Prevalence of anorectal mucosal melanoma (ARMM) has increased. In addition, use of immunotherapy to treat the disease has also increased, over an 11-year period, results from a retrospective study has shown. This study was published in the World Journal of Surgery.
Mucosal melanomas in general, and ARMM in particular, represent rare forms of melanoma with very poor prognoses. The main objectives of this study were to investigate the prevalence of this disease and discern whether specific management practice trends exist.
The National Cancer Database (NCDB), a nationwide, hospital registry, clinical oncology database jointly sponsored by the American College of Surgeons and the American Cancer Society, was interrogated for cases of ARMM captured during the period from 2004 to 2015. Information on patient demographic characteristics, socioeconomic status, comorbidities, treatments, and clinical outcomes, as well as hospital and tumor characteristics (ie, size and nodal status) were collected.
A retrospective analysis of the 1333 cases of ARMM included in the NCDB showed a significant increase in prevalence of the disease from 2004 (6.99%) to 2015 (10.53%; P <.001) when the denominator was all 1333 cases of ARMM included in the cohort.
With respect to types of treatment administered, 48.77%, 11.75%, 8.68%, and 8.68% were treated with surgery alone, surgery with radiation, surgery with immunotherapy, and surgery with chemotherapy, respectively. Although consistent use of chemotherapy and radiation therapy was observed across the study time period, corresponding increases were seen for both surgery (7.18% to 9.76%; P <.01) and immunotherapy (7.24% to 21.27%; P< .001). The increase in surgery use was gradual; however, the increase for immunotherapy use started in 2013 and was sharp.
A total of 221 patients with ARMM received immunotherapy, representing 16.93% of the ARMM cohort. After adjustments for confounding factors, younger age (eg, 50 to 59 years vs 80 years and older; P <.001), positive nodes (P <.01), and larger tumor size (eg, 5 cm or larger compared with smaller than 3 cm; P =.03) were found to be independent predictors of immunotherapy use.
For patients receiving immunotherapy, overall survival (OS) at 2 and 5 years were 43.57% and 20.50%, respectively, and median OS was 19.35 months. Two-year OS was significantly improved for patients receiving immunotherapy vs not (49.21% vs 42.47%; P =.03), but percentages of patients alive at 5 years were not significantly different for the 2 groups.
Some study limitations recognized by the study authors include the absence of data on tumor grade or stage, and no detail on the subtype or dosage of the immunotherapeutic agents administered.
“A change in paradigm in the management of ARMM is necessary in an attempt to improve survival,” the authors concluded, suggesting that “personalized molecular analysis should be performed to identify patients with specific genetic mutations that might be an appropriate target for immunotherapeutic agents or specific target therapies, which have shown promise in early clinical trials.”
Taylor JP, Stem M, Yu D, et al. Treatment strategies and survival trends for anorectal melanoma: is it time for a change? [published online March 4, 2019]. World J Surg. doi: 10.1007/s00268-019-04960-w