Study looks at factors that influence life expectancy of childhood cancer survivors

Many factors influence the life expectancy of childhood cancer survivors: not getting enough exercise, being underweight, and being worried about their future health or their health insurance. These are the findings of research led by Cheryl Cox of the St. Jude Children's Research Hospital in the US, published in Springer's Journal of Cancer Survivorship. The study found that, on average, childhood cancer survivors passed away before they were 40 years old.

Health-related behavior, self-perceived health status, and health concerns often influence mortality in the general population. However, the study led by Cox is the first to assess how these factors impact the longevity of adult survivors of childhood cancer, whose life expectancy can be reduced by as much as 28 percent because of the late effects of their cancer and treatment.

Cox's team found that malignant tumors, (42 percent), and heart (20 percent) and lung (7 percent) problems cause most deaths among childhood cancer survivors, who, on average, pass away at around 37.6 years of age. Data collected between 1970 and 1986 for the Childhood Cancer Survivor Study were analyzed. Because the group about whom information was gathered has now aged, the researchers could assess the factors (other than those of the initial diagnoses and treatment) that influenced life expectancy. In all, the information of 445 participants who died from causes other than cancer or non-health-related events (such as accidents) were matched and compared with 7,162 surviving participants.

Many factors that increase the risk of dying in the general population were also found to be true for childhood cancer survivors. These include not having a life partner, not having gone far in high school, and living on an annual income of below $20,000. Black people were also at a higher risk. In addition, early deaths were linked to being underweight and making frequent visits to physicians, especially during the last two years of life. Male survivors who participated in exercise three times a week generally live longer than those doing no physical activity. Alcohol consumption increased life expectancy.

More uniquely, childhood cancer survivors' mortality risk saw a threefold increase due to other-related causes if they described their general health as being "poor" or "fair." It was also affected by being very worried about their future health and ability to obtain health insurance. Worry and anxiety can affect health, and ultimately mortality, indirectly through behavior such as smoking, poor nutrition and inactivity, and directly through changes in a person's immunity or endocrine and cardiovascular systems.

"Lifestyle behavior, self-reported health status, worries and concerns, and frequent use of medical care are associated with mortality in survivors of childhood cancer," concludes Cox. "These factors independently contributed to mortality in survivors who were, on average, less than 40 years of age."