Pediatric cancer survivorship: the Childhood Cancer Survivor Study--editor's foreword.

It was my pleasure to work closely over the past 6 months with Drs Robison, Hudson, and Sklar in assembling this collection of reports about the late effects of cancer treatment derived from systematic study of childhood cancer survivors by the Childhood Cancer Survivor Study (CCSS) investigators. The impetus for this issue came from a hallway conversation that I had with Les Robison, PhD, at the American Society of Clinical Oncology Annual Meeting in 2007 after a Journal of Clinical Oncology (JCO) editors meeting. The CCSS has published its findings widely among high-impact general medical journals, JCO, and other cancer-focused journals, as well as pediatrics journals. To keep up with all of these results, one would have to read broadly or piece together thematic topics through concerted literature searches. Thus, I concluded, it was time to get this body of information housed in one place—and where better to do this than as a JCO Review Series issue? The CCSS cohort reflects childhood cancer treatments that were designed and delivered between 1970 and 1986, and many of the childhood cancer survivors alive today were exposed to those treatments. They and their physicians can clearly benefit from a synthesis of what the CCSS investigators have found. The CCSS investigators will continue to accumulate further knowledge as the CCSS cohort passes through midlife, and perhaps we will need another summary a decade from now. Children receiving cancer treatment today have benefited tremendously from the results of the CCSS studies, primarily through the development of risk-adapted therapies that limit exposure to treatments with high risk for serious late effects (eg, more limited use of radiation therapy). Although there are differences in tissue toxicities between children and adults, the findings from the CCSS may foreshadow some of the complications we are likely to see in adults treated for cancer who are now long-term survivors (eg, young adults treated for lymphoma, testes cancer, or leukemia). To some extent, childhood cancer survivors may represent the canary in the coal mine, providing some insights regarding what to look out for and guiding oncologists as they tailor therapy for adults to maximize survival while minimizing late effects. We should also be very impressed by the ability of the pediatric oncology community to come together, leading the way in the study of survivorship and late effects of cancer treatment. With the growing number of adult cancer survivors, we are making modest inroads in collecting information on the late effects of treatment. However, we face the challenge of tracking about 100 different kinds of cancer and have relatively few patients on clinical trials, so we are less able to make attribution of late effects to specific treatment regimens. Much of our survivorship outcomes information comes from convenience samples or administrative data, where specific information about cancer treatment and concurrent comorbidity may be limited. Although adult clinical trial participants may be a select group, they do provide a unique patient sample in which to study the late effects of contemporary treatments, and systematic late effects research should be encouraged within the cooperative group setting. In adult cancer survivors, reducing the burden of treatments and late effects in survivors is more likely to come through efforts at early detection, risk-adapted therapies, and personalization of treatment—through avoidance of toxic treatments that may not be necessary in some groups of patients. Nevertheless, we should take inspiration from the accomplishments of the CCSS investigators, and learn that our responsibility for the care of the patient with cancer does not end when the treatment is completed—it extends for months and years beyond.