Independent association of sex, age and the melanoma subtype with histological regression in invasive melanomas: A retrospective study

Background Histological regression represents an immunologic host response and has been associated with better prognosis in cutaneous melanoma. Objective To investigate the independent association of clinicopathological features associated with histological regression in the subgroups of localized (stage I/II) and stage III invasive melanomas. Methods This was a retrospective study of Greek patients in the European Association of Dermato-Oncology (EADO) database, with invasive melanomas of the nodular melanoma (NM) or superficial spreading melanoma (SSM) subtype. Results In a total of 561 cases, histological regression was present in 160 (28.5%). The median age of patients was 53 years old and 47.6% were males. Most melanomas were stage I and II (87.2%) and 59% were thin (Breslow ≤1 mm). There were 78.6% SSM and 21.4% NM. In multivariate logistic regression analysis, in the subgroup of stage I and II melanomas, age older than 50 years (OR: 1.67 95% CI: 1.09–2.55) and male sex (OR: 1.92, 95% CI: 1.26–2.92) were independent predictors associated with the presence of regression. In addition, the nodular subtype (versus SSM) was an independent factor less likely associated with the presence of regression (OR: 0.49, 95% CI: 0.25–0.96). Breslow thickness > 1.0 mm (OR: 1.16, 95% CI: 0.71–1.88) and localization were not significantly associated with regression. In stage III melanomas, older age was significantly associated with the presence of regression, while the nodular subtype was less likely to be independently associated with presence of regression. Conclusions In our study, male sex, age and nodular subtype were independently associated with histological regression. These results suggest possible sex- and subtype-related differences in the immunological responses in melanomas, warranting further studies.