International consensus to define outcomes for trials of chemoradiotherapy for anal cancer (CORMAC-2): defining the outcomes from the CORMAC core outcome set by Robert Samuel, Stephen R. Knight, Richard Adams, Prajnan Das, Jennifer Dorth, David Finch, Marianne G. Guren, Maria A. Hawkins, Susan Moug, Lakshmi Rajdev, David Sebag-Montefiore, Andrew G. Renehan, Rebecca Fish, Miguel A. Rodriguez-Bigas, Pratik Adusumilli, Ahmed Allam Mohamed, Mario Alvarez Gallego, Eva Angenete, Ane Appelt, Maaike Berbee, Danielle Brogden, Peter Brown, Lucy Buckley, Nathalie Casanova, Rachel Cooper, Nuno Couto, Peter Coyne, Tamzin Cuming, Charlotte Deijin, Kristopher Dennis, Cathy Eng, Alexandra Gilbert, Duncan Gilbert, Karyn Goodman, Rashmi Jadon, Anders Johnsson, Arunansu Kar, Ethan Ludmir, Marie-Louise Lydrup, Ivan Lyra-Gonzalez, Stefania Manfrida, Rebecca Muirhead, Sarah O'Dwyer, Thomas Rackley, Lukasz Raszewski, Leslie Samuel, Mark Saunders, Andrew Scarsbrook, Eva Segelov, Timothy Simmons, Paul Sutton, Nicholas Symons, Deborah Williamson