NEW YORK (Reuters Health) – A longitudinal surveillance program that included skin-cancer screening and education about self-exams was associated with significantly thinner and earlier-stage melanomas at diagnosis in members of melanoma-prone families, according to a new study.
“Tumor thickness, which measures how deep the tumor grows beneath the surface of the skin, is associated with an increased risk of death from melanoma. The thicker the tumor, the higher the risk,” Dr. Michael Sargen of the National Cancer Institute (NCI), in Rockville, Maryland, told Reuters Health by email.
Although melanoma thickness at initial diagnosis has been declining generally in the United States, statistical modeling showed that this did not fully account for the new findings, Dr. Sargen and his colleagues report in Cancer Epidemiology, Biomarkers and Prevention.
The researchers looked at data from a longitudinal familial-melanoma study begun by the NCI in 1976. Families were eligible for the study if they had two (later, three) first-degree relatives with melanoma.
On enrollment and at later in-person visits, study participants received whole-body screening for melanoma, educational materials about melanoma prevention and early detection, and strategies for protecting their skin from ultraviolet damage. Participants, all of whom were white, were also counseled to follow up with their local dermatologists annually for whole-body screening exams.
Minimum follow-up was five years.
Out of 56 families and 1,319 individual study participants, 293 developed invasive melanoma, with 600 confirmed melanomas. The current analysis separated these patients into a pre-study group of 246 who were diagnosed before joining the study and a prospective group of 47 who were diagnosed after joining.
Data from Surveillance, Epidemiology, and End Results cancer registries (white patients only) were used to compare the general U.S. population with the NCI study cohort. Mean age at first melanoma diagnosis was 38 years in the NCI cohort and 55 in the SEER cohort (P<0.001).
Among the NCI prospective group, melanomas were significantly likelier to be T1 stage (83%) than among the pre-study cases (40%). Similarly, mean Breslow thickness in the prospective group was 0.6 mm versus 1.1 mm in the pre-study group (P<0.001).
Findings were similar for individuals with and without the CDKN2A and CDK4 melanoma-susceptibility genes, the team notes.
They say it’s unknown if the decreasing melanoma thickness within NCI families is associated with improved survival. However, the proportion of T1 cases, which are associated with a five-year survival of 99%, was increased in the prospective group, “suggesting that the trends in thickness may improve melanoma-specific survival in this high-risk population.”
Of note, the two individuals in the NCI cohort who developed the most primary melanomas had used tanning beds.
Dr. Sargen commented, “Anyone concerned about melanoma should discuss the benefits and frequency of screening with their healthcare provider,” taking into account such factors as “family history of disease, the absence or presence of gene variants that predispose to melanoma, UV exposure history, and clinical risk factors such as fair skin, red hair, freckling, and atypical (also known as dysplastic) moles.”
It’s unclear why melanoma thickness at diagnosis in the general U.S. population has been decreasing since 1973, when the United States started tracking these data, he added. The trend likely results from several factors, Dr. Sargen said, including increased skin cancer screening and public-health campaigns educating people about the appearance of early melanoma lesions.
Dr. Sancy A. Leachman, chair of the department of dermatology at Oregon Health and Science University, in Portland, told Reuters Health by email, “This paper bridges an important information gap” in the latest U.S. Preventive Services Task Force skin-cancer-screening guidelines.
Those guidelines “suggest that screening for high-risk populations is warranted, but provided little guidance with respect to specific populations that should be considered high-risk,” said Dr. Leachman, who was not involved in the new work. “This paper shows that the hereditary melanoma population is one of the high-risk populations that will benefit.”
The study was funded by the NCI. One of the six co-authors disclosed personal fees from Myriad Genetics outside the submitted work.
SOURCE: https://bit.ly/3uGNybd Cancer Epidemiology, Biomarkers and Prevention, online April 2, 2021.
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