Lymphedema
Risk is Greatly Increased with Boost of Radiation to Axillary
Nodes
Behind the Cancer Headlines®
The significant risk of developing lymphedema
may outweigh the benefit of receiving an extra boost of radiation to lymph
nodes possibly involved in early-stage breast cancer. That is the conclusion of
a study presented at the Annual Meeting of the American Society for Therapeutic
Radiology and Oncology in
Lymphedema is an uncomfortable swelling of a limb caused by a build-up of lymphatic fluid. This occurs when the lymph vessels are damaged and/or nodes are removed. The disruption of lymphatic flow prevents the proper drainage, causing a back-up of fluid. About 15-20% of women with breast cancer who have lymph nodes removed during surgery will develop lymphedema.
"We know radiation can increase one's risk of
developing lymphedema, so it's important to determine
whether the radiation technique or dose contributes," explained Shelly B.
Hayes, M.D., a resident in the radiation oncology department at
Standard therapy for women with early-stage breast cancer calls for radiation following a lumpectomy. The radiation field includes the whole affected breast and some of the lymph nodes under the arm, called the axillary lymph nodes.
Doctors may also irradiate the lymph nodes found in the upper axilla and above the clavicle, depending on the number of nodes removed and the number that test positive for cancerous cells. Sometimes, an additional dose or "boost" of radiation is added to the axillary region.
"The reason we irradiate the lymph node regions is to prevent recurrence of disease in those locations," Hayes said. "When an aggressive lymph-node dissection is performed, the utility of additional radiation is questionable. This is the subject of some debate."
Hayes' study consisted of 2,581 women with early-stage
breast cancer treated at
"The most striking result we found involved women who had more than four positive lymph nodes," explained Hayes. "They were four times more likely to develop lymphedema when treated with a boost, despite similar risks of nodal recurrences.
"Given the increased risk of lymphedema
and the lack of evidence supporting improvements in nodal recurrences from the
boost, we should carefully consider these results before delivering a boost to
our patients," Hayes concluded.
SOURCES:
48th Annual Meeting of the American Society for Therapeutic
Radiology and Oncology,