Malignant plural effusion visualized by ¹⁸F-FDG PET/CT: The possible role of presence of hypoxia in cancer cells

Introduction: In mouse modes of human cancer cells, we have previously reported that cancer cell clusters in ascites associated with high¹⁸F-FDG accumulation visualized by autoradiography due to the presence of severely hypoxia of these cancer cells (J Nucl Med 2010;51:632-8, Transl Oncol. 2014; 7: 240-7). The objective of this study was to examine (18)F-FDG uptake in cancer cell clusters of plural effusion in patients with PET/CT.

Methods: The study was approved by IRBs and written consents were obtained from all patients. A total of 20 patients with pathologically confirmed lung cancer and presence of plural effusion, and 5 patients with benign plural effusion after pathological confirmation or follow up were included in this study. After 6 hours fasting, patients were intravenously injected ¹⁸F-FDG (0.1mCi/Kg body weight); patients were positioned supine on the scanning bed and PET/CT scan was performed 1 h after ¹⁸F-FDG injection to obtain whole body PET imaging.

Results: The intratumoral ¹⁸F-FDG accumulation was generally heterogeneous in primary lesions of lung cancer. Plural effusion is generally low ¹⁸F-FDG avid, however, cancer cells deposit of plural effusion as visualized by CT always associated with high¹⁸F-FDG accumulation (Figure 1). On the other hand, little ¹⁸F-FDG accumulation is visualized in benign plural effusion and without detectable cells deposit in CT imaging.

Conclusions: In patients, cancer cells in plural effusion associate with high FDG accumulation, therefore, ¹⁸F-FDG PET/CT may be used to differentiate plural effusion. High FDG accumulation in cancer cells clusters of plural effusion possibly due to the presence of hypoxia as we identified in animal model of ascites tumors (Transl Oncol. 2014; 7: 240-7). Acknowledgements: the author thank the technique support of Dr. Yong Li MD, PhD, PET Center, the First Affiliated Hospital of Harbin Medical University, Harbin, China. The author’s research is supported by an internal grant of Shenzhen People's Hospital.