Mitomycin C (MMC)

Mitomycin C (MMC) is a chemotherapy drug and alkylating agent used in cancer treatment, including intravesical therapy for non-muscle-invasive bladder cancer (NMIBC). It works by damaging the DNA of rapidly dividing cancer cells, leading to cell death.

Key Uses in Bladder Cancer:

• Adjuvant therapy after transurethral resection of bladder tumor (TURBT) to reduce recurrence.
• Alternative to BCG in low- or intermediate-risk NMIBC when BCG is unavailable or contraindicated.
• Sometimes used as a single-dose instillation immediately after TURBT to prevent tumor implantation.

Administration (Intravesical):

• Given via a catheter into the bladder.
• Retained for 1–2 hours before voiding.
• Typical schedule:
  • Single postoperative dose (within 24 hrs of TURBT).
  • Induction course: Weekly for 6–8 weeks.
  • Maintenance: Monthly for up to 1 year in some cases.

Mechanism of Action:

• Forms DNA cross-links, preventing replication and transcription.
• Acts as a bioreductive alkylator, becoming activated in hypoxic (low-oxygen) tumor environments.

Side Effects:

• Local:

  • Bladder irritation (dysuria, frequency, hematuria).
  • Chemical cystitis (less common than with BCG).

• Systemic (rare, if absorbed):

  • Myelosuppression (low blood counts).
  • Allergic reactions (rash, fever).
  • Bladder contracture (long-term use).

Efficacy:

• Reduces recurrence by ~15–20% in low-risk NMIBC (less effective than BCG for high-risk tumors).
• Often used when BCG is unavailable or for patients who cannot tolerate immunotherapy.

Contraindications/Precautions:

• Bladder perforation during TURBT (risk of systemic absorption).
• Severe urinary tract infections (UTIs).
• Pregnancy (teratogenic).

Comparison to BCG:

Alternatives:

• Gemcitabine (intravesical): Another chemo option for BCG-unresponsive cases.
• Docetaxel/Valrubicin: Used in BCG-refractory disease.