Purpose

RATIONALE: Drugs used in chemotherapy, such as bendamustine hydrochloride, work in different ways to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. Monoclonal antibodies, such as rituximab, can block cancer growth in different ways. Some block the ability of cancer cells to grow and spread. Others find cancer cells and help kill them or carry cancer-killing substances to them. Bortezomib may stop the growth of cancer cells by blocking some of the enzymes needed for cell growth. Biological therapies, such as lenalidomide, may stimulate the immune system in different ways and stop cancer cells from growing. It is not yet known whether giving bendamustine hydrochloride and rituximab together alone is more effective than giving bendamustine hydrochloride and rituximab together with bortezomib or lenalidomide in treating follicular lymphoma. PURPOSE: This randomized phase II trial is studying giving bendamustine hydrochloride and rituximab together with or without bortezomib followed by rituximab with or without lenalidomide to see how well they work in treating patients with high-risk stage II, stage III, or stage IV follicular lymphoma.