This trial studies the side effects of radiation therapy used alone, and if it can achieve a high cure rate in the treatment of patients with MALT lymphoma. Radiation therapy uses high energy sources to kill cancer cells and shrink tumors. This treatment may improve the patient's lymphoma.

PRIMARY OBJECTIVE:

I. To determine the efficacy and toxicity of radiation therapy alone in treating stage 1 and 2 MALT lymphoma for newly diagnosed patients and for the patients who failed other treatment modalities.

OUTLINE:

Patients undergo radiation therapy once daily (QD) 5 times weekly over 3.5-5 weeks.

After completion of study treatment, patients are followed up at 6-8 weeks, and then every 3-4 months for year 1, every 4-6 months for year 2, every 6 months for years 3 and 4, and once yearly thereafter.

Inclusion Criteria:

• Patients with newly diagnosed stage 1 and 2 MALT lymphoma are eligible for this study
• Patients with Helicobacter (H.) pylori positive gastric MALT lymphoma are recommended to have treatments with antibiotics prior to enrollment to this protocol
• Patients who failed other treatment modalities (e.g. chemotherapy, antibiotics therapy etc) are also eligible as far as they never had stage 3 or 4 disease during the course of the disease or disease progression to the opposite side of the diaphragm (as the time course of the response to antibiotic therapy can be very variable among patients, sometimes requiring more than one year for complete response, failure to antibiotic therapy can be very variable among patients, sometimes requiring more than one year for complete response, failure to antibiotic treatment will be defined as no response or progression of the disease documented by endoscopy and biopsy)
• Patients who have had stage 4 diseases due to bilateral parotid gland or ocular/ocular adnexal involvement or due to multiple sites within Waldeyer's ring will still be eligible

Exclusion Criteria:

• Patients who had previous radiation dose to the site of the current primary disease which would lead to violation of known radiation tolerance limit of that particular site if treated again
• Patients with MALT lymphoma of the skin whose lesions are separated by more than 5 cm will be ineligible
• Previous or concurrent malignancy in any form would not be an exclusion criterion. However, patients who receive chemotherapy for concurrent malignancy will be excluded from statistical analysis
• Low blood cell counts would not be exclusion criteria as far as the patient is willing to accept supportive measures such as transfusions, filgrastim and epoetin