In a nationwide population–based cohort study reported in JAMA Dermatology, Blomberg Drejøe et al evaluated the long-term risk of skin cancer and related outcomes among patients with chronic lymphocytic leukemia (CLL). By leveraging comprehensive Danish health registries, the investigators aimed to provide clinically meaningful risk estimates to inform patient counseling and surveillance strategies.
Study Details
This matched cohort study included 8,352 patients (median age = 70.7 years, interquartile range = 62.2–78.3 years) diagnosed with CLL between 1990 and 2020, an 41,760 matched controls without CLL. Matching was performed at a 1:5 ratio based on age, sex, geographic region, socioeconomic factors, and comorbidity burden. Patients with prior diagnosis of skin cancer or other causes of immunosuppression were excluded.
Follow-up began at the time of CLL diagnosis and continued until the occurrence of skin cancer, metastasis, death, emigration, or study end. The primary outcomes were 10-year absolute risks of overall skin cancer and specific subtypes—including basal cell carcinoma, squamous cell carcinoma, melanoma, Merkel cell carcinoma, and cutaneous lymphoma—as well as skin cancer–specific metastasis and death.
Key Results
Over a median follow-up period of more than a decade, patients with CLL had a significantly higher 10-year risk of developing skin cancer (13.5%, 95% confidence interval [CI] = 12.7%–14.3%) compared with matched controls (6.9%, 95% CI = 6.6%–7.2%), corresponding to an absolute risk difference of 6.6 percentage points (95% CI = 5.7–7.4, P < .001). The increased risk was observed across most skin cancer subtypes, with basal cell carcinoma (8.6% vs 5.4%) and squamous cell carcinoma (4.7% vs 1.4%) accounting for the largest differences. Elevated risks were also noted for melanoma (1.0% vs 0.6%) and cutaneous lymphoma (1.8% vs 0.1%); the difference in Merkel cell carcinoma risk was not statistically significant. In addition, patients with CLL experienced earlier onset of skin cancer, with a median time to diagnosis of 5.3 years compared with 7.4 years in control patients.
Clinically meaningful increases were also observed in adverse outcomes. The 10-year risk of skin cancer–specific metastasis was higher in patients with CLL vs controls (0.7% vs 0.1%), as was the risk of skin cancer–related death (0.3% vs 0.1%). Nonmelanoma skin cancers accounted for the majority of skin cancer–related deaths among patients with CLL, while melanoma was the predominant cause in the control patients.
The authors concluded: “This cohort study found that patients with CLL had an increased risk of developing skin cancer, mainly basal cell carcinoma and squamous cell carcinoma. Skin cancer–specific metastasis and death were also more frequent among patients with CLL, although the absolute risk remained low given markedly higher all-cause mortality.”
Mathias Ørholt, MD, of the Department of Plastic Surgery and Burns Treatment, Copenhagen University Hospital, Copenhagen, Denmark, is the corresponding author for the JAMA Dermatology article.
DISCLOSURE: For full disclosures of the study authors, visit jamanetwork.com.
