Pivotal Role of Liquid Biopsy in Diagnosing, Managing and Monitoring Early and Advanced Stages of Lung Cancer among Asian Population

RATIONALE: Non-small cell lung cancer (NSCLC) remains the leading cause ofcancer-related deaths among Asian population. Liquid biopsy is a new technology thatprovides information on tumor gene profiling through examination of cell-free DNA(CfDNA) in whole blood. This produces data on genetic alterations found in tumortissue that could be used for prompt and effective management of NSCLC.MATERIALS AND METHODS: Between September 2016 and December 2016, weretrospectively collected and reviewed the medical records of thirty-five patients whowere suspected or diagnosed of lung cancer, then underwent serum epidermal growthfactor receptor (EGFR) for further investigation. Liquid biopsy results were comparedwith the subjects’ final diagnosis.RESULTS: The final diagnoses revealed eighteen (51%) benign and seventeen (49%)malignant cases. Fourteen out of seventeen malignant cases were diagnosed asadenocarcinoma. The remaining three out of seventeen subjects’ diagnoses were:anaplastic giant cell, carcinoid tumor and thyroid cancer with lung metastasis. Thesethree were considered as true negative for EGFR liquid biopsy results. The fourteenmalignant cases were divided into two categories which were surgical and chemotherapyor TKI groups. In the surgical group, five were positive for tissue EGFR mutationfollowed by a negative serum EGFR results post-surgery. One out of the five casesreported negative serum EGFR just four days post-operatively.In the chemotherapy or tyrosine kinase inhibitor (TKI) group, four out of nine weretested prior to treatment with three positive results. One was negative serum EGFR buthad positive tissue EGFR. One case out of nine reported positive EGFR followed by anegative EGFR at thirteen days while on treatment. The last four subjects were testedduring prolonged treatment. Two from the four cases reported negative results. Onedetected resistance and the last case was negative EGFR but later deteriorated.CONCLUSION: Liquid biopsy’s roles include lung cancer screening, treatmentevaluation, assessment of recurrence or resistance, an alternative for tissue biopsy anda complementary blood test with radiographic imaging. This test substantially improvespatient care and outcomes at all stages of lung cancer.Keywords: lung cancer diagnosis, Non-small cell lung cancer, liquid biopsy, epidermalgrowth factor receptor