Spindle cell melanoma: Incidence and survival, 1973-2017

Abstract

Spindle cell melanoma (SCM) is a rare morphological subtype of melanoma, which is relatively uncharacterized. The aim of the present study was to investigate the incidence of SCM, its general demographics, basic clinico-pathologic features, treatment outcomes and disease-specific prognostic factors. SCM cases were sampled from the Surveillance, Epidemiology and End Results (SEER) Program (1973-2017). A total of 4761 SCM cases were identified, with a median age of 66 years. The female:male ratio was 0.62:1. Statistically significant overall survival (OS) and disease-specific survival (DSS) rate differences were identified depending on age, sex, ethnicity, tumor location, T stage, N stage, M stage, pathological grade, AJCC stage, SEER stages and surgical treatment (P<0.05). Multivariate Cox regression analysis revealed that age >66 years, T3+T4 stage disease, positive N stage and SEER historic stage of regional and distant metastasis tumor were associated with poor DSS and OS rates. In summary, SCM was most common in Caucasian people of 60~80 years of age with a predominance in males. Patient's age, ethnicity, T stage, N stage, and SEER historic stage were identified as independent prognostic factors of SCM in terms of DSS and OS.

Keywords: epidemiology and end results; incidence; prognostic factor; spindle cell melanoma; the surveillance.

Figure 1.

The age and sex distribution of spindle cell melanoma cases.

Figure 2.

Overall survival curves of patients with spindle cell melanoma compared according to (A) age, (B) sex, (C) tumor location, (D) ethnicity, (E) AJCC stage, (F) T stage, (G) pathological grade, (H) N stage, (I) treatment, and (J) M stage. The log-rank test was utilized to compare the curves. AJCC, American Joint Committee on Cancer; T, tumor; N, node; M, metastasis.

Figure 3.

Disease specific survival curves of patients with spindle cell melanoma compared according to (A) age, (B) sex, (C) pathological grade, (D) AJCC stage, (E) ethnicity and (F) T stage, (G) tumor location, (H) M stage, (I) treatment and (J) SEER stage. The log-rank test was utilized to compare curves. AJCC, American Joint Committee on Cancer; T, tumor; N, node; M, metastasis; SEER, Surveillance, Epidemiology and End Results.