Hypothesised cutaneous sites of origin of stage III melanomas with unknown primary: A multicentre study. Issue 3 (25th April 2022)

• Record Type: Journal Article
• Authors: Clayton, Bethan; Muneeb, Ferhan; Hughes, Maria Celia B.; Grant, Megan E.; Khosrotehrani, Kiarash; Smithers, B. Mark; Spina, Romina; Campana, Luca G.; Oudit, Deemesh; Green, Adele C.
• Is Part Of: International journal of cancer. Volume 151:Issue 3(2022)
• Page Start: 396
• Page End: 401
• Publication Date: 2022-04-25
• Subjects: anatomic site -- body sites -- cutaneous melanoma -- melanoma -- unknown primary; Cancer -- Periodicals; Cancer -- Prevention -- Periodicals; 616.994
• DOI: 10.1002/ijc.34020
• Languages: English
• ISSNs: 0020-7136

Abstract

Abstract: Based on molecular evidence that melanomas with unknown primary (MUPs) arise from the skin, we hypothesised that sites of MUPs are disproportionately on trunk and lower limbs, sites that are not readily visible to patients and clinicians. We tested this hypothesis by inferring the anatomic site of origin of MUPs from the corresponding known cutaneous sites of melanoma patients with known primary tumours (MKPs). We analysed data from three separate cohorts of patients from Brisbane, Australia (n = 236); Manchester, UK (n = 51) and Padova, Italy (n = 33), respectively, who first presented with stage III melanoma with lymph node metastases. We matched two MKP patients to each MUP patient based on lymph node dissection (LND) site, age and sex, and imputed cutaneous sites of origin of MUPs from their two matched MKPs for study countries, giving two possible sites for each MUP per centre. Overall, results showed that MUP patients were predominantly male, and trunk was the most likely origin, comprising around a third to a half of MUPs across the three cohorts. The remaining MUP inferred sites varied by country. In the Australian cohort, the legs accounted for a third of imputed sites of MUPs, while in the UK and Italian cohorts, the most frequent site was the arms followed by the legs. Our findings suggest the need for regular and thorough skin examination on trunk and limbs, especially in males, to improve early detection of cutaneous melanoma and reduce the risk of metastatic disease at the time of presentation. Abstract : What's new? Molecular evidence points to the cutaneous origin of melanomas with unknown primary (MUPs). However, whether regressed or overlooked melanomas on specific cutaneous locations are associated with MUPs remains unclear. Assuming a skin origin, the authors imputed the likely sites of origin of stage III MUPs from the corresponding cutaneous sites of matched patients with known primary melanoma. The trunk was the most likely origin of MUPs, followed by the limbs, with males being more affected. The findings underscore the need for thorough skin examination of the trunk and limbs, especially in males, to reduce the risk of MUPs.