Plasma Metabolomics as a Tool to Distinguish PET-positive Malignant From PET-positive Benign Nodules

Positron emission tomography-computed tomography (PET-CT) is an important technique in lung cancer staging, where almost no lung lesion goes undetected. However, PET-CT often fails to discriminate between malignant and non-malignant PET-positive solitary pulmonary nodules (SPNs) with a specificity of only 23%. 40-50% of those patients are advised to repeat their CT after three to six months to follow up on their lesions' progression, delaying a clear and correct cancer diagnosis and subsequent therapy. In more than 10% of the patients with an SPN on the PET-CT scan, an uncertain lung cancer diagnosis based on the PET-positive lesion leads to surgery that appears to be unnecessary. This project aims to use the plasma glutamate concentration as a biomarker to complement PET-CT in the discrimination between malignant and non-malignant PET-positive SPNs. The investigators will validate a plasma glutamate determination by high- performance liquid chromatography (HPLC) since this test needs to be rapid, cheap, minimally invasive, and available in every hospital. In addition to the analysis of plasma glutamate, other plasma metabolites will be screened to check for other potential biomarkers to discriminate between malignant and non-malignant PET-positive SPNs. Together with the PET-CTs' basic parameters, a quick measurement of fasted plasma glutamate and potentially other biomarker levels right before undergoing a PET-CT scan will support a more rapid lung cancer diagnosis and treatment, resulting in less risk for disease progression. In conclusion, our approach will improve the accuracy of lung cancer diagnosis, and avoid unnecessary surgery.

Sex

All

Inclusion Criteria:

* patients who undergo a PET-CT scan at ZOL for a lung nodule, who are willing to provide written informed consent

Exclusion Criteria:

* no fasting starting 6h prior to blood sampling;
* medication intake on the morning of blood sampling;
* fasting blood glucose concentration is higher than 200 mg/dL in the morning of blood sampling;
* history of cancer during the past five years;
* treatment for cancer during the past five years.

• BACKGROUNDVanhove K, Giesen P, Owokotomo OE, Mesotten L, Louis E, Shkedy Z, Thomeer M, Adriaensens P. The plasma glutamate concentration as a complementary tool to differentiate benign PET-positive lung lesions from lung cancer. BMC Cancer. 2018 Sep 3;18(1):868. doi: 10.1186/s12885-018-4755-1. PMID 30176828
• BACKGROUNDDerveaux E, Geubbelmans M, Criel M, Demedts I, Himpe U, Tournoy K, Vercauter P, Johansson E, Valkenborg D, Vanhove K, Mesotten L, Adriaensens P, Thomeer M. NMR-Metabolomics Reveals a Metabolic Shift after Surgical Resection of Non-Small Cell Lung Cancer. Cancers (Basel). 2023 Apr 3;15(7):2127. doi: 10.3390/cancers15072127. PMID 37046788