Lesion Analysis in PERCIST 1.0: Clinical Ease versus Research Requisite-Where Does the Balance Exist?

Area of Science:

• Nuclear Medicine
• Oncology
• Radiology

Background:

• SUVmax is a common semiquantitative parameter for PET response evaluation, focusing on a single lesion's metabolic activity.
• Newer parameters like tumor lesion glycolysis (TLG) and whole-body metabolic tumor burden (MTBwb) are being explored for more comprehensive response assessment.
• This study compares SUVmax, TLG, and MTBwb in advanced non-small cell lung cancer (NSCLC) for response evaluation, overall survival (OS), and progression-free survival (PFS).

Purpose of the Study:

• To evaluate and compare different semiquantitative PET parameters (SUVmax, TLG, MTBwb) for response assessment in advanced NSCLC.
• To analyze the efficacy of these parameters in predicting overall survival (OS) and progression-free survival (PFS).
• To determine the optimal timing (early vs. late) for response evaluation in NSCLC patients undergoing tyrosine kinase inhibitor therapy.

Main Methods:

• ¹⁸F-FDG-PET/CT imaging was performed on 23 advanced NSCLC patients (Stage IIIB-IV) before therapy.
• Quantitative PET parameters including SUVmax and TLG were measured for single (most metabolic) lesions, multiple lesions, and MTBwb.
• Parameters were compared for early and late treatment response evaluation and analyzed for correlation with OS and PFS.

Main Results:

• No significant difference in response evaluation was observed when comparing single lesion (SUVmax), multiple lesions, or MTBwb.
• Early response evaluation (22 DC, 1 NDC) showed a statistically significant association with OS compared to late evaluation (20 DC, 3 NDC).
• The observed differences in response evaluation remained consistent regardless of whether single lesions, multiple lesions, or MTBwb were used for measurement.

Conclusions:

• Single most metabolic lesion measurements provide similar disease response and OS information as multiple lesions or MTBwb.
• Late-phase imaging offers no significant advantage over early-phase imaging for response evaluation in advanced NSCLC.
• Early response evaluation using the SUVmax parameter presents a favorable balance between clinical practicality and research requirements.