Long-Term Second Cancer Risk Increased After Stem Cell Transplant

NEW YORK DEC 04, 2006 (Reuters Health) - Patients who undergo myeloablative allogeneic hematopoietic stem cell transplantation (allo-HSCT) for hematologic malignancies have an 85% increased risk of developing a second, solid malignancy, a Canadian study shows.  

The risk is especially high in patients age 40 or older at the time of the transplant and "unexpectedly" among those who received stem cells from a female donor.  This latter observation has not been previously reported in the literature, the authors note, and its explanation is uncertain.

Drs. Genevieve Gallagher and Donna L. Forrest of the British Columbia Cancer Agency and the University of British Columbia in Vancouver reviewed the records of 926 patients who underwent myeloablative allo-HSCT for a variety of diseases over a period of 18 years.

A total of 28 patients developed 30 solid tumors at a median of 6.8 years after allo-HSCT, for a 10-year cumulative incidence of 3.1%.  Exclusion of nonmelanoma skin cancer and carcinoma in situ of the cervix brought the incidence down to 2.3%.

The age- and sex-adjusted relative risk of a second solid cancer after allo-HSCT, compared to the general population of British Columbia, was 1.85. 

In multivariate analysis, the relative risk of a second solid tumor was 4.75 for patients aged 40 or older at the time of transplant.  The relative risk was 3.83 for patients who had a female stem cell donor.

Men who received stem cells from a female donor had a 4.7 increased relative risk of a second tumor compared with men who received stem cells from a male donor.

The most common second cancers were basal cell and squamous cell carcinoma followed by cancers of the lung, oral cavity, colon and bladder.

"Since the risk of developing a solid neoplasm after allo-HSCT continues to increase with time," the authors note, "extended follow-up will be needed to more fully assess the incidence and risk factors for their development."

SOURCE:

• Cancer 2007.