Abstract 1930: Trends of invasive and in-situ melanoma diagnosis in the U.S

Abstract

Abstract Melanoma, accounts for about 4% of skin cancer cases, but is associated with 79% of skin cancer deaths. The number of new cases of melanoma in the US is rising dramatically. The incidence of in-situ melanoma is increasing at a more rapid rate than for melanoma overall. This may be due to better awareness, improved screening techniques and access to dermatologists that result in early diagnosis of melanoma. There is also concern that over the last few years, pathologists have had a lower threshold to diagnose in-situ melanoma due to medico-legal reasons. However, the lesions that are being called in-situ melanoma are most certainly severely dysplastic (atypical) nevi that are considered melanoma precursor lesions. The distinction is important to make an accurate diagnosis when providing medical care to a patient. We investigated the trend of diagnosis and melanoma invasive versus in situ in three national prospective cohorts of women and men: Nurses’ Health Study I (1976-2008, age at enrollment 30-55), Nurses’ Health Study II (1989-2007, age at enrollment 25-42), and Health Professionals Follow-up Study (1986-2008, age at enrollment 40-75). We accrued 940 invasive and 424 in situ cases in NHS I, 447 invasive and 326 in situ cases in NHS II, and 310 invasive and 153 in situ cases in HPFS. In each cycle of 2-year follow-up, the incidence rate of melanoma steadily increased, and the increased incidence rate of in-situ melanoma was substantially greater than invasive melanoma. These trends were similar in all three cohorts. The ratio of invasive and in-situ melanoma in each cycle 2-year follow-up decreased more than 5 folds over the follow-up period in the NHS I and II. The decrease was not apparent in HPFS. In this study, we found that in-situ melanoma incidence has continued to rise in the US in the last few decades, especially among women where the rate of in-situ melanoma increased more sharply compared to invasive melanoma incidence. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1930. doi:10.1158/1538-7445.AM2011-1930