What is the recommended R‑CHOP immunochemotherapy schedule (agents, doses, 21‑day cycle, and total number of cycles) for an otherwise healthy adult with stage I diffuse large B‑cell lymphoma limited to a cervical lymph node, after excision showing an 8 mm residual PET‑avid node and no disease on CT of neck, abdomen, and pelvis?

R-CHOP Regimen for Stage I DLBCL Limited to Cervical Lymph Node

For an otherwise healthy adult with stage I diffuse large B-cell lymphoma limited to a cervical lymph node with an 8 mm residual PET-avid node, administer 3–4 cycles of R-CHOP-21 (rituximab 375 mg/m² plus standard CHOP chemotherapy every 21 days) followed by involved-field radiotherapy (30–40 Gy). 1

Risk Stratification and Treatment Selection

Your patient appears to have low-risk, stage I disease without adverse risk factors (single nodal site, no bulky disease, normal CT imaging). This clinical scenario falls into the category requiring abbreviated chemotherapy plus radiotherapy rather than full-course treatment. 1

Key Pre-Treatment Requirements

• Calculate the age-adjusted International Prognostic Index (aa-IPI) to confirm low-risk status (likely aa-IPI = 0 in this case). 1
• Assess cardiac function with left ventricular ejection fraction (LVEF) measurement before initiating doxorubicin. 1
• Screen for hepatitis B, hepatitis C, and HIV prior to rituximab administration. 2, 3
• Obtain baseline complete blood count, LDH, and uric acid levels to assess tumor burden and tumor lysis syndrome risk. 3

Standard R-CHOP-21 Dosing Schedule

Each 21-day cycle consists of:

• Rituximab: 375 mg/m² IV on Day 1 1, 2, 4
• Cyclophosphamide: 750 mg/m² IV on Day 1 4, 5
• Doxorubicin: 50 mg/m² IV on Day 1 4, 5
• Vincristine: 1.4 mg/m² IV on Day 1 (maximum dose capped at 2 mg regardless of body surface area) 3, 4, 5
• Prednisone: 40–100 mg/m² orally on Days 1–5 4, 5

Total number of cycles: 3–4 cycles of R-CHOP-21 for stage I non-bulky disease without adverse risk factors. 1

Consolidation Radiotherapy

After completing abbreviated chemotherapy, administer involved-field radiotherapy (IFRT) at 30–40 Gy to the initial disease site. 1

• The combination of abbreviated R-CHOP plus IFRT provides excellent disease control in limited-stage DLBCL, with 5-year progression-free survival of 82% and overall survival of 92%. 1
• IFRT improves in-field control and event-free survival compared to chemotherapy alone in stage I–II disease. 1
• The 8 mm residual PET-avid lymph node is an appropriate target for consolidation radiotherapy. 1

Critical Supportive Care Measures

Mandatory Prophylaxis

• Tumor lysis syndrome prevention: Although your patient has limited disease burden, assess uric acid and LDH levels; consider allopurinol or rasburicase if tumor burden is significant. 1, 2, 3
• Prophylactic G-CSF (granulocyte colony-stimulating factor): Recommended for patients >60 years and strongly considered for all patients receiving curative-intent therapy to prevent febrile neutropenia and avoid dose reductions. 1, 2, 3
• PCP prophylaxis: Initiate sulfamethoxazole/trimethoprim. 3
• Herpes virus prophylaxis: Initiate acyclovir. 3

Hepatitis B Monitoring

• For patients with prior HBV exposure, administer antiviral prophylaxis or perform periodic HBV-DNA monitoring with prompt antiviral therapy if reactivation occurs. 2, 6

Dose Management Principles

• Avoid dose reductions due to hematologic toxicity whenever possible; use prophylactic G-CSF instead of lowering chemotherapy intensity, as dose reductions are associated with significantly poorer outcomes. 1, 2, 3
• Maintain full weight-based dosing for all agents (except vincristine, which is capped at 2 mg) even in obese patients. 3

CNS Prophylaxis Considerations

CNS prophylaxis is NOT indicated for your patient. 1, 3

• CNS prophylaxis should be reserved for patients with high-intermediate or high-risk IPI, involvement of more than one extranodal site, elevated LDH, or disease affecting the testis, kidney, or adrenal glands. 1, 3
• Your patient has stage I disease limited to a single cervical lymph node with normal imaging elsewhere, placing them at very low risk for CNS involvement. 1

Why Not R-CHOP-14?

Do not use R-CHOP-14 (14-day cycles) instead of standard R-CHOP-21. 1, 3, 5

• A pivotal randomized British trial of 1,080 patients demonstrated no survival advantage for R-CHOP-14 over R-CHOP-21 (2-year overall survival 82.7% vs 80.8%, HR 0.90, p=0.38). 3, 5
• No molecular or clinical subgroup—including younger high-risk patients—derived benefit from dose intensification with R-CHOP-14. 3, 5

Why Not Full-Course R-CHOP × 6–8 Cycles?

Full-course R-CHOP (6–8 cycles) is reserved for stage III–IV disease or stage I–II disease with adverse risk factors. 1

• For young, low-risk patients (aa-IPI = 0) without bulky disease, abbreviated chemotherapy (3–4 cycles) plus IFRT is the standard approach and provides excellent outcomes. 1
• Consolidation radiotherapy to initial non-bulky sites has proven benefit when combined with abbreviated chemotherapy in the pre-rituximab era, and this approach remains standard in the rituximab era for limited-stage disease. 1

Common Pitfalls to Avoid

• Do not omit radiotherapy in stage I disease after abbreviated chemotherapy; the combination of 3–4 cycles of R-CHOP plus IFRT provides superior disease control compared to chemotherapy alone. 1
• Do not reduce chemotherapy doses for hematologic toxicity without first attempting prophylactic G-CSF support. 1, 2, 3
• Do not administer CNS prophylaxis in low-risk, stage I disease without adverse features. 1, 3
• Do not use R-CHOP-14 under the assumption of superiority; it provides no benefit over R-CHOP-21. 1, 3, 5

Expected Outcomes

With abbreviated R-CHOP plus IFRT for stage I DLBCL:

• 5-year progression-free survival: 82% 1, 7
• 5-year overall survival: 92–93% 1, 7
• 2-year progression-free survival: 97% in PET-negative patients after 3 cycles of R-CHOP 1