Annual Screening for Skin Cancers Should Be Implemented in High-Risk Allogeneic Hematopoietic Stem Cell Transplant Recipients

Hematopoietic stem cell transplantation (HCT) has changed the landscape for the treatment of both malignant and nonmalignant hematological conditions. This change in landscape has also brought on new challenges such as the increased risk of secondary malignancies posttransplantation. Of particular note is the higher incidence of skin cancers posttransplantation in HCT recipients compared to the general population. Consequently, there is a need to examine whether we should screen allogeneic HCT recipients as stringently as solid organ transplantation (SOT) recipients for skin cancer. Currently, posttransplantation screening guidelines for skin cancer in HCT recipients are not sufficiently defined. In 2012, the Center for International Blood and Marrow Transplant Research, the European Group for Blood and Marrow Transplantation, and the American Society of Blood and Marrow Transplantation jointly issued recommended screening and preventive practices for the care of HCT recipients. Notably, the relevant recommendations for skin cancers involved (1) counseling patients on prevention and early detection of skin cancers and (2) prompt referral to a dermatologist for assessment of suspicious skin lesions. The first recommendation involves counseling on the use of adequate skin protection, avoidance of excessive sun exposure, and routine self-examination of the skin. More generally, the working group also recommends advising patients of the risks of secondary malignancies and screening clinical assessment to be performed annually. However, the guidelines do not go as far as to explicitly recommend for an annual dermatological examination for recipients of HCT. This is likely due to the lack of available evidence at the time. Even in the context of SOT, most international clinical practice guidelines rated the recommendation of an annual dermatological examination as based on very low to low quality of evidence. A recent study assessed the incidence and risk factors for skin cancer in ~2000 adult allogeneic HCT recipients in Boston, MA, from 1995 to 2013. The reported age-adjusted incidences of squamous cell carcinoma (SCC), basal cell carcinoma (BCC), and melanoma were 1000, 692, and 141, respectively, per 100 000 person-years for allogeneic HCT recipients. The group identified additional risk factors for skin cancer: (1) prior chronic lymphocytic leukemia (CLL) for SCC and BCC and (2) reduced-intensity conditioning for BCC. The authors posited prior CLL as a risk factor for secondary malignancies because of a greater likelihood of prolonged intrinsic and iatrogenic immunosuppression before the HCT. Reduced-intensity conditioning regimens are becoming increasingly common in the context of HCT because of the lower risk of transplant-related infection and mortality. This study identifies how this type of regimen is a risk factor for BCC posttransplantation. The study also supports a previously identified risk factor for nonmelanoma skin cancer: chronic graft-versus-host disease (GvHD). A population-based cohort study conducted in Denmark found similar results: allogeneic HCT recipients had an increased risk of SCC, BCC, and melanoma, with respective hazard ratios of 18.3, 3.1, and 5.5 compared with the general population. Notably, in SOT recipients the incidences for SCC and melanoma were 812 and 75, respectively, per 100 000 personyears, which are comparable to the rates observed in HCT recipients. In a Dutch study, the incidence for BCC after renal transplantation was 330 per 100 000 person-years. Based on the above studies, SCCs are the most common type of skin cancer following both types of transplantation, a characteristic that is not observed in the general population, where BCCs are usually more common. Hence, there is a need to reassess whether more concrete guidelines on annual dermatological examination should be extended to allogeneic HCT recipients and especially to individuals who are >60 years of age, receiving reduced-intensity conditioning and high-dose total body irradiation, and afflicted by CLL in the past or GvHD after the transplantation.