Nineteen cases with synchronous multiple primary cancers studied by ¹⁸F-FDG PET/CT

Area of Science:

• Oncology
• Nuclear Medicine
• Radiology

Background:

• Synchronous multiple primary cancers (SMPC) present diagnostic challenges.
• Accurate identification of SMPC is crucial for effective treatment planning and patient outcomes.

Purpose of the Study:

• To assess the diagnostic utility of 18F-FDG PET/CT in patients with pathologically confirmed SMPC.
• To analyze the metabolic characteristics of synchronous primary tumors using 18F-FDG PET/CT.

Main Methods:

• Retrospective analysis of 19 patients with pathologically confirmed SMPC.
• Review of clinical data and 18F-FDG PET/CT imaging characteristics.
• Measurement of maximum standardized uptake value (SUVmax) and calculation of ΔSUVmax between primary tumors.

Main Results:

• 38 lesions were identified, predominantly in the gastrointestinal tract (16) and lung (10).
• Adenocarcinoma was the most common pathology (18/38).
• Mean SUVmax was 8.5±6.9, with 30/38 lesions showing SUVmax > 2.5. Mean ΔSUVmax was 57.3%±24.6%, indicating metabolic heterogeneity.

Conclusions:

• SMPC frequently involves the gastrointestinal tract, with adenocarcinoma being the most common type.
• 18F-FDG PET/CT is effective in diagnosing SMPC.
• ΔSUVmax effectively differentiates the metabolic profiles of synchronous primary cancers, suggesting different origins.