|
 Researchers found the highest rates in Hawaii and on the East and
West coasts, but also in a few landlocked states, such as Vermont
and Minnesota, according to the results published in the
International Journal of Cancer.
"Overall, even in states with a lower burden of cancer, the numbers
are still high," said the study's lead author, Dr. Farhad Islami,
director of surveillance research at the American Cancer Society.
"As previous research has shown, over 90% of those cancers are from
UV and the main source of that is exposure to the sun and indoor
tanning. So essentially, most of them are preventable."
Islami and his colleagues found melanoma rates ranged from 15 cases
per year in Alaska to 65 per year in Hawaii and attributed the
differences to a combination of factors, including the strength of
the sun's rays, variations in the amount of time people spent in
outdoor activities and the use of indoor tanning salons.
To get a sense of how melanoma rates might have changed over time
and how they might vary from place to place, the researchers first
sought to establish a baseline by looking at the number of melanomas
recorded between 1942 and 1954 by the state of Connecticut, which
established the first statewide population-based cancer registry in
the U.S.
Islami and his colleagues assumed that most of the melanomas
recorded in Connecticut in the early 40s and 50s would not be
related to sun exposure because of the state's more northern
latitude and because melanomas diagnosed in that time period would
reflect sun exposure accumulated in the 1930s or earlier, when
clothing styles offered more complete skin coverage. That meant that
the Connecticut numbers could work as a stand-in for minimal UV
exposure, Islami said.
For more recent melanoma statistics, the researchers turned to a
U.S. database of newly-diagnosed cancer cases, focusing on melanomas
reported between 2011 and 2015.
After comparing recent melanoma rates to those from the Connecticut
baseline, and accounting for patient age, the researchers found that
94.3% of cases were among non-Hispanic white people, and that UV
exposure could explain 91% of the total between 2011 and 2015, or
338,701 of 372,335 cases nationwide.
Overall, melanoma rates are lowest among people with darker skin,
and among black people in the U.S. the incidence is 1 case per
100,000 population, while among Hispanic people the rate is 4.5 per
100,000 and among non-Hispanic whites it's 27 per 100,000, the study
team notes.
[to top of second column] |
To avoid capturing variations in the incidence of melanomas that
were due to differences in state racial makeup, the researchers
focused on rates among non-Hispanic whites and found that multiple
states along the East and West coasts had UV-attributable incidence
rates exceeding 25 per 100,000. Delaware came in at 37.1 per
100,000; Georgia, at 36.5; California at 33.8; Maryland at 32.6;
North Carolina at 29.5; Florida at 29.2; Oregon at 28.5; South
Carolina at 28.1; Washington at 27.8; New Jersey at 27.7 and New
Hampshire at 26.5.
Rates were also above 25 per 100,000 in several inland states: Utah
came in at 40.4 per 100,000; Vermont at 31.4; Minnesota at 27.9;
Idaho at 27.6 and Kentucky at 25.7.
"People in many states located on the East and West coasts tend to
go to the beaches," Islami said. "In states like Utah, people spend
a lot of time skiing or engaged in other outdoor activities."
While the new study is interesting and underscores the importance of
minimizing UV exposure, it does make a number of assumptions, said
Dr. Laura Ferris, an associate professor of dermatology at the
University of Pittsburgh School of Medicine and director of clinical
trials for UPMC dermatology.
First, the authors are assuming that only sun exposure has changed
over the years and that residents of Connecticut in the 30s weren't
getting much sun - that probably doesn't apply to farmers and other
people working outside, Ferris said. Second, the authors are
assuming that people spent their entire lives in the state in which
they were diagnosed, she added.
Third, although the authors acknowledge the possibility that doctors
are more tuned in to the possibility of melanoma now and are thus
diagnosing more, it's not clear what impact melanoma screening has
had on diagnosis rates, Ferris said. "If you look at other cancers,
the rates are always higher in groups that get screened."
SOURCE: https://bit.ly/37C6PPg International Journal of Cancer,
online February 17, 2020.
[© 2020 Thomson Reuters. All rights
reserved.] Copyright 2020 Reuters. All rights reserved. This material may not be published,
broadcast, rewritten or redistributed.
Thompson Reuters is solely responsible for this content. |
