Actinic keratoses are precancerous skin lesions that are treated to prevent progression to cutaneous squamous cell carcinoma. Keratinocyte carcinomas include basal cell carcinoma and cutaneous squamous cell carcinoma. Cryosurgery is preferred to treat a single or limited number of actinic keratosis lesions, whereas field-directed therapies, such as topical fluorouracil, topical imiquimod, photodynamic therapy, topical tirbanibulin, and off-label topical fluorouracil plus calcipotriene, are preferred treatments for multiple lesions or significant field cancerization. For basal cell carcinoma, low-risk lesions may be treated with standard surgical excision, electrodesiccation and curettage, or topical agents for superficial subtypes. Basal cell carcinoma that is high risk or in cosmetically or functionally sensitive areas warrant Mohs surgery or similar techniques that provide complete margin assessment. Squamous cell carcinoma in situ can be managed with topical therapies, photodynamic therapy, electrodesiccation and curettage, or Mohs surgery for high-risk sites. Invasive cutaneous squamous cell carcinoma should be treated surgically, typically with 4- to 6-mm margins for low-risk tumors and Mohs surgery for tumors that are high-risk or located in cosmetically or functionally sensitive areas. Radiation is an alternative for patients who are not candidates for surgery. Systemic hedgehog pathway inhibitors are approved for locally advanced or metastatic basal cell carcinoma in patients who are not candidates for surgery or radiation therapy, although adverse effects often limit tolerance. Checkpoint inhibitor immunotherapy can be used in certain advanced cases of basal cell or cutaneous squamous cell carcinoma.
Nelson M, Nash J, Hamel RK. Skin Cancer: Management of Precancers and Keratinocyte Carcinomas. FP Essent. 2026;564:23-32.
Case 3. XR is 95-year-old woman with limited life expectancy. You evaluate her at the skilled nursing facility and perform a shave biopsy of a 1-cm ulcerated, erythematous patch on her left shoulder. The biopsy reveals a low-risk superficial basal cell carcinoma. The patient and her family are not interested in standard surgical excision and ask what other treatment options they should consider.
Actinic Keratosis
Actinic keratosis is a common precancerous skin lesion caused by chronic sun exposure. Although the risk of any single lesion progressing to cutaneous squamous cell carcinoma is low (0.1% per year or less), the cumulative risk increases with multiple lesions.1–5 The true prevalence is difficult to quantify due to the lack of a universal definition for actinic keratosis. Its prevalence is higher in regions with warmer climates and greater UV exposure and in individuals with Fitzpatrick skin type I or II.6 A 2004 estimate suggested that nearly 40 million people were affected in the United States.7 In the Netherlands, a population-based study of people with predominantly fair skin showed that actinic keratosis affected 49% of males and 28% of females 45 years or older.8
Actinic keratosis typically manifests in older adults as a rough, scaly, gritty papule or macule on sun-exposed areas such as the face, scalp, ears, or forearms (Table 1).9–11 Patients may have persistent rough/dry patches that do not improve with moisturizers. Dermoscopic features include pigmented patterns (brown or gray dots in annular or granular distributions) or nonpigmented patterns (pink pseudonetwork with white globules [strawberry-like pattern]).
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