Keratinocyte Carcinoma Incidence by Race and Ethnicity in Older Adults With Medicare Coverage.

This cohort study examines raw and age-adjusted differences in the incidence of keratinocyte carcinoma among Medicare beneficiaries by race and ethnicity.

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.

Anatomic Locations of Procedurally Treated Keratinocyte Carcinomas in the US Medicare Population.

Importance: Keratinocyte carcinomas are the most common cancers in the US. However, keratinocyte carcinomas are not included in US national cancer registries, and information on the anatomic locations of keratinocyte carcinomas is lacking. Objective: To investigate the anatomic location of keratinocyte carcinomas in the US using a large claims data set. Design, Setting, and Participants: We performed a cohort study using a deidentified, random sample of 4 999 999 fee-for-service Medicare beneficiaries aged 65 years or older (2009-2018). Main Outcomes and Measures: Proportion of procedurally treated keratinocyte carcinomas at each anatomic location, identified by linking diagnosis and treatment codes. Results: A total of 2 415 514 keratinocyte carcinomas were identified in 792 393 beneficiaries. The mean (SD) age was 76.6 (8.1) years, 410 364 (51.8%) were women, and 96.7% were White. Of the 2 415 514 keratinocyte carcinomas, 796 542 could be subtyped into basal cell carcinoma (33.0%), 927 984 into squamous cell carcinoma (38.4%), and 690 988 (28.6%) could not be subtyped. The most common location of squamous cell carcinomas was the head and/or neck (44.3%) followed by upper limbs (26.7%). The most common location of basal cell carcinomas was head and/or neck (63.8%), followed by trunk (14.9%). In women, keratinocyte carcinomas were most common on the head and/or neck (47.3%) followed by upper and lower limb (18.5% and 16.6%, respectively). In men, keratinocyte carcinomas were most common on the head and/or neck (58.7%) followed by upper limb and trunk (17.3% and 11.4%, respectively). Conclusions and Relevance: The results of this large Medicare cohort study highlight the anatomic locations of keratinocyte carcinomas over recent years and show the predominance of lesions occurring at head and/or neck anatomic location. This foundational information on keratinocyte carcinoma anatomic locations in the US is valuable for improved keratinocyte risk factor differentiation and skin cancer surveillance.