A new preliminary study has highlighted that patients who receive a hematopoietic stem cell transplant (HSCT), face a considerable risk of developing a second cancer, especially if they are older during the time of the transplant or have received stem cells from a female donor.
The study was carried out by Canadian scientists who caution that future stem cell treatments for ailments such as spinal cord injury and heart failure might also carry a cancer risk, the New Scientist reported on Monday on its website.
The scientists at the British Columbia Cancer Agency in Canada in the study reviewed the medical records of more than 900 adult patients who had received haematopoietic stem cell transplants, also known as bone marrow transplants, in the past two decades, with the vast majority of these transplant recipients suffering from leukaemia, the report said.
To estimate the risk and identify risk factors associated with this outcome, Genevieve Gallagher, M.D. and Donna L. Forrest, M.D. of the BC Cancer Agency and the University of British Columbia, retrospectively reviewed the medical records of 926 patients treated with myeloablative stem cell transplants over an 18-year period.
They found that at their institution the 10-year incidence of second cancers in these patients was 3.1 percent. When nonmelanoma skin cancer and carcinoma in situ of the cervix were excluded, incidence was 2.3 percent. That risk was 1.85 times that of the general population. The median time to diagnosis was almost 7 years after transplant. The most commonly reported second cancers were cancers of the skin (basal and squamous cell), lung, oral cavity, and colon.
Men who received stem cells from female donors had more than twice the risk of developing cancer compared with women who received the same, according to the study which is the first study to demonstrate that stem cells from women carry a greater cancer risk than those from men.
However, experts point out that the findings are preliminary and that the analysis did not control for confounding factors such as whether a patient smoked or maintained a healthy body weight and it therefore remains unclear exactly how much the stem cell transplants contributed to the risk of second cancers.