Sentinel Lymph Node Biopsy Reduced Morbidity Compared to Full Axillary Lymph Node Dissection
The correct answer is B: Sentinel lymph node biopsy fundamentally changed breast cancer surgery by reducing morbidity compared to full axillary lymph node dissection (ALND), while maintaining equivalent oncologic outcomes in appropriately selected patients. 1
Primary Impact: Dramatic Reduction in Surgical Morbidity
The introduction of sentinel lymph node biopsy (SLNB) revolutionized breast cancer surgery by substantially decreasing postoperative complications without compromising survival outcomes:
Quantified Morbidity Reduction
- Lymphedema rates dropped from 27-34% with ALND to 2.6-6% with SLNB alone, representing an 11.5% absolute reduction in postsurgical complications 2, 3, 4
- Arm pain decreased from 38% with ALND to 14% with SLNB 4
- Seroma formation reduced from 24% to 7% 4
- Infection rates fell from 9% to 3% 4
- The 2025 ASCO guideline quantifies that completion ALND would need to be performed in 104 patients to avoid one invasive disease-free survival event at 5 years, but would cause nine patients to experience severe or very severe arm morbidity 1
Equivalent Oncologic Outcomes
Multiple high-quality randomized trials demonstrate that SLNB alone provides equivalent cancer control:
- 15-year follow-up data shows no statistically significant differences in event-free survival (72.8% vs 72.9%) or overall survival (82.0% vs 78.8%) between SLNB alone and ALND 2, 5
- Axillary recurrence rates remain extremely low at 0.1-2.0% with SLNB alone, comparable to ALND 1, 5, 4
- The SENOMAC trial confirmed these findings in a broader population with cT1-T3 N0 tumors and one to three positive sentinel node macrometastases, showing no improvement in 5-year recurrence-free survival with completion ALND 1
Why the Other Options Are Incorrect
Option A: Did Not Eliminate Surgery
SLNB did not eliminate the need for surgery altogether—it remains a surgical procedure that replaced the more extensive ALND in appropriately selected patients 1. Surgery is still required to identify and remove the sentinel node(s).
Option C: Did Not Increase Axillary Clearance
SLNB actually decreased the extent of axillary clearance by removing only 1-2 sentinel nodes (mean 1.92 nodes) rather than the 10-30 nodes typically removed during complete ALND 1. This reduction in surgical extent is precisely what reduces morbidity.
Option D: Did Not Replace Radiation Therapy
SLNB did not replace radiation therapy. In fact, most patients in the pivotal trials received whole breast radiation therapy, and regional nodal irradiation is often administered in patients with positive sentinel nodes who do not undergo completion ALND 1, 6. The AMAROS trial specifically compared ALND to axillary radiation therapy (not SLNB replacing radiation) 1.
Current Clinical Application
For clinically node-negative patients with early-stage breast cancer, SLNB has become the standard of care, replacing routine ALND for staging 1, 2. The technique is most accurate when combining both blue dye and radioisotope, achieving successful sentinel node identification in 93-97% of cases 1, 7.
Critical Caveat
SLNB should only be performed by experienced surgeons with demonstrated low false-negative rates (<10%) and high successful mapping rates (>90%) 1, 2. The false-negative rate averages 8.4% across all trials, but drops to 6.3% in high-volume centers with successful mapping rates >90% 1.