What is the primary treatment approach for nasopharyngeal cancer?

Primary Treatment Approach for Nasopharyngeal Cancer

Radiation therapy (RT) is the mainstay of treatment for nasopharyngeal cancer, with the addition of concurrent chemotherapy for locally advanced disease. 1

Treatment by Stage

Early Stage Disease (Stage I and IIA)

• RT alone is the standard treatment for early-stage nasopharyngeal cancer 1
• A total dose of 70 Gy is needed for eradication of gross tumor and 50-60 Gy for elective treatment of potential risk sites 1
• Intensity-modulated RT (IMRT) may offer improvement in local tumor control and reduction in radiation xerostomia in early-stage disease 1, 2

Intermediate Risk (Stage IIB)

• Concurrent chemoradiotherapy should be considered for stage IIB disease 1
• Treatment strategies similar to those for stage III-IV disease are often applied 1

Advanced Disease (Stage III-IVA,B)

• RT with concurrent cisplatin-based chemotherapy is the standard of care 1
• Cisplatin is the standard agent used in concurrent chemoradiotherapy with level I evidence 1
• Adjuvant chemotherapy with cisplatin and fluorouracil following concurrent chemoradiotherapy may be beneficial, though its role remains debatable 1
• Induction chemotherapy has shown improvement in disease-free survival and may be considered in locally advanced disease, though it is not standard treatment 1

Radiation Therapy Technique

• RT is targeted to the primary tumor and adjacent regions at risk of microscopic spread, as well as both sides of the neck 1
• Elective nodal irradiation is recommended for N0 stage disease 1
• To minimize late toxicity (particularly to adjacent neurological structures):
  • Fractional dose should not exceed 2 Gy per daily fraction 1
  • Excessive acceleration with multiple fractions >1.6-1.9 Gy/fraction should be avoided 1
• IMRT is now the preferred RT treatment modality as it delivers high doses to target structures while sparing adjacent healthy tissues 2

Treatment of Recurrent or Metastatic Disease

• Small local recurrences are potentially curable with options including:
  • Nasopharyngectomy
  • Brachytherapy
  • Radiosurgery
  • Stereotactic RT
  • Intensity-modulated RT
  • Combination of surgery and RT with or without concurrent chemotherapy 1
• Regional recurrence is managed by radical neck dissection if resectable 1
• For metastatic disease, palliative chemotherapy should be considered for patients with adequate performance status 1
• Platinum-5-fluorouracil combination regimens are commonly used as first-line therapy 1
• Other active agents include taxanes (paclitaxel, docetaxel), gemcitabine, capecitabine, irinotecan, vinorelbine, ifosfamide, doxorubicin, and oxaliplatin