Expert consensus on the potential benefits of early cancer detection does not exist for most cancer types. We convened 10 practicing oncologists using a RAND/UCLA modified Delphi panel to evaluate which of 20 solid tumors, representing >40 American Joint Committee on Cancer (AJCC)-identified cancer types and 80% of total cancer incidence, would receive potential clinical benefits from early detection. Pre-meeting, experts estimated how long cancers take to progress and rated the current curability and benefit (improvement in curability) of an annual hypothetical multi-cancer screening blood test. Post-meeting, experts rerated all questions. Cancers had varying estimates of the potential benefit of early cancer detection depending on estimates of their curability and progression by stage. Cancers rated as progressing quickly and being curable in earlier stages (stomach, esophagus, lung, urothelial tract, melanoma, ovary, sarcoma, bladder, cervix, breast, colon/rectum, kidney, uterus, anus, head and neck) were estimated to be most likely to benefit from a hypothetical screening blood test. Cancer types rated as progressing quickly but having comparatively lower cure rates in earlier stages (liver/intrahepatic bile duct, gallbladder, pancreas) were estimated to have medium likelihood of benefit from a hypothetical screening blood test. Cancer types rated as progressing more slowly and having higher curability regardless of stage (prostate, thyroid) were estimated to have limited likelihood of benefit from a hypothetical screening blood test. The panel concluded most solid tumors have a likelihood of benefit from early detection. Even among difficult-to-treat cancers (e.g., pancreas, liver/intrahepatic bile duct, gallbladder), early-stage detection was believed to be beneficial. Based on the panel consensus, broad coverage of cancers by screening blood tests would deliver the greatest potential benefits to patients., Competing Interests: I have read the journal’s policy and the authors of this manuscript have the following competing interests: LS, SA, HB, JB, GTB, LC, MC, PC, BJM, DJW reported consulting fees from Partnership for Health Analytic Research (PHAR), LLC and GRAIL, LLC, a subsidiary of Illumina, Inc., currently held separate from Illumina, Inc. under the terms of the Interim Measures Order of the European Commission dated 29 October 2021. ARK and AK are employees of GRAIL, LLC, a subsidiary of Illumina, Inc., currently held separate from Illumina, Inc. under the terms of the Interim Measures Order of the European Commission dated 29 October 2021, who supported this study, and reported stock or stock options in Illumina (parent company of GRAIL, LLC, a subsidiary of Illumina, Inc., currently held separate from Illumina, Inc. under the terms of the Interim Measures Order of the European Commission dated 29 October 2021). MSB, IY, and CC are employees of Partnership for Health Analytic Research (PHAR), LLC which was paid by the following to conduct research related to the work described in the manuscript: Abbvie, Amgen, AstraZeneca, Biomarin Pharmaceuticals, BMS, Celgene, Dompe, Eisai, Exact Sciences Corporation, Genentech, GRAIL, LLC, a subsidiary of Illumina, Inc., currently held separate from Illumina, Inc. under the terms of the Interim Measures Order of the European Commission dated 29 October 2021, Ionis, Jazz, Kite, Novartis, Otsuka, Recordati, Regeneron, Sanofi US Services, Takeda Pharmaceuticals USA. This does not alter our adherence to PLOS ONE policies on sharing data and materials., (Copyright: © 2022 Schwartzberg et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)