Surviving childhood cancer is not the end of the battle. As Hutchinson Center researchers have long known, the risk of a second cancer or other chronic illness is a threat that looms into adulthood. For thirty years, the Center has been following patients in efforts to ensure that those patients receive quality medical care after leaving the Center.
The three decades of research at the Hutchinson Center are mirrored by a larger, international study of childhood cancer survivors treated at 27 institutions, including the Hutchinson Center. The Childhood Cancer Survivor Study (CCSS), which started in 1993, examined a wide variety of cancers among children diagnosed between 1970 and 1986. The collaboration gathered data from almost 14,000 survivors, including 10,400 who are now adults, and a control group of more than 3,000 adult siblings.
The authors concluded that as a group, adult childhood-cancer survivors were eight times as likely as their siblings to have severe or life-threatening chronic health conditions such as a second cancer, heart attack, congestive-heart failure, kidney dysfunction, severe musculoskeletal problems and disorders of the endocrine system.
"These findings are an echo of our own experience," said Dr. Paul Martin, director of LTFU. "We have observed similar outcomes in our patients. This study identifies problems in patients who have had other diseases that we have not been able to study. The two mirror each other."
The CCSS is the largest study of its kind, and as such, attracted much needed international attention to the problem; but the basic premise that childhood cancer survivors face an uphill battle is familiar to investigators at the Hutchinson Center.
"While the results of this study were not entirely applicable to the transplant population, it does magnify what we already knew — that childhood cancer survivors must be closely followed for a lifetime," said Dr. Jean Sanders, director of the Hutchinson Center's pediatric stem-cell transplantation program.
"I was surprised by the magnitude of the findings," said Dr. Debra Friedman, a co-author of the paper and Associate Member in the Clinical Research Division. "But what's important to take away from this study is that patients may be at risk for long-term complications, even though they were not in the highest risk groups in this study. Transplant patients need to stay in close contact with LTFU to understand how to monitor for those risks. Having a primary health care provider who can monitor patients for problems and keeping an open line of communication with LTFU is critical. The same is true for all childhood cancer survivors, who can now be followed in the Center's Survivorship Program."
The risk for these chronic health problems is due to chemotherapy and radiation treatment, the authors concluded, and such secondary illnesses may not become apparent for many years. Five treatment combinations were associated with a tenfold-increased risk of severe or life-threatening conditions; four of the combinations included chest, abdominal or pelvic radiation.
Friedman noted that due to the knowledge researchers have gained about adverse health-related outcomes for cancer survivors, therapies have been modified to decrease the risk of late effects, while maintaining and, in many cases, improving efficacy. "It is only through continued research using cohorts like the CCSS that we will be able to ascertain whether the changes we have made will indeed result in fewer and less severe late effects," she said.
The message for physicians and other caregivers is to be aware of potential long-term complications from chemotherapy and radiation that may not become apparent for a long time, Friedman said. "Most survivors and physicians don't see a lot of post-treatment complications early on, and can get lulled into a false sense of security that they won't see late effects of therapy."
For survivors, "It's important that they take note of the study's data and advocate for themselves," she said. "They need to be sure to have regular annual follow-up exams by a physician who has knowledge of late effects after cancer treatment. Many of the health conditions identified in the study can be detected early and mitigated by early intervention. Some of the late effects of treatment are so uncommonly seen in young adults, that physicians who are not aware of the risks may not consider them when patients present with unusual symptoms. For example, coronary artery disease is not usually seen in people in their 30s."
However, less than 20 percent of adult survivors of childhood cancer are followed at a cancer center or by an oncologist, the report said. "The monitoring of survivors is an important part of their overall health care," the authors wrote.
The Long-Term Follow-Up (LTFU) Program at the Hutchinson Center has a long-standing history of providing information and consultation about late effects of treatment to bone marrow and stem cell transplant patients and their physicians. While LTFU is not able to provide routine lifetime follow-up care, it can provide information about screening and monitoring for late effects of treatment for survivors and their community health care providers. For this reason, it is important for each transplant patient to maintain contact with LTFU. A description of LTFU services and many of the recommendations for routine lifetime screening can be found on our website at http://www.fhcrc.org/science/clinical/ltfu.
Dr. Friedman became director of Pediatric Hemotology-Oncology at the Monroe Carell Jr. Children's Hospital at Vanderbilt University in 2008.