Mohs Micrographic Surgery Outcomes Associated with Treatment Facility Factors

Improved long-term survival was associated with academic centers and top decile-volume facilities (TDVF) for patients with invasive melanoma who were treated with Mohs micrographic surgery (MMS), according to findings from a retrospective cohort study published in JAMA Dermatology. But there is a lack of data on whether facility-level factors influence its effectiveness, and research of other cancer resections has shown a correlation between facility-level factors and patient outcomes; academic affiliation and case volume are the 2 most established variables.

Investigators analyzed data from the National Cancer Database (NCDB) on cases of T1a-T2a invasive melanoma diagnosed from 2004 to 2014 and treated with MMS. Facilities with an average MMS-treated melanoma case volume of 8 or more per year, corresponding with the 90^th percentile of facilities, were considered TDVFs; all others were considered low-volume facilities (LVFs). Investigators used the Commission on Cancer accreditation system to determine academic affiliation of the cancer centers. The primary outcome was overall survival.

Of the 4,062 patients in the final survival analysis (mean age 60 years, SD 16.3), 45.5% were women, 96.3% were non-Hispanic White, 92% had no comorbidities, and 57.7% had private insurance. Most tumors (77.4%) were less than 0.8 mm and without ulceration (96.7%), and 78.5% of patients had confirmed clinically negative lymph node disease status.

Of the 462 facilities analyzed, 27.5%  were defined as academic institutions and 13.4% as TDFVs. Patients at academic centers were significantly older (median age 64 years, SD 12) than those treated at nonacademic centers (median age 53 years, SD 18.1) (P <.001). There was a similar, although less pronounced, age discrepancy between TDVFs and LVFs (median age 62 years, SD 16 vs. median age 58 years, SD 16.4 ). Head and neck tumors were more common at academic vs nonacademic centers (48.6% vs 26.9%; P <.001) and TDVFs vs LVFs (47% vs 26.4%; P <.001). Lentigo maligna melanoma tumors comprised more of the cases at academic vs nonacademic centers (20.1% vs 8.8%; P <.001) and TDVFs vs LVFs (81.3% vs 74%; P <.001), and nodal staging was reported more often by academic vs nonacademic centers (79.7% vs 77%; P =.04) and TDVFs vs LVFs (81.3% vs 74%; P <.001).

Multivariable survival analyses of the 4,062 patients showed that treatment at academic facilities was associated with a nearly 30% reduction in the hazard of death compared with nonacademic facilities (hazard ratio [HR], 0.730; 95% CI, 0.596-0.895). Treatment at TDVFs vs LVFs was associated with improved survival (HR, 0.795; 95% CI, 0.648-0.977). In a sensitivity analysis that excluded all cases without confirmed clinically negative lymph node disease status, patient survival was improved at academic vs nonacademic centers (HR, 0.713; 95% CI, 0.555-0.916; P =.008) but there was no significant improvement in survival at TDVFs vs LVFs (HR 0.828; 95% CI, 0.643-1.067; P =.14).

As investigators reported outcomes as all-cause survival and did not include information on local recurrence or disease-specific survival, they were unable to analyze the association between these outcomes and facility characteristics. In addition, the NCDB only reports hospital-based data which prevented investigators from including community settings in the study, and some academic centers do not report their data to the NCDB either.

“Further study of the underlying differences in survival, as well as the development of consensus standards for [MMS], may help to reduce such variations in patient outcomes across treatment centers” for T1a-T2a invasive melanoma, the study authors concluded.

Reference

Cheraghlou S, Christensen SR, Leffell DJ, Girardi M. Association of treatment facility characteristics with overall survival after mohs micrographic surgery for T1a-T2a invasive melanoma. JAMA Dermatol. Published online March 31, 2021. doi:10.1001/jamadermatol.2021.0023