Prognostic Significance of Volume-Based PET Parameters in Cancer Patients

Abstract

Accurate prediction of cancer prognosis before the start of treatment is important since these predictions often affect the choice of treatment. Prognosis is usually based on anatomical staging and other clinical factors. However, the conventional system is not sufficient to accurately and reliably determine prognosis. Metabolic parameters measured by 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) have the potential to provide valuable information regarding prognosis and treatment response evaluation in cancer patients. Among these parameters, volume-based PET parameters such as metabolic tumor volume and total lesion glycolysis are especially promising. However, the measurement of these parameters is significantly affected by the imaging methodology and specific image characteristics, and a standard method for these parameters has not been established. This review introduces volume-based PET parameters as potential prognostic indicators, and highlights methodological considerations for measurement, potential implications, and prospects for further studies.

Prognostic Value of Metabolic Tumor Volume and Total Lesion Glycolysis in Head and Neck Cancer: A Systematic Review and Meta-Analysis

“…High volumetric parameters were significant variables in predicting a worse prognosis except in 1 study (20). The cutoff values of MTV ranged between 7.7 and 45 cm 3 and those of TLG ranged from 55 to 330. The mean quality score was 79.4%, ranging from 70% to 85%.…”

“…Standardized uptake value (SUV) is a semiquantitative measure of the normalized concentration of radioactivity in a lesion, and maximum SUV (SUVmax) is one of the most widely used parameters in clinical practice (1). However, SUVmax shows the highest intensity of 18 F-FDG uptake within the region of interest or volume of interest (VOI) and cannot represent total tumor uptake for the entire tumor mass (3).…”

“…PET using 18 F-FDG has become a standard modality for staging, restaging, and monitoring the treatment response in a variety of tumors (3). In addition, it is more accurate than conventional staging in HNC, overcoming the limitations of morphologic imaging modalities (1).…”

“…Then, TLG can be calculated by multiplying MTV by mean SUV, which weights the volumetric burden and metabolic activity of tumors (3)(4)(5). Commercially available tools for tumor analysis enable rapid and easier measurement of MTV or TLG (3). These parameters could be used to reflect disease burden and tumor aggressiveness in some kinds of malignant tumors (6).…”

“…MTV and mean SUV can be measured by contouring margins defined by thresholds. Then, TLG can be calculated by multiplying MTV by mean SUV, which weights the volumetric burden and metabolic activity of tumors (3)(4)(5). Commercially available tools for tumor analysis enable rapid and easier measurement of MTV or TLG (3).…”