SAN ANTONIO (FRONTLINE MEDICAL NEWS) – Axillary dissection can be avoided in patients with early breast cancer and limited sentinel node involvement, investigators reported at the San Antonio Breast Cancer Symposium.

Both disease-free survival (DFS) and overall survival (OS) were similar in a population of patients with cT1-T2 N0M0 breast cancer and sentinel node micrometastases who underwent axillary dissection (AD), compared with those who did not. Complications associated with axillary surgery can be avoided in this population, without any adverse effect on survival.

“Our findings are fully consistent with those of the Z0011 trial, which after 10 years found no differences between the AD and no-AD groups for any endpoint in patients with moderate disease burden in the axilla undergoing conservative breast surgery,” said study author Viviana Galimberti, MD, of the European Institute of Oncology in Milan.

In the ACOSOG Z0011, trial, the use of sentinel node biopsy alone was not inferior to AD in patients with limited sentinel node metastasis treated with breast conservation and systemic therapy.

“We also suggest that non-AD is acceptable treatment in patients scheduled for mastectomy,” Dr. Galimberti said.

For patients with breast cancer and metastases in the sentinel nodes, AD has been the standard of care, but for those with limited sentinel node involvement, it was hypothesized that AD might not be necessary.

The phase 3 IBCSG 23-01 study was a multicenter, randomized, noninferiority trial that compared DFS in breast cancer patients with one or more micrometastases (greater than or equal to 2 mm) in the sentinel nodes who were randomized to either AD or no axillary dissection (no-AD). The 5-year results, which were published in 2013 in the Lancet Oncology ( 2013 Jun;14[7]:e251-2 ) showed no difference in DFS between the two groups.

At the meeting, Dr. Galimberti reported on outcomes after an extended median follow-up of 9.8 years. A cohort of 934 women (931 evaluable) were enrolled from 27 centers from 2001 to 2010 and randomized to either AD or no AD (467 in the no-AD group and 464 in the AD group).

The results were similar to those reported at 5 years. The 10-year DFS rates were similar for both cohorts; 77% for non-AD vs. 75% for AD (hazard ratio [no-AD vs. AD], 0.85; 95% confidence interval, 0.65-1.11; log-rank P = .23; noninferiority P = .002).

The rate of axillary failure in the no-AD group was low, Dr. Galimberti pointed out, at 1.7% and 0.8% among women who underwent breast-conserving surgery. There were nine ipsilateral axillary events in the no-AD group vs. three in the AD group, and 45 deaths in the no-AD group vs. 58 in the AD group. The 10-year OS was 91% (95% CI, 88%-94%) in the no-AD group and 88% (95% CI, 85%-92%) in the AD group (HR [no-AD vs. AD], 0.77; 95% CI, 0.56-1.07; log-rank P = .19).

There was no difference between groups for the main endpoint of DFS or the secondary endpoint of OS, said Dr. Galimberti.

In subgroup analyses, which included tumor size, estrogen-receptor status, progesterone-receptor status, tumor grade, and type of surgery, there were no subgroups identified that benefited from AD over no-AD.

“Our data fully support the change in clinical practice that started after the early published results,” Dr Galimberti concluded. “No AD is now standard treatment in early breast cancer when the sentinel node is only minimally involved.”

The study received no outside funding and the authors had no disclosures.

SOURCE: Galimberti et al. SABCS Abstract GS5-02