Effect of surgical treatment for anorectal melanoma: a propensity score-matched analysis of the Surveillance, Epidemiology, and End Results programme data

Abstract

ObjectiveAnorectal melanoma (AM) is a rare but aggressive tumour with limited information in the existing literature. This study aimed to assess the effect of surgical treatment for AM and predict the prognosis of affected patients.DesignA retrospective cohort study.SettingData of patients diagnosed with AM between 1975 and 2016 in the USA were collected from the Surveillance, Epidemiology, and End Results (SEER) database.ParticipantsThis study enrolled a total of 795 patients with AM from the SEER database and the validation cohort comprised 40 patients with AM enrolled from Chinese institutes.Primary and secondary outcome measuresOverall survival (OS) and AM-specific survival (AM-SS).ResultsA total of 795 patients with AM diagnosed between 1975 and 2016 were enrolled in this study. Data over the past four decades showed a trend of increase in incidence rate. A nomogram based on a multivariate Cox regression model was generated to predict AM-SS. The C-index of the nomogram was 0.74 (95% CI 0.71 to 0.77) on internal verification. In the validation cohort, the C-index of the nomogram was 0.72 (95% CI 0.68 to 0.76). The results of propensity score matching (PSM) analysis showed that patients who underwent surgical treatment achieved significant survival (OS: log-rank=17.41, p<0.001; AM-SS: log-rank=14.55, p<0.001). Patients who underwent surgery were stratified into local and extended surgery subgroups. AM-SS and OS were also compared after PSM, but the results were not significantly different between the two surgery subgroups (all p>0.05).ConclusionsThe nomogram based on the analysis of SEER data showed good performance in predicting OS and AM-SS. Patients with AM can benefit from surgery; however, extensive surgery and appendectomy may not improve AM-SS or OS.

A rare case of a primary malignant anorectal melanoma

“…The authors observed that despite the slightly better 5-year survival rate of LE (32% vs 23%), a statistically significant reduction in recurrence was found in APR group (OR=0.15; 95% CI: 0.08-0.28, p<0.00001) 9 . Lei et al 11 analyzed 795 ARM patients from the USA Surveillance, Epidemiology, and End Results (SEER) database. A nomogram based on a multivariate Cox regression model was generated to predict ARM-Specific Survival.…”

Prognostic models based on lymph node density for primary gastrointestinal melanoma: a SEER population-based analysis

“…ER refers to tumour resection and LN removal, and LR refers to tumour resection without LN dissection. Two studies based on the SEER database showed that compared with LR, ER did not increase the survival rate of patients with primary melanoma of the AM,24 25 even with confounding variables controlled 25. However, patients having regional metastasis with LN density less than 20% may gain benefits with ER.…”

Anorectal melanoma

“…22,23 Furthermore, several retrospective studies demonstrate no survival benefit for APR compared to LE, (Tables 2 and 3). 2,[4][5][6][7][8][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] Thus, in the absence of any demonstrable survival benefit, APR is now discouraged for the treatment of anorectal melanoma whenever technically feasible.…”

“…Prognosis of early cutaneous melanoma is relatively favorable with 5‐year survival rates of 99.5%, 70.6%, and 31.9% for localized, regional, and distant cutaneous melanoma, respectively 1 . Anorectal melanoma is a rare subtype of melanoma and accounts for only 1% of all melanoma diagnoses and 25% of mucosal melanomas in the United States; however, its incidence is increasing 2–5 . Despite the excellent general prognosis for localized cutaneous melanoma and recent improvements seen in survival for patients with distant metastatic disease, the outcomes for most patients with anorectal melanoma remain poor.…”

“…Two retrospective reviews of 96 and 47 patients did not find a statistically significant difference in survival between anal and rectal primary tumor sites. 7,8 However, in a 2022, SEER-based analysis of 765 patients with anorectal melanoma by Lei et al 5 rectal melanoma was identified as having a worse melanoma-specific survival than anal melanoma.…”