Among patients with T1a-T2a invasive melanoma excised with Mohs micrographic surgery (MMS), those treated at academic and higher-volume facilities had improved long-term survival compared with those treated at other facilities, as reported by researchers in JAMA Dermatology.
The retrospective cohort study included 4062 adult patients from the National Cancer Database (NCDB) who were diagnosed with nonmetastatic, T1a-T2a melanoma from 2004 to 2014 and treated with MMS at 462 centers. Patients had an overall median age of 60 (SD 16.3) years; 2213 (54.5%) were men, and 3913 (96.3%) were non-Hispanic White.
Top decile–volume facilities (TDVFs) were defined as having an average case volume more than 8 cases per year, corresponding to the 90th percentile of facilities. All other institutions were considered low-volume facilities (LVFs). Overall survival was the primary outcome.
Of the 462 total treatment facilities, 127 (27.5%) were considered academic institutions and treated 2305 (56.8%) of the patients; 62 (13.4%) of the centers were TDVFs and treated 2513 (61.9%) of the patients. Most (37 [59.7%]) of the TDVFs were academic institutions. The median facility case volume was 3.71 (interquartile range [IQR], 2.00-9.87) at academic centers and 1.75 (IQR, 1.29-2.90) at nonacademic centers (Wilcoxon rank-sum test, P <.001).
The annual case volume for LVFs ranged from 1.00 to 7.82, with a median of 1.80 (IQR, 1.33-3.00). For TDVFs, the annual case volume was 8.00 to 127.29, with a median of 15.7 (IQR, 10.5-26.25).
Patients who were treated at academic centers were significantly older than those treated at nonacademic centers (median [SD], 64 [12.8] years vs 53 [18.1] years; Wilcoxon rank sum test, P <.001). Also, patients treated at TDVFs were older than those treated at LVFs (62 [16.0] years vs 58 [16.4] years, respectively). A total of 417 deaths occurred and the median follow-up was 4.45 years, with a maximum follow-up of 12.90 years (IQR, 2.48-7.04 years).
Regression models including facility type showed that MMS treatment at academic facilities was associated with significantly improved overall survival compared with treatment at nonacademic facilities, with about a 30% reduction in deaths (hazard ratio [HR], 0.730; 95% CI, 0.596-0.895). Treatment at TDVFs also was associated with improved survival compared with treatment at LVFs (HR, 0.795; 95% CI, 0.648-0.977).
A sensitivity analysis that excluded all patients without confirmed clinically negative lymph node disease status also showed improved survival for patients treated at an academic facility compared with those treated at a nonacademic facility (HR, 0.713; 95% CI, 0.555-0.916; P =.008). Treatment at TDVFs did not have a statistically significant association with improved outcomes (HR, 0.828; 95% CI, 0.643- 1.067; P =.14).
The researchers noted that they were unable to control for use of immunohistochemical stains to evaluate MMS sections because of the lack of data. Also, outcomes in the data set were reported as all-cause survival and did not include information on local recurrence or disease-specific survival. Furthermore, the NCDB is a hospital-based registry, which limited the generalizability of the findings to community settings.
“This study noted significant interfacility variation in overall survival after MMS for early-stage invasive melanoma,” the study authors commented. “…Strategies aimed at creating more uniform treatment practices may help to improve overall patient survival for this procedure across centers,” they concluded.
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