Received: 30 October 2018
Accepted: 27 November 2019
First Online: 5 December 2019
Ethics approval and consent to participate
: The study protocol was reviewed and approved by the Institutional Review Board and Ethics Committee of the School of Medicine, <i>Universidad Nacional Autónoma de México</i> (registration number 054/2014), and of the <i>Instituto Nacional de Cancerología</i> (registration numbers 011/028/IBI and CB/771). All participants signed the informed consent form prior the interview by one of two interviewers.
: Not applicable.
: All authors certify that there are no affiliations with or involvement in any organization with a direct financial interest in the subject matter or material discussed in the paper.