Risk of second primary in situ and invasive melanoma in a Dutch population-based cohort: 1989–2008

Authors


  • Funding sources
    This study was funded by the Dutch Cancer Society (KWF). The increasing burden of second primary cancers in the Netherlands: trends in incidence, survival and causes-of-death since 1970 (EMCR 2008–4132).

  • Conflicts of interest
    None declared.

Robert J.T. van der Leest.
E-mail: r.vanderleest@erasmusmc.nl

Summary

Background  Patients with melanoma are at increased risk of developing a subsequent melanoma.

Objectives  To estimate the risks of developing a second primary in situ or invasive cutaneous melanoma after a first melanoma, between 1989 and 2008.

Methods  Patients were followed until diagnosis of a second melanoma, date of death or end of study. Cumulative risks, standardized incidence ratio (SIR, observed second melanomas divided by background age-, calendar- and sex-specific incidence rates of melanoma, as recorded in the Netherlands Cancer Registry) and absolute excess risk (AER, observed minus expected per 10 000 person-years) of second melanomas were calculated.

Results  In total, 10 765 patients with in situ melanoma and 46 700 with invasive melanoma were included. The cumulative risks of a second invasive melanoma after a first in situ or invasive melanoma at 20 years of follow-up were 6·2% and 5·0%, respectively. The relative risk of developing any melanoma (in situ or invasive) after any first melanoma (measured as SIR) varied from 12·4-fold [invasive after invasive melanoma; 95% confidence interval (CI)  = 11·6–13·2] to 26·4-fold (in situ after in situ melanoma; 95% CI = 22·6–30·7) increase compared with the general population. SIRs and AERs remained elevated up to 20 years after the first melanoma.

Conclusions  This study shows significantly increased long-term risks (both relative and absolute) of developing a second invasive melanoma after a first melanoma (invasive and in situ), and might serve as a basis for follow-up guidelines.

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