People who undergo skin screening subsequently experience higher rates of biopsies (aHR 1.85, 95% CI 1.69-2.04) and melanoma (aHR 1.29, 95 CI 1.02-1.63), especially for in situ melanoma.
Clinical Pearls
This study investigated the possible overdiagnosis of melanoma by comparing subsequent melanoma incidence and biopsy rates among patients subjected to skin screening compared to those who were not
The authors observed 967 first-incident melanomas (381 invasive) during 197,191 person-years of follow-up
The higher risk of melanoma diagnosis associated with skin screening was evident for in situ melanoma (aHR 1.45, 95% CI 1.09–1.92) but not invasive melanoma (aHR 1.05, 95% CI 0.72–1.54)
People who undergo skin screening subsequently experience higher rates of biopsies (aHR 1.85, 95% CI 1.69- 2.04) and melanoma (aHR 1.29, 95% CI 1.02-1.63), especially for in situ melanoma
Discussion:
While the incidence of cutaneous melanoma is found to be increasing in many populations, there is concern that elevated diagnostic scrutiny is leading to overdiagnosis and detection of indolent melanomas that may otherwise never become clinically apparent in a patient’s lifetime. Subsequent overdiagnosis may lead to overtreatment and inefficient use of our healthcare system, patient harm, and inflated costs. In order to investigate the potential of this phenomenon, the authors conducted a prospective cohort study to explore the incidence and clinical course of cutaneous melanoma.
The QSkin study sample was a prospective cohort study containing 43,762 men and women aged 40–69 years in 2010–11. Two analyses were performed, the primary exposure analysis investigated melanoma diagnosis and biopsies after primary exposure (skin examination prior to baseline) and the secondary exposure analysis evaluated patients who had skin biopsy in first year of follow-up. After exclusion criteria were applied, 38,682 patients were included in the primary analysis and 35,825 patients were included in the secondary analysis.
The primary outcome of the study was incident, histologically confirmed melanoma (invasive and in situ combined) diagnosed in years 2–7 after enrollment and the secondary outcome consisted of one or more skin biopsies in years 2–6 after enrollment. At baseline, 72.8% of patients reported skin examination by a doctor in the 3 years before enrollment and 9.2% of patients had at least one skin biopsy. Results displayed significantly higher rates of melanoma (aHR 1.29,95% CI 1.02–1.63) and subsequent biopsies (aHR 1.85, 95% CI 1.69–2.04) in those who had undergone physician skin examination prior to enrollment. Using the secondary definition of screening, authors observed about 2.6-fold higher rates of skin biopsies in subsequent years (2–6 years of follow-up) in the screened when compared to the unscreened populations, after adjusting for all known confounders.
The results of this study indicate that using two different definitions of skin screening and after considering known risk factors, patients undergoing physician-based screening for skin cancer have melanoma detection rates at least 29% higher than those not undergoing screening. These findings suggest that heightened surveillance leads to a proportion of melanomas being diagnosed that otherwise may not have come to clinical attention.
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