MERIT-NHL as an addendum to the International Registry of Radioimmunotherapy (RIT registry) pooling clinical data of patients who suffered from a non-Hodgkin´s lymphoma also includes the documentation of the respective FDG-PET and CT-image files in an online archive.

Based on these documented clinical and imaging data, the MERIT study group centrally performs an intra- as well as interindividual evaluation of follicular CD20+ lymphoma lesions before and after radioimmunotherapy. According to this, the aim of the MERIT-NHL study is to prospectively identify yet unknown patient- and lesion specific prognostic factors predicting patient´s outcome in line with the therapeutic modality radioimmunotherapy.

Inclusion Criteria:

• standard radioimmunotherapy with 90-yttrium-labeled anti-CD20-antibodies in treatment of relapsed and/or refractory follicular NHL or partial remission after induction chemotherapy
• finding of at least one image-guided measurable lymphoma lesion
• existence of FDG-PET- and CT-image data of at most 8 weeks before treatment
• signed patient´s agreement for RIT registry and MERIT-NHL

Exclusion Criteria:

• other therapy modalities than standard radioimmunotherapy (e.g. consolidation)
• solely CNS-lymphoma or primary effusion lymphoma

Patients who suffer from a relapsed and/or refractory follicular non-Hodgkin´s lymphoma (FL) or patients with partial remission after induction chemotherapy of FL