Principles of Radiation Therapy in Older Adults

Abstract

The specialty of radiation oncology has significantly evolved over the past few decades. Historically, large volumes of normal tissue were irradiated along with the tumor due to the prevailing techniques and equipment in the era of two-dimensional delivery. This led to an increased incidence of side effects, causing difficulty for elderly patients to tolerate treatment. Not only were toxicities higher but also the radiation dose could not be escalated due to uncertainty about tumor location and dose to the intended target. With the advent of computer integration into the radiation oncology clinic, the therapeutic window improved dramatically. For the first time, tumors could be visualized in three dimensions so that a new technique called 3D conformal radiation therapy (3D-CRT) evolved. The tumors could now be delineated such that the dose could be spatially encompassed with more precision than ever before. This led to significant improvements in local control for a variety of tumor types with fewer side effects, which is of particular concern in elderly patients, who usually present with a higher number of comorbidities that can limit treatment toleration. This chapter will discuss advances in radiotherapy and their significance for elderly patients. It will also discuss considerations for neoadjuvant, definitive, adjuvant, and palliative radiation in a geriatric population across tumor sites, with a focus on toxicity and tolerability.