RT Journal Article SR Electronic T1 Lead time bias in estimating survival outcomes JF Gut JO Gut FD BMJ Publishing Group Ltd and British Society of Gastroenterology SP 538 OP 539 DO 10.1136/gutjnl-2015-310199 VO 65 IS 3 A1 Antonio Facciorusso A1 Jose Ferrusquía A1 Nicola Muscatiello YR 2016 UL http://gut.bmj.com/content/65/3/538.abstract AB