The potential benefits and harms of cancer screening – perspectives from the US Preventive Services Taskforce

Lecture by Prof Mark Ebell, University of Georgia, USA

Supported by the HRB Primary Care Clinical Trials Network Ireland
(a collaboration between NUI Galway, RCSI and the Irish College of General Practitioners)

While there are many kinds of cancer, for only a few is there evidence that the potential benefits of screening outweigh the potential harms. While potential benefits are substantial for a small number of those screened (a death averted), all patients experience some degree of inconvenience, and many are subjected to the harms of biopsies and other follow-up tests. A new kind of harm, increasingly recognized and present with most kinds of cancer screening, is overdiagnosis. As our technology has evolved, we are able to detect smaller and smaller lesions that may appear cancerous, actually do not behave like a cancer. About 1 in 5 persons who have a breast or lung cancer detected by screening would have lived a full life with the cancer never causing any symptoms (“overdiagnosis”). Dr Ebell will discuss the process of the US Preventive Services Task Force for making screening recommendations, how their recommendations compare with those in Ireland, the harms of both underdiagnosis and overdiagnosis, and what we can learn from each other about balancing benefits and harms.

Professor Mark Ebell is a graduate of the University of Michigan’s Medical School, Family Medicine Residency, and School of Public Health. He is currently a Professor in the Department of Epidemiology and Biostatistics in the College of Public Health at the University of Georgia. Dr Ebell is Editor-in-Chief of Essential Evidence and Deputy Editor of the journal American Family Physician. He is author of over 350 peer-reviewed articles and is author or editor of seven books, with a focus on evidence-based practice, systematic reviews, medical informatics, and clinical decision-making. Dr Ebell served on the US Preventive Services Task Force from 2012 to 2015, and in 2019 will be a Fulbright Scholar at RCSI in Dublin, Ireland.