Author reply

Abstract

As Drs. Ragaz and Jackson point out, the topic of postmastectomy radiation therapy is a complex, controversial and interesting one. The benefit of radiation therapy in reducing the risk of locoregional recurrence has been well documented and an improvement in survival has been demonstrated in some randomized trials.1-3 In its simplest form, the postmastectomy controversy has two major components: identifying patient subsets that derive the greatest survival benefit from radiation treatment and establishing the regions or radiation fields to be treated. The Danish and British Columbia trials demonstrated a survival benefit and included full locoregional irradiation. These radiation fields include: the chest wall, the internal mammary lymph nodes, the entire axillary lymph region, and the supraclavicular fossa. Although the benefit of internal mammary irradiation is being evaluated in a prospective trial, in many European and Canadian centers these comprehensive radiation treatment fields still are the standard. This is not so in the U.S. Breast carcinoma physicians in the U.S. responded to the controversies surrounding postmastectomy radiation by convening a consensus meeting. Believers and doubters assembled in Pittsburgh in 1998 and argued the data for 2 days. At the conclusion of the “consensus,” one of the few points of general agreement was that when postmastectomy radiation therapy is used, the axillary lymph node region should not be treated routinely.4 The postmastectomy treatment fields in the U.S. generally omit full axillary irradiation after a level I/II dissection because the risk of axillary lymph node recurrence is very low and the complication rates increase. The increased risk of arm edema with full axillary lymph node irradiation after dissection is well documented and to my knowledge the survival benefit of treating this particular field has not been established. Certainly if the survival benefit is proportional to the risk of dissemination from residual tumor cells in the area, then the axillary lymph node region would be among the lowest risk areas because recurrence rates for this region are on the order of 2–3%. If one accepts that view, then the only compelling reason to treat the axilla would be if there were tumor recurrence features unique to the presence of extracapsular extension. Our study, and others, have found that the recurrence rate in the axilla is no different for patients with extracapsular extension when compared with other lymph node positive patients.5-7 It still is uncertain which field arrangements offer the greatest benefit and the lowest risk when treated after mastectomy, axillary lymph node dissection, and chemotherapy. The two regions of greatest controversy are the internal mammary lymph nodes and the axilla. If it is ever proven that the inclusion of the axillary field improves survival after a standard axillary lymph node dissection, reconsideration will need to be given to full radiation treatment of the axillary lymph node region. Irene Gage M.D.*, * Division of Radiation Oncology, Department of Oncology, The Johns Hopkins Hospital, Baltimore, Maryland