Creast cancer recurrence can be reduced by therapy to the lymph nodes in certain breast cancer patients, although it offers no survival benefit, results of two large clinical trials show. The nodal radiation was given supplementary to the standard treatment of whole-breast irradiation after mastectomy in patients with node-positive or high-risk node-negative disease.
The study involved women with axillary node-positive, which is cancer in the lymph glands under the arm, or high-risk node-negative breast cancer, meaning no cancer in under arm nodes, but cancer with bad prognostic features. It investigated the effectveness adding regional lymph node irradiation to whole-breast irradiation, in comparison with whole-breast irradiation alone.
Radiotherapy applied to the chest wall and regional lymph nodes (under the arm, above the collar bone and under the breast bone), referred to as regional nodal irradiation, is used after breast-conserving surgery in women with node-positive breast cancer who are treated with adjuvant systemic therapy. The treatment diminishes breast cancer recurrence and improves survival.
Study leader Dr. Tim Whelan, professor of oncology at McMaster University’s Michael G. DeGroote School of Medicine and a radiation oncologist at Hamilton Health Sciences Juravinski Cancer Centre, said:
“This study is important because it shows that additional radiation to the surrounding lymph nodes provides added benefit to women, particularly those with involvement of the lymph nodes in the axilla.”
Current treatment for most women with breast cancer involves breast-conserving surgery, followed by radiation to the whole breast. A crucial unanswered question was if the addition of regional nodal irradiation to the usual radiation of the breast would enhance outcomes.
“Additional radiation to the surrounding lymph nodes reduced the risk of subsequent recurrence of breast cancer both locally, such as under the arm, and at sites distant from the breast, such as the bone, liver and lung. The treatment did not increase survival, but follow-up is still relatively early,” said Whelan.
The study was conducted over 14 years and involved more than 1,800 patients and a team of investigators from Canada, the Unites States and Australia.
“Further research is necessary to determine which women are most likely to benefit and who may avoid the additional radiation,” said Whelan.
He added that it is exciting that another study performed in Europe has showed very similar findings.
Timothy J. Whelan, B.M., B.Ch., et al.
Regional Nodal Irradiation in Early-Stage Breast Cancer
N Engl J Med 2015; 373:307-316July 23, 2015DOI: 10.1056/NEJMoa1415340