Long-Term Risk of Cutaneous Squamous Cell Carcinoma After Actinic Keratosis
Posted: Wednesday, April 21, 2021
Lisa J. Herrinton, PhD, of Kaiser Permanente, Oakland, California, and colleagues investigated the long-term risk of developing cutaneous squamous cell carcinoma after a diagnosis of actinic keratosis. The investigators explained that although further research is necessary to fully grasp the effect of actinic keratosis treatment on the risk of cutaneous squamous cell carcinoma, they did discover an increase of cutaneous squamous cell carcinoma in patients with these lesions. Their 10-year longitudinal study was published in JAMA Dermatology.
Data were extracted from the medical records of 220,236 patients with actinic keratosis; those with a history of melanoma, HIV, organ transplant, or cutaneous squamous cell carcinoma within 30 days of diagnosis were excluded. Control patients (220,236) were randomly selected and matched with each diagnosed patient based on index date, race/ethnicity, sex, and age.
The median follow-up was 4.2 years for participants with actinic keratosis and 3.2 years for those in the control group. Development of cutaneous squamous cell carcinoma occurred in 8.9% of individuals with actinic keratosis and 3.2% of individuals in the control group; mean incidence rates were 1.92 and 0.83, respectively. The overall correlation of cutaneous squamous cell carcinoma with actinic keratosis yielded a hazard ratio of 1.90. Increased age, history of basal cell carcinoma, male sex, and White race seemed to increase the incidence.
Patients with lesions who were 49 years or younger tended to be more likely than those without them to develop cutaneous squamous cell carcinoma by nearly sevenfold (hazard ratio [HR] = 6.77). Patients from 50 to 59 years had a hazard ratio of 3.20; older patients had a hazard ratio of 2.00.
More than half of cutaneous squamous cell carcinoma events developed in patients with one or two lesions. Risk seemed to increase with the number of lesions removed in individuals who received cryotherapy (HR = 1.89), yet the risk was intermediate in those who underwent field therapy. At the 10-year mark, the cumulative incidence of cutaneous squamous cell carcinoma reached 17.1% and 5.7% for patients with actinic keratosis and those in the control group, respectively.
Disclosure: The study authors reported no conflicts of interest.
