Managing the Elderly in Radiotherapy using Geriatric AssEssment: 'MERGE'
Anita O’Donovan reports from Dublin, Ireland, on the need for greater understanding of the specialised care requirements of older patients
Patients over the age of 65 represent the majority of patients with cancer i.e. approximately 60%1. At least half of these patients will require radiotherapy at some stage, as part of their disease trajectory2. In Ireland alone, there will be a 50% increase in the number of cancer cases by 2025, with 60% of these in patients over the age of 653. This is also mirrored worldwide 4-6.
This poses a real problem for the oncology profession, given the known lack of clinical trials in older patients7-10. Radiation oncology has even less than medical and surgical oncology. What little evidence exists for older adults, favours fitter patients, rather than the broad spectrum encountered clinically. Selection of more appropriate inclusion criteria and trial endpoints is thus advocated in oncology trials, in order to “geriatricize” trial design11-13. This has been highlighted by Nipp et al14, who described the need for “pragmatic” clinical trials for older cancer patients.
Segregation from co-existing geriatric care
Many oncology healthcare professionals feel ill-equipped to deal with these projected demographic changes. Despite the fact that the majority of cancer patients are in older age groups, most oncologists receive little training in the specialised care of older patients. When an older patient presents for radiotherapy, they are often segregated from their co-existing geriatric care, as the oncology and geriatric medicine disciplines often work in isolation, with little collaboration about patients. This seems unusual, given the known importance of the multidisciplinary team in oncology, seen as the cornerstone of patient management. The geriatrician is notably absent from such meetings in many institutions, something that must change in order to provide more holistic care to the older person. The geriatrician’s involvement is essential in identifying and potentially reversing frailty, as well as providing recommendations on overall care.
Frailty has been defined in the gerontology literature as disability, impairment in activities of daily living, or increased vulnerability to adverse outcomes15. Two schools of thought prevail, the phenotype of frailty defined by Fried16, from the Cardiovascular Health Study (CHS), and Rockwood’s clinical frailty criteria17, based on cumulative deficits on Comprehensive Geriatric Assessment (CGA) domains. The latter has been deemed more useful in a clinical setting, as it also encompasses cognitive, psychological and social factors, as well as many others. Accumulation of these deficits is linked to increased risk of hospitalisation, higher health care costs, and overall mortality8.
Geriatric Assessment and ‘staging the ageing’
Comprehensive Geriatric Assessment (CGA), or Geriatric Assessment (GA) as it’s commonly abbreviated to in oncology, is a multidimensional, interdisciplinary assessment that includes functional status, comorbidity, cognition, psychological status, nutrition, social support and polypharmacy, amongst others18. This assessment can provide a broader overall understanding of individual characteristics that affect life expectancy, functional decline, cognition and patient’s own wishes, as well as how oncologic treatment might affect them 19. These are important factors to consider when deciding on a course of treatment. The International Society of Geriatric Oncology and National Comprehensive Cancer Network guidelines for older adults advocate the use of GA in all older patients with cancer20, 21 Geriatric Assessment is vital in “staging the ageing” i.e. assessing physiologic and functional capacity, which in turn has implications for being able to predict treatment tolerance and toxicity22-25. A more recent study, of the ELCAPA patient population, one of the largest studies of older cancer patients published to date, identified subgroups based on GA that were predictive of overall outcome, hospital admission within six months and a fatal outcome within one year26. When coupled with targeted interventions, the benefits of GA in older patients may include prolongation of life, prevention of hospitalisations and admissions to long-term care facilities, prevention of geriatric syndromes, recognition of cognitive deficits, and improvement of health status27.
Cognitive assessment and dementia
As an example, cognitive assessment is one of the key components of GA, and determines a patient’s ability to provide informed consent, as well as their suitability for neurotoxic treatment. Dementia is an independent prognostic factor for survival and must be considered in any discussion of treatment for older patients. After age 65, the risk of developing Alzheimer’s disease doubles about every 5 years28. Recent studies have established a link between Androgen Deprivation Therapy (ADT) for prostate cancer and Alzheimer’s disease29, 30. Neurotoxicity associated with cranial irradiation is another emerging risk factor for the development of dementia in older adults31, 32. From a medicolegal perspective, it is also important to determine a patient’s capacity to provide informed consent for treatment. This can only be achieved by carrying out a baseline cognitive assessment.
Physical function – gait speed, grip, and falls
Physical function is usually assessed in radiation oncology using either the Eastern Cooperative Oncology Group (ECOG)33 or Karnofsky performance 34 status scales. This would appear relatively one dimensional to a geriatrician, who would consider such things as gait speed, balance, grip strength and lower extremity strength, as these are more predictive of patient outcomes35. In particular, gait speed has been shown to be a significant predictor of mortality across numerous studies36, a simple assessment, but with much predictive value. Grip strength is associated with sarcopenia 37, 38, i.e. decreased muscle mass and quality, the latter also associated with poorer outcomes in cancer patients 39-41.
