Across the age spectrum, various factors contribute to distress. However, few studies have specifically evaluated the factors contributing to distress in older adults with cancer. In our study cohort of older adults with cancer, significant distress (score ≥ 4 on the Distress Thermometer) was identified in 41% of patients. By using a brief, comprehensive, self-administered geriatric assessment questionnaire, we were able to explore the relationship between distress and several variables that independently predict morbidity and mortality in older adults, such as functional status, comorbid medical condition, nutritional state, and social support. The following variables were significantly associated with increased distress scores by bivariate analysis: poor physical functioning, having more than three comorbid medical conditions, poor eyesight, requiring services at home, and needing more time or requiring assistance to complete the geriatric questionnaire. A multivariate regression model based on the significant bivariate findings revealed that poor physical function correlated significantly with distress.
Previous studies that used the distress thermometer reported distress scores of ≥ 4 in 42.5% to 66.6% of patients with cancer.26,28–33
These studies were performed in patients of all ages. Risk factors for distress included younger age33
; female sex29,31,34
; poor performance status27,29
; and physical,28,29,32,33
problems. Our finding of distress in 41% of older adults with cancer is slightly lower than the prevalence reported in other studies, reinforcing the findings in previous reports that demonstrate that younger age is a risk for distress and therefore older age may be protective.
The study results also help to pinpoint the unique causes of distress that face older adults with cancer. In particular, loss of independence is a key risk factor contributing to distress. This finding is consistent with the risk factors for distress reported in the geriatric literature for patients without cancer4,6–8
but are particularly relevant for patients with cancer, given that the burden of cancer or cancer therapy can further jeopardize an older adult's physical independence. The impact of therapy on a patient's ability to maintain independence plays a key role in the decision about whether a patient will proceed with treatment. This was illustrated in a survey of older adults in which the majority reported that they would refuse potentially life sustaining therapy if that therapy would cause functional or cognitive decline.35
Functional decline is often associated with feeling that one is a burden to others.36
This is especially true among patients who are terminally ill.36,37
In a report of 43 patients (median age, 70 years) who requested physician-assisted suicide in Oregon, the most frequent underlying illness was cancer (72%), and the most common end-of-life concerns were loss of autonomy (79%) and the inability to participate in activities that make life enjoyable (77%).38
In daily oncology practice, functional status is reported as a Karnofsky performance score39
or Eastern Cooperative Oncology Group40
performance status. These brief scales of functional status predict overall survival and treatment morbidity, but they do not evaluate a patient's ability to complete specific daily activities, nor do they provide information about the impact of functional decline on someone's mental health. This study highlights the importance of asking these questions in daily practice. Studies of interventions aimed at improving or assisting with physical function in order to decrease distress in older patients with cancer need to be conducted. In addition, research into the longitudinal impact of cancer and cancer therapy on an older patient's physical function is warranted for patients and physicians to weigh the risks and benefits of cancer therapies.
We recognize the limitations of this study. First, the study consisted of a convenience sample of patients seen in an outpatient oncology practice and the majority of study participants were female (71%), white (95%), diagnosed with breast cancer (41%), and treated at a tertiary care cancer center. This may limit the ability to generalize these results to all adults with cancer. Second, the time from initial diagnosis and the timing since initiation of specific cancer therapies were not captured. The current or recent receipt of chemotherapy may influence the distress level. Third, these data were obtained by self-report, and it is possible that patients may have over- or underestimated their own abilities on certain self-report measures. In addition, there may be domains other than those evaluated in the geriatric assessment questionnaire that are predictors of distress. We did not capture a problem list, which is often used in association with the Distress Thermometer, and this might have provided further insight into causes of patient distress. Finally, we do not know whether distress or declines in physical function are directly due to cancer or another specific comorbid medical condition.
Despite these limitations, this study has important strengths. Few studies have specifically evaluated predictors of distress in older adults with cancer, a population that is expected to grow rapidly in the next 25 years. Our study demonstrates that a significant proportion of patients (41%) score above the threshold for psychological distress and that poorer physical function is associated with increased distress levels. From these results, we conclude that screening tools to evaluate an individual's distress level and physical function should be incorporated into daily oncology practice, and interventions should be put in place to maintain or assist with physical functioning. Ultimately, further research is needed to determine whether these interventions would decrease the distress and suffering that accompanies a cancer diagnosis in older adults.