Consolidation Treatment With Y90-Ibritumomab Tiuxetan After R-CHOP Induction in High Risk Patients According to Follicular Lymphoma International Prognostic Index (FLIPI) With Follicular Lymphoma

Inclusion Criteria:

* Signature of the written informed consent by the subject or his/her legal representative before initiation of any trial specific procedure.
* Patients older than 18.
* Histologic diagnosis of CD20+, grade 1-3a follicular lymphoma as per the WHO classification.
* High-risk patients according to FLIPI before initiation of induction chemotherapy.
* Stage II-IV prior to initiation of induction treatment, or any stage in patients with grade 3 follicular lymphoma.
* Complete or partial response to the induction scheme.
* ECOG scale performance status 0 - 2.
* Life expectancy greater than 3 months.
* In women of childbearing age, use of a reliable contraceptive method.
* A suitable bone marrow reserve:

  * Lower than 25% Bone marrow infiltration by lymphoma.
  * Hb 10 g/dL. PMN leukocytes 1,500 cel/mm3, platelets 100,000/mm3
  * Suitable hepatic, renal and cardiac function:

    * creatinine \<2,5 x UNL (upper normality limit).
    * bilirubin or ALT/AST \< 2,5 x UNL

Exclusion Criteria:

* Patients with no objective clinical response to induction chemotherapy.
* \> 25% bone marrow infiltration following induction chemotherapy.
* Platelets \< 100,000 before radioimmunotherapy.
* Severe and/or uncontrolled concomitant disease:
* Hepatic, renal, cardiovascular, neurological or metabolic disease.
* Cardiac failure, ischemic cardiopathy, ischemic cardiopathy with a history of myocardial infarction or angor, or major ventricular arrhythmia.
* Positive regarding HBV, HCV, HIV.
* Active acute or chronic infection.
* Social, psychic or geographic disability to satisfy any of the treatment schemes.
* Pregnant and/or breastfeeding women, or adult patients of childbearing age who are not using a safe birth control device throughout the study treatment and at least 12 months thereafter.
* Known or suspected hypersensitivity, or confirmed or suspected adverse reaction to the study drugs and other related compounds (Rituximab, Ibritumomab tiuxetan, a history of sensitivity to murine proteins, dexametasone, cyclophosphamide and other anthracyclines, cytarabine).