Measuring side effects after radiotherapy for pharynx cancer

Abstract

Data on side effects after radiotherapy is needed to establish the benefits and drawbacks of new treatments, but side effects are not quantified as easily as survival or local control. Side effects may be quantified using physical measures. Unfortunately, only few endpoints exist where a physical measure is obtainable, and the case of a patient-relevant measure is even rarer. Radiotherapy is often followed by complex symptoms not easily quantifiable by the observer. Quantitative patient reported side effects can be retrieved using validated questionnaires, but this kind of data is often difficult to interpret and the correlation with clinically observable or measurable changes not straightforward.

The exploitation of the possibilities of highly conformal radiotherapy and multimodality treatment depends on a better understanding of the correlation between dose, volume, modifying factors, and side effects. Using pharynx cancer as an example, the purpose of this article is to summarize the possibilities and limitations of different methods for measurement of radiotherapy-induced side effects.