Frailty and outcomes after systemic treatment in older patients with cancer

Half of the people diagnosed with cancer in the Netherlands are aged 70 years or older. This group is highly diverse: while some older adults remain fit and independent, others are frail due to additional health problems. Frail older patients are more likely to experience side effects from cancer treatments, which can lead to hospital admissions, reduced quality of life, and higher healthcare costs. Despite this, older adults are often underrepresented in clinical studies, limiting our understanding of how well they tolerate cancer treatments.<br>This PhD thesis examined the association between frailty and treatment outcomes in older patients receiving systemic cancer treatments, such as chemotherapy, hormonal therapy, and targeted therapies. We showed that frail patients more frequently experience severe side effects from chemotherapy and are at higher risk of declining quality of life and physical independence. Based on these findings, we initiated the DOSAGE trial, in which older patients with metastatic colorectal cancer receive dose-reduced chemotherapy, aiming to lower side effects while preserving quality of life. At the same time, we found that some treatments—such as hormonal therapy and the targeted drug palbociclib for breast cancer—are generally well tolerated by older patients.<br>Overall, these findings underline the importance of assessing frailty before starting cancer treatment to support more personalized care for older adults.<br>