Chemoradiation Therapy for Cervical Cancer
Chemoradiation therapy (CRT) for cervical cancer consists of concurrent cisplatin-based chemotherapy (typically weekly cisplatin 40 mg/m²) with external beam radiation therapy (EBRT) followed by brachytherapy, and is the standard of care for locally advanced cervical cancer (stages IB2-IVA). 1
Components of CRT for Cervical Cancer
External Beam Radiation Therapy (EBRT)
- Initial dose of 40-45 Gy to the whole pelvis delivered over 4-5 weeks
- CT-based treatment planning with conformal blocking is standard of care
- Treatment volume includes:
- Gross disease (if present)
- Parametria and uterosacral ligaments
- Sufficient vaginal margin (at least 3 cm from gross disease)
- Presacral nodes and other nodal volumes at risk
- For node-negative patients: external iliac, internal iliac, and obturator nodal basins
- For higher risk patients: common iliac nodes
- For patients with documented common iliac/para-aortic involvement: extended field up to renal vessels 1
Brachytherapy
- Critical component following EBRT for patients with intact cervix
- Typically begins after sufficient tumor shrinkage from EBRT
- Total doses from combined EBRT and brachytherapy:
- At least 80 Gy to point A for small tumors
- 85 Gy or higher for larger tumors 1
Chemotherapy
- Weekly cisplatin 40 mg/m² during EBRT is the most commonly used regimen
- Alternative options for patients who cannot tolerate cisplatin:
- Carboplatin
- Non-platinum regimens 1
Timing Considerations
- The entire radiation course (EBRT + brachytherapy) should be completed within 8 weeks
- Treatment delays should be avoided as extending treatment beyond 6-8 weeks can result in approximately 0.5-1% decrease in pelvic control and cause-specific survival for each extra day 1
Treatment Efficacy
- CRT has demonstrated significant improvement in both disease-free survival (DFS) and overall survival (OS) compared to radiation alone
- Meta-analysis of 18 randomized trials showed absolute 5-year survival benefits of:
- 8% for overall disease-free survival
- 9% for locoregional disease-free survival
- 7% for metastases-free survival 1
Common Side Effects and Management
- Acute effects (typically resolve after treatment):
- Diarrhea
- Bladder irritation
- Fatigue
- Hematologic toxicity (particularly with concurrent chemotherapy)
- Late effects:
- Potential injury to bladder, rectum, bowel, and pelvic skeletal structures
- Risk of major complications is related to dose and volume of normal tissue irradiated 1
Special Considerations
- For younger patients (<45 years with early-stage disease), ovarian transposition can be considered before pelvic RT to avoid treatment-related menopause 1
- Intensity-modulated RT (IMRT) is becoming more widely available but requires careful attention to target definition, immobilization, and reproducibility 1
- For patients with significant comorbidities or elderly patients who cannot tolerate chemotherapy, accelerated radiotherapy (6 fractions per week) may be considered as an alternative to standard CRT 2
Follow-up After CRT
- Physical examination every 3-6 months for first 2 years, every 6-12 months for years 3-5
- Annual cervical/vaginal cytology
- Imaging (CT, PET/CT, MRI) as indicated based on symptoms or examination findings
- Patient education regarding symptoms of recurrence 1
CRT represents a significant advancement in the treatment of cervical cancer, with concurrent cisplatin-based chemotherapy and radiation therapy demonstrating superior outcomes compared to radiation therapy alone. The treatment approach should be completed within the recommended timeframe to maximize efficacy while managing toxicities appropriately.