0.9775). 15-year disease-free survival amounted to 62% and 57%, respectively (p = 0.5153). For patients without RT, according to the age groups (= 45 vs > 45 years), the 15-year rates of isolated LRR were 9% and 9%, respectively (p = 0.9910). In the T2 subgroup, the estimated 15-year isolated LRR rate was 30% (9/38) without and 10% (6/76) with RT (RR, 0.33; 95% CI, 0.12-0.92; p = 0.0244). 15-year disease-free survival amounted to 32% and 50%, respectively (p = 0.1213). For patients without RT, according to the age groups (< or = 45 vs > 45 years), the 15-year rates of isolated LRR were 57% and 16%, respectively (p = 0.0049).

CONCLUSION: Patients with T1 tumor and one to three positive nodes are at low risk of isolated LRR either with or without RT. Patients with T2 tumor and one to three positive nodes are at high risk of isolated LRR without RT. Our findings support the routine use of PMRT in patients with T2 tumor, especially those aged < or = 45 years.