According to PET response criteria, how should treatment response in solid tumors be evaluated based on changes in SUV?

In the context of evaluating treatment response in solid tumors using PET, the most relevant criterion is the percentage change in the standardized uptake value (SUV) of the hottest lesions. This approach is centered around identifying metabolic changes in the areas that are most active, which can provide the clearest indication of treatment efficacy.

Evaluating percentage change in the hottest lesions allows for a more sensitive measure of response since these lesions are typically the ones of greatest concern and relevance for treatment outcomes. The use of the hottest lesions ensures that the analysis focuses on the areas of most significant metabolic activity, which is often crucial in determining how well a treatment is working.

The absolute change in SUV could potentially miss smaller lesions that respond well to treatment but start with a lower baseline uptake. Meanwhile, looking at overall average changes or changes across all lesions might not accurately reflect the dynamics occurring in the most aggressive or clinically significant lesions. These methods may dilute the insights gained from the most prominent lesions, which are typically the focus in assessing how well a treatment is controlling the disease.

Thus, percentage change in the hottest lesions provides a valuable metric for assessing treatment response, helping to guide further therapy and management decisions effectively.