Rituximab (R) plus CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisolone) combination is considered as the new gold standard for the first-line treatment of elderly patients with diffuse large B-cell lymphoma (DLBCL).

The study is aimed to evaluate the overall response rate and the safety of four cycles of R-CHOP chemotherapy and followed by rituximab augmentation (weekly four times infusion) in newly diagnosed DLBCL patients with aged more than 70 years.

1. Four cycles of R-CHOP chemotherapy for the induction treatment [Dose intensity of CHOP chemotherapy is modulated according to Charlson Comorbidity Index (CCI)]

   If patients with CCI <1

   • Rituximab: 375 mg/m2, day 1 every 3 weeks.
   • Conventional dose of CHOP chemotherapy repeat every 3 weeks.

   If patients with CCI ≥1

   • Rituximab: 375 mg/m2, day 1 every 3 weeks.
   • 75% of conventional CHOP repeat every 3 weeks.

2. Rituximab augmentation

   • Rituximab: 375 mg/m2, every week x 4 times.
   • Trimethoprim-sulfamethoxazole 1 tablet per day during augmentation

Inclusion Criteria:

1. Histologically confirmed CD20 positive DLBCL

2. Age ≥ 70

3. Ann Arbor stage II, III and IV

4. No prior chemotherapy or radiotherapy for DLBCL

5. Performance status (Eastern Cooperative Oncology Group) ≤ 2

6. At least one or more bidimensionally measurable lesion(s)

   • ≥ 2 cm by conventional computerized tomography (CT)
   • ≥ 1 cm by spiral CT
   • skin lesion (photographs should be taken) ≥ 2 cm
   • measurable lesion by physical examination ≥ 2 cm

7. Cardiac ejection fraction ≥ 50% as measured by echocardiogram without clinically significant abnormalities

8. Adequate renal function: serum creatinine level < 2 mg/dL (177 μmol/L)

9. Adequate liver functions:

10. Adequate bone marrow functions:

    hemoglobin ≥ 9 g/dL absolute neutrophil count ≥ 1,500/μL and platelet count ≥ 75,000/μL, unless abnormalities are due to bone marrow involvement by lymphoma

11. Life expectancy more than 6 months

12. Informed consent

Exclusion Criteria:

1. Other subtypes of non-Hodgkin's lymphoma
2. Patients who transformed follicular lymphoma or other indolent lymphoma
3. Primary Central Nervous System (CNS) DLBCL
4. CNS involvement by lymphoma or any evidence of spinal cord compression.
5. Patients with a known history of human immunodeficiency virus (HIV) seropositivity or hepatitis C virus (+).
6. Any other malignancies within the past 5 years except curatively treated non-melanoma skin cancer or in situ carcinoma of cervix uteri
7. Pregnant or lactating women, women of childbearing potential not employing adequate contraception
8. Other serious illness or medical conditions