[1] Univ Texas MD Anderson Canc Ctr, Houston, TX 77030 USA
[2] Mayo Clin, Scottsdale, AZ USA
[3] Univ Texas MD Anderson Canc Ctr, Dept Biostat, Houston, TX 77030 USA
[4] Univ Texas MD Anderson Canc Ctr, GI Med Oncol Dept, Houston, TX 77030 USA
[5] Univ Texas MD Anderson Canc Ctr, Dept Gastrointestinal Med Oncol, Houston, TX 77030 USA
[6] Mayo Clin Arizona, Scottsdale, AZ USA
[7] Mayo Clin, Canc Ctr, Phoenix, AZ USA
[8] Univ Texas MD Anderson Canc Ctr, Gastrointestinal Med Oncol, Houston, TX 77030 USA