After decades of growth efforts to reverse melanoma epidemic intensify

In April, researchers from the Mayo Clinic in Rochester, Minn., published a study that indicated rates of melanoma had increased eightfold among young women and fourfold among young men since the 1970s.

Dozens of mainstream media outlets picked up on the single-center study, and the “dramatic” rise in melanoma incidence — particularly among women aged 18 to 39 years — dominated the headlines.

However, the fact that melanoma rates were on the rise — and that there had been considerable spikes in incidence among certain population groups — was not news to those in the melanoma community.

Oncologists, epidemiologists and dermatologists have known about the increase for years. Although the incidence rates for some of the most common cancers — such as prostate, lung, colorectal, bladder and cervical — decreased between 1999 and 2008, the incidence of melanoma increased an estimated 45% between 1992 and 2004. Among whites, melanoma incidence has increased more than 60% during the past 30 years, according to the NCI.

“If you look at overall US data for melanoma, there is no question the incidence rate has increased,” Alan Geller, MPH, RN, told HemOnc Today. “It has been increasing essentially since they started keeping this data in 1935, and if you look at it over a long period of time, we are talking about a multifold increase in incidence rate across all ages and both genders.”

Geller, senior lecturer at Harvard School of Public Health, and several other experts in the field of melanoma spoke with HemOnc Today about what some are calling the melanoma “epidemic,” who is most at risk, the possible causes behind it and what can be done to reverse the trend.

Young women, high risk

The overall rise in melanoma incidence is of tremendous concern to those who treat skin cancer, but experts recognize certain populations require increased and immediate attention.

According to SEER data taken from 1992 to 2005, melanoma incidence among non-Hispanic whites remains more than five times higher than that of any other race/ethnicity, and it is estimated to be 10 times higher than that of blacks. Adolescent and young adult women also are experiencing exponential increases in melanoma rates. Rates for whites are at least 20 times those for blacks.

In the Mayo Clinic study, Reed and colleagues identified patients aged 13 to 39 years who were diagnosed with their first melanoma between 1970 and 2009 in Olmsted County, Minn. Their findings indicate the incidence of melanoma in this population was 5.4 per 100,000 person-years between 1970 and 1979, and 43.5 per 100,000 person-years between 2000 and 2009.

“Melanoma is increasing faster than anything else we have seen in oncology,” Jerry D. Brewer, MD, a dermatologist at the Mayo Clinic in Rochester, Minn., and a researcher on the Olmsted County study, told HemOnc Today. “Young white women are getting [melanoma] eight times more often now than in 1970, and although the word epidemic is overused in medicine, it would be accurate to call this rise an epidemic.”

In this population of younger women, data seem to indicate that early-stage thin melanomas comprise a larger percentage of overall incidence. A meta-analysis by Norgaard and colleagues looked at studies published between 2005 and 2010 that discussed melanoma incidence. Most research articles they evaluated found a greater increase in thin melanomas than thick melanomas, except in older patients.

Mortality of middle-aged men

Despite the dramatic increase in incidence among young women, they are only one of two groups that have experts concerned.

“Incidence is increasing in young women, but they are not at a higher risk for dying,” said Marianne Berwick, PhD, MPH, chief of the division of epidemiology, biostatistics and preventive medicine, and associate director for population science at the University of New Mexico Cancer Center. “It is still older men at high risk for mortality due to melanoma.”

SEER data suggest the incidence of melanoma among white men increased by an estimated 8.9% per year since 2003. In addition, melanoma is one of only three cancers — the others being liver and esophageal cancer — for which the mortality rates are increasing among men.

Finally, in contrast to young women, the Norgaard meta-analysis found that thick melanomas were more commonly diagnosed in older populations, particularly men.

However, Geller said he worries that the differences in mortality between these age groups may only be short-lived.

“For young women, it appears that a greater proportion of late-stage melanoma is now being diagnosed compared with earlier data,” Geller said.

In addition, an early diagnosis of melanoma — which typically has cure rates in the 90th percentile — may not be as safe as previously anticipated.

In 2011, Jemal and colleagues published a study in the Journal of the American Academy of Dermatology that examined melanoma incidence and mortality trends in 12 cancer registries within SEER from 1992 to 2006. They stratified the data by age and sex, as well as by tumor thickness.

Their results indicated that incidence of melanoma in non-Hispanic whites was increasing across all tumor thickness categories. Among those aged at least 65 years, the rate of thick tumors increased almost as much as thin tumors. From 1998 to 1999 — and from 2004 to 2005 — data indicated that melanoma deaths attributed to thin lesions increased from 24% to 31% in men and remained constant in women at 27%.

Possible causes

There are several potential causes for the increase in incidence.

Some early research has looked at the role of heavy metal exposure, or exposure to polychlorinated biphenyls, Berwick said. Other investigators are trying to determine why the rates of melanoma incidence are not increasing as much in middle-aged and older women, and the possibility of a protective effect of estrogen.

