Age and comorbidity considerations related to radiotherapy and chemotherapy administration

Oncological treatment decision-making is a highly complex enterprise integrating multiple patient, tumor, treatment, and professional factors with the available medical evidence. This management complexity can be exacerbated by the interplay of patient age and comorbid non-cancer conditions that can affect patient quality of life, treatment tolerance, and survival outcomes. Given the expected increase in median age (and associated comorbidity burden) of Western populations over the next few decades, the use of evidence-based therapies that appropriately balance treatment intensity and tolerability to achieve the desired goal of treatment (radical, adjuvant, salvage, or palliative) will be increasingly important to health care systems, providers, and patients. In this review, we highlight the evidence related to age and comorbidity, as it relates to radiotherapy and chemotherapy decision making. We will address evidence as it relates to age and comorbidity considerations separately and also the interplay between the factors. Clinical considerations to adapt radiation and/or chemotherapy treatment to deal with comorbidity challenges will be discussed. Knowledge gaps, future research, and clinical recommendation in this increasingly important field are highlighted as well.