Rituximab, Combination Chemotherapy, and Yttrium Y 90 Ibritumomab Tiuxetan in Treating Patients With Relapsed Follicular Non-Hodgkin Lymphoma

DISEASE CHARACTERISTICS:

* Histologically confirmed grade 1, 2, or 3 follicular non-Hodgkin lymphoma

  * Stage II, III, or IV disease (according to the Ann Arbor staging system)
* CD20-positive disease
* Initial disease bulk ≤ 10 cm
* In first or second relapse after prior treatment with a rituximab-containing chemotherapy regimen (R-chemo) or chemotherapy alone

  * Relapse must have occurred ≥ 6 months after completion of R-chemo

    * Relapse that occurred \< 6 months after completion of chemotherapy alone allowed
* Has at least one of the following symptoms requiring initiation of treatment:

  * Nodal mass \> 5 cm in its greater diameter
  * B symptoms
  * Elevated serum lactate dehydrogenase (LDH) or β2-microglobulin
  * Involvement of ≥ 3 nodal sites (each with a diameter \> 3 cm)
  * Symptomatic splenic enlargement
  * Compressive syndrome
* No primary refractory disease
* No large pleural or peritoneal effusions
* No CNS disease

PATIENT CHARACTERISTICS:

* ECOG performance status 0-2
* Life expectancy ≥ 6 months
* Absolute granulocyte count ≥ 1,500/mm³
* Platelet count ≥ 1,000/mm³
* Serum creatinine \< 1.5 times upper limit of normal (ULN)
* Total bilirubin \< 1.5 times ULN
* AST \< 5 times ULN
* No active obstructive hydronephrosis
* No evidence of active infection requiring IV antibiotics
* No advanced heart disease or other serious illness that would preclude study evaluation
* No known HIV infection
* No human anti-mouse antibody (HAMA) reactivity
* No known hypersensitivity to murine antibodies or proteins
* Not pregnant or nursing
* Negative pregnancy test
* Fertile patients must use effective contraception during and for 12 months after completion of study treatment
* No other prior malignancy, except for adequately treated skin cancer, cervical cancer in situ, or other cancer for which the patient has been disease-free for 5 years

PRIOR CONCURRENT THERAPY:

* See Disease Characteristics
* At least 4 weeks since prior investigational drugs and recovered
* No prior radioimmunotherapy