Findings support wider excision margins in melanoma

Source: healio.com/hematology-oncology, May 2015

CHICAGO — A surgical excision margin of 3 cm yielded significantly improved disease-specific survival but not OS in a cohort of patients with high-risk melanoma, according to findings presented at the ASCO Annual Meeting.

Andrew J. Hayes, MD, of The Royal Marsden National Health Service Trust London, compared 1 cm and 3 cm clinical excision margins in a cohort of 900 high-risk patients with primary cutaneous melanoma who had a Breslow thickness of at least 2 mm.

Researchers randomly assigned 453 patients to undergo surgery with a 1 cm clinical excision margin and 447 patients to a 3 cm clinical excision margin. The two arms were balanced in terms of median tumor thickness and percentage of ulceration.

The median follow-up duration was 8.8 years (interquartile range, 6.3-11.3). There have been 494 deaths, of which 359 were associated with melanoma.

Univariate analysis results demonstrated a 24% increase in melanoma-related mortality in the 1-cm group compared with the 3-cm group (HR = 1.24; 95% CI, 1-1.52). This trend persisted in multivariate analysis (HR = 1.27; 95% CI, 1.02-1.59).

The number of overall deaths was higher in the 1 cm group (253 vs. 241), but univariable results indicated that the difference was not statistically significant (HR = 1.14; 95% CI, 0.96 to 1.36).

Results of the multivariable analysis also indicated 1 cm excision margins increased the risk for death compared with 3 cm excision margins, but the association did not reach statistical significance (HR = 1.19; 95% CI, 0.99-1.45).

“In multivariate analysis, we saw the usual suspects in terms of prognosis, including sex, thickness, ulceration and site,” Hayes said.

Other findings demonstrated an OS rate of 54.3% among women and 45.7% among men (HR = 1.38; 95% CI, 1.11-1.71). The HR for melanoma-specific survival was 1.38 (95% CI, 1.07-1.17) for men compared with women.

Ulceration was absent in 61.6% of the cohort. When ulceration was present, the HR was 1.68 (95% CI, 1.38-2.04) for OS and 1.75 (95% CI, 1.39-2.2) for melanoma-specific survival.

Approximately one-third of disease sites were in the distal limb (31.6%), whereas 22.4% were in the proximal limb and 45.9% were in the trunk. Multivariate analyses indicated disease in the proximal limb impacted OS (HR = 1.23; 95% CI, 0.93-1.63) and melanoma-specific survival (HR = 1.44; 95% CI, 1.03-2.03). Researchers also reported OS (HR = 1.41; 95% CI, 1.09-1.81) and melanoma-specific survival (HR = 1.69; 95% CI, 1.24-2.29) for trunk disease sites.

“We have demonstrated a significant increase in melanoma-specific mortality associated with a 1 cm margin compared to a 3 cm excision margin,” Hayes said.