Genetic factors also play a role in incidence, Brewer said. They include having blonde or red hair, blue or green eyes, or a high number of moles.

“Having said that, genetics is just one of many factors that contribute to development of melanoma,” Brewer said. “The other things are things that we can control, such as sun exposure.”

During the past few decades, lifestyles have changed for most of the population.

People spend more recreational time in the sun than they did in the 1950s and 1960s, said Sanjiv S. Agarwala, MD, chief of oncology and hematology at St. Luke’s Cancer Center in Bethlehem, Pa., and a HemOnc Today Editorial Board member.

“The sun is our friend and gives us a lot of good things, but we have to be careful,” Agarwala said. “Given the sedentary indoor lifestyle adopted by much of working society, we are not designed to be in the shade all the time and then go into the sun.”

Recreational sunbathing and beach tanning have grown in popularity as the culture has adopted a “sun-kissed” look as a measure of beauty. In addition, the advent of air travel has expanded access to tropical climates and made it easier to vacation in sunny destinations.

“Thirty or 40 years ago, we didn’t have that,” Geller said. “We now have an expanded opportunity to spend more unprotected time in the sun in locations like Florida, Arizona or the tropics.”

Indoor tanning

Cumulative sun exposure may explain the increasing incidence of melanoma among older men. However, many in the field suggest the increase among young women is directly related to indoor tanning. Prior research on the associations between melanoma and indoor tanning has found that females aged 16 to 29 years account for about 70% of tanning salon patrons.

“There are other recent reports about tanning beds that suggest that if you go to a tanning bed on a regular basis your chances of melanoma are 74% higher,” Brewer said.

These data have led to increasing restrictions on indoor tanning use among teens. As many as 36 states have at least some restrictions on tanning in this age group. Several states — including Vermont, New York, New Jersey and California — have passed or are considering passing legislation that bans those aged younger than 18 years from using indoor tanning beds.

“We have to educate the public on the risk of tanning beds,” Agarwala said. “Young people are getting exposed to dangerously high and ultra-concentrated levels of UV light in these tanning beds.”

The Indoor Tanning Association — which represents manufacturers, distributors and facility owners — issued a press release that called those states’ actions a “slippery slope.”

“The Indoor Tanning Association believes that the decision regarding whether or not a teen is allowed to suntan is a decision for parents, not government,” the association said in a press release. “Proponents of these laws always exaggerate the risks of exposure to ultraviolet light in order to get the attention of the public, the media and the government.  It is a fact that ultraviolet light from a sunbed is the same as that from the sun, and regular, moderate, non-burning exposure is essential for good health.”

Reversing the trend

As efforts intensify to slow and, ultimately, reverse the trends of melanoma incidence, the US population and the country’s public policymakers could learn a great deal from the Australians, said John M. Kirkwood, MD, co-leader of the University of Pittsburgh Cancer Institute’s melanoma program and a HemOnc Today Editorial Board member.

“Sun-smart behavior and solar sunbathing prohibitions in society have been around since the 1980s in Australia, where there is a very pale and often freckling type complexion population,” Kirkwood said.

The Cancer Council Australia launched its “Slip! Slop! Slap!” program in 1980, and it has come to be considered one of the country’s most successful health campaigns. The program encourages everyone to slip on a shirt, slop on sunscreen and slap on a hat.

“This program reaches out to kids at an early age with the help of a cartoon character, called Sid the seagull, who is more well known in Australia than, for example, Bert and Ernie in our country,” Geller said.

Public education about sun avoidance and proper sun protection is vital to changing behavior, Geller and Kirkwood said.

The use of good sun barriers — such as wearing hats and long sleeves — and providing shade in recreational areas such as school yards are good first steps. Another is widespread wise application of the current best-generation sunblocks, which include titanium dioxide and zinc oxide.

“Regardless, this isn’t something that once it begins, we will see a dip in statistics within a year,” Kirkwood said. “It is something that clearly has a window of years between adoption of sun-smart behavior and a population reduction in the incidence of melanoma and non-melanoma skin cancers.”

However, public education is only half the battle. Increased focus and attention on melanoma within the health care community also are essential, Geller and Kirkwood said.

“If everybody were more attuned to looking at skin, you could remove atypical moles before they become melanoma,” said Geller, who suggests every doctor who sees a patient perform a quick skin exam of at least the back, or at a minimum question patients about moles they may have noticed.

“In the same way that we wouldn’t think of an examination of a woman being complete without a breast exam, we have to begin to think about our largest organ, our skin,” Kirkwood said. “[It] must become part of the routine exam of our patients, especially among medical oncologists, internists and general practitioners.” – by Leah Lawrence

Should sun exposure be encouraged or discouraged as a method of vitamin D production?

Sensible sun exposure should be encouraged.

