Mixed response on regorafenib treatment for GIST (gastro-intestinal stromal tumor) according to 18F-FDG-PET/CT

Clinical significance of 18F-FDG PET/CT imaging in 32 cases of gastrointestinal stromal tumors

Objectives

To explore the clinical significance of ¹⁸F-FDG metabolic imaging in the diagnosis and biological risk assessment of gastrointestinal stromal tumors (GIST).

Methods

This study is a clinical retrospective study. The research subjects were patients with GIST who were admitted to our hospital from January 2014 to December 2019 and underwent ¹⁸F-FDG metabolic imaging, and the relationship between biological risk and FDG metabolism was analyzed retrospectively.

Results

A total of 32 patients with GIST were included in this study, of which 17 patients had very low and low-risk lesions, and the FDG metabolism level did not increase; five patients had moderate-risk gastric lesions, and the FDG metabolism level was abnormally increased; 10 patients had high-risk lesions, and except for one patient with multiple lesions, the FDG metabolism level of these patients was increased.

Conclusions

The level of glucose metabolism is abnormally increased in tumor cells with vigorous mitosis and has higher biological risk. The ¹⁸F-FDG metabolism level can determine the biological risk of GIST and whether high-risk lesions involve other tissues and organs, as it more comprehensively reflects the distribution of lesions, the activity of tumor cells and the stage of the disease.

18F-FDG PET/CT Evaluation of Crizotinib and Lorlatinib Therapy in Metastatic ROS-1-Positive Non-Small Cell Lung Cancer

ROS-1-positive non-small cell lung cancers (NSCLCs) are rare (approximately 1% of all NSCLCs) and require a first-line treatment by crizotinib. Crizotinib resistance is frequent within the first 12 months of treatment. Lorlatinib is a novel tyrosine kinase inhibitor of ROS-1 recently indicated for metastatic or locally advanced crizotinib-resistant NSCLC. We report the use of lorlatinib as second-line with a complete tumoral response after only 3 months of treatment. This case shows the major role of F-FDG PET/CT in treatment evaluation and monitoring targeted therapy in metastatic NSCLC.