Among women with node-positive or high-risk node-negative early-stage breast cancer, the addition of regional nodal irradiation to whole-breast irradiation reduced the rate of breast cancer recurrence, a recent study published in The New England Journal of Medicine has shown; however, regional nodal irradiation did not improve overall survival.
For the study, researchers sought to determine whether the addition of regional nodal irradiation to whole-breast irradiation improved outcomes in women with breast cancer undergoing breast-conserving surgery.
Researchers enrolled 1,832 women with node-positive or high-risk node-negative breast cancer who were treated with breast-conserving surgery and adjuvant systemic therapy between March 2000 and February 2007.
Patients were randomly assigned 1:1 to receive whole-breast irradiation plus regional nodal irradiation or whole-breast irradiation alone.
Results showed that at the 10-year follow-up, there was no significant difference in survival between the two groups (HR = 0.91; 95% CI: 0.72, 1.13; P=0.38).
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Researchers found that the disease-free survival rate was higher in the nodal irradiation group compared with the control group (82.0% vs. 77.0%; HR = 0.76; 95% CI: 0.61, 0.94; P=0.01), suggesting that the addition of regional nodal irradiation reduced the rate of cancer recurrence.
In regard to safety, patients in the nodal irradiation treatment arm experienced higher rates of grade 2 or higher acute pneumonitis (P=0.01) and lymphadema (P=0.001) than those who received whole-breast irradiation alone.
- Whelan TJ, Olivotto IA, Parulekar WR, et al. Regional nodal irradiation in early-stage breast cancer. N Engl J Med. 2015;373:307-316.