What are the recommended chemotherapy dosing regimens for metastatic breast, colorectal, non‑small cell lung, and prostate cancers in an adult with normal renal (creatinine clearance > 60 mL/min) and hepatic function?

Recommended Chemotherapy Dosing for Metastatic Cancers

For adults with normal renal and hepatic function, use the following evidence-based regimens for metastatic disease:

Metastatic Colorectal Cancer

First-line combination chemotherapy with FOLFOX or FOLFIRI is recommended for patients appropriate for intensive therapy 1, 2. These regimens provide superior response rates, progression-free survival, and overall survival compared to fluoropyrimidine monotherapy.

FOLFOX Regimens (mFOLFOX6)

• Oxaliplatin: 85 mg/m² IV over 2 hours, day 1
• Leucovorin: 400 mg/m² IV over 2 hours, day 1
• 5-FU: 400 mg/m² IV bolus day 1, then 1200 mg/m²/day × 2 days (total 2400 mg/m² over 46-48 hours) continuous infusion
• Repeat every 2 weeks 1, 2

Important note: The oxaliplatin dose range is 85-130 mg/m² every 2 weeks, but 85 mg/m² is preferred as there is no evidence that higher doses are more active 2.

FOLFIRI Regimen

• Irinotecan: 180 mg/m² IV over 30-90 minutes, day 1
• Leucovorin: 400 mg/m² IV infusion to match duration of irinotecan, day 1
• 5-FU: 400 mg/m² IV bolus day 1, then 1200 mg/m²/day × 2 days continuous infusion
• Repeat every 2 weeks 1, 2

Alternative: CapeOx (CAPOX)

• Oxaliplatin: 130 mg/m² IV over 2 hours, day 1
• Capecitabine: 850-1000 mg/m² PO twice daily for 14 days
• Repeat every 3 weeks 1, 2

Critical caveat: North American patients may experience greater toxicity with capecitabine than European patients and may require the lower starting dose of 850 mg/m² 1.

Monoclonal Antibody Additions

When adding bevacizumab to chemotherapy:

• With FOLFOX/FOLFIRI: 5 mg/kg IV day 1, every 2 weeks 1
• With CapeOx: 7.5 mg/kg IV day 1, every 3 weeks 1

Second-Line Therapy

• If refractory to FOLFOX/CapeOx: Use FOLFIRI (irinotecan 180 mg/m² with 5-FU/LV as above) 2
• If refractory to FOLFIRI: Use FOLFOX or CapeOx 2

Metastatic Breast Cancer

Treatment selection depends on hormone receptor (HR) and HER2 status, with sequential single-agent chemotherapy preferred over combination therapy for most patients to optimize quality of life 3, 4.

HR-Positive, HER2-Negative Disease

Start with endocrine therapy unless clinically aggressive disease mandates rapid response 3, 4. When chemotherapy is needed:

Single-agent options (preferred):

• Capecitabine: 850-1250 mg/m² PO twice daily, days 1-14, repeat every 3 weeks 1, 5
• Paclitaxel: 80 mg/m² IV weekly 6, 5
• Docetaxel: 60-100 mg/m² IV every 3 weeks 3, 5
• Vinorelbine: monotherapy (specific dosing per institutional protocols) 3, 4

HER2-Positive Disease

First-line: Trastuzumab with chemotherapy 3, 4

• Trastuzumab: 4 mg/kg IV loading dose, then 2 mg/kg IV weekly (or 6 mg/kg every 3 weeks after loading with 8 mg/kg) 6
• With paclitaxel: 80 mg/m² IV weekly for 12 weeks, then continue trastuzumab to complete 1 year 6

Second-line (per recent guidelines):

• Trastuzumab deruxtecan if available; if not, use trastuzumab emtansine; if unavailable, use capecitabine + lapatinib 7

Triple-Negative Disease

Single-agent chemotherapy is standard 7:

• Capecitabine: 850-1250 mg/m² PO twice daily, days 1-14, every 3 weeks 5
• Paclitaxel: 80 mg/m² IV weekly 5
• Eribulin: 1.4 mg/m² IV days 1 and 8, every 21 days (for heavily pretreated patients) 5

Combination Regimens (useful in certain circumstances)

• AC: Doxorubicin 60 mg/m² + Cyclophosphamide 600 mg/m² IV day 1, every 21 days 6
• Docetaxel/Capecitabine: Docetaxel 75 mg/m² day 1 + Capecitabine 950 mg/m² twice daily days 1-14, every 3 weeks 5

Key principle: Continue chemotherapy beyond third-line only in patients with good performance status and response to previous therapy 3, 4.

Metastatic Non-Small Cell Lung Cancer

Platinum-based doublet chemotherapy is standard for patients with good performance status 8, 9.

First-Line Regimens (all equally effective)

Cisplatin-based:

• Gemcitabine/Cisplatin: Gemcitabine 1000-1250 mg/m² days 1 and 8 + Cisplatin 75-80 mg/m² day 1, every 21 days 9
• Paclitaxel/Cisplatin: Paclitaxel 175-200 mg/m² + Cisplatin 75-80 mg/m² day 1, every 21 days 9
• Docetaxel/Cisplatin: Docetaxel 75 mg/m² + Cisplatin 75 mg/m² day 1, every 21 days 9

Carboplatin-based (for patients with borderline renal function):

• Paclitaxel/Carboplatin: Paclitaxel 175-200 mg/m² + Carboplatin AUC 5-6 day 1, every 21 days 9

Critical note: Use the Cockcroft-Gault formula for creatinine clearance when calculating carboplatin dosing with Calvert's formula. In Japan, adjusting serum creatinine by +0.2 mg/dL when using enzymatic method is suggested, though this may reduce efficacy in elderly patients (≥75 years) 10.

Metastatic Prostate Cancer

The provided evidence does not contain specific chemotherapy dosing regimens for metastatic prostate cancer. Based on general medical knowledge, docetaxel-based chemotherapy is standard:

• Docetaxel: 75 mg/m² IV every 3 weeks with prednisone 5 mg PO twice daily (standard of care, though not detailed in provided evidence)

Universal Principles

Dosing Modifications

• Limit chemotherapy orders to 24-hour units (e.g., 1200 mg/m²/day NOT 2400 mg/m² over 48 hours) to minimize medication errors 1
• Leucovorin 400 mg/m² = levo-leucovorin 200 mg/m² 1

Treatment Duration

• Colorectal cancer: Consider treatment interruptions or maintenance with fluoropyrimidine alone after 3-6 months if cumulative toxicity occurs or disease control is achieved 2
• Breast cancer: Optimal duration is unknown; balance response with quality of life 3, 4

Sequencing Strategy

Exposure to all active cytotoxic agents in various sequences results in longest survival 2. The order of administration matters less than ensuring patients receive all appropriate agents during their treatment continuum.