What is the NCCN‑recommended dosing schedule for CAPOX (capecitabine and oxaliplatin) in adult patients with resected or advanced colon cancer, including dose adjustments for impaired renal function, elderly or frail patients, hepatic dysfunction, and peripheral neuropathy?

CAPOX Dosing for Colon Cancer per NCCN

The NCCN-recommended CAPOX regimen consists of oxaliplatin 130 mg/m² IV over 2 hours on day 1, plus capecitabine 850-1000 mg/m² orally twice daily for 14 days, repeated every 3 weeks. 1

Standard Dosing Schedule

Core Regimen Components

• Oxaliplatin: 130 mg/m² IV infusion over 2 hours on day 1 1, 2, 3
• Capecitabine: 850-1000 mg/m² orally twice daily on days 1-14 1, 2, 3
• Cycle frequency: Repeat every 3 weeks 1, 2, 3

Duration of Treatment

Adjuvant Setting:

• Standard duration: 8 cycles (24 weeks/6 months total) for most stage III colon cancer patients 2
• Shortened duration: 3 months (4 cycles) may be used for high-risk stage II and low-risk stage III patients based on IDEA study results 2
• Timing: Must initiate within 3 weeks after postoperative recovery and no later than 2 months postoperatively 2

Metastatic/Advanced Disease:

• Continue until disease progression or unacceptable toxicity, without predetermined cycle limit 2, 3

Critical Dosing Considerations for North American Patients

The NCCN explicitly notes that North American patients experience greater toxicity with capecitabine than European patients and may require lower starting doses. 1

• Most European data used capecitabine 1000 mg/m² twice daily as standard 1
• NCCN recommends considering 850 mg/m² twice daily as starting dose for North American patients 1
• For good performance status patients, 1000 mg/m² twice daily may be used with close monitoring in the first cycle 1
• The relative efficacy of lower capecitabine doses has not been addressed in large-scale randomized trials 1

Dose Modifications for Specific Situations

Renal Impairment

• Creatinine clearance 30-50 mL/min: Reduce capecitabine to 750 mg/m² twice daily 4, 5
• Creatinine clearance <30 mL/min: Capecitabine is contraindicated (general medical knowledge)

Oxaliplatin-Related Neurotoxicity

Discontinue oxaliplatin after 3-4 months (or sooner) if significant neurotoxicity develops (≥ grade 2), but continue capecitabine alone to complete the full 6-month treatment duration. 2, 3

• This approach prevents cumulative neurotoxicity while maintaining treatment efficacy 2, 3
• Oxaliplatin may be reintroduced if previously discontinued for neurotoxicity rather than disease progression 1

Elderly Patients (≥70 years)

• Consider starting with capecitabine 1000 mg/m² twice daily with close first-cycle monitoring 6, 4
• Patients over 65 years have 34% risk of grade 3 or higher toxicity 6
• Limited evidence supports oxaliplatin benefit in patients ≥70 years without high-risk features 2

Alternative Biweekly Schedule for Elderly/Frail Patients

• Oxaliplatin: 85 mg/m² IV on day 1, every 2 weeks 5
• Capecitabine: 1000 mg/m² (or 750 mg/m² if CrCl 30-50 mL/min) twice daily on days 1-7, every 2 weeks 5
• This regimen showed 49% response rate with better tolerability in elderly patients 5

Addition of Biologic Agents

When combining CAPOX with bevacizumab (metastatic disease):

• Bevacizumab: 7.5 mg/kg IV on day 1, every 3 weeks 1
• Bevacizumab may be safely administered at 0.5 mg/kg/min (7.5 mg/kg over 15 minutes) 1

Critical warnings:

• Do not combine multiple biologic agents together 1, 3
• Do not continue bevacizumab beyond progression on a bevacizumab-containing regimen 1
• Avoid anti-EGFR therapy for right-sided primary tumors 3

Monitoring Requirements

First Cycle Surveillance

Close monitoring during the first treatment cycle is mandatory, with particular attention to: 6

• Hand-foot syndrome (occurs in up to 73% of patients, 11% grade 3) 6
• Diarrhea (10-28% of patients) 3, 6
• Peripheral sensory neuropathy (85% of patients) 3
• Coagulation parameters in patients on anticoagulants 6

Ongoing Monitoring

• Use CT chest/abdomen/pelvis with contrast or chest CT with abdominal/pelvic MRI to monitor treatment response 3, 6
• Do not use PET/CT to monitor therapy progress 3, 6

Common Pitfalls to Avoid

1. Do not use CAPOX beyond 6 months in the adjuvant setting unless within a clinical trial 2

2. Do not continue oxaliplatin if grade 2 or higher neurotoxicity develops—switch to capecitabine monotherapy to complete 6-month duration 2, 3

3. Do not assume European dosing (1000 mg/m² capecitabine) is appropriate for all North American patients—toxicity profiles differ significantly 1, 6

4. Do not use single-agent capecitabine as salvage therapy after failure on a fluoropyrimidine-containing regimen—this has been shown to be ineffective 1

5. Do not use CAPOX in patients with dMMR/MSI-H Stage II disease—they may not benefit from fluoropyrimidine-based therapy 2