Bach reported that he has received speaking fees from Genentech. Dr. Detterbeck reported that he was reimbursed for travel costs associated with his work on the Oncimmune advisory board, and has participated without compensation in a symposium on CT screening sponsored by Covidien. Dr.Berry reported that he is co-owner of Berry Consultants LLC which designs adaptive clinical trials for pharmaceutical companies, medical device companies and NIH cooperative groups. To the best of his knowledge none of these parties have any interest in lung cancer screening. Dr. Gould reported that he receives grant support from the National Cancer Institute. Dr. Jett reported that he has grants pending for work related to screening and early detection of lung cancer with Oncimmune and Isense. Dr. Sabichi reported her membership on the National Cancer Institute's PDQ Prevention and Screening Editorial Board and her possession of a pending patent for a test for the detection of bladder cancer. Dr. Wood reported his participation in the development of the National Comprehensive Cancer Network's clinical practice guidelines for lung cancer screening in his role as Chair of the NCCN Lung Cancer Screening Panel.

Purpose Clinical use of analytical tests to assess genomic variants in circulating tumor DNA (ctDNA) is increasing. This joint review from ASCO and the College of American Pathologists summarizes current information about clinical ctDNA assays and provides a framework for future research. Methods An Expert Panel conducted a literature review on the use of ctDNA assays for solid tumors, including pre-analytical variables, analytical validity, interpretation and reporting, and clinical validity and utility. Results The literature search identified 1,338 references. Of those, 390, plus 31 references supplied by the Expert Panel, were selected for full-text review. There were 77 articles selected for inclusion. Conclusion The evidence indicates that testing for ctDNA is optimally performed on plasma collected in cell stabilization or EDTA tubes, with EDTA tubes processed within 6 hours of collection. Some ctDNA assays have demonstrated clinical validity and utility with certain types of advanced cancer; however, there is insufficient evidence of clinical validity and utility for the majority of ctDNA assays in advanced cancer. Evidence shows discordance between the results of ctDNA assays and genotyping tumor specimens and supports tumor tissue genotyping to confirm undetected results from ctDNA tests. There is no evidence of clinical utility and little evidence of clinical validity of ctDNA assays in early-stage cancer, treatment monitoring, or residual disease detection. There is no evidence of clinical validity and clinical utility to suggest that ctDNA assays are useful for cancer screening, outside of a clinical trial. Given the rapid pace of research, re-evaluation of the literature will shortly be required, along with the development of tools and guidance for clinical practice.