Visual Examination For Skin Cancer

Visual Examination for Skin Cancer

Pamela A. Popper, President

Wellness Forum Health

The only justification for cancer screening programs is that they should reduce the risk of dying of the particular cancer for which the screening test is used. Enthusiasm for cancer screening is based on the idea that if cancer is found early, when it is more treatable, the risk of death is lower.

At this time, only one screening test has been shown to deliver this result – pap tests that screen for cellular changes that can lead to cervical cancer. In every country in which pap testing has been instituted, the death rate from cervical cancer has dropped – significantly.

Many other screening tests have become “routine,” but there is no evidence that use for population screening reduces death rates. For example, colonoscopy has some value as a diagnostic tool, but not as a means for reducing death from colorectal cancer. The Canadian Task Force on Preventive Health Care removed it from the list of standard screenings several years ago.[1] A recent large randomized controlled trial showed that colonoscopy did not reduce the risk of developing colorectal cancer, death from colorectal cancer, or risk of all-cause mortality.[2] 

The data is even worse for prostate cancer screening: the chance of benefit is extremely low, while the risk of being harmed is at least 30 times higher.[3]

What about skin cancer screening? It’s summertime, and people are outside in the sun more regularly. Many doctors and the sunscreen industry promote the false idea that almost any sun exposure is a risk factor for skin cancer, and regular visual examinations are encouraged. There is no evidence that this is reducing death rates, but not only dermatologists, but also family practice docs and internists are looking for skin cancer. The US Preventive Services Task Force recommends against this practice because it has led to more diagnoses but without any change in the death rate. It is estimated that 4000 excisions are required to prevent one death from melanoma. Additionally, specialists (dermatologists) have no better track record than general practice docs in finding early-stage cancer.[4]

The belief in early detection as a means for reducing death remains high despite these data, and one company has developed a direct-to-consumer screening app with the idea that people can examine themselves and find cancer. Perhaps artificial intelligence might be better than doctors?

Well, not so much. A study presented at the European Academy of Dermatology and Venereology showed that the consumer app incorrectly classified Merkel Cell Carcinomas as low risk 17.9% of the time, and a particular type of melanoma was categorized as low risk 22.9% of the time. Nearly two-thirds of benign lesions (62.2%) were classified as high risk. This means that if widely used, most people with harmless moles and lesions would be told they had serious cancer who did not – exactly the problem with other cancer screening programs.

You might think that in response to this dismal result, the dermatologists would lose enthusiasm for this app. You would be wrong. Full speed ahead. It just needs more work and development, was the conclusion.[5]

Bottom line: Before agreeing to any cancer screening test, make sure it has been proven to reduce the risk of dying from cancer.


[1] https://canadiantaskforce.ca/guidelines/published-guidelines/colorectal-cancer/ accessed 7.31.2019

[2] Bretthauer M, Loberg M, Wieszcry P et al. “Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death.” NEJM https://www.nejm.org/doi/full/10.1056/NEJMoa2208375

[3] Turini G, Gjelsvik A, Renzulli J. “The State of Prescreening Discussions About Prostate-specific Antigen Testing Following Implementation of the 2012 United States Preventive Services Task Force Statement.” Urology 2017 Jun;104:122-130

[4] Bibbins-Domingo K, Grossman D, Curry S et al (USPSTF members). “Screening for Skin Cancer: US Preventive Services Task Force Recommendation Statement: US Preventive Services Task Force.” JAMA. 2016;316(4):429-435.

[5] Skin Cancer App Fails to Identify Rare, Aggressive Cancers. Oct 15 2021 https://www.practiceupdate.com/c/125242/2/1/?elsca1=emc_enews_daily-digest&elsca2=email&elsca3=practiceupdate_onc&elsca4=oncology&elsca5=newsletter&rid=MTM1MTQ0NTcxMjk3S0&lid=20844069