St. Jude follows outcomes of stem cell transplant survivors

Sep 11 2007

Patient care at St. Jude doesn't stop when the child is cured. The end of successful therapy is the start of many years of follow-up care. This care is aimed at helping make the recovery process successful and preparing the family and hometown doctor for long-term complications that might arise from the disease or its treatment.

Some of these children survive their catastrophic disease thanks in part to a hematopoietic stem cell transplant (HSCT). In this procedure, healthy hematopoietic stem cells (primitive cells that continually produce new red and white blood cells as well as platelets) from a donor are injected into a recipient with the aim of rebuilding normal blood cells after eradication of the patient's own hematopoietic stem cells from the use of intensive chemotherapy with or without total body irradiation.

While HSCT can save children, the aggressive therapy used to eradicate cancer cells and prevent rejection of the transplant can lead to long-term medical complications for a decade or so; and this problem is growing, since more and more children are surviving allogeneic HSCTs, according to Wing Leung, MD, PhD, director of Bone Marrow Transplantation and Cellular Therapy. Therefore, it's increasingly important to study the long-term effects of HSCT on this group of patients. Allogeneic transplants are those obtained from a genetically similar but not identical donor.

Leung and former St. Jude researcher Hyunah Ahn led a team of investigators in a comprehensive series of annual tests on 155 patients who survived HSCT in order to identify the “late events” (medical problems linked to therapy that occur years after discharge from the hospital) they experienced. A report on their findings appears in the August 2007 issue of the journal Medicine .

The researchers found that only 20 (13 percent) of the 155 patients had no medical problems related to HSCT, while 18 (12 percent) had one long-term health problem, 71 (46 percent) had two to four conditions and 46 (30 percent) had five to nine conditions.

In addition, the investigators identified five risk factors that made children vulnerable to late complications. Three of these factors were related to treatment: total body irradiation, higher radiation dose and graft-versus-host reaction. The other two were patient related—specifically, being female and being younger in age at the time of HSCT.

Among the 155 patients receiving HSCT, the cumulative incidence of long-term events the investigators observed included bone death (14 percent), kidney problems (27 percent), hypothyroidism—reduced thyroid function—(45 percent), growth hormone deficiency (31 percent), abnormally low production of sex hormones in females (57 percent) and males (20 percent), bone thinning (48 percent), cataracts (43 percent) and poor lung function (63 percent).

“One key finding was that many people had more than one endocrine problem,” Leung said. “This suggests that patients should undergo comprehensive tests for various endocrine problems rather than just for certain hormone deficiencies, since hormone therapy could improve the lives of these young survivors.”

“The practical use of our findings is that such information would help the patient's hometown physician anticipate potential late term events following HSCT,” said Ching-Hon Pui, MD, Oncology chair. “Primary health care providers who know the clinical history and risk factors of patients who have had HSCT can improve the quality of life for such patients by identifying and treating these complications early.”

Other St. Jude authors of this paper include Sean Phipps, PhD, Behavioral Medicine; Teresa Smith, Kwan Gan and Madeline O'Connor, RN, PhD, all of the Cancer Center; and Gregory Hale, MD, Kimberly Kasow, DO, Raymond Barfield, MD, PhD, and Renee Madden, MD, of Oncology / Bone Marrow Transplantation and Cellular Therapy.

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