Previously unknown risk factors for secondary skin cancer linked with allogeneic hematopoietic cell transplantation (HCT) have been identified, researchers report after a retrospective analysis.

“We confirmed [graft-versus-host disease] as a risk factor, identified [chronic lymphocytic leukemia] as an additional risk factor, and found that patients who received myeloablative transplants in adulthood had fewer [basal cell carcinomas] than their counterparts,” Peggy A. Wu, MD, of the Beth Israel Deaconess Medical Center in Boston, and her colleagues wrote in the Journal of Investigative Dermatology.

The team analyzed 1,974 patients who underwent transplantation for various types of hematologic cancer and survived for a minimum of 100 days following transplant. Among this cohort, 119 patients developed various forms of skin cancer, including basal and squamous cell carcinoma.

Reports of skin malignancy were confirmed using physician records and pathology reports. Dr. Wu and her colleagues excluded patients whose indication for transplant was a primary immunodeficiency or Fanconi anemia.

“Reflecting advances that allow older patients to be eligible for HCT, the median age at transplantation of our cohort was one of the oldest (51.1 years) in the literature,” the researchers wrote.

In univariable models, the researchers found that prior chronic lymphocytic leukemia (CLL) (hazard ratio, 2.2; 95% CI, 1.3-3.7), chronic graft-versus-host disease (GVHD) (HR, 3.1; 95% CI, 1.7-5.4), and age at transplant of more than 60 years (HR, 10.8; 95% CI, 3.3-35.6) were all linked to an increased risk for squamous cell carcinomas. A multivariable analysis found that these factors continued as significant risk factors.

For basal cell carcinomas, the risk factors identified were prior CLL (HR, 3.5; 95% CI, 2.0-6.4), acute GVHD (HR, 1.9; 95% CI, 1.1-3.3), and chronic GVHD (HR, 3.2; 95% CI, 1.6-6.5) using univariable models. These factors all continued to be significant in multivariable analysis.

Additionally, the researchers found that a myeloablative conditioning regimen and total body irradiation were protective against development of basal cell carcinomas in univariable models. However, the protective effect continued for myeloablative condition in the multivariable model only.

“To our knowledge, previously unreported risk factors in this contemporary cohort include prior CLL for squamous cell carcinoma and basal cell carcinoma and reduced-intensity conditioning for basal cell carcinoma,” the researchers wrote.

The study was supported by the Skin Cancer Foundation, Women’s Dermatologic Society, Harvard Catalyst, and Harvard University. The authors reported having no conflicts of interest.

SOURCE: Wu PA et al. J Invest Dermatol. 2019 Mar;139(3):591-9.