A Literature Review of Suicide in Cancer Patients

Linda Anguiano, MSN, RN; Deborah K. Mayer, PhD, RN, AOCN, FAAN; Mary Lynn Piven, PhD, PMHCNS-BC; Donald Rosenstein, MD

Disclosures

Cancer Nurs. 2012;35(4):E14-e26. 

In This Article

Results

After the database search, 193 articles were identified that mentioned suicide and cancer. However, when the inclusion criteria were applied, 22 articles were selected; 2 additional articles were retrieved from reference lists from these 22 articles for a total of 24 articles for this review. Among the 24 articles reviewed, 13 reported suicide risk factors, 9 evaluated tools used to detect increased suicide risk, and 2 discussed suicide prevention strategies for the terminal cancer patient. Major findings associated with suicide rates included type of cancer, gender, age, depression, and time from diagnosis.

Cancer Type

Four studies identified specific cancer sites associated with increased suicide risk, whereas 21 articles reported results under the broad category of cancer. The 4 site-specific malignancies with higher suicide rates included prostate, pancreatic, lung, and head and neck. In a population-based retrospective cohort study of older men living in South Florida from 1983 to 1993 who committed suicide, a total of 667 suicides were completed of which 20 were in men with prostate cancer.[12] The incidence of suicide in this study population was 55.32 per 100,000 older men, compared with 274.7 per 100,000 for older men with prostate cancer. Overall, the risk of suicide in men with prostate cancer was 4.24 times the age- and gender-specific cohort.[12] Miller et al[14] examined 1 of the first population-based studies to establish the relative risk of suicide in Americans 65 years or older while controlling for medical and psychiatric comorbidity. In a multivariate analysis, the only medical illness associated with suicide was cancer (odds ration [OR], 2.3; 95% confidence interval [CI], 1.1–4.8). There were a total of 19 suicides among patients with a cancer diagnosis of which 8 were in men with prostrate cancer. This study demonstrated a suicide rate of 23% (8 of 35) among those patients with prostate cancer.[14]

In a review of patients with cancer, Passik and Breitbart[15] focused on the connection between pancreatic cancer, depression, and suicidal ideation. Examination of psychiatric consultation data at Memorial Sloan Kettering Cancer Center revealed that one-third of cancer patients found to have suicidal ideation were patients with major depression.[15] The study reported that for cancer patients with localized disease, only 25% experienced depressive symptoms compared with 77% of patients with advanced cancer disease. Similar findings have been reported in patients with pancreatic cancer who are usually diagnosed at an advanced stage. In a summary of 52 case reports of patients with pancreatic cancer, 71% had symptoms of depression, 48% had anxiety-related disorders, and 29% had both.[15] The authors reported that suicidal ideation is likely to be associated with depression in patients with advanced cancer.

Akechi et al[7] evaluated predictive factors for suicidal ideation in 89 newly diagnosed patients with unresectable lung cancer. He found that 15% of patients had some degree of suicidal ideation at 6 months after initial diagnosis. Risk factors, identified using multivariate analysis, indicated that pain at baseline (OR = 3.72) and the development of a depressive disorder (OR = 27.97) were significantly associated with development of suicidal ideation. The report concluded that comprehensive cancer care should include pain management and appropriate psychiatric intervention in an effort to minimize suicidal ideation. A retrospective review by Kendal[11] of 1.3 million cancer cases from the SEER database found a significant association between head and neck cancers in men and suicide (0.32%; 95% CI, 0.26–0.39).

In summary, having prostate, lung, head and neck, or pancreatic cancer was associated with higher rates of suicide or suicidal ideation. These studies were limited as they were primarily retrospective analyses of case reports. The Akechi trial was small, and it is difficult to apply these findings to other cancer populations. It is noteworthy that there have not been prospective studies evaluating depression and suicide in common malignancies such as breast and colon cancer.

