Mohs surgery may not boost survival over standard excision of melanomas on trunk, extremities

Reuters Health - 29/10/2020 - Compared with wide local excision (WLE), Mohs micrographic surgery (MMS) does not appear to increase overall survival in patients with trunk or extremity melanomas, according to a retrospective study.

"In contrast to our previous work, which demonstrated a statistically significant survival benefit for MMS over WLE for all-stage cutaneous melanoma of the head and neck, this study failed to demonstrate a statistically significant difference in survival outcomes between MMS and WLE treatment modalities when trunk and extremity tumors were evaluated," Dr. Addison M. Demer of the University of Minnesota, in Minneapolis, told Reuters Health by email.

MMS is gaining popularity in the U.S. and is associated with improved overall survival (OS) for some types of melanomas, Dr. Demer and his colleagues note in JAMA Dermatology. However, they add, "It remains unclear if there is a survival advantage . . . when it is used for the treatment of all-stage melanomas of the trunk and extremity."

The researchers examined data on more than 188,000 such cases covered in the National Cancer Database between 2004 and 2015. The mean age of patients was 58.8 years; 97.7% underwent WLE and the remaining 2.3% received MMS.

Multivariate analysis showed no significant OS difference between MMS and WLE for tumors of the trunk, upper extremity, lower extremity or a combination of trunk and extremity, with hazard ratios ranging from 0.93 to 1.10.

Among factors significantly associated with increased all-cause mortality were greater age, positive surgical margins, tumor ulceration and a Charlson-Deyo comorbidity score of 2 or more.

Among possible explanations for the similarity between OS in patients treated with either surgical approach, say the researchers, is that when treated with WLE, melanomas of the head and neck and special sites are associated with 9.1% positive margin and 9.9% local recurrence rates. In trunk and extremity tumors, the corresponding proportions for both are just 1.7%.

Therefore, they add, "it is unsurprising that a significant survival benefit has been observed for tumors treated with MMS on the head and neck, but not the trunk and extremities."

"These data have important implications for clinical management," concluded Dr. Demer. "Firstly, the results suggest that MMS may be considered a reasonable treatment option for select trunk and extremity melanomas. Secondly, the data support current U.S. practice patterns, where MMS is typically reserved for head and neck and special site tumors."

By David Douglas

SOURCE: https://bit.ly/2HEtFhS JAMA Dermatology, online October 21, 2020.



Posted on 29 October 20206 November 2020