De-Escalation of Breast Surgery: Less Is More

Surgical management of early-stage breast cancer has evolved over the last two decades towards de-escalation. Surgeries have become less extensive and the question of whether any surgical intervention is need for the axilla remains open for debate.

In the prospective, noninferiority INSEMA trial, women with clinical stage T1 or T2 tumors, clinical axillary node–negative disease (both by exam and imaging with ultrasound), and a plan for breast-conserving surgery were randomized (1:4) to treatment without axillary surgery or to sentinel lymph node biopsy (SLNB). Patients undergoing SLNB found to have 1 to 3 macrometastases were further randomized to completion axillary dissection or no further axillary surgery (data not mature).

Among the per-protocol population of 4858 patients, 90% had clinical stage T1 tumors and 79% had surgically confirmed pathological T1 tumors. Approximately 98% of tumors were ER-positive and only 3.6% were HER2-positive. Postoperative adjuvant therapy was similar between groups, except slightly more patients in the surgery group received chemotherapy.

With a median follow-up of 73.6 months, the omission of SLNB was noninferior to surgery for the primary endpoint of 5-year invasive disease-free survival (91.9% and 91.7%). Incidence of axillary recurrence was 1.0% versus 0.3%, respectively, and incidence of death from any cause was1.4% versus 2.4%. Not surprisingly, patients not undergoing SLNB had less arm edema/pain and greater arm/shoulder mobility.