Can18F-FDG PET/CT overcome endoscopy in the staging of gastrointestinal involvement in Mantle Cell Lymphoma? A retrospective multi-center cohort analysis.

Abstract Background. Mantle-cell lymphoma (MCL) represents the 5-7% of all lymphoid malignancies. In 15-30% of cases by different data, MCL may affect the gastrointestinal tract (GI), but the real frequency by endoscopy and imaging could be significantly higher. Actually, by guidelines there are no recommendations for GI endoscopy in every patient with MCL. Therefore, we conducted the present multi-center study with the aim to evaluate the performance of the 18F-FDG PET/CT in the detection of GI involvement in patients with MCL and establish whether it is possible to omit endoscopy.Methods. We retrospectively evaluated 79 patients with newly diagnosed MCL, who had performed a pretreatment 18F-FDG PET/CT scan and GI endoscopy with biopsy. Results. By PET/CT, overall GI tract involvement was found in 24% of patients. The performance of PET/CT have been evaluated by sensitivity, specificity, positive predictive value, negative predictive value and accuracy in the upper and lower GI tract. Using Cohen's k test, PET/CT and EGD with biopsy showed a fair agreement (0.20, 66.6%). However, PET/CT and colorectal biopsy showed a moderate agreement (0.49, 76%). Conclusion. Analyzed data suggest that the performance of 18F-FDG PET/CT is not excellent in the detection of gastric lesions by MCL, and thus EGD with biopsy has yet to be considered a "golden standard" in this subset, while colonoscopy could be omitted due to a higher accuracy and specificity. Taking into account the limit of the retrospective nature of the study, data should be confirmed on larger and prospective cohort.