Postmastectomy Radiotherapy in Women with T1–T2 Tumors and One to Three Positive Lymph Nodes : Analysis of the Breast International Group 02-98 Trial
Menée à partir des données d'un essai portant sur 684 patientes traitées par mastectomie pour un cancer du sein de stade T1 à T2 avec 1 à 3 ganglions atteints, cette étude évalue l'effet d'une radiothérapie adjuvante sur le risque de récidive locorégionale, la survie spécifique et la survie globale
Purpose : The purpose of the current study was to analyze the impact of postmastectomy radiation therapy (PMRT) for patients with T1-T2 tumors and 1-3 positive lymph nodes enrolled on the Breast International Group (BIG) 02-98 trial. Materials and Methods : The BIG 02-98 trial randomized patients to receive adjuvant anthracycline with or without taxane chemotherapy. Delivery of PMRT was non- randomized and performed according to institutional preferences. This current analysis was performed on participants with T1-T2 breast cancer and 1-3 positive lymph nodes who had undergone mastectomy and axillary nodal dissection. The primary objective of the present study was to examine the effect of PMRT on risk of locoregional recurrence (LRR), breast cancer specific survival (BCSS) and overall survival (OS). Results : We identified 684 patients who met the inclusion criteria and were included in the analysis, of whom 337 (49%) had received PMRT. At 10 years, LRR risk was 2.5% in the PMRT group and 6.5% in the no PMRT group (HR =0.29, 95% CI, 0.12 to 0.73; P=0.005). Lower LRR after PMRT was noted for patients randomized to receive adjuvant chemotherapy with no taxane (10-year LRR: 3.4% vs. 9.1%, P=0.02). No significant differences in BCSS (84.3% vs. 83.9%) or OS (81.7% vs 78.3%) were observed according to receipt of PMRT. Conclusion : Our analysis of the BIG 02-98 trial, shows excellent outcomes in women with T1-2 tumors and 1-3 positive lymph nodes found in axillary dissection. Although PMRT improved LRR in this cohort, however the number of events remained low at 10 years. In all groups, 10-year rates of LRR were relatively low, compared with historical studies. As such, the use of PMRT in women with 1-3 positive nodes, should be tailored to individual patient risks.