CAF Regimen Shows Modest Overall Survival Benefit Over CMF, But Not Disease-Free Survival
Based on the highest quality evidence, CAF (cyclophosphamide, doxorubicin, 5-fluorouracil) demonstrates a slight overall survival advantage over CMF (cyclophosphamide, methotrexate, 5-fluorouracil), but does not improve disease-free survival and comes with significantly greater toxicity. Given this trade-off, CAF cannot be definitively recommended as superior to CMF 1.
Key Evidence on CAF vs CMF Efficacy
The definitive head-to-head comparison from Intergroup Protocol INT-0102 enrolled 2,690 high-risk, node-negative breast cancer patients and found 1:
- Disease-Free Survival (DFS): CAF was NOT significantly better than CMF (77% vs 75% at 10 years; HR = 1.09; 95% CI, 0.94-1.27; P = 0.13)
- Overall Survival (OS): CAF showed a slight advantage (85% vs 82% at 10 years; HR = 1.19 for CMF vs CAF; 95% CI, 0.99-1.43; one-sided P = 0.03)
- Toxicity: CAF produced significantly greater toxicity than CMF
This marginal OS benefit of approximately 3% at 10 years must be weighed against the increased toxicity burden, particularly cardiac toxicity from doxorubicin.
Current Guideline Positioning
The 2018 ASCO guidelines 2 and 2019 ESMO guidelines 3 have effectively moved beyond both CAF and CMF as preferred regimens:
- Anthracycline-taxane combinations are now the optimal strategy for patients who can tolerate them, particularly those at high risk
- CMF is positioned as an acceptable alternative when anthracycline-taxane regimens are contraindicated
- CAF is not specifically recommended in modern guidelines, having been superseded by superior regimens
The guidelines specifically note that docetaxel-doxorubicin-cyclophosphamide (TAC) was shown to be superior to fluorouracil-doxorubicin-cyclophosphamide (FAC/CAF) 2, further diminishing CAF's role.
Supporting Evidence on Sequencing
Additional research provides context on anthracycline use:
- A 2004 Italian study found that sequential DOX→CMF significantly reduced relapse risk (HR 0.68; P = 0.0017) and death (HR 0.74; P = 0.018) compared to alternating regimens in patients with >3 positive nodes 4
- However, a 2011 study showed no difference between epirubicin→CMF versus CMF→epirubicin sequences in rapidly proliferating breast cancer 5
- A 2009 single-institution study found no significant difference between doxorubicin-cyclophosphamide (AC) and CMF for metastasis occurrence 6
Clinical Decision Algorithm
When anthracycline-taxane regimens are appropriate:
- Use anthracycline-taxane combinations (AC→taxane, FEC→docetaxel, or TAC) rather than CAF 2
When anthracyclines without taxanes must be used:
- For high-risk disease requiring optimal-dose anthracycline: Use a three-drug regimen with cumulative doxorubicin ≥240 mg/m² 2
- CAF could be considered, but the marginal OS benefit over CMF (3% at 10 years) may not justify the increased toxicity 1
When anthracyclines are contraindicated:
- CMF remains the preferred non-anthracycline option (classic oral cyclophosphamide days 1-14 with IV methotrexate-fluorouracil days 1 and 8, every 28 days for 6 cycles) 2
- Docetaxel-cyclophosphamide (TC) is an alternative offering improved DFS and OS compared to AC 2
Critical Caveats
- Cardiac function is paramount: The doxorubicin in CAF increases cardiotoxicity risk. Patients with borderline cardiac function should not receive CAF 2
- The 3% OS advantage is marginal and may not outweigh quality of life impacts from increased toxicity in many patients
- Modern regimens have superseded both: Neither CAF nor CMF represents current optimal therapy when anthracycline-taxane combinations are feasible
- Hormone receptor status matters: The INT-0102 trial showed tamoxifen benefit only in HR-positive disease, emphasizing the importance of tailoring endocrine therapy appropriately 1