SEATTLE – The use of
Compared with conventional wide local excision, survival was significantly improved among patients treated with Mohs, and a subgroup analysis showed that the survival benefit remained for patients with risk factors.
“At 10 years, overall survival was about 21% higher for those treated with Mohs surgery versus those treated with conventional surgery,” said lead author Shayan Cheraghlou, MD, a dermatology resident at the New York University School of Medicine. “On multivariable analysis, which controlled for tumor and patient factors, Mohs was associated with an over 40% reduction in the hazard for death.”
The findings were presented at the annual meeting of the American College of Mohs Surgery.
MCC is a rare, aggressive, neuroendocrine cutaneous malignancy that carries a high mortality rate. The estimated 5-year survival for patients with localized disease is about 50%, Dr. Cheraghlou noted. “That extrapolates to about 55% for T1 tumors and down to about 30% for T4 tumors.”
Although it’s considered to be a rare cancer, the incidence of MCC has been rapidly rising, and in fact it doubled during the period from the 1990s to the 2010s.
Most commonly treated with wide local excision with or without adjuvant radiation therapy, Mohs as monotherapy may offer an alternative treatment option for patients with MCC. It is generally accepted that the optimal treatment for tumors without regional lymph node involvement is surgical, but the data regarding the optimal surgical approach are mixed. Current National Comprehensive Cancer Network guidelines state that either Mohs surgery or wide local excision can be used.
“However, these guidelines do not indicate a preference for one modality over the other,” said Dr. Cheraghlou, “and present them as interchangeable treatment options.”
A growing body of literature supports Mohs surgery for many types of rare tumors, including MCC. For example, as previously reported at the 2021 ACMS meeting, one study found that Mohs surgery compared favorably with the standard treatment approach when it came to recurrence rates for patients with MCC. The 5-year disease-specific survival rate was 91.2% for patients with stage I disease and 68.6% for patients with stage IIa. These rates were comparable with rates for historical control patients who were treated with wide local excision, with or without radiation (81%-87% for stage I disease, and 63%-67% for stage II).
Study details
In the current study, Dr. Cheraghlou and colleagues sought to evaluate the association of the type of surgical approach with patient survival after excision of early-stage MCC. They conducted a retrospective cohort study using the National Cancer Database to identify cases of MCC with T1/T2 tumors. A total of 2,313 patients who were diagnosed from 2004 to 2018 with pathologically confirmed negative lymph node involvement and who were treated with Mohs surgery or wide lesion excision were included in the analysis.
“About 90% were T1 tumors, about 40% were located on the head and neck, and the vast majority – about 60% – were treated with wide local excision,” he explained. “Only about 5% received Mohs surgery for treatment of the primary tumor.”
But when the researchers assessed survival outcomes, they found that treatment with Mohs surgery was associated with significantly improved overall survival.
The unadjusted 3-, 5-, and 10-year survival rates for patients treated with Mohs was 87.4% (SE: 3.4%), 84.5% (SE: 3.9%), and 81.8% (SE: 4.6%), respectively, while for wide lesion excision, the rates were 86.1% (SE: 0.9%), 76.9% (SE: 1.2%), and 60.9% (SE: 2.0%), respectively.
For patients who underwent treatment with narrow margin excision, survival rates were similar as for those treated with wide lesion excision, with 3-, 5-, and 10-year survival rates of 84.8% (SE: 1.4%), 78.3% (SE: 1.7%), and 60.8% (SE: 3.6%), respectively.
On multivariable survival analysis, Mohs surgery was associated with significantly improved survival, compared with wide lesion excision (hazard ratio, 0.594; P = .038). This was also true after multivariable analysis for patients who had one or more NCCN risk factors, for whom improved survival was also seen with Mohs (HR, 0.530; P = .026).
The results did not differ after a sensitivity analysis that included T3 and T4 tumors.
Given that the use of Mohs was so infrequent, compared with standard surgery, the researchers investigated the factors that were associated with the use of Mohs. High-volume MCC centers were significantly more likely to utilize Mohs than wide lesion excision (odds ratio, 1.993; P < .001), compared with other facilities.
“This study has important implications going forward,” Dr. Cheraghlou concluded. “We think it’s important how few patients were treated with Mohs for Merkel cell, and it was slightly more likely to happen in a high-volume center.”
The reasoning for that may be that high-volume centers are more likely to have a surgeon trained to perform Mohs surgery for MCC. “Or perhaps they are more attuned to the benefits of this procedure,” he said. “We can’t tell that from our data, but its notable that it’s such a small proportion of patients – especially when we consider that it is associated with improved survival for the patients who receive it.”
He added that efforts to increase the utilization of Mohs may yield improved local control and overall survival for these patients. “And perhaps with more data, future versions of guidelines may indicate a preference for Mohs over conventional incisions.”