Efficiency of Detecting New Primary Melanoma among Individuals Treated in a High-risk Clinic for Skin Surveillance

Abstract

Importance: A previous single-center study observed fewer excisions, lower health care costs, thinner melanomas, and better quality of life when surveillance of high-risk patients was conducted in a melanoma dermatology clinic with a structured surveillance protocol involving full-body examinations every 6 months aided by total-body photography (TBP) and sequential digital dermoscopy imaging (SDDI). Objective: To examine longer-term sustainability and expansion of the surveillance program to numerous practices, including a primary care skin cancer clinic setting. Design, Setting, and Participants: This prospective cohort study recruited 593 participants assessed from 2012 to 2018 as having very high risk of melanoma, with a median of 2.9 years of follow-up (interquartile range, 1.9-3.3 years), from 4 melanoma high-risk clinics (3 dermatology clinics and 1 primary care skin cancer clinic) in New South Wales, Australia. Data analyses were conducted from February to September 2020. Exposures: Six-month full-body examination with the aid of TBP and SDDI. For equivocal lesions, the clinician performed SDDI at 3 or 6 months. Main Outcomes and Measures: All suspect monitored or excised lesions were recorded, and pathology reports obtained. Outcomes included the incidence and characteristics of new lesions and the association of diagnostic aids with rates of new melanoma detection. Results: Among 593 participants, 340 (57.3%) were men, and the median age at baseline was 58 years (interquartile range, 47-66 years). There were 1513 lesions excised during follow-up, including 171 primary melanomas. The overall benign to malignant excision ratio, including keratinocyte carcinomas, was 0.8:1.0; the benign melanocytic to melanoma excision ratio was 2.4:1.0; and the melanoma in situ to invasive melanoma ratio was 2.2:1.0. The excision ratios were similar across the 4 centers. The risk of developing a new melanoma was 9.0% annually in the first 2 years and increased with time, particularly for those with multiple primary melanomas. The thicker melanomas (>1-mm Breslow thickness; 7 of 171 melanomas [4.1%]) were mostly desmoplastic or nodular (4 of 7), self-detected (2 of 7), or clinician detected without the aid of TBP (3 of 7). Overall, new melanomas were most likely to be detected by a clinician with the aid of TBP (54 of 171 [31.6%]) followed by digital dermoscopy monitoring (50 of 171 [29.2%]). Conclusions and Relevance: The structured surveillance program for high-risk patients may be implemented at a larger scale given the present cohort study findings suggesting the sustainability and replication of results in numerous settings, including a primary care skin cancer clinic.