Gender Differences

In the general American population, males are 4 times more likely to commit suicide than females.[11] Five articles reported male gender as a risk factor for completed suicides. One retrospective study from the Cancer Registry in Norway reported that of the 490,245 patients who died from cancer, 589 committed suicide. The relative suicide risk was increased for both men and women; however, men were at higher risk with a standardized mortality ratio (SMR) of 1.55 (95% CI, 1.41–1.71) as compared with women, who had an SMR of 1.35 (95% CI, 1.17–1.56).[10]

A large Danish study included 564,517 cancer patients diagnosed between 1971 and 1999 and found that 1241 had died as a result of suicide (0.22%).[19] The suicide rate in this study was higher for men than women. The age standardized (world) suicide rates (WSTP) per 100,000 ranged from 16.8 to 30.2 for men and 6.1 to 16.3 for women. A similar large retrospective study from the Thames Cancer Registry in England from 1996 and 2005 reported a significantly increased risk of suicide in men. The study reported an SMR of 1.45 (95% CI, 1.20–1.73) for men compared with 1.19 (95% CI, 0.88–1.57) for women.[17] A gender comparison study of 1.3 million cancer patients from the US Surveillance, Epidemiology, and End Results (SEER) registry, a population-based database regarding the pathology, disease extent, social factors, treatment, and causes of death of people with cancer in the United States, also noted that male sex is a risk factor.[11] The results of this study concluded that women completed suicide rate (0.02%) was about one-fifth that of men (0.1%). The suicide hazards ratio for women was 1 and men, 6.2. This study showed a 4.8 times excess in overall number of male suicides over female suicides, which is consistent with the general American population ratio[11] of 4.5.

In summary, as in the general US population, suicide risk is higher in male cancer patients than in female cancer patients. Extensive population-based studies have confirmed the increased rate in the male population. There are no studies that make this comparison by gender or in a specific cancer diagnosis such as lung cancer.

Older Oncology Patients

In the US population, suicide in the context of medical illness is higher in older adults.[14] Miller et al[14] focused on the risk of suicide in older Americans with cancer. In a case-controlled study of 1408 patients aged 65 years and older, he noted that 128 had died as a result of suicide during a study period from 1994 to 2002. In an adjusted analysis, the only medical condition associated with suicide was cancer (OR = 2.3). The authors concluded that the risk of suicide in older adults was higher among patients with cancer than among patients with other medical illnesses.

Misono et al[3] reviewed the SEER database in an effort to identify cancer patient and disease characteristics associated with higher suicide rates. This study found higher suicide rates in men (SMR = 2.09), white race (SMR = 1.88), and older age at diagnosis (SMR = 2.42 in patients aged 65–69 years). The age-adjusted suicide rate in the general population was 22.0 per 100,000 person years for ages 80 to 84 years, yet this study revealed a suicide rate of 52.4 among the same age group with cancer. The higher rates were notable among men who demonstrated a suicide rate of 100.3 per 100,000 in those patients aged 80 to 84 years. This study also found an increased suicide rate in older (>65-year) patients with cancer. This risk increased as age increased and older men were at the highest risk. An analysis of cancer type would help further define special populations at higher risk of suicide.

Depression/Hopelessness

In a recent study of patients with cancer, depression was determined to be the major risk factor for suicidality (r = 0.36–0.39, P < .01). Hopelessness was also reported as increasing the risk for suicide (r = 0.45–0.49. P < .01). In this study of advanced cancer patients by Wilson et al,[20] "feeling oneself a burden to others" was found to be a moderate to extreme concern to patients (39.1%). A study by Breitbart et al[8] found that depressed cancer patients were 4 times more likely to have a desire for hastened death (DHD) compared with those patients without depression (47% vs 12%). A retrospective study of 1721 cancer patients referred for a psychiatric consultation found that 220 had major depression (12.8%) and more than half of these (113) demonstrated suicidal ideation. Major depression was a significant risk factor for suicidal ideation in this study (OR = 1.80; 95% CI, 1.89–2.37; P = .0001).[7]

Recent Cancer Diagnosis

Hem et al[10] studied a cohort of patients from the Cancer Registry of Norway who were linked to a suicide diagnosis in the Registry of Deaths from 1960 to 1997. During this period, 589 cancer patients committed suicide; 407 were males. The risk of death from suicide was highest in the first months after diagnosis. The SMR was 3.09 for men and 2.18 for women within the first 5 months of diagnosis. After 12 months from diagnosis, the SMR decreased to 1.57 for men and 1.72 for women. Hem et al[10] concluded that the relative risk was elevated for both sexes in the first months after diagnosis (P < .001) and significantly decreased with time (P = .005).

