T3N0 POSTMASTECTOMY RADIATION ONLY TO CHEST WALL

Post-Mastectomy Nodal Radiation Unnecessary for Node-Negative Breast Cancer

By Megan Rauscher

NEW YORK (Reuters Health) Sept 22 - Irradiation of axillary and supraclavicular lymph nodes is unnecessary in women whose axillary nodal status following mastectomy is negative, according to research presented Sunday at the 50th annual meeting of the American Society for Therapeutic Radiology and Oncology in Boston.

"This study demonstrates an extremely low rate of regional nodal failure in patients with pathologically node-negative breast tumors following complete dissection that are greater than 5 centimeters or have close/positive margins following mastectomy and adjuvant radiotherapy to the chest wall alone," the study team wrote in a meeting material abstract.

"Avoidance of regional node radiotherapy and its risks of lymphedema and pulmonary toxicity may be an acceptable approach in these selected patients," they concluded.

Mastectomy followed by radiation is currently recommended for women with breast tumors greater than 5 centimeters and negative lymph nodes, Dr. Penny Anderson, attending physician in the radiation oncology department at Fox Chase Cancer Center, Boston, explained in a statement.

"We typically irradiate the chest wall because it's been shown to improve survival. Out of an abundance of caution, many radiation oncologists also treat the surrounding lymph nodes, but there is little evidence that this improves outcome," she noted.

Dr. Anderson and her colleagues evaluated the need for lymph node irradiation in 64 patients with pathologic node-negative breast cancer treated by mastectomy and radiation from 1985 to 2006. Fifty-three patients received radiation therapy to the chest wall only and 11 patients received radiation to the regional lymph nodes in addition to the chest wall.

After a median follow up of 78 months, "we found an extremely low rate of recurrences in the lymph nodes among those who didn't have them irradiated," Dr. Anderson said.

Only 1 of the 53 patients who received chest wall radiation only developed a recurrence in an axillary lymph node. None of the patients who received chest wall and node radiation had a recurrence.

The 5-year overall survival rates were 91 percent for the women who received radiation to the chest wall only and 100 percent for those who also received radiation to chest wall and lymph nodes. There was no statistically significant difference noted between the local, regional or distant recurrence rates between the two groups.