Axillary surgery does not improve outcomes for early-stage breast cancer
Key takeaways:
- Patients with early invasive breast cancer who did not receive axillary surgery had noninferior outcomes as those who had surgery.
- Five-year survival appeared comparable with surgery and without.
SAN ANTONIO — Surgical axillary staging as part of breast-conserving therapy may not be necessary for certain patients with early invasive breast cancer, according to findings presented at San Antonio Breast Cancer Symposium.
Women with node-negative breast cancer who did not get sentinel lymph node biopsies achieved noninferior invasive DFS compared with those who had the procedure, findings of the INSEMA trial showed.
“This practice-changing concept is suitable for patients presenting with low-grade, hormone receptor-positive/HER2-negative invasive breast cancer with tumor size up to 5 cm,” Toralf Reimer, MD, PhD, deputy director and senior physician of gynecology at University Women’s Clinic and Polyclinic at Klinikum Südstadt Rostock in Germany, and colleagues wrote in the abstract.
Background and methods
Sentinel lymph node biopsy replaced axillary lymph node dissection as a staging procedure about 20 years ago and it has resulted in “surgical de-escalation,” according to investigators.
Reimer and colleagues investigated whether sentinel lymph node biopsies could be omitted altogether for women with early-stage disease.
The trial included patients diagnosed with early invasive breast cancer (tumor size5 cm or less; c/iT1–2 c/iN0) who had been scheduled for breast-conserving therapy.
Researchers included 4,858 patients (median age at diagnosis, 62 years; range, 24-89; 78.6% stage I disease; 98.5% hormone receptor positive) from Germany and Austria in the protocol set.
Investigators randomly assigned participants 4:1 to receive sentinel lymph node biopsy (n = 3,896) or not (n = 962).
Invasive DFS served as the primary endpoint.
Researchers set a noninferiority HR for no surgery vs. sentinel lymph node biopsy as less than 1.271.
Results
Median follow-up was 73.6 months (interquartile range, 61.3-86.4).
Results showed comparable estimated 5-year invasive DFS rates among women who did not have sentinel lymph node biopsy as those who did (91.9% vs. 91.7%), with the HR of 0.91 (95% CI, 0.73-1.14) meeting the noninferiority threshold.
Overall, 10.8% of patients experienced a first invasive DFS event.
First invasive DFS event rates did not differ dramatically between the no biopsy group and the biopsy group. This finding appeared consistent for invasive locoregional recurrences (1.9% vs. 1.4%), including axillary recurrences (1% vs. 0.3%); invasive contralateral breast cancer (1% vs. 0.6%); distant metastases (2.7% vs. 2.7%); secondary malignancies (3.3% vs. 3.9%) and death (1.4% vs. 2.4%).
Five-year OS rates appeared similar between cohorts (98.2% vs. 96.9%).
“The INSEMA trial — enrolling 5,500 patients — significantly demonstrated that omitting [sentinel lymph node biopsy] in clinically node-negative patients with early breast cancer and scheduled for breast-conserving therapy did not result in inferior outcome,” Reimer said during a presentation. “This de-escalation concept avoiding complete axillary surgery is suitable for patients with an age 50 years and older and with low tumor characteristics.”
The findings were published simultaneously in The New England Journal of Medicine.
In an accompanying editorial, Monica Morrow, MD, FACS, surgical oncologist with Memorial Sloan Kettering Cancer Center, commended the INSEMA trial investigators for providing data that can advance treatment for this patient population.
The INSEMA data — coupled with findings from the previously reported SOUND trial, which showed avoiding an axillary procedure for patients with small breast cancer up to 2 cm is noninferior to sentinel lymph node biopsy — “provide a glimpse into the future,” Morrow wrote.
“Sentinel lymph node biopsy is associated with low but measurable morbidity, and elimination of the procedure decreases the treatment burden on patients,” Morrow wrote. “But if the omission compromises recommendations for adjuvant therapy and leads to whole-breast irradiation in a candidate for partial-breast irradiation or to the omission of CDK4/6 inhibitor therapy because of uncertainty about nodal status, is this the most appropriate course? Successful de-escalation of any therapeutic approach requires multidisciplinary consideration of the effects on the entire treatment plan; INSEMA and SOUND data provide a strong foundation for consideration of how to incorporate the elimination of sentinel lymph node biopsy into practice.”
References:
- Morrow M. N Engl J Med. 2024;doi:10.1056/NEJMe2414899.
- Reimer T, et al. Abstract GS2-07. Presented at: San Antonio Breast Cancer Symposium; Dec. 10-13, 2024; San Antonio.
- Reimer T, et al. N. Engl J Med. 2024;doi:10.1056/NEJMoa2412063.
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Reimer T, et al. Abstract GS2-07. Presented at: San Antonio Breast Cancer Symposium; Dec. 10-13, 2024; San Antonio.