Postmastectomy radiation in patients with four or more positive nodes

Postmastectomy radiotherapy (PMR), a local therapeutic modality, is recommended to treat breast cancer patients with multiple involved axillary lymph nodes (a marker of increased systemic risk). Bothered by this conceptually flawed treatment approach we evaluated the impact of PMR on the treatment of women with four or more involved axillary lymph nodes. We identified 1164 patients treated from 1982 through 1999 with mastectomy. We reviewed the records of the 223 who demonstrated four or more positive axillary lymph nodes. Of these 128 were treated by mastectomy only and 95 by PMR. The mastectomy-only group demonstrated a mean tumor size of 3.5 cm, a median of seven axillary nodes involved, and a median of 24.9 nodes harvested. The PMR group had a mean tumor size of 4.3 cm with nine positive nodes out of a median total of 23.3 harvested. The difference in mean tumor size was statistically significant (P = 0.01). The locoregional recurrence (10.9% vs 12.6%), distant recurrence rates (42.2% vs 35.8%), and 5-year survival (51% vs 55%) were not statistically different between the mastectomy-only group versus the PMR group, respectively. Adding PMR to breast cancer treatment demonstrated no improvement in outcome. Despite limitations of this retrospective study the results strongly support evaluation of PMR by a high-quality randomized prospective trial.