Nodal radiation in breast cancer does not improve survival

Abstract

Two separate clinical studies by Timothy Whelan and Philip Poortmans and their colleagues demonstrate that, in early stage breast cancer, addition of regional lymph node irradiation to standard radiation does not improve overall survival, but reduces recurrence. In the MA.20 trial, 1832 women were randomly assigned to breastconserving surgery with either whole-breast irradiation alone or with additional regional nodal irradiation. At the 10-year follow-up (median follow-up of 9·5 years), 82·8% of patients who received nodal radiation were alive, compared with 81·8% in the control group (hazard ratio [HR] 0·91, 95% CI 0·72–1·13; p=0·38). Disease-free survival was higher in the nodal-irradiation group versus the control group (82·0% vs 77·0%; HR 0·76, 95% CI 0·61–0·94; p=0·01). 1·2% of patients in the nodal-irradiation group had grade 2 or higher acute pneumonitis, and 8·4% had lymphoedema, compared with 0·2% and 4·5% respectively. The EORTC trial included 4004 women randomly assigned to either whole-breast wall or thoracic-wall irradiation alone or in combination with regional nodal irradiation. Overall survival at 10 years in the nodal irradiation group was 82·3% compared with 80·7% for those receiving standard irradiation (HR 0·87, 95% CI 0·76–1·00; p=0·06). Disease-free survival was better in the nodal-irradiation group versus the control group (72·1% vs 69·1%; HR 0·89, 95% CI 0·80–1·00; p=0·04). More pulmonary fi brosis occurred in the nodal-irradiated patients, 4·4% versus 1·7%, more cardiac fi brosis, 1·2% versus 0·6%, and more cardiac disease, 6·5% versus 5·6%. In both studies, subgroup analyses indicate some patients may derive greater benefi t from nodal irradiation. “These are very mature studies with solid data”, said Nancy Davidson (University of Pittsburgh Cancer Institute, Pittsburgh, PA, USA) and added that they may help determine which women should receive nodal radiation. Outstanding questions remain as to those patients who have one to three lymph nodes’ involvement, Davidson said. She added that, with more recent systemic adjuvant treatments available, outcome for all women with the disease is likely to be better now than during the trial. Ultimately, the choice to treat with nodal radiation will depend on individual patient’s tumour genetic subtypes and age, amongst other factors, explained Davidson.