Skin Cancer Overdiagnosis in White Americans Is Increasing, Study Says

According to a recent study published in BMJ Evidence-Based Medicine, the overdiagnosis of skin cancer among White American patients has been significantly increasing over time.

Increasing Rates Model | image credit: Monster Ztudio

From 1975 to 2016, the prevalence of cutaneous melanoma in the US has grown drastically from 8.3 to 49.1 cases per 100,000 people. The authors of the present study note that, despite the growing frequency of cutaneous melanoma diagnoses, mortality rates have not changed over this time period. With the rise of these cases, some concern has emerged regarding the overdiagnosis of melanoma—especially considering the harm associated with overtreatment.

“Quantifying the frequency of overdiagnosis is important for policy makers, health care providers, and patients to make judgements about the potential harms and benefits of screening,” the authors wrote.

Ideally, estimating cancer overdiagnoses would be extrapolated from randomized control trials (RCTs) that include long-term follow-up after individual screenings; however, these types of RCTs are lacking in melanoma research. A promising method that was successfully implemented in Australia utilized a plethora of observational data to assess present and past lifetime risk of being diagnosed with melanoma. To fill in this gap on American patients, researchers applied this method to draw estimations about the likelihood of melanoma overdiagnosis in the US.

This analysis only included White patients due to the higher rates of developing melanoma, melanoma-related mortality, and likelihood of undergoing screening for cutaneous melanoma (and thus being misdiagnosed) this population experiences. Overdiagnosis was estimated by subtracting the proportion of clinically relevant cancers from the total amount of detected cancers in a population.

Data were gathered from the National Cancer Institute’s Surveillance, Epidemiology and End Results (SEER) database to determine incidences of cutaneous melanoma (invasive and in situ). Nine registry databases were used, spanning data between 1975 and 2018. To estimate the potential misdiagnosis of melanoma across the entire US population in 2018, data were also gathered from the US Cancer Statistics Public Use Database.

Results showed that the lifetime risk for melanoma diagnosis between 1975 and 2018 rose from 3.2% to 6.4% for White men and from 1.6% to 4.5% for White women. According to the researchers’ estimation, the rates of overdiagnosis in 2018 for White men and women were 49.7% and 64.6%, respectively. In total, these figures represent 43,709 men and 38,943 women, 7848 and 11,050 of whom experienced an overdiagnosis of melanoma that year.

In this same period, in situ melanoma rates grew from 0.17% to 2.7% in White men and 0.08% to 2.0% in White women. Researchers estimated that overdiagnosis occurred in 89.4% and 85.4% of White men and women, respectively. These percentages total out to 35,961 and 27,893 men and women who experienced a melanoma in situ overdiagnosis.

The lifetime risks for melanoma diagnosis for White men and women in 2018 were an estimated 3.2% and 2.9%, respectively.

To conclude, the authors emphasized the importance of identifying such a large proportion of individuals who experienced a melanoma in situ diagnosis. This result points to a future avenue of focus for intervention efforts in skin care. More attention is warranted for the estimation of skin cancer diagnosis because, they added, this issue is multifactorial and the consequences of overdiagnosis have physical, economic, and psychological ramifications.

Reference

Adamson AS, Naik G, Jones MA, Bell KJ. Ecological study estimating melanoma overdiagnosis in the USA using the lifetime risk method. BMJ Evid Based Med. Published online January 19, 2024. doi:10.1136/bmjebm-2023-112460