Adult survivors of childhood cancer have an increased risk for suicidal thoughts, even decades after their cancer treatments ended, according to a study led by Dana-Farber Cancer Institute scientists.

The researchers report in the Journal of Clinical Oncology that nearly eight percent of childhood cancer survivors said they have experienced suicidal thoughts, or ideation. Survivors of brain and central nervous system cancers were most likely to have had suicidal thoughts. Those who were in poor health or who had cancer-related pain or treatment-related chronic conditions also were at greater risk for suicidal thoughts. The paper is published on the journal's Web site and later will appear in a print edition.

"Our findings underscore the importance of recognizing the connection between childhood cancer survivors' physical health issues and their risk for suicidal thoughts, as some of the conditions may be treatable," said Christopher Recklitis, Ph.D., MPH, the study's lead author and a psychologist and director of research in the Perini Family Survivors' Center at Dana-Farber.

The researchers analyzed data from 9,126 adult survivors of pediatric cancers who were part of the Childhood Cancer Survivor Study (CCSS), a multi-institutional study coordinated through St. Jude Children's Research Hospital in Memphis to track long-term effects of cancer and its treatment. The participants were 18 years or older, had been diagnosed with cancer before the age of 21, and been diagnosed at least five years prior to participating in the study. The vast majority (8,464, or 92.7 percent) were diagnosed with cancer more than a decade before, and more than a quarter (2,564, or 28.4 percent) were diagnosed more than 20 years prior.

The survivors were compared to a non-cancer control group made up of 2,968 of the survivors' nearest-in-age siblings who also participated in the CCSS.

Recklitis and his colleagues found that 7.8 percent of the survivors reported having suicidal thoughts, compared with 4.5 percent of the control group. Survivors of brain and central nervous system cancers were the most likely to experience suicidal thoughts (10.6 percent), while survivors of non-Hodgkin lymphoma were the least likely (6.7 percent). "Although the vast majority of survivors reported no suicidal ideation, the significant minority of survivors with thoughts of suicide is a serious concern," said Recklitis, who is also an assistant professor of Pediatrics at Harvard Medical School and Children's Hospital Boston.

The data did not show any link between suicidal thoughts and a survivor's age or sex, but there was an association with low levels of education, lower household incomes, and recent unemployment. Those who had never married or were no longer married were more likely than those married to report suicidal thoughts.

Among the sibling control group, age was associated with risk for suicidal thoughts for those ages 18-24 but not other age groups.

Childhood cancer survivors, due to the intensive treatments they received, are at risk for developing chronic medical problems later in life. The researchers found that health problems in adulthood were very strongly associated with the survivors' suicidal thoughts. For example, 28.8 percent of survivors reporting "poor" overall health had suicide ideation, compared with only 3.3 percent of survivors who said their health was "excellent." Being physically disabled was associated with suicide ideation, as were the number and severity of chronic medical conditions, and cancer related pain. Even when depression was accounted for, physical health problems remained a significant predictor of suicidal thoughts.

The relationship between physical health and suicide ideation, Recklitis emphasized, has important implications for the clinical care of survivors. Because survivors who experience suicidal thoughts often are diagnosed with chronic medical conditions that require medical care, the researchers suggest that this group's relatively high use of medical services provides an opportunity to help identify and address their emotional needs.

"Perhaps more importantly," Recklitis said, the study's results are "an important reminder to clinicians that cancer survivors who have significant physical health problems may have significant emotional problems as well. While our health care system and our culture drive us to treat physical and emotional suffering very differently, clearly we need an integrated approach to helping survivors with their physical health problems and the emotional distress that can be associated with them."

In addition to Recklitis, the study's other authors are Lisa Diller, M.D., Xiaochun Li, Ph.D., and Julie Najita, Ph.D., Dana-Farber; Leslie Robison, Ph.D., St. Jude Children's Research Hospital, Memphis; and Lonnie Zeltzer, M.D., Mattel Children's Hospital at the University of California, Los Angeles School of Medicine.

The study was supported in part by a grant from the American Foundation for Suicide Prevention, and the CCSS is supported by grants from the National Cancer Institute.