Skin Cancers in Medicare Beneficiaries With Actinic Keratoses.

Importance: Actinic keratoses (AK) are common premalignant skin lesions with a small risk of progressing to cutaneous squamous cell carcinoma (SCC). There is some evidence that patients with AKs also have increased risks of other skin cancers beyond SCC. However, the absolute risks of skin cancer in patients with AKs are unknown. Objective: To calculate the absolute and relative risks of future skin cancer in Medicare beneficiaries with AKs. Design, Setting, and Participants: This retrospective cohort study was performed using a deidentified, random sample of 4 999 999 fee-for-service Medicare beneficiaries from 2009 through 2018. Patients with treated AKs were included, and patients with seborrheic keratoses (SKs) were included as a comparator group. All patients were required to have at least 1 year between data set entry and first AK or SK. Patients with a history of skin cancer were excluded. Data were analyzed from September 2022 to March 2023. Main Outcomes and Measures: Outcomes were first surgically treated skin cancer, including keratinocyte carcinoma (including SCC and basal cell carcinoma [BCC]) and melanoma. The absolute risks of skin cancer in patients with AKs were evaluated. Skin cancer risks in patients with AKs were compared with patients with SKs using adjusted competing risks regression. Results: A total of 555 945 patients with AKs (mean [SD] age, 74.0 [7.4] years; 55.4% female) and 481 024 patients with SKs (mean [SD] age, 73.3 [7.3] years; 72.4% female) were included. The absolute risk of skin cancer after a first AK was 6.3% (95% CI, 6.3%-6.4%) at 1 year, 18.4% (95% CI, 18.3%-18.5%) at 3 years, and 28.5% (95% CI, 28.4%-28.7%) at 5 years. Patients with AKs had increased risk of skin cancer compared with patients with SKs (any skin cancer: adjusted hazard ratio [aHR], 2.17; 95% CI, 2.15-2.19; keratinocyte carcinoma: aHR, 2.20; 95% CI, 2.18-2.22; SCC: aHR, 2.63; 95% CI, 2.59-2.66; BCC: aHR, 1.85; 95% CI, 1.82-1.87; and melanoma: aHR, 1.67; 95% CI, 1.60-1.73). Conclusions and Relevance: In this cohort study, older patients with AKs had substantial absolute risks, as well as elevated relative risks, of skin cancer. AKs may be clinical markers of UV exposure and increased skin cancer risk, including SCC, BCC, and melanoma. However, guidelines are lacking for follow-up skin cancer surveillance in patients with AKs. Efforts to develop evidence-based recommendations for skin cancer surveillance in patients with AKs are paramount.

Current Understanding of Seborrheic Keratosis: Prevalence, Etiology, Clinical Presentation, Diagnosis, and Management.

Seborrheic keratosis (SK) is among the most common cutaneous lesions, affecting some 83 million Americans. Biologically benign, SK lesions do not require removal for medical reasons unless histologic confirmation of the clinical diagnosis is required or the lesions are traumatized and/or become symptomatic. These macular or popular pigmented lesions are often of cosmetic concern to patients. In addition, their natural history of gradually increasing in size, thickness, and/or pigmentation often serves as the impetus compelling patients to present to a dermatologist for evaluation and skin cancer screening; SK is diagnosed and managed primarily by dermatologists. Data regarding SK prevalence and management from a survey of 594 practicing, board-certified dermatologists are summarized herein: Dermatologists report they diagnose an average of 155 patients per month with SK. Among SK patients presenting to dermatologists, 33% have more than 15 SK lesions and 67% have 15 or fewer SK lesions. On average, dermatologists treat 43% of their SK patients to remove lesions. Cryosurgery is the most common removal method. Other commonly employed removal methods include shave excision, electrodessication, curettage or a combination of these. While these procedures can be used to remove SK lesions effectively, each has potential drawbacks and careful patient selection is required to optimize cosmetic results particularly in skin of color patients and patients with thick or numerous lesions. While there is great interest from both patients and providers in a topical non-invasive treatment for SK, no effective topical therapeutic agent has been developed, and this remains an area of unmet need.