World-wide skin cancer epidemiology
Although the data concerning the epidemiology of skin cancer worldwide is limited, one expert says that dermatologists appear to be making a difference in melanoma, particularly in younger individuals, offering a beacon of hope in the fight against skin cancer.
“I do think what we are seeing is the curve bend in younger people, and I believe that is largely a result of the dermatologic community’s effect through public education. How much of that is primary prevention and how much is early detection remains unclear. Nevertheless, something is working in younger people and we need to figure out what that is, and sustain it,” says Allan C. Halpern, M.D., Chief of the Dermatology Service at Memorial Sloan-Kettering Cancer Center, New York.
Although melanoma is the least common among all skin cancers, it is associated with the highest mortality. The best epidemiological data worldwide that currently exists comes through the United States, Australia, and the UK; there is some data from the rest of the world as well, however not as robust. There is a rising incidence of melanoma over the past 50 years and according to Dr. Halpern, the currently available data shows that melanoma incidence varies significantly across the world, and it is essentially a problem of the Caucasian population especially in North America, Australia, and New Zealand.
According to Dr. Halpern, the U.S. data shows that the significant rise in incidence of melanoma is much higher than the rise in mortality. In addition, Dr. Halpern says that the actual number of people in the United States with a personal history of melanoma (also known as melanoma prevalence) is very significant (estimated to be about 1 million individuals), likely because the majority of people over the last decades with melanoma have had their melanomas caught in the early stages, allowing for an early therapeutic intervention.
Melanoma mortality in the United States is also on the rise and more so in males than in females, but the real key here Dr. Halpern explained, is that it is rising very differently among age groups.
“In younger male and female individuals under 55 years of age, we’ve actually seen melanoma mortality come down recently,” Dr. Halpern says. He recently spoke at the Skin Cancer Foundation’s 16th World Congress on Cancers of the Skin, Vienna, Austria.
According to Dr. Halpern, although melanoma mortality between 55-65 years of age is still going up, this trend is slowly settling. Above 65 years of age however, mortality is still rising but much more dramatically in men than women. Nevertheless, inroads have been made in the fight against melanoma Dr. Halpern says, possibly most reflective in the lower mortality rates seen among younger individuals.
“We are not seeing the difference at the population based level yet and in fact, it is likely going to get worse in the short term because of the baby boomer generation aging, as well as melanoma in males over 55 being a dramatically increasing problem. However, while over the next couple of decades the incidence of melanoma is going to continue to increase, there is real progress here and the hope is that the progress that we are seeing in young people is going to play out over time,” Dr. Halpern says.
One of the biggest challenges for dermatologists over the next couple of decades looking forward will be confronting the rapidly rising mortality in melanoma patients over 55 years of age. Perhaps the best way to meet this challenge is primarily through early detection because for those people prevention is still important but for most of them, Dr. Halpern says, the horse is already out of the barn.
“Part of the solution here is understanding that the 55 and above age group represents a very different community that needs to be reached. This is a patient population that is inherently more engaged with the health care system, so we should take better advantage of such opportunities to better educate and care for this population in terms of melanoma and melanoma prevention,” Dr. Halpern says.
Unfortunately, the data on non-melanoma skin cancer (NMSC) is less optimal, he says. This may be because NMSC is so common and less likely to lead to mortality that very few places are trying to keep track of the data. This is a huge and growing problem that needs to be addressed going forward and not surprisingly, the incidence of NMSC is going up among the sparse data that has been collected.
“What we do not have for NMSC is great trend data by age group, so we do not know if we are bending the curve here. One important way that this alarming trend could be reversed is through stepped up efforts in primary prevention,” Dr. Halpern says.
This would include very important lifestyle and behavioral pattern changes of individuals such as employing appropriate sun protection when exposed to natural light, as well as avoiding the artificial ultraviolet light from tanning beds all together. According to Dr. Halpern, the message is identical for melanoma and NMSC regarding primary prevention and sun exposure whereas for early detection, one looks for different lesion characteristics. Since, the overwhelming majority of detection right now is not by physicians but by patients, the early detection messaging is appropriately more focused around melanoma.
Nevertheless, increased efforts must be made to detect all types of skin cancers, especially in a time where the world’s population is increasing in longevity. The aging of the population has huge implications in the optimal management of skin cancer patients long-term, Dr. Halpern says, especially for NMSC where the numbers have steadily risen to alarming heights.
According to Dr. Halpern, one of the major current central themes of cancer screening is that while no specialist has lost the enthusiasm for the importance of early detection to save lives from cancer, the whole world of cancer screening has become much more conscious of the concept of over-diagnosis. The concept of over-diagnosis addresses the fact that there are cancers that are inherently indolent to us (i.e. basal cell carcinoma), or even if the cancer is not that indolent, the patient will not die because of that cancer but instead because of another disease process associated with advanced age. As such, finding every one of those cancers early could be viewed as a harm unimagined.
“The harder you look for cancer, the bigger the risk that you are going to find these indolent cancers, and the harder you look for cancers in people with a limited life expectancy, the more likely you are to find cancers that in fact are not going to play out in their natural lifetime. This detection pressure could potentially lead to over-diagnoses. Dermatologists need to recognize and be conscious of this risk as they try to improve the detection of melanoma and skin cancer overall,” Dr. Halpern says.
Disclosures: Dr. Halpern reports no relevant disclosures.