The Role of Tissue and Liquid Biopsy in the Clinical Management of Adult Lung Cancer Patients in King Abdul-Aziz Medical City in Riyadh, Saudi Arabia.

Background Lung cancer is the most fatal malignancy worldwide, characterized by uncontrolled growth in the tissue of the lung(s). The diagnosis of lung cancer depends on the medical history of the patient, along with the physical examination, and various imaging studies. Furthermore, sputum cytology, thoracentesis, or a tissue and liquid biopsy can be examined. The TNM (tumor size, lymph nodes, and metastasis) system is used for staging and grading lung cancer. This study aimed to evaluate the role of tissue vs liquid biopsy in the clinical management of adenocarcinoma, at King Abdulaziz Medical City, Riyadh. Methods In this cross-sectional study, all adenocarcinoma patients treated between January 2016 to December 2018 were included using consecutive sampling. The participants were ≥ 18 years old patients with histologically confirmed adenocarcinoma (stage IIIb/IV) regardless of the mutation status. This data was collected through chart review. Data analysis was performed using the IBM Statistical Software for Social Sciences (SPSS) software, version 22 (IBM SPSS Statistics for Windows, Armonk, NY).  Results A total of 58 participants were included in the analysis. All of them had undergone a tissue biopsy, while only 16 patients underwent liquid biopsy. Out of all patients, 26% of patients had tissue biopsy-related complications (TBRC), with pneumothorax being the most common complication. Single gene testing for epidermal growth factor receptor (EGFR) for patients who underwent tissue biopsy showed a 35% mutation rate. For the anaplastic lymphoma kinase (ALK) gene, 13% were found to be mutated; for the ROS proto-oncogene 1 (ROS1) gene, only 7% were seen to be mutated. For a panel of 12 genes, 25% had the tumor protein 53 (TP53) gene mutation and 39% had the gene Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations. For patients who underwent a liquid biopsy, 20% had the TP53 mutation, 43% had the EGFR mutations on a single gene test and 42% on a panel test, and 10% had the KRAS mutation. Conclusion We found that tissue and liquid biopsy showed genetic mutations, particularly with EGFR, TP53, and KRAS genes, among adenocarcinoma patients. Identifying genetic changes in adenocarcinoma patients is essential for charting a targeted therapy. Primary EGFR mutations and rearrangements of ALK or ROS1 are the only gene mutations that can be done with specific tyrosine kinase inhibitors available for clinical practice. Therefore, we recommend further studies to evaluate the role of tissue and liquid biopsy in clinical practice.