Funding for this research was provided by:
Cancer Research UK (CRUK/A13405, C20/A20917)
Addenbrooke's Charitable Trust, Cambridge University Hospitals (24/15 A/Noble, RG82557)
Received: 29 November 2017
Accepted: 5 April 2018
First Online: 4 May 2018
Ethics approval and consent to participate
: VocTox received National Research Ethics Service (NRES) Committee East approval in February 2013 (13/EE/0008).
: The authors declare that they have no competing interests.
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