No Increase in Suicide Risk Among Childhood Cancer Survivors: Study

Survivors of childhood cancer have a similar risk of having suicidal thoughts compared with the general population, but appear to have a lower risk of suicidal behavior and suicidal death, according to a new analysis.

The findings contrast with previous studies that have suggested an increased risk.

The new study, which included data on 7312 survivors of childhood cancer, was published in Cancer.

"Our results indicating that survivors had a lower risk of suicidal behaviors and mortality are positive," said study author Tara Brinkman, PhD, an associate member in the Department of Epidemiology and Cancer Control and Department of Psychology, St Jude Children's Research Hospital, Memphis, Tennessee.

"However, one potential reason for these findings may be that survivors in our study were participants in a long-term follow-up cohort," she added. What this meant in practice was that survivors who did report suicide ideation were contacted by a licensed social worker, she explained. The social worker then completed a suicide screening and provided recommendations and referrals to community mental health providers, as appropriate.

"As a result, survivors may have been more likely to receive appropriate mental health treatment in response to their distress and suicide ideation, and less likely to engage in subsequent suicidal behaviors," she told Medscape Medical News.

Previous Studies Have Suggested Increased Risk

Previous studies have found that survivors of childhood cancer are at risk of suicidality, the authors note in their article.

For example, data from the Childhood Cancer Survivor Study (CCSS) has shown that there is a nearly twofold increase in suicidal ideation among adult survivors of childhood cancer compared with their siblings (J Clin Oncol. 2010;28:655-661. Cancer. 2014;120:271-277).

However, findings from the CCSS cohort found no elevated risk of suicide mortality among adult survivors of childhood cancer compared with age-, sex-, and calendar year-matched rates in the general population (J Natl Cancer Inst. 2008;100:1368-1379. J Clin Oncol. 2001;19:3163-3172).

Conversely, studies conducted in Europe have suggested higher rates of hospitalizations and deaths attributed to suicide in this population, the authors note. In view of these conflicting results, the researchers set out to examine the issue in their own study.

No Increased Risk

In their study, Brinkman and colleagues assessed suicide mortality among 7312 survivors of childhood cancer who were 18 years of age or older and at least 5 years removed their cancer diagnosis. They also evaluated risk factors for acute suicidal ideation among 3096 survivors who had been clinically evaluated, and the prevalence of acute ideation was compared with that of 429 individuals from the community who served as controls.

In addition, the prevalence of 12‐month suicidality among 1255 survivors was evaluated and compared with population data.

A total of 21 survivors (2.9%) died by suicide. This subgroup was primarily comprised of non-Hispanic Whites (95.2%) and men (85.7%).

Compared with the control group, adult survivors of childhood cancer had a significantly lower rate of death by suicide (standardized mortality ratio [SMR], 0.60).

Several risk factors for suicidal ideation were identified. These included survivors of central nervous system tumors (risk ratio [RR], 1.52) and non-Hodgkin lymphoma (RR, 1.42) who had a higher risk of suicidal ideation compared with the reference group of leukemia survivors. Childhood cancer treatment exposures were not associated with suicidal ideation.

In a separate analysis, being single, widowed, or divorced (RR, 1.50), being unable to pay bills during the previous year (RR, 1.47), and current unemployment or underemployment (RR, 1.38) were also associated with a higher risk of acute suicidal ideation, as were sleep disturbances (RR, 1.33), anxiety (RR, 2.19), and depression (RR, 12.30).

Of 1255 survivors who completed the National Survey on Drug Use and Health (NSDUH), about 5% reported ideation (65 survivors), 1.2% reported planning, and 0.5% reported a suicide attempt. Compared with a matched NSDUH control group, these survivors reported lower — although not significantly lower — rates of suicidal ideation (standardized incidence ratio [SIR], 0.68) and significantly lower rates of planning (SIR, 0.17) and attempts (SIR, 0.07).

These results applied only to adult survivors of childhood cancers, Brinkman emphasized; all participants in the current study were 18 years of age or older.

"While we certainly see suicidal ideation and behaviors in children and younger survivors, we have not yet examined the prevalence of these behaviors in the St Jude Life Cohort," she said. "We have plans to conduct this research in the near future."

The study was supported by the National Cancer Institute, and support to St Jude Children's Research Hospital was provided by a Cancer Center Support (CORE) grant and the American Lebanese Syrian Associated Charities (ALSAC).

Brinkman has reported no relevant financial relationships. Coauthor Kevin R. Krull has reported receiving grants from the National Cancer Institute for work performed as part of the current study.

Cancer. Published online September 23, 2020. Abstract

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