SAN ANTONIO — Women with early breast cancer who have less extensive axillary surgery see no effect on their 10-year rates of locoregional recurrence and mortality than do those who have more extensive surgery, according to findings from a large meta-analysis.
Less extensive surgery also reduced patients' risk for lymphedema, according to research (abstract GS02-05) presented on December 7 at the 2023 San Antonio Breast Cancer Symposium (SABCS).
These results, which included data from more than 20,000 women, may "reassure" patients and clinicians that more extensive axillary lymph node dissection "does not improve outcomes in many women with early-stage breast cancer," said Andrea V. Barrio, MD, a breast surgeon at Memorial Sloan Kettering Cancer Center, New York City, who was not involved in the study.
Gurdeep S. Mannu, DPhil, of the University of Oxford, United Kingdom, who presented the findings at SABCS, explained that the optimal surgical management of the axilla remains uncertain in this patient population.
To better understand the long-term risks and benefits of more vs less aggressive axillary surgery in early breast cancer, Mannu and colleagues performed a meta-analysis of 29 randomized trials conducted over six decades, which included data on 20,285 women. The trials compared more vs less extensive axillary surgery as well as axillary surgery vs axillary radiotherapy.
In trials comparing more vs less extensive axillary surgery, researchers found that 83% of locoregional recurrences occurred in the breast or in multiple sites/unspecified locations, and the remaining 17% occurred in isolated axilla or other local recurrences, such as in the supraclavicular fossa or internal mammary chain.
Those with recurrences in the breast or multiple sites/unspecified locations did not benefit from more extensive surgery, demonstrating similar recurrence rates (RR) (RR for breast, 1.13; 95% CI, 0.92-1.40; RR for other, 0.89; 95% CI, 0.67-1.18).
The group with recurrences in isolated axilla or other local recurrences tended to do better with more extensive surgery (RR, 0.43 and 0.41, respectively).
Overall though, after a median follow-up of 10 years, differences in locoregional recurrence rates at any site did not differ among patients who had more vs less extensive axillary surgery (RR, 0.91; P = .22). This finding held even when restricting the analysis to women with node-positive disease/unknown nodal status (RR, 1.00; P = .98) and for node-negative women (RR, 0.88; P = .15).
Mannu and colleagues observed similar findings for distant recurrence, breast cancer mortality, and death from any cause.
"But where there was quite a striking difference was in morbidity," said Mannu.
To examine rates of lymphedema — the surgical complication that has been "one of the main motivations" for the deescalation trials of the past few decades — the researchers focused on more recent trials, which "are most relevant to women treated today," Mannu explained.
These showed that more extensive axillary surgery was associated with almost 2.5-times the rate of lymphedema compared with less extensive treatment (odds ratio [OR], 2.43).
Finally, the team compared axillary dissection with axillary radiotherapy across five trials and found no significant differences in the treatment approaches in terms of locoregional occurrence, distant recurrence, breast cancer mortality, and death from any cause.
However, once again, a notable difference in rates of lymphedema occurred, with axillary dissection associated with higher rates compared with radiotherapy (OR, 1.79).
This is "probably the largest meta-analysis comparing more vs less axillary surgery," Barrio told Medscape Medical News.
"When we have one or two positive sentinel nodes, anywhere from 30%-50% of women will have additional positive lymph nodes that we're not removing" with less extensive surgery, she explained. This study shows that, even then, this "doesn't seem to impact on survival."
This is "likely related to better medical treatment and radiation techniques that can treat that disease just as well as big surgery, but with less lymphedema," she added.
Nevertheless, Barrio believes that there are "situations where we still feel that axillary lymph node dissection is important: in women with advanced cancer, like inflammatory breast cancer, and in women who've received chemotherapy upfront, then had surgery, and still have positive nodes after the chemo."
The study was funded by Cancer Research UK, British Heart Foundation, Medical Research Council.
No relevant financial relationships have been declared.
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