Skin cancer screening is not backed by current research

Wernli KJ, Henrikson NB, Morrison CC et al. Screening for skin cancer in adults: Updated evidence report and systematic review for the US Preventive Services Task Force JAMA. 2016;316:436-437

Review question

Does screening for skin cancer decrease the number of deaths caused by skin cancer?  How accurate is skin cancer screening and what harms can it cause? Does screening help detect skin cancer earlier and does earlier detection reduce deaths?

Background

Skin cancer is one of the most common cancers affecting men and women. Certain skin cancers, especially melanomas, can lead to very poor health outcomes, including death. Some doctors screen all patients for skin cancer by visually examining their skin for suspicious spots (called visual skin cancer screening), in hopes of detecting skin cancer early. However, previous research has failed to show that the benefits of screening outweigh the harms.

How the review was done

This is a review of 13 studies conducted from 2000 to 2012, including a total of 88 088 223 participants. All the studies were of fair or good quality, but none were randomized control trials.

• All participants were 15 years and older and from developed countries, including Germany, Australia and the USA.
• In some studies, participants underwent skin cancer screening by having their skin partially or fully examined by a family doctor, dermatologist or plastic surgeon. Results were compared to comparison groups who were not screened for skin cancer to determine whether screening was able to identify cases of cancer.
• In some studies, researchers then measured the number of people who died due to skin cancer. Other studies measured the harms of screening (number of unnecessary skin excisions) and accuracy of skin cancer screening (did screening accurately identify a case of skin cancer). Additional studies looked at whether screening allowed skin cancer to be detected earlier and whether earlier detection reduced deaths.

What the researchers found

In one fair quality study, people screened for skin cancer were less likely to die from melanoma than those who were not screened. Another study showed that screening allowed melanomas to be detected earlier – which, according to a number of studies, might decrease one’s risk of dying.

Some studies found that screening done by dermatologists and plastic surgeons, rather than family physicians, was more accurate. Of the people who screened positive and received skin biopsies, only 1 in 22 to 44 people actually had cancer. Screening and associated biopsies were not without harms – in one study, 7.1% of people felt their biopsy sites had a poor appearance.

Conclusion

There is some limited, poor quality evidence to suggest that screening for skin cancer may reduce deaths and allow for earlier detection of skin cancer. These findings are not enough to prove that the benefits of screening outweigh the harms, as the accuracy of skin cancer screening was not high. More high quality research is needed to study the impact of skin cancer screening, as well as to see if screening might be more effective in people who have a high risk of developing skin cancer.