NEW ORLEANSRadiation therapy after mastectomy reduces locore-gional
recurrence rates for breast cancer patients with positive lymph nodes,
positive surgical margins, or both, according to the results of a large
retrospective study presented at the 44th Annual Meeting of the American
Society for Therapeutic Radiology and Oncology (ASTRO abstract 153).
Certain Patients Benefit
"According to our data, there are certain patients who can greatly benefit
from postmastectomy radiation," said lead investigator Wendy A. Woodward, MD,
PhD, a resident in the Department of Radiation Oncology, M.D. Anderson Cancer
Center. "Patients whose cancer involves 20% or more of the removed lymph
nodes or who have close or positive surgical margins can significantly reduce
their chances of a recurrence with postoperative radiation therapy."
Postmastectomy radiation reduces locoregional recurrence for all patients
with breast cancer, Dr. Woodward said. However, determining what threshold of
risk warrants the risks associated with treatment remains controversial.
Finding patterns and predictors of locoregion-al recurrence can help
determine which patients should emphatically be offered postoperative
radiation therapy, she said.
The study patientsdrawn from five prospective trials totaling 1,800
patientswere treated with mastectomy followed by doxorubicin-based
chemotherapy. Results from the 469 patients who received postoperative
radiation therapy were compared with those of the 1,031 patients who did not.
Median follow-up was 10 years.
Postmastectomy radiation therapy reduced isolated (without distant
metasta-ses) locoregional recurrence rates for all patients regardless of the
number of nodes involved. This benefit occurred despite the less favorable
prognostic factors of the patients who received radiation therapy, including
greater tumor size, higher tumor stage, and increased number of positive
nodes, Dr. Woodward said.