Asymptomatic patients ( aged @ years ) with low-tumour-burden follicular lymphoma ( grades @ , @ , and @a ) were randomly assigned centrally ( @:@:@ ) , by the minimisation approach stratified by institution , grade , stage , and age , to watchful waiting , rituximab @ mg/m ( @ ) weekly for @ weeks ( rituximab induction ) , or rituximab induction followed by a maintenance schedule of @ further infusions given at @-monthly intervals for @ years ( maintenance rituximab ) .