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Impact of physical comorbidities on cancer treatment and its outcomes in geriatric populations: A systematic review
ABSTRACT
Background:
Cancer is one of the predominant causes of morbidity and mortality in geriatric populations worldwide, particularly in developed countries owing to the proportionately high ageing population. Frailty, comorbidities, financial burden, treatment-related adverse effects, lack of social support, transportation and treatment facilities are some of the hindrances in cancer treatment among the geriatric population in particular. Of these factors, comorbidity poses a major clinical challenge in cancer diagnosis, prognosis and treatment owing to its heterogeneous nature in terms of number as well as severity. While accurate comorbidity assessment and appropriate treatment administration can result in better treatment outcomes in older cancer patients, evidence related to geriatric cancer populations is limited as these individuals are often excluded from regular clinical trials due to age and comorbid conditions.
Objective:
To determine the prevalence of physical comorbidity and determine the impact of physical comorbidities and rurality on treatment (delay in treatment initiation, completion/dose alteration/treatment-related adverse effects) and its outcomes (survival and quality of life) in geriatric cancer populations.
Methods:
Scientific databases Embase and Pubmed were searched for published scientific literature on physical comorbidity and geriatric cancer patients. Google Scholar was searched for scholarly literature published in non-indexed journals. Snowballing was done to identify research papers that may have been missed from the above searches.
Results:
In the 29 studies, comorbidities ranged from 37.9-74.3% in colorectal cancer, 74-81% in head and neck cancer, and 12.6-49% in breast cancer. Moderate comorbidities ranged from 13-72.9% and severe comorbidities from 2.5-68.2%. Chemotherapy was the most common treatment for cancer in these cases, used alone or in combination with other treatment procedures (75.9%). Comorbidity increased with age, with both factors (comorbidity and age) affecting the treatment choice and process. Physical comorbidities significantly affected treatment initiation, causing delay, toxicity and discontinuation. Geriatric cancer patients were given less vigorous and non-standard treatments and were also less likely to be ‘offered’ treatment. Where patients are given more vigorous treatment, they showed better survival outcomes in a few studies. Appropriate treatment in geriatric cancer patients increased both overall and disease related survival rates. This systematic review shows that treatment choice should be based on biological age and functional status of the elderly rather than chronological age. None of the studies noted rurality as a distinct variable.
Conclusions:
This systematic review concludes that there is evidence to substantiate the adverse effect of comorbidity on treatment and survival outcomes, although the mechanism by which comorbidity impedes or impacts treatment is unknown in many cases. Low quality proof is available, however, for considering functional status and biological age in treatment decisions. Rurality was not featured as a variable in any of the studies assessed. Future studies which substantiate the value of comprehensive geriatric assessment before treatment initiation in cancer patients, including assessment of the nature and severity of comorbidities, could lessen the effect of comorbidities on the treatment process.
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