Received: 26 April 2019
Accepted: 16 October 2019
First Online: 8 November 2019
Ethics approval and consent to participate
: The research has ethics approval from The Instituto Angolano Contra o Cancer (IACC) ethical committee.
: Our manuscript does not contain any individual person’s data in any form.
: No conflict or declarations of interest. <b>Disclaimer:</b> Where authors are identified as personnel of the Internacional Agency for Research on Cancer / World Health Organization, the authors alone are responsible for the views expressed in this article and they do not necessarily represent the decisions, policy or views of International Agency for Research on Cancer / World Health Organization.