By Daneng Li, MD
- By 2030, approximately 70% of all cancer diagnoses will occur in patients age 65 or older. However, older adults with cancer are significantly underrepresented in clinical trials.
- Chronologic age alone is not reliable in predicting overall life expectancy, physical function, or the ability to tolerate treatment in older adults with cancer. Chronologic age alone should not exclude patients from the use of therapies that could prolong survival.
- Incorporation of geriatric assessment and tools to predict life expectancy into daily oncology practice are pivotal in determining the ideal treatment plan for older adults with cancer.
As the U.S. population continues to age, an estimated 88.5 million Americans will be 65 years or older by 2050.1 Chronologic age has been identified as a risk factor for numerous malignancies.2 Treatment approaches and recommendations made to older adults with cancer remain significantly different compared to their younger counterparts,3 and older adults with cancer are significantly underrepresented in clinical trials.4 For example, in a study investigating clinical trial participation, only 9% of trial participants were 75 years or older, despite representing 31% of the overall patient population.5 In another study, 11% of physicians reported age alone as the reason for not enrolling older adults onto clinical trials.6 As a result, a paucity of data to help guide oncologists in the treatment of older adults with cancer currently exists.
By 2030, approximately 70% of all cancer diagnoses will occur in patients age 65 or older.7 The challenges facing oncologists in the treatment of this vulnerable older population with various malignancies is something I personally encounter on a daily basis. As an early-career medical oncologist specializing in geriatric oncology, more than 80% of my clinical practice is devoted to treating adults aged 65 or older with various breast and gastrointestinal malignancies. An average clinic day consists of consultation questions such as: Which type of adjuvant therapy should be prescribed to a 78-year-old woman with triple-negative breast cancer? What treatment should an 82-year-old highly functional man with metastatic pancreatic adenocarcinoma receive? How should the treatments be dosed? What adjuvant therapy should be recommended for a 75-year-old woman with stage III colon cancer and a prior history of falls?
By taking care of this vulnerable elderly patient population on a day-to-day basis, I have quickly learned that chronologic age alone is not reliable in predicting overall life expectancy, physical function, or the ability to tolerate treatment in older adults with cancer.8 Rather, aging is a heterogeneous process in regard to individual changes in physiologic status, comorbidities, and cancer biology. In treating older adults with cancer, chronologic age alone should not exclude patients from the use of therapies that could prolong survival.9,10 However, the benefit of treatment in terms of prolonging survival must be weighed against potential treatment toxicities and the overall impact on quality of life. Individualization of treatments for older adults with cancer requires more data beyond just chronologic age.11 Although no definitive guidelines are currently available to fully address all of the clinical scenarios above, research by geriatric oncologists has laid the foundation of tools that may help to fill these knowledge gaps in order to improve the care of older adults with cancer.
Incorporation of geriatric assessment into daily oncology practice is pivotal to identifying older adults at risk for adverse outcomes and pinpointing interventions to potentially decrease this risk.12 Busy oncologists often use the Karnofsky Performance Status (KPS) scale or the Eastern Cooperative Oncology Group (ECOG) Scale of Performance Status alone as major indicators of global function in older adults with cancer in order to guide treatment recommendations. Although these measures are quick and easy to use, studies have shown that they cannot identify older adults at risk for treatment toxicity. Conversely, a geriatric assessment can identify significant vulnerabilities not typically found by practicing oncologists13 and can be used to predict the risk of treatment toxicity.14,15 For example, a recent study by Jolly et al. showed that geriatric assessment was able to detect one major deficit in approximately 70% of patients with a normal KPS score.16 Therefore, brief and easy-to-use geriatric assessment tools have already been developed and are available to help oncologists better evaluate older adults with cancer in order to make more informed treatment decisions.
The Cancer and Aging Research Group (CARG) geriatric assessment chemotherapy toxicity calculator (mycarg.org) is a tool I use frequently in my clinics. This tool is quick, easy to learn, and can be filled out within a few minutes of speaking with a patient and imputing some of the patient’s laboratory values. The toxicity calculator then provides a risk score, which can allow oncologists to quickly develop a sense of potential for chemotherapy-related toxicity in their older adult patients with cancer. With the additional information provided, oncologists are then able to adjust chemotherapy treatment recommendations accordingly.
As an example, I recently encountered a 74-year-old patient with stage IV pancreatic cancer with a KPS rating of 70 but a CARG toxicity score of 15 (range 0 to 19), translating to a 92% risk of grade 3 or higher toxicity. Based on the KPS scale alone, one could have considered treating the patient with standard combination gemcitabine-based therapy. However, the toxicity score provided concern, and the patient was started on treatment with only single-agent, dose-reduced gemcitabine (with plans for escalating the dose and number of drugs if she tolerated the first dose). Even with single-agent, dose-reduced gemcitabine, the patient developed grade 3 neutropenia and thrombocytopenia after the first dose. Luckily, these were the only significant toxicities encountered, and further adjustments in treatment were made. Incorporation of geriatric assessment into routine oncologic care is warranted; it can only help to provide oncologists with additional necessary tools to better tailor treatments for older adults with cancer.
In addition to geriatric assessment, use of tools to predict life expectancy17-19 is also essential in determining the ideal treatment plan for older adults with cancer. Patients and their families often struggle with decisions regarding the willingness to risk toxicity from treatment for the potential benefits in overall survival. In facing this struggle, I often try to provide comprehensive estimates in life expectancy in the setting of other comorbid medical conditions. Quick online tools such as ePrognosis (eprognosis.ucsf.org) can further help to define the patient’s life expectancy in the absence of cancer. Discussions regarding prognosis will always be difficult. By using tools to define life expectancy on a more individualized basis, oncologists should be better equipped to guide their older adult patients through the difficult treatment decision-making process, thereby, facilitating shared decision making with patients and their families.
Although tools focused on life expectancy and geriatric assessment currently exist to help in the care of older adults with cancer, clinical trials specifically targeting this vulnerable patient population will be needed in order to further optimize care. Both the Institute of Medicine and ASCO have released consensus statements regarding the need to increase the breadth of knowledge available in the treatment of older adults with cancer.20,21 Like many oncologists, I have often struggled to find geriatric-specific trial data on which to fully support treatment recommendations for my older adult patients with cancer. Moving forward, clinical trial selection and design must change quickly in order to incorporate and adapt to a rapidly growing older patient population. Eligibility criteria for clinical trials must be less stringent in hopes to include more older adults. In addition, traditional oncology trial endpoints of disease-specific and overall survival will simply not be enough. Rather, important geriatric outcome measures, such as risk of severe toxicity, maintenance of functional independence, impact of therapy on cognition and mood, and the need for caregiver assistance, should all be included in future therapeutic clinical trials.
As the U.S. population continues to age, the number of older adults with various malignancies will increase in drastic numbers. Education on the use of available tools such as life expectancy calculators or incorporation of geriatric assessment into clinical practice will be vital to help guide physicians throughout the shared decision-making process with older adults contemplating cancer treatment. In addition, a rapid push for changes in oncology clinical trial designs will attempt to close the gap in knowledge by providing desperately needed geriatric-specific trial data to base treatment recommendations for older adults.
The time has come for all oncologists to make a concerted effort to improve the care of this vulnerable patient population. By adapting in both clinical practice and research, the goal to better optimize and personalize the care of all older adults with cancer can be achieved.
About the Author: Dr. Li is an assistant clinical professor in the department of medical oncology and therapeutics research at City of Hope.