Definition: CMF is a classic chemotherapy regimen used primarily for early-stage breast cancer. The acronym stands for:
- Cyclophosphamide
- Methotrexate
- Fluorouracil (5-FU)
Components & Mechanism of Action
| Drug | Class | Mechanism of Action |
|---|---|---|
| Cyclophosphamide | Alkylating agent | Crosslinks DNA strands → inhibits DNA replication and transcription → cell death |
| Methotrexate | Antimetabolite (antifolate) | Inhibits dihydrofolate reductase → blocks DNA synthesis and repair |
| Fluorouracil (5-FU) | Antimetabolite (pyrimidine analog) | Inhibits thymidylate synthase → disrupts DNA synthesis |
Typical Dosing Schedule
| Drug | Dose | Route | Schedule |
|---|---|---|---|
| Cyclophosphamide | 600 mg/m² | IV | Day 1 |
| Methotrexate | 40 mg/m² | IV | Days 1 and 8 |
| Fluorouracil | 600 mg/m² | IV | Days 1 and 8 |
| Cycle repeats every 28 days | Typically for 6 cycles |
Indications
- Adjuvant treatment for early-stage breast cancer (especially hormone receptor-positive or negative)
- Occasionally used in metastatic breast cancer
Common Toxicities
| Toxicity | Notes/Management |
|---|---|
| Myelosuppression | Neutropenia, anemia, thrombocytopenia; monitor CBC |
| Nausea & vomiting | Moderate emetogenic risk; use antiemetics |
| Mucositis | Methotrexate-related; oral care and supportive treatment |
| Alopecia | Less frequent/severe compared to other regimens |
| Diarrhea | Possible, monitor hydration |
| Hemorrhagic cystitis | Low risk with standard dose cyclophosphamide; encourage hydration |
Clinical Considerations
- Monitor CBC with differential regularly to guide treatment delays or dose adjustments.
- Methotrexate clearance depends on renal function; dose adjustment or delay may be required if renal impairment develops.
- Supportive care includes antiemetics, hydration, and infection prophylaxis as needed.
- Not commonly used in modern regimens but remains a reference standard and option in certain clinical scenarios.
Practice Pearls
- CMF is less commonly used today due to the advent of taxane- and anthracycline-based regimens but is still relevant in some clinical contexts.
- Always review patient renal and hepatic function before administering methotrexate.
- Educate patients on signs of infection due to neutropenia and mucositis to prevent complications.
Key Takeaway:
CMF is a well-established chemotherapy regimen for breast cancer combining alkylating and antimetabolite agents with manageable toxicity, primarily used as adjuvant therapy though less common in current practice due to newer regimens.