RATIONALE: Treatment for diffuse large B-cell non-Hodgkin's lymphoma may cause side effects and secondary cancers later in life. An observational study that evaluates patients after undergoing six courses of combination chemotherapy with or without rituximab and radiation therapy may help doctors predict a patient's response to this treatment and help plan the best treatment.

PURPOSE: This observational study is evaluating patients with diffuse large B-cell non-Hodgkin's lymphoma to see how well treatment on clinical trial CAN-NCIC-LY9 works.

OBJECTIVES:

• Gain information on the long-term efficacy of 6 courses of CHOP (cyclophosphamide, doxorubicin hydrochloride, prednisone, and vincristine)-like chemotherapy with vs without rituximab (plus involved-field radiotherapy to primary bulky disease) in young patients with good-prognosis diffuse large B-cell non-Hodgkin's lymphoma treated on protocol CAN-NCIC-LY9.
• Gain information on late toxicities, including secondary neoplasm occurring in young good-prognosis patients treated on protocol CAN-NCIC-LY9.

OUTLINE: This is a multicenter study.

Patients successfully completing treatment on protocol CAN-NCIC-LY9 are followed every 3 months for 2 years, every 6 months for 3 years, and then annually thereafter.

PROJECTED ACCRUAL: A total of 667 patients will be accrued for this study.

DISEASE CHARACTERISTICS:

• Patients recruited for protocol CAN-NCIC-LY9 and evaluated in the first planned final analysis as of June 2005

PATIENT CHARACTERISTICS:

• Not specified

PRIOR CONCURRENT THERAPY:

• See Disease Characteristics