Improved survival following cancer treatments has heightened the need for developing better understanding of the issues surrounding cancer survivorship and quality of life. The majority of previous studies on suicide and depression have focused on terminally ill patients, with little work undertaken into broader cancer populations, including patients likely to be long term survivors.
In the first study, Stephanie Misono and colleagues, from the Fred Hutchinson Cancer Research Center, (Seattle, USA) used two large databases - the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program and that of the National Center for Health Statistics - to compare the incidence of suicide among cancer patients with that of the general population. Comparisons with the general US population were based on mortality data collected by the National Center for Health Statistics. The study represents the first time such comparisons had been made in the US. Additionally, the investigators set out to identify disease characteristics, such as the anatomic site of cancers, associated with particularly high suicide rates.
Altogether, a total of 5,838 suicides were identified among 3,594,750 persons with cancer observed for 18,604,308 person-years, giving an age-, sex-, and race-adjusted suicide rate of 31.4/100,000 person-years. The corresponding suicide rate for the general US population was found to be 16.7/100,000 person-years. Statistical analysis produced a Standardised Mortality Ratio (SMR) of 1.88 - meaning that cancer patients were 1.88 times as likely to commit suicide as the general population.
Higher suicide rates among patients with cancer were associated with male sex, white race, and being unmarried. Suicide rates were also higher among patients with advanced disease at diagnosis, but not among patients with multiple primary tumours. Suicide rates were highest among patients with cancers of the lung and bronchus (81.7/100,000 person-years), followed by stomach (71.7/ 100,000 person years), and cancers of the oral cavity and pharynx (53.1/100,000 person years). The authors speculate that patients with lung cancer may struggle with their grave prognoses, while head and neck cancers can have a particularly devastating effect on quality of life "through impact on appearance and essential functions such as speech, swallowing and breathing".
"Our data suggest that the psychological experience of cancer survivors deserves further attention, as urged by the Institute of Medicine, particularly because appropriate use of psychosocial interventions in patients with cancer can make a positive impact on quality of life," write the authors.
Limitations of the study, they add, include causes of death being subject to "misclassification", that they were unable to evaluate the potentially confounding role of co-morbid medical and psychiatric conditions, and the fact they were unable to identify patients with cancer who committed suicide from the general population data.
In the second study, Jane Walker and colleagues from the University of Edinburgh Cancer Research Centre (UK), surveyed 2,924 consecutive patients attending a cancer outpatients clinic between June 2003 and December 2004. The investigators used the nine-item Patient Health Questionnaire (PHQ-9), a widely used self-report screening tool, which included the critical question (item 9) asking whether patients had entertained thoughts of being "better off dead or of hurting themselves in some way" in the previous two weeks.
Results were available on 2,924 patients, with 7.8 % (229 out of 2,924) responding positively to item 9. Of these 5.4 % (159 of 2,924) reported experiencing such thoughts on several days over the two week period, 1.6 % (46 of 2,924) on more than half the days and 0.8 % (24 of 2,924) nearly every day. When demographic and clinical variables were considered, clinically significant emotional distress and substantial pain, (and to a lesser extent, older age) were the only variables found to be associated with a positive response.
"Although progress has been made in prolonging and improving the quality of life of patients with cancer, this survey reveals that a substantial number of patients report thoughts of being better off dead or thoughts of hurting themselves. This is a sobering finding, and it clearly requires further investigation," write the authors, adding that further assessment is required to identify those at high risk of attempting suicide. Identifying and treating patients who are experiencing emotional distress and substantial pain, add the authors, might contribute to reducing the risk of suicide.
Limitations of the study include the fact that it used a self-completed screening measure, rather than an interview, so that the investigators had to rely on patients' interpretation of the questions. Furthermore, the study did not include all the factors that may be associated with thoughts of being "better off dead or of hurting yourself", such as the patients' general health and social support.
In an accompanying editorial, Timothy Quill, from the University of Rochester Medical Center, Rochester, (New York, USA) writes: "Qualitative studies will be needed to deepen our understanding of the range of thoughts, feelings, hopes and fears present in many seriously ill patients, so we can better distinguish clinical depression and anxiety that might be amenable to medical treatment from the range of normal sadness and fear that can be acknowledged and explored but not necessarily treated."
Systematic screening, he adds, is essential. "It is important to ask about suicidal thoughts and intent regularly, especially at times of transition when disease is worsening, symptoms are increasing or the patient is entering a more serious phase of illness. Creating an environment where these issues can be openly explored without being judged is critical."
Luigi Grassi, chair of Psychiatry at University of Ferrara. ( Italy) agrees: "These studies reinforce the need to talk to patients about the psychosocial aspects of their lives, their feelings about their cancer, the levels of stress that they are suffering and to find out what else is going on in their lives. To identify patients most at risk, assessments of psychological state should be undertaken at all consultations, in much the same way that we now consider their pain."
One problem, he added, is that once patients are identified not all cancer centres, particularly those in smaller hospitals, offer psycho-oncology services. Furthermore, oncologists can experience difficulty in persuading patients to agree to a psychiatric referral. "But if you identify depression early you can prevent it from progressing, and as in other areas of medicine - prevention is better than cure," said Grassi.
References
Walker J, Waters R, Murray G et al. Better Off Dead: Suicidal Thoughts in Cancer Patients. Journal of Clinical Oncology. Published online August 11, 2008, 10.1200/JCO.2007.11.8844
Misono S, Weiss N, Fann J, et al. Incidence of Suicide in Persons With Cancer. Journal of Clinical Oncology. Published online August 11, 2008, 10.1200/JCO.2007.13.8941
Quill T. Suicidal Thoughts and Actions in Cancer Patients. Journal of Clinical Oncology. Published online August 11, 2008, 10.1200/JCO.2008.18.3129
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