Related Experiment Video
Updated: Aug 29, 2026
Single-Port Robotic-assisted Transaxillary Breast-conserving Surgery: A Prospective, Single-arm, Non-randomized Phase IIa Clinical Trial
Published on: August 19, 2025
Randomized clinical trial comparing level II and level III axillary node dissection in addition to mastectomy for
T Tominaga1, S Takashima, M Danno
1Breast Cancer Centre, Toyosu Hospital, Showa University School of Medicine, 4-1-18 Toyosu, Koutou-ku, Tokyo 135-8577, Japan. t-tominaga@hkg.odn.ne.jp
Background:
In addition to mastectomy, level II and level III axillary node dissection procedures are performed widely in Japan. A randomized clinical trial was performed to determine which procedure was more effective.
Methods:
One group of women had resection of the pectoralis minor muscle and dissection of level I, II and III axillary lymph nodes (level III dissection). In a second group, the pectoralis minor muscle was left intact and level III axillary lymph node dissection was not performed (level II dissection). A total of 1209 women with stage II breast cancer were enrolled in the study and randomly assigned to one of the two groups.
Results:
The 10-year cumulative survival rate was 86.6 per cent after level II and 85.7 per cent after level III axillary dissection (hazard ratio (HR) 1.02; P = 0.931, log rank test). The 10-year disease-free survival rate was 73.3 and 77.8 per cent respectively (HR 0.94, P = 0.666). Overall survival and disease-free survival rates in the two groups were similar after both procedures. The duration of surgery was significantly shorter (P < 0.001) and blood loss was significantly less (P = 0.001) after level II dissection. In a survey of patients' symptoms on follow-up, no significant differences were found between the two procedures.
Conclusion:
The addition of pectoralis minor muscle resection and level III axillary lymph node dissection to mastectomy for stage II breast cancer did not improve overall or disease-free survival rates.