Humans have always depended on the sun for their vitamin D requirement. The amount of sunlight it would take to make vitamin D does not increase risk for melanoma or nonmelanoma skin cancer. More importantly, most melanomas occur on the least sun-exposed areas. In addition, research has shown that occupational sun exposure decreases your risk for melanoma.

The major causes of melanoma are being redheaded, having a large number of moles on your body, bad genetics, and the number of sunburning experiences as a teenager and young adult. To imply that sensible sun exposure, which has been essential for our vitamin D requirement, increases risk for melanoma is not true.

Unfortunately, in the United States, the conservative part of the dermatology community will not compromise on this issue. Representatives from this community recommend avoiding all sun exposure your entire life, which — in my opinion — does not make sense.

In Australia, which has very public and widely accepted sun protection messaging, 40% of the population is now vitamin D deficient. It is thought that this deficiency may be due, at least in part, to the country’s “Slip! Slop! Slap!” sun protection campaign. Now, the Australian Dermatology Society is recommending sensible sun exposure. 

I define sensible sun exposure as having arms and legs — as well as abdomen and back, when possible — exposed to an amount of sunlight that is about 50% of the time it would take to get a minimal erythemal dose (light pinkness to the skin 24 hours after exposure). That is approximately 10 to 15 minutes of sun exposure between 10 a.m. and 3 p.m., the only times of the day your body can efficiently make vitamin D. I then recommend wearing good sun protection — either covering the skin with clothing or applying a broad-spectrum sunscreen with SPF 30 — thereby taking advantage of the beneficial effect of the sun while preventing damaging effects from excessive exposure.

A healthy level of vitamin D has been shown to help reduce the risk of a variety of chronic illnesses, including type 1 and type 2 diabetes, multiple sclerosis, infectious diseases, heart disease and some cancers. Because of the potential health benefits of vitamin D, I recommend a three-part process for preventing vitamin D deficiency. That includes some sensible sun exposure, dietary sources of vitamin D and vitamin D supplementation.

Always avoid sunburn, which is most damaging to the skin and increases risk for both nonmelanoma and melanoma skin cancers.

Michael F. Holick, PhD, MD, is director of the Vitamin D, Skin and Bone Research Laboratory at Boston University Medical Center, and the author of The Vitamin D Solution. Disclosure: Dr. Holick reports no relevant financial disclosures.

 

Deliberate sun exposure should be discouraged as a method of vitamin D production.

In the United States, milk was fortified with vitamin D to prevent the latitudinal and seasonal vitamin D deficiency that naturally occurs. Although the optimal level of 25-hydroxyvitamin D is not established, 30 ng/mL to 40 ng/mL is a reasonable target for adequate levels. An individual practicing effective sun protection may require 1,000 to 2,000 IU per day to achieve levels of 30 ng/mL to 40 ng/mL. The quantity of skin exposed, the darkness of skin pigmentation, the time of year and latitude influence vitamin D synthesis. Although it is difficult to consume sufficient vitamin D from typical diets, oral supplements and intermittent testing of blood levels during seasons with low ambient sunlight would appear to be a reasonable course of action.

Skin cancer is caused by exposure to ultraviolet radiation — a  known carcinogen — which is in the same category as cigarettes, mustard gas and arsenic. Melanoma and squamous cell carcinoma are preventable with regular adequate sun protection by those at risk to develop skin cancer. Patients at high risk for skin cancer because of phenotypic characteristics — fair skin, freckling and tendency to sunburn — as well as those who live in or visit sunny climates, or who have a family history of melanoma or cutaneous squamous cell carcinoma, should routinely practice sun protection. This recommendation applies to those in locations with relatively high levels of ambient sunlight, such as Arizona, California and Florida, and those living in temperate climates who often vacation in sunny places.

Regular adequate sun protection means habitual use of sun protection to prevent burning as a child, as a teen, and as an adult. What is a little bit pink or a little bit red skin? It is a sunburn! Sunburn is prevalent with about 50% of adults, and 65% of whites aged 18 to 29 years reporting at least one sunburn in the past 12 months. A little bit of carcinogenic exposure repetitively over several years is too much risk.

In 2012, there will be more than 76,000 new invasive melanoma cases in the United States and more than 9,000 deaths. Since 2004, incidence rates of invasive melanoma among whites have increased almost 3% per year in both men and women. In the United States, invasive melanoma is the fifth-leading cancer in men and the sixth in women. In the United States, there will be an almost equal number of new cases of melanoma in situ in 2012.

If physicians send mixed messages about sun exposure, then people will become confused about the importance of practicing sun protection to reduce their risk of deadly, disabling or disfiguring skin cancer. Urging patients to take vitamin D dietary supplements and monitor their blood levels seems to be a better use of health resources than treating skin cancer.

June K. Robinson, MD, is a research professor of dermatology at Northwestern University Feinberg School of Medicine in Chicago. Disclosure: Dr. Robinson reports no relevant financial disclosures.