Response Assessment of Gastric Adenocarcinoma Using ⁶⁸Ga-FAPI-46 and 18 F-FDG PET/CT : Highlighting the Role of the Tumor Microenvironment in Therapy Resistance.
Mahsa Sheikhnezami, Mohammad Hadi Samadi, Ramin Sadeghi et al.
✦ AI-curated · Sources linked
Case in brief
A 71-year-old woman with recurrent gastric adenocarcinoma exhibited colonic wall involvement on a follow-up CT scan. Initial 18F-FDG PET/CT indicated intense uptake in the colonic and omental regions, suggesting recurrent malignancy. Post-chemotherapy, while 18F-FDG PET/CT showed metabolic improvement, 68Ga-FAPI PET/CT revealed persistent uptake in the colonic wall and peritoneum, indicating ongoing clinical deterioration and highlighting a potential treatment resistance linked to the tumor microenvironment.
What made this case unusual
The case illustrates a discordance between 18F-FDG and 68Ga-FAPI PET/CT findings, suggesting differential responses between tumor cells and cancer-associated fibroblasts, which is atypical in treatment assessments.
Diagnostic / clinical pearl
Clinicians should consider the role of the tumor microenvironment in treatment resistance, as indicated by persistent uptake in FAP-targeted imaging despite metabolic improvement on standard PET imaging.
Why it matters
This case underscores the importance of integrating FAP-targeted strategies in treatment planning, as traditional imaging may not fully capture therapeutic responses related to the tumor microenvironment.