Radiotherapy Versus Radiotherapy Plus Chemotherapy in Early Stage Follicular Lymphoma

Radiotherapy is the only modality which has been proven to have curative potential in patients with localised low grade lymphoma. Despite excellent control of the local tumour, most patients relapse outside the area treated with radiation and most of these ultimately die from lymphoma. This study tests the hypothesis that the addition of six cycles of chemotherapy plus rituximab (systemic chemotherapy) can eradicate undetectable lymphoma deposits outside the radiation field and thereby improve the cure rate. The study will specifically test the hypothesis that six cycles of adjuvant CVP chemotherapy (cyclophosphamide, vincristine, prednisolone) in combination with Rituximab will improve progression-free survival for patients with stage I and II low-grade follicular lymphoma treated with involved-field radiotherapy (IFRT). That is, will patients given radiotherapy plus systemic chemotherapy live longer or remain free from disease longer than patients treated with radiation alone? Radiotherapy alone is widely regarded as the standard treatment for this disease. There are a number of secondary endpoints to the study, as follows: 1. Comparison the pre- and post-treatment prevalence of the t(14:18) translocation, in peripheral blood and bone marrow, of patients treated with either IFRT alone or IFRT plus chemotherapy. This translocation is potentially a marker for minimal residual disease and eradication of the marker from blood cells may have prognostic implications. The clinical value of "molecular remission" as an early predictor of freedom from progression (FFP) and survival will be assessed. 2. Comparison of overall survival and FFP for patients treated with IFRT alone with overall survival and FFP for patients treated with combined IFRT and systemic therapy. Delay of progression of disease may be of limited value if overall survival is the same. 3. Comparison of acute and late toxicity and second malignancy rates for patients treated with IFRT or IFRT plus systemic therapy. 4. Delineation of the location of first relapse in relation to radiation therapy fields.