A McMaster study found no increase in overall survival, but a reduction in breast cancer recurrence when additional radiation is given to the lymph nodes as well as the standard treatment of whole-breast irradiation after breast-conserving surgery.
The research examined the addition of regional nodal irradiation to whole-breast irradiation compared with whole-breast irradiation alone, and was published in the New England Journal of Medicine. It was led by Tim Whelan, professor of oncology and a radiation oncologist at Hamilton Health Sciences, Juravinski Cancer Centre., and involved a team of investigators from Canada, the United States and Australia.
The study involved more than 1,800 women with axillary node-positive breast cancer (cancer in the lymph glands under the arm) or high-risk node-negative breast cancer (no cancer in under arm nodes, but cancer with bad prognostic features).
Currently, most women with breast cancer are treated with breast-conserving surgery followed by radiation to the whole breast. An important unanswered question was whether the addition of regional nodal irradiation to the usual radiation of the breast would improve 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," said Whelan. "The treatment did not increase survival, but follow-up is still relatively early."