Oral malignancies following HSCT: graft versus host disease and other risk factors.

Allogenic hematopoietic stem cell transplantation (HSCT), a procedure that is widely used in the treatment of a large number of malignant and non-malignant hematological diseases, is still associated with a wide range of complications, one of the most important of which is graft versus host disease (GVHD). The patients undergoing allogenic HSCT are also at high risk of developing secondary neoplasms, particularly leukemias and lymphomas. Solid tumors are less frequent, and the incidence appears to increase over time; the most frequent solid tumors are squamous cell carcinomas. We found that almost all studies of solid cancers occurring after transplantation are based on relatively small numbers of cases which have been monitored for short periods, and little information is available on individual cancers. In particular, reports of oral cancers in HSCT are very few. Potential risk factors associated with the development of secondary solid cancers after HSCT have been well described. They include graft versus host disease (GVHD), preoperative regimens, with either radio-chemotherapy or chemotherapy alone, conditioning regimes, immunosuppressive GVHD prophylaxis, viral infection and chronic stimulation as a result of viral antigens, antigenic stimulation from histocompatibility differences between recipient and donor, primary diagnosis, interaction of any of these factors with genetic predisposition, and other factors such as sex and age. All patients treated with HSCT should therefore be closely followed over the long term with the aim of identifying the onset of secondary tumors as early as possible.