The most common grade 3 or worse adverse events were neutropenia ( 38 [ 26 % ] of 149 patients in the fluorouracil plus leucovorin group vs 52 [ 36 % ] of 146 patients in the FOLFOX group ) , leucopenia ( eight [ 5 % ] vs 12 [ 8 % ] ) , febrile neutropenia ( four [ 3 % ] vs one [ < 1 % ] ) , diarrhoea ( four [ 3 % ] vs two [ 1 % ] ) , and nausea ( one [ < 1 % ] vs two [ 1 % ] ) .