For many older individuals, the decision to undergo treatment for cancer is viewed as a tradeoff between loss of function and extension of life: a decision that often is complicated by concomitant issues such as comorbid medical conditions, frailty, functional declines, family dynamics, and social and psychological issues. This poses several challenges and affords opportunities for healthcare professionals conducting research with older cancer patients who are undergoing treatment. The current article presents a summary of a roundtable discussion of the issues that face older individuals with cancer during the treatment phase of a cancer diagnosis. The issues covered include the importance of conducting thorough assessments, addressing methodological issues, differentiating age from cohort issues, reducing patient and healthcare provider misperceptions, and taking a multidisciplinary approach to care. To address the aforementioned issues, future research directions in the treatment phase of the cancer continuum should include encouraging transdisciplinary work; increasing age-related, behaviorally focused research that also is sensitive to differentiating age and cohort effects; understanding the impact of comorbidity; and separating out the influences of age, comorbidity, and performance status.