The need to reexamine axillary lymph node dissection in invasive breast cancer

The manuscript by Silverstein et al.’ is most timely and pertinent in the continuing evolution of tissue conservation in the management of patients with breast cancer. There has been general acceptance over the past two decades that breast preservation rather than mastectomy is appropriate treatment for the majority of cases of primary invasive breast cancer and most cases of small mammographically detected duct carcinoma in situ (DCIS). The next conventional surgical operation to reappraise in the management of patients with invasive breast cancer is axillary lymph node dissection, which, incidentally, has already been abandoned for DCIS because of the extremely low rate of lymph node metastasis.* As the authors stated, ”it may now be time to consider eliminating routine node dissection for lesions more advanced than DCIS, but with extremely low likelihood of axillary node involvement.”’ The authors concluded that a 3% incidence of axillary metastasis, as they reported, is too low to justify the morbidity and expense of a procedure that mandates a hospital admission, general anesthesia, and a total cost of perhaps $10,000, including charges for the operating room, recovery room, hospital room, surgeon, and anesthesiologist.’ Silverstein et al. stated, “How can we justify 100 node dissections in an attempt to find three patients with positive nodes to treat with chemotherapy, one of whom, at most, will be helped?”’ The authors beg the question of how the threshold of probability of axillary lymph node metastasis should be set so that axillary lymph node dissection is of such low yield that it does not justify the high cost, morbidity, possibility of arm edema, and, particularly, the marginal gain from the use of adjuvant systemic therapy. Is a 10% or 20% threshold rate of axillary metastases low enough to justify not doing a dissection? This becomes an exercise in analyzing risk:benefit ratios. For example, a 15% rate of