Sentinel lymph node biopsy, axillary dissection and breast cancer: radiation oncologist's viewpoint

Sentinel lymph node (SLN) identification and biopsy in breast cancer have been carried out successfully since the early 1990s. In early-stage breast cancer, the negative predictive value of a SLN biopsy is as high as 93%-100%. With a negative SLN, no axillary treatment would be required and the breast can be treated by tangential radiation fields. Currently, for a patient with a positive SLN, axillary dissection is recommended. Axillary irradiation can replace surgery with a low risk of recurrence (< 7%). The modern practice of radiotherapy, delivering a dose of 50 Gy to the axilla, has a low rate of late morbidity. Hence, it is now time to plan clinical trials comparing axillary irradiation with axillary dissection in SLN-positive, early-stage breast cancer. These approaches to the axilla, guided by the status of the SLN can reduce arm problems in women with breast cancer and improve their quality of life. Just as the treatment of the primary breast tumour has changed from Halstedian mastectomy to conservation surgery combined with breast irradiation, SLN biopsy may allow a move away from surgical axillary clearance and the associated morbidity in the future.