Document is current

Article History

Received: 6 September 2017

Accepted: 31 January 2018

First Online: 9 February 2018

Ethics approval and consent to participate

: This study was approved by the University of Michigan Institutional Review Board (IRB # HUM00099459). This study was determined not to require review by the University of Michigan Health System Comprehensive Cancer Center Protocol Review Committee as it did not involve a cancer-related therapeutic clinical research protocol or a cancer prevention or control research protocol. A waiver of informed consent was granted based on the following University of Michigan Institutional Review Board criteria all being met: 1. The research involved no more than minimal risk to the subjects; 2. The waiver would not adversely affect the rights and welfare of the subjects; 3. The research could not practicably (i.e., feasibly) be carried out without the waiver or alteration (given the retrospective nature spanning over 20 years during which many patients died); 4. Whenever appropriate, it was agreed that the subjects would be provided with additional pertinent information obtained from the study.

: Not applicable.

: The authors declare that they have no competing interests.

: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.