Melanoma of the hand and foot: epidemiological, prognostic and genetic features. A systematic review

Background While early recognition and prognosis of melanoma as a whole have improved, particular forms of rarer, under-recognized or more severe tumours require increasing attention. Among them, melanomas located on the hand and/or foot (hand and foot melanoma, HFM) have been the subject of few and heterogeneous studies, with variable and sometimes confusing results, and have not been targeted to date by comprehensive literature reviews. Objectives To perform a formal, systematic review of the literature, focusing on epidemiology, risk factors, prognosis and genetic characteristics of HFM. Methods All data sources were identified through searches on Medline, Scopus and Cochrane databases. Articles were selected and evaluated according to predefined quality criteria. Results Among 1185 articles screened for relevance, 37 met the inclusion criteria. Data analysis brought to light important particularities of IIFMs: they are rare in all ethnic groups of developed countries, but have been insufficiently studied in the developing world. About half are of the specific acral lentiginous melanoma (ALM) subtype. Previous trauma and naevi on the soles/toes were identified as two main risk factors in case control studies. Genetic or environmental factors other than sun exposure are likely to play a role but require further investigation. Compared with melanoma at other sites, their prognosis is poor mainly as a consequence of later diagnosis, but possibly also because of an intrinsic negative effect of the HFM/ALM subtype. Standard prognostic factors of melanoma have been insufficiently validated to date in HFM. Finally, their molecular genetic: particularities could lead to specific targeted therapies in the near future. Conclusions Overall, HFM could represent a particular subgroup of rare, potentially severe melanomas, requiring specific management from their prevention up to their treatment.