Radiotherapy Versus Radiotherapy Plus Chemotherapy in Early Stage Follicular Lymphoma

Inclusion Criteria:

* Adult patients (≥ 18 years old) with histologically documented "follicular lymphoma, grade 1", grade 2", or "follicular lymphoma, grade 3a" diagnosed following an excisional, incisional or generous core biopsy. (i.e. an FNA alone is insufficient.)
* Disease limited to stages I and II after adequate staging
* Anticipated life expectancy \> 5 years
* Given written informed consent
* Been assessed by a radiation oncologist and a medical oncologist/ haematologist
* WCC \> 3.0 x 10\^9/L, platelet count \> 100 x 10\^9/L, serum creatinine \< 0.15 mmol/L
* Ability to commence radiotherapy within 6 weeks of randomisation
* Women using effective contraception, are not pregnant and agree not to become pregnant during participating in the trial and during the 12 months thereafter. Men agree not to father a child during participation in the trial and during the 12 months thereafter.

Exclusion Criteria:

* Received previous systemic cytotoxic chemotherapy.
* Received previous radiotherapy, (except superficial radiation therapy for non-melanoma skin cancers).
* Received previous immunotherapy.
* A medical contraindication to radiotherapy, chemotherapy, or rituximab.
* Any previous or concurrent malignancy other than curatively treated non-melanoma skin cancer, level 1 malignant melanoma, or in situ cervical cancer, unless disease and treatment-free for 5 years.
* Such extensive involvement of the thorax that treatment with radiation therapy alone would be hazardous because of excessive lung irradiation, even if a shrinking field technique were employed.
* Suspected or confirmed pregnancy. Must not be lactating.
* Patients who have known human immuno-deficiency virus (HIV) infection or active hepatitis B (HBV).
* Treatment within a clinical study within 30 days prior to study entry.