The importance of local-regional radiotherapy with conventional or high-dose chemotherapy in the management of breast cancer patients with ≥ 10 positive axillary nodes

Abstract

Purpose: To assess the effect of local-regional radiotherapy (RT) on the outcome of breast cancer patients with ≥ 10 positive axillary lymph nodes who have received modern conventional or high-dose systemic therapy. Methods and Materials: A total of 55 women with local-regionally confined breast cancer involving 10 or more axillary nodes were treated between October 1983 and January 1996. Local-regional therapy consisted of modified radical mastectomy in 39 and breast-conserving surgery in 16. Postoperative radiotherapy was given to 44 of the 55 patients. Radiotherapy consisted of tangential fields to the chest wall or intact breast to a median dose of 50.40 Gy. A total of 86% (38 of 44) received regional nodal irradiation as follows: 35 patients received RT to the supraclavicular (SC) region and axillary midplane to a median dose of 50.40 Gy and 46.20 Gy, respectively; 3 patients received RT to the SC region without inclusion of the axilla to a median dose of 50.40 Gy. All patients received adjuvant standard-dose systemic chemotherapy, 9 of whom received additional intensification chemotherapy followed by autologous bone-marrow transplant (ABMT) or peripheral blood stem-cell transplant (PBSC). Twenty-five patients received adjuvant tamoxifen. Results: With a median follow-up of 30 months, the crude overall survival (OS) and disease-free survival (DFS) for the entire group were 67% and 53%, respectively. On univariate analysis of various clinical, pathological, and therapy-related features, radiotherapy emerged as the most important factor influencing the relapse rate. The addition of RT was significantly associated with an improved DFS ( p = 0.003), specifically by prolonging the time to disease progression. The median time to failure was 61 months and 12.5 months with and without RT, respectively. Patients receiving RT also appeared to survive longer; however, the groups were not statistically different ( p = 0.10). Analysis of the patterns of failure showed local-regional recurrence (LRR) as the first site of failure in 12 (22%) of 55 and distant failure in 20 (36%) of 55. Univariate results revealed both radiotherapy and tamoxifen to be significantly associated with decreased LRR rates ( p = 0.0001 and p = 0.03, respectively); only RT remained independently significant on multivariate analysis. Conclusion: Local-regional radiotherapy is an essential component of the management of breast cancer patients with extensive nodal involvement, despite the use of contemporary adjuvant chemotherapy including high-dose regimens with autologous rescue. In addition to the expected improvement in LRR, radiotherapy is also associated with significantly prolonged DFS and a trend for improvement in OS.