Therapy response evaluation with positron emission tomography-computed tomography

Area of Science:

• Oncology
• Nuclear Medicine
• Radiology

Background:

• Fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) is utilized for evaluating therapy response in solid tumors.
• Its adoption in clinical trials is limited by protocol variability and lack of universal response criteria.

Purpose of the Study:

• To discuss the challenges and potential of FDG PET-CT in assessing treatment response in solid tumors.
• To explore the utility of semiquantitative methods and descriptive terminology in clinical practice versus clinical trials.

Main Methods:

• Review of current practices and proposed criteria for FDG PET-CT response assessment.
• Discussion of semiquantitative metrics like standard uptake value (SUV) for tissue glucose metabolism.
• Analysis of the applicability of clinical trial response terms (e.g., partial response, complete response, progressive disease) in clinical practice.

Main Results:

• Gestalt impression can be accurate for identifying progressive disease and complete response in individual patients.
• Semiquantitative methods, such as SUV, can describe glucose metabolism and therapeutic changes if quality control is maintained.
• Clinical trial response terms have specific meanings and definitions that are difficult to apply in routine clinical practice.

Conclusions:

• Standardized acquisition and processing protocols, along with universal response criteria, are crucial for broader FDG PET-CT adoption in clinical trials.
• In clinical practice, descriptive terminology agreed upon by imaging physicians and clinicians may be more practical than strict clinical trial criteria.
• Careful quality control is essential for the reliable use of semiquantitative FDG PET-CT data in assessing treatment response.