The dramatic advances in targeted therapies for late-stage melanoma capture the headlines, but a recent Australian study quietly concluded thataccording to , a dermatologist and director of clinical trials in the department of dermatology at the University of Pittsburgh.
“I think it’s really important that we recognize the importance of preventing skin cancer, and not just early detection, not just treatment of late disease,” Dr. Ferris said at a virtual forum on cutaneous malignancies jointly presented by Postgraduate Institute for Medicine and Global Academy for Medical Education.
She highlighted the Australian cost-effectiveness, which used Markov modeling of data from two published population-based, randomized controlled trials carried out in Queensland, Australia.
The cost-effectiveness study compared the estimated long-term impact of three different approaches to control of melanoma: a primary prevention strategy, which basically consisted of promoting daily sunscreen use and other forms of sun protection; early detection through annual whole-body skin examinations by physicians starting at age 50; and no intervention. The analysis provided estimates of the number of cases of melanoma, deaths caused by melanoma, nonmelanoma skin cancers, and quality of life outcomes over the course of 30 years starting in 50-year-old men and women.
Primary prevention through sun protection was the clear winner, as shown by the results:
- A 44% reduction in the incidence of melanoma, compared with early detection via annual physician skin examinations.
- A 39% reduction in projected melanoma deaths compared with early detection, which in turn achieved only a 2% reduction when compared with no intervention.
- 27% fewer keratinocyte cancers excised than with annual skin examinations.
- A 21.7% reduction in societal costs, compared with an early-detection program.
Daily sunscreen use for primary prevention was also associated with a modest 0.1% increase in quality-adjusted life-years. “Prevention is low cost, low risk, and effective,” Dr. Ferris observed.
The investigators noted that, while residents of the Australian state of Queensland are mainly fair-skinned and confront high UV radiation levels throughout the year, somewhat limiting the generalizability of the study findings, the relationships between the costs of interventional strategies and their outcomes should be proportional in other countries.
True enough, but a strategy of annual skin examinations starting at age 50 years as modeled in the Australian study is not the most productive way to conduct a melanoma early-detection program, Dr. Ferris said. She noted that data from the National Cancer Institute’s Surveillance, Epidemiology, and End Resultsshow that the median age at diagnosis of melanoma in the United States is 65 years, while the median age at death caused by the malignancy is 71 years. That information is helpful in formulating strategies to improve early detection through more focused, higher-yield screening.
Case in point: European investigators have estimated that, by screening everyone age 50 years and older, 475 people need to be screened and an average of 19.6 lesions must be biopsied in order to detect one melanoma. But by reserving screening for those age 50 years and up who have any one of three risk factors – a personal history of melanoma, atypical nevi, or at least 40 common nevi – those numbers drop dramatically: 98 people need to be screened and 13.5 lesions biopsied to detect one melanoma. And by further narrowing the screened population to those age 65 years or older with any of the three risk factors, 63 seniors would need to be screened and 9.2 lesions excised to find one melanoma.
Total-body skin examinations are time-consuming for dermatologists. In a recent U.S., investigators determined that the additional face-to-face time required per skin cancer detected by doing a total-body skin exam in adults who present to a dermatologist for another reason is 4.5 hours. And that’s just the time involved in detecting any type of skin cancer.
“To get that number for melanoma, multiply by 15 to 20,” Dr. Ferris said.
The investigators also determined that, for each decade of advancing age and increment in lighter skin phototype, the number-needed-to-examine in order to identify one skin cancer of any type decreased.
“By focusing on patients who are older and have fair skin types we can get that time down to about 1 hour,” commented Dr. Ferris, who penned anon the study.
While many dermatologists recommend that people with a high common nevus count undergo frequent screening for melanoma because they are at particularly high risk for invasive disease, a couple of recent studies challenge that notion, she pointed out. One was a retrospectiveof 326 consecutive new melanoma patients which found that patients with a higher nevus count had thinner melanomas and a greater likelihood of in situ melanoma. Patients who presented with invasive melanoma had a mean total nevus count of 31.5 lesions, while those with in situ melanoma averaged 57.2 nevi. Each additional nevus was associated with a 4% reduction in the likelihood of invasive melanoma, independent of age and sex.
The otherincluded 566 newly diagnosed melanoma patients in two U.S. centers. Among the 56% of patients who were younger than 60 years, those who had more than 50 total nevi were 68% less likely to have a thick melanoma in a logistic regression analysis that controlled for demographic factors, as well as anatomic location of the melanoma, histologic subtype, and skin cancer screening frequency. In contrast, younger patients with more than 5 atypical nevi were 2.43-fold more likely to have thicker melanomas than were those with no such lesions. The lesson, according to the investigators, is that total nevus count isn’t a reliable determinant of a patient’s risk status or the need for skin examinations.
Dr. Ferris reported no financial conflicts of interest regarding her presentation.
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