Investigator choices of standard chemotherapy: irinotecan as a single agent +/- cetuximab OR capecitabine as a single agent, OR FOLFOX (leucovorin calcium [folinic acid][FOL] + fluorouracil [F] + oxaliplatin [OX]) OR CAPEO(capecitabine [CAPE] or Xeloda® [XEL] + oxaliplatin [OX]) OR FOLFIRI (leucovorin calcium [folinic acid][FOL] + fluorouracil [F] + irinotecan [IRI]) +/- cetuximab OR cetuximab as a single agent.