Narrow excision shows positive results in treatment of melanoma near critical areas

Key takeaways:

• 5-mm margins do not increase the risk of melanoma-specific mortality or local recurrence compared with 10-mm margins.
• Narrow vs. wide excision showed lower rates of flap/graft reconstruction (11.2% vs. 30.7%).

In the treatment of melanoma that is close to critical structures, narrow excision saw similar rates of mortality and recurrence compared with wide excision, but fewer rates of reconstructive surgery, according to a study.

“Wide local excision with 10-mm margins cannot always be performed at sites close to critical structures, such as the scalp or face,” Andrea Maurichi, MD, of the melanoma surgical unit at Fondazione IRCCS Istituto Nazionale dei Tumori in Milan, and colleagues wrote. “Furthermore, patients with melanoma at such sites who are candidates for [wide local excision (WLE)] with 10-mm margins may decline the procedure after being informed about potential adverse effects and functional compromise.”

Maurichi and colleagues assessed the outcomes of a narrower, 5-mm WLE and its association with local recurrence and melanoma-specific mortality in patients with T1a melanomas close to critical structures compared with 10-mm excision margins.

The study included 1179 patients aged 18 years or older that were diagnosed with T1a cutaneous melanoma close to critical structures between 2001 and 2020. A total of 626 patients received 10-mm excision and 553 received narrow excision.

Results showed that the melanoma-specific mortality (MSM) rates over 10 years were 1.8% (95% CI, 0.8%-4.2%) in the 10-mm groups and 4.2% (95% CI, 2.2%-7.9%) in the 5-mm group.

The 10-mm group saw a slightly lower local recurrence rate of 5.7% (95% CI, 3.9%-8.3%) compared with 6.7% (95% CI, 4.7%-9.5%) in the 5-mm group.

According to the authors, the main finding of this study was that treating primary T1a melanomas with WLE using 5-mm margins instead of 10-mm margins does not increase the risk of higher MSM or local recurrence rates. Instead, subdistribution hazard ratios (sHR) showed that Breslow thickness greater than 0.4 mm (sHR = 2.42; 95% CI, 1.59-3.68) and mitotic rates greater than 1/mm² (sHR for a single increment = 3.35; 95% CI, 2.59-4.32) are associated with worse MSM.

Although those with 5-mm excisions did not show different results from those with 10-mm excisions in terms of MSM or recurrence, they did show lower rates of reconstructive surgery.

Linear repair was done in 69.3% and 88.8% in the 10-mm and 5-mm groups, respectively, with 30.7% and 11.2% also having a flap or graft reconstruction. The difference in frequencies for flap or graft reconstruction was significant between groups with an odds ratio of 0.29 (95% CI, 0.21-0.39).

“In this cohort study, WLE with narrow margins in primary pT1a melanomas was not associated with worse outcomes but was associated with significantly fewer reconstructive surgeries,” the authors concluded. “Because this association was found in melanomas of the head and neck, acral, and genital sites, there is no plausible reason why it could not be extrapolated to other locations.”