Follow-up Examination on the Worldwide Increase in Malignant Melanoma: 3 Questions with Neel Helvind, MD

MD Magazine recently reported on a study in JAMA Dermatology pointing to an alarming increase in the worldwide incidence of malignant melanoma (MM). The study, conducted in Denmark, shows that the incidence of MM has doubled during the past 25 years, despite targeted awareness campaigns and a focus within the dermatology community on early detection and treatment.

In a recent e-mail interview, study co-author Neel Maria Helvind, MD, from the Department of Plastic Surgery, Breast Surgery, and Burns, University Hospital Rigshospitalet, Copenhagen, Denmark, answered some questions and shed additional light on the study results.

MD Magazine: You note in the study that the increase in MM incidence is most likely NOT simply the result of greater awareness leading to overdiagnosis. This is an important finding. Why do you think this misperception persists, and can you offer some thoughts on how dangerous this can be?

Dr. Helvind: We believe that the increasing incidences of malignant melanoma and in situ melanoma in Denmark are a true phenomenon. We base this conclusion upon our findings of increasing incidences in not only thin and pre invasive melanomas, but also in thick and intermediate malignant melanoma (>1.00 mm Breslow thickness) and the fact that Danish mortality rates have not declined, which would be expected if the increasing incidences were solely caused by greater awareness and increased diagnosis of thin, less clinically harmful lesions.

Also, we noted that the increase in incidence of malignant melanoma was especially pronounced in areas prone to intermittent UV-radiation and in the population older than 60 years of age, who have most likely received a large amount of harmful UV-radiation because they have had the financial freedom to travel on sun-vacations at a point in time when there was little focus on the harmful effects of UV-radiation. This is in line with the etiology of malignant melanoma and supports the theory of a true increase in incidence. Furthermore, the histopathological criteria of melanoma diagnostics have not changed over the study period, and the task of diagnosing has been handled by a small group of specialist pathologists in centralized melanoma centers, which ensures as high a degree of consensus as possible, limiting the risk of diagnostic drift.

However, we also see an effect of secondary preventions leading to increased awareness and early diagnosis, as the relative amount of thin and in situ lesion and the relative 5-year survival increase over time. The truth is that we are probably seeing a mixed picture and it is therefore not entirely accurate to call it a misconception. The danger lies in denying the component of a true increase in incidence, since this could lead to diminished efforts in secondary prevention and consequently delayed diagnosis with more progressed cancers as a result.

MD Magazine: Do you have any insights as to why the mortality rate of MM has remained stable in the US and in Spain but continues to rise elsewhere?

Dr. Helvind: In general, we believe that the quality of the Danish, American and Spanish health care systems, databases, primary and secondary preventions is comparable. Thus the difference cannot be written up to confounding factors but perhaps rather depends on genetic and geographical differences between our populations. In Denmark, we have a relatively larger population of Fitzpatrick skin types one and two (fair skin, freckles, blond or red hair, does not tan well), which makes us relatively more disposed for developing melanomas. Also, the temperatures and UV-index in Denmark is relatively lower for a large part of the year. This makes us more prone to intermittent UV-radiation, as we wear covering clothing from September to June and then expose our skin to sudden UV-radiation when travelling or during our relatively short summers.

MD Magazine: Studies have shown that men are more likely than women to never use sunscreen, and I suspect men may also be more reluctant to seek early treatment for visible marks. Are there awareness efforts in Denmark that focus exclusively on the male population? If not, should there be?

Dr. Helvind: There are not.

In Denmark, the focus of primary preventions has primarily been changing sun habits such as shade-seeking and more covering clothing. We put less emphasis on the use of sunscreen than many other countries, among other things because people often use sunscreen incorrectly (they apply too little too infrequently) and neglect to seek shade or cover their skin when using sunscreen, even though sunscreen cannot offer full protection at mid-day.

It is true that there is a larger amount of thick melanomas and higher mortality in the male population, indicating later diagnosis in men, perhaps due to patient’s delay, but the incidence of malignant melanoma in Denmark has consistently been slightly higher for women than for men throughout the study period. This indicates that women have the same, if not a slightly higher, risk of developing malignant melanoma as men. Thus, we believe that our resources in primary prevention are best spent divided equally between the sexes, but if the relative amount of thick malignant melanomas and mortality continues to increase in men, male-targeted secondary preventions to increase awareness further and bring down patient’s delay could be considered.

MD Magazine: Thank you, Dr. Helvind.