R-CHOP Dosing for Diffuse Large B-Cell Lymphoma
The standard R-CHOP-21 regimen consists of rituximab 375 mg/m², cyclophosphamide 750 mg/m², doxorubicin 50 mg/m², vincristine 1.4 mg/m² (capped at 2 mg maximum), and prednisone 40-100 mg/m² daily for 5 days, administered every 21 days. 1
Standard Dosing by Age and Risk Group
Patients Aged ≤60 Years (Good Risk, aaIPI 0-1)
- Six cycles of R-CHOP-21 with eight total doses of rituximab is the current standard 1
- Alternative for early stage (I-II): Three cycles R-CHOP plus involved field radiation 1
- If using R-CHOP-14 (every 14 days), six cycles are sufficient 1
Patients Aged 60-80 Years
- Eight cycles of R-CHOP-21 with eight doses of rituximab administered every 21 days is the standard 1
- If R-CHOP-14 is used, six cycles of CHOP with eight cycles of rituximab are sufficient 1
Patients Aged >80 Years
- R-CHOP can typically be used until age 80 in fit patients 1
- For very elderly patients, rituximab with attenuated chemotherapy may be considered 1
Specific Component Doses
Rituximab
Cyclophosphamide
Doxorubicin (Hydroxydaunorubicin)
Vincristine (Oncovin)
- 1.4 mg/m² intravenously (maximum dose capped at 2 mg) on day 1 1, 2
- The 2 mg cap is based on neurotoxicity concerns when used in CHOP and R-CHOP regimens 1
Prednisone
- 40-100 mg/m² orally on days 1-5 of each cycle 2, 3
- R-CHOP-21 typically uses 40 mg/m² daily 2
- R-CHOP-14 uses 100 mg daily 2
R-CHOP-14 vs R-CHOP-21: Evidence-Based Decision
R-CHOP-21 remains the standard of care, as dose intensification with R-CHOP-14 has not demonstrated superiority. 2, 4
- A large phase 3 trial (1,080 patients) showed no improvement in 2-year overall survival (82.7% vs 80.8%) or progression-free survival (75.4% vs 74.8%) with R-CHOP-14 compared to R-CHOP-21 2
- A separate trial in elderly patients (602 patients aged 60-80) confirmed no benefit from dose-dense R-CHOP-14, with 3-year event-free survival of 56% vs 60% favoring R-CHOP-21 4
- R-CHOP-14 was associated with increased toxicity including higher rates of grade 3-4 thrombocytopenia (9% vs 5%) and greater need for red blood cell transfusions (47% vs 31%) 2, 4
Dosing in Obese Patients
Calculate doses using actual body surface area without arbitrary caps or reductions. 1
- Full weight-based dosing should be used for all chemotherapy agents in obese patients 1
- Dose reductions due to obesity alone are not recommended and may compromise outcomes 1
- The only exception is vincristine, which is capped at 2 mg regardless of BSA due to neurotoxicity 1
Critical Dosing Principles
Avoid Dose Reductions
- Dose reductions due to hematological toxicity should be avoided in patients treated with curative intent 1
- Febrile neutropenia justifies prophylactic use of granulocyte colony-stimulating factor rather than dose reduction 1
Timing Considerations
- Proceed immediately with full-dose R-CHOP without delaying chemotherapy start after prephase treatment 5
- Standard cycle length is every 21 days for R-CHOP-21 1
Tumor Lysis Syndrome Prophylaxis
- Special precautions are required in cases with high tumor load to avoid tumor lysis syndrome 1
Essential Supportive Care
Mandatory Prophylaxis
- PCP prophylaxis with sulfamethoxazole/trimethoprim (or equivalent) throughout treatment and for 6-12 months after rituximab completion 5
- Herpes virus prophylaxis with acyclovir or equivalent 5
Blood Product Management
- Irradiate all blood products to prevent transfusion-associated GVHD in patients receiving rituximab-containing regimens 5
Common Pitfalls to Avoid
- Do not reduce doses arbitrarily in obese patients—this compromises efficacy without improving safety 1
- Do not use R-CHOP-14 expecting superior outcomes—it increases toxicity without survival benefit 2, 4
- Do not omit growth factor support after febrile neutropenia—maintain dose intensity instead 1
- Do not exceed 2 mg vincristine dose regardless of BSA calculation due to neurotoxicity risk 1