In a recent study of suicide in cancer patients from England, Robinson et al[17] found that the relative risk of suicide was greatest in the first year after cancer diagnosis. The SMR was 2.42 for men and 1.44 for women in the first year. The authors concluded that there was a critical period just after diagnosis in which suicide risk was high. Yousaf et al[19] explored suicides among Danish cancer patients from 1971 to 1999. They reported that after a cancer diagnosis, suicide risk was highest in the first 1 to 3 months for men and between 3 and 12 months for women.[19]

In summary, multiple studies have identified the first months after cancer diagnosis as higher risk for suicide. More data exploring specific cancer diagnosis and extent of disease may be helpful in further defining this risk. Interventions identifying early detection of depression or suicidal ideation may help prevent suicide.

Suicide Risk Screening Tools Depressed cancer patients are more likely to have a high DHD compared with patients without depression (47% vs 12%).[8] Consequently, systematic approaches to screening for suicide ideation with validated instruments hold promise for improved mental healthcare for patients with cancer. Eight studies from a general oncology population explored various screening tools in an effort to identify suicide risk. Tools used to assess depression in these articles included the Beck Hopelessness Scale (BHS); Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria; Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition (SCID); Endicott criteria using the Hamilton Depressive Rating Scale; Edinburgh Postnatal Depression Scale; Hospital Anxiety and Depression Scale; Schedule of Attitudes towards Hastened Death; Patient Health Questionnaire (PHQ-9); 13-item structured interview of symptoms and concerns; and simply asking the question "are you depressed."

Clinical signs and symptoms of major depression are often also present as signs and symptoms in cancer patients making it difficult to differentiate them.[9] Anorexia, weight loss, low energy, and sleep disturbances are common as a result of both disease and treatment processes. Some study authors have proposed to drop these somatic symptoms from assessment screening tools that evaluate depression in this population. The prevalence of major depression in cancer patients has been recorded as low as 5% to 6% in 1 study to as high as 40% in others.[9] This variability is most likely related to differences in how depression was measured in these studies. The gold standard for the diagnosis of depression is a clinical examination administered by someone trained to use the SCID; instead, many studies used brief screening with varying psychometric qualities, cancer type, and disease stage.[9] A study by Ciaramella and Poli[9] using 2-structured methods for assessing major depression found that 49% of patients were considered depressed when evaluated using the SCID screening tool; however, when somatic symptoms were eliminated using the Endicott criteria, only 29% were depressed. Using both depression tools, the SCID and Endicott criteria, 28% were found to have a current depressive episode. These results suggested that the prevalence of major depression in cancer patients was 28%, which is similar to depression in other medical illnesses.[9] The sensitivity and specificity of self-reported depression screening have been studied for both cancer patients and those with mental illness. Symptoms, age, and gender were found to bias scores.[9]

Hopelessness is a powerful predictor of suicidal ideation and completed suicides.[5] Abbey et al[5] found that the BHS could be improved when used with the terminally ill, by removing problematic items like the question "I can't imagine what my life will be like in ten years" or "I have enough time to accomplish the things I want to." This study examined abbreviated versions of the BHS for use in the terminally ill population. All 3 versions reported adequate reliability and validity as measures of hopelessness for the terminally ill. When compared with the original 20-item scale, the 7- and 13-item versions had slightly more variance at end of life despair measures (ideation and hastened death). The 3-item version performed well accounting for as much variance as did the longer original. In summary, multiple tools have been used to help identify those patients who may be at high risk for suicide because of depression, helplessness, or DHD.

Desire for hastened death, as defined by Abbey and colleagues,[5] in the context of advanced cancer is a multidimensional construct, not necessarily pathological, and may have multiple meanings unrelated to taking one's life. Three distinct experiences of the meaning include DHD as a hypothetical exit plan, an expression of despair, and as a manifestation of letting go. It often served as a adaptive purpose of managing distress.[16]

The PHQ-9 is a validated self-report measure that is used to screen for mental disorders.[21,22] One item of the PHQ-9 asks, "In the last 2 weeks how often have you been bothered by the following problem: thoughts that you would be better off dead or hurting yourself in some way?". In a study of 330 cancer patients, an association was found for those who endorsed this question and suicidality; those with higher scores were more likely to be suicidal on interview.

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