Assessment of falls risk is important in all patients over the age of 65, as one in three will experience a fall42, 43. A comprehensive assessment, such as that advocated by NICE guidelines44, should be carried out in order to eliminate precipitating factors, such as polypharmacy, poor vision, inadequacy of the home environment etc. Certain types of concurrent chemotherapy, such as taxol, can exacerbate risk factors, due to the onset of peripheral neuropathy. Androgen deprivation therapy can also increase risk, due to its impact on muscle mass in prostate cancer patients 45. Combined with the side-effects of radiotherapy, e.g. fatigue, the patient at high risk of falling is increasingly vulnerable.
Social support is also important for patients who are required to attend daily radiotherapy treatments. Many may already be in a caregiving role, or may require caregivers themselves at some point in the future, as a result of cancer, or its treatment.This is one area where the radiotherapy service can facilitate the patient and afford greater convenience. Considering shorter overall treatment schedules in radiation therapy may be very helpful in such cases, if they provide the appropriate management of course. One example is in the treatment of Glioblastoma Multiforme (GBM). For patients identified as elderly/frail, 25Gy in 5 fractions has been shown to be non-inferior to 40Gy in 1546, the previous standard of care for such cases47. A further example is hypofractionation in prostate cancer48.
Seeking consensus on assessment
Although GA has long been used in Geriatric Medicine, there is no agreement on the best approach for oncologists to take when incorporating aspects of GA. Understandably, as GA was never intended to predict how patients will respond to radiotherapy or chemotherapy. Puts et al49have highlighted the lack of standardisation with regard to GA domains and assessments in the published literature to date. This further hinders advancement of the geriatric oncology field, due to an inability to compare studies. To overcome this, two parallel Delphi consensus studies50, 51, were carried out in Europe and the US to gain consensus on what should be assessed in older patients with cancer. Radiation oncologists also participated in this study, and conceded that the assessments in Fig 1 below should be added to existing oncologic assessments for patient’s over the age of 70. This assessment should be carried out at baseline, and at follow-up appointments, at a minimum. For certain sites, it may be pertinent to do so more often. A study on head and neck cancer patients undergoing radiotherapy has highlighted the need for regular re-evaluation of GA domains during radiotherapy, i.e. weekly, as the toxicity of chemoradiation results in significant decline52.
Radiotherapy – a more suitable alternative for older patients?
Few studies have looked at radiotherapy alone as a treatment modality, the vast majority including medical oncology patients. This is understandable given the systemic toxicity and more competing demands on organ systems involved in chemotherapy administration. Radiotherapy on the other hand is considered a well-tolerated treatment for older adults, often a suitable alternative to either chemotherapy or surgery, when neither of the latter is suitable for less fit older adults. One notable example, which has revolutionised the care of older lung cancer patients, is the use of Stereotactic Ablative Radiotherapy (SABR) for patients considered unsuitable for surgery53, 54. Technological advances and the accompanying reduction in toxicity have also provided a favourable advantage for all patients, but especially older patients. In general, there do not appear to be significant differences between younger and older patients in relation to reported toxicity during radiotherapy, although older patients were more likely to report difficulty with walking after completion of radiotherapy and greater distress55. Again, this reinforces the need for GA to estimate baseline function and optimise function where possible.
GA and the multidiciplinary team
There is a notable shortage of geriatricians worldwide, and in the absence of access to this specialty, radiation therapy as a profession must respond appropriately. GA is known to be time and resource intensive, and recent studies have sought to develop shorter screening tools specifically for oncology patients56-59. Neve et al60, in a small study of head and neck cancer patients undergoing radiotherapy, found that patients identified as vulnerable by G8, were less likely to complete radiotherapy. However, none of the screening approaches developed to date have been validated in radiotherapy61. One potential solution to the resource implications of GA, is the sharing of responsibility among the multidisciplinary team. Traditionally the education of healthcare practitioners has largely taken place in isolation to one another. Recent focus in policy documents on measures to improve the quality of healthcare has resulted in a need to adequately prepare qualified health professionals to work together in a more collaborative manner62, 63. There is a greater need for increased cooperation and communication across the health and social care system. In radiation oncology, this would place the onus on the radiation oncologist, nursing colleagues, allied health professionals and radiation therapists to expand their role and undertake GA as part of their formal evaluation of their patients.
There is an unexploited potential for the radiation therapy community to respond to our increasingly older cohort of patients, with smart measures, such as the use of technology, or optimisation of existing technology to incorporate GA. One example is gait speed. As mentioned above, its predictive power is well known, and there is ample opportunity to measure this during the numerous patient trajectories in and out of the treatment room. Sarcopenia, another potential frailty measure that is increasingly researched in cancer patients, is another measure that is relatively easy to capture given the multitude of CT scans that our patients receive64.
Of course we need more research to validate these approaches, and there is an urgent need to “geriatricize” existing trials in radiotherapy, in order to build an evidence base that accurately represents all of the patient population i.e. fit, vulnerable and frail. To my knowledge, there are no definitive publications assessing the predictive value of GA on radiation toxicity or adherence. These studies are long overdue. There is also a very large unmet need in the merging of oncology and geriatric medicine disciplines.
Anita O’Donovan, Assistant Professor, Discipline of Radiation Therapy,Trinity Centre for Health Sciences, St. James’s Hospital campus, James’s St., Dublin 8, Ireland. D08 W9RT