Single versus multiple primary melanomas

Abstract

BACKGROUND:In patients with multiple primary melanomas (MPM), mean tumor thickness tends to decrease from the first melanoma to the second melanoma, and prognosis may be improved compared with the prognosis for patients who have a single primary melanoma (SPM). In this study, the authors compared the clinicopathologic features of patients with MPM and SPM to better characterize the differences between these 2 groups and to determine whether or not there is an inherent difference in tumor aggression. METHODS: In total, 788 patients with melanoma who were enrolled prospectively in the Interdisciplinary Melanoma Cooperative Group database from 2002 to 2008 were studied. Patients with SPM and with MPM were compared with regard to clinical and primary melanoma characteristics. RESULTS: Of 788 patients with melanoma, 61 patients (7.7%) had 2 or more primary melanomas. The incidence of developing a second primary melanoma 1 year and 5 years after initial melanoma diagnosis was 4.1% and 8.7%, respectively, and most of the risk accumulated within the first year. The incidence of MPM was greater in patients aged !60 years than in those aged 60 years. The absence or presence of mitosis and other tumor characteristics did not differ significantly between patients with SPM and patients with MPM (P ¼ .61). CONCLUSIONS: No difference was observed in the presence or absence of mitoses, a marker of tumor proliferation, in SPM and MPM. Because it has been demonstrated that the presence of mitosis is a powerful prognostic marker, the current findings suggested that the tumors behave similarly in patients with SPM and patients with MPM. The authors concluded that differences in tumor thickness and prognosis between SPM and MPM more likely are caused by factors other than tumor biology, such as increased surveillance. Cancer 2012;118:4184-92.

Skin protection behaviour and sex differences in melanoma location in patients with multiple primary melanomas

“…In 35% of patients the second melanoma was diagnosed within 1 year of the diagnosis of the first melanoma (see Table 3), which is similar to previous reports. 5,6 This lower Clark level for subsequent melanomas and the increased detection of a subsequent melanoma in the first year is likely to be due to both increased physician's examination and patients' selfexamination. The lower Clark level of subsequent melanomas may also reflect improved sun-protection and sunscreen usage by these patients.…”

“…1 Significant risk factors for the development of melanoma include the number of common naevi, a positive family history of melanoma, age over 60 years, dysplastic naevus syndrome and atypical naevi. [3][4][5][6][7] Other factors such as fair skin or eye colour, increased freckling and number of sunburns are also important risk factors for the development of skin cancer. 8,9 The regular use of sunscreen can reduce the rate of squamous cell carcinoma (SCC) and melanoma development.…”

Survival for Patients With Single and Multiple Primary Melanomas

“…8 Another study investigated whether a less aggressive biology in MPM, represented by mitotic rate, was a possible explanation for the generally thinner lesions in MPM and SPM but concluded that it was not and that other factors such as increased surveillance or genetic constitution probably contribute. 10 …”

“…That similar mitotic rates have been observed for SPM and MPM suggests little difference in underlying biologic aggressiveness between SPM and MPM lesions. 10 …”

“…9 Additionally, the possibility that both initial and subsequent melanomas are thinner in MPM than SPM has given rise to speculation that MPM may be biologically different from SPM. 2,10 …”