Five-year follow-up of appendiceal neoplasm risk in periappendicular abscess in the Peri-Appendicitis Acuta Randomized Clinical Trial.

from January 2013 to April 2016. This long-term follow-up at a minimum of 5 years was added to the study protocol subsequently targeted to assess the follow-up group patients initially declining to undergo appendectomy after study termination. First, this long-term MRI follow-up was added to ensure patient safety based on the high appendiceal tumor rate at 1-year follow-up. 1 Patients gave a separate written informed consent for this imaging. Second, this observational follow-up assessed the long-term outcomes of the trial patients initially diagnosed with an appendiceal tumor by reviewing their medical records. The detailed methods and primary results have been previously published 1. The difference between groups in age was tested using Mann–Whitney U-test. The study was approved by the Ethical Committee of Turku University Hospital district and conducted in accordance with the Declaration of Helsinki following the relevant portions of the Consolidated Standards of Reporting Trials (CONSORT) reporting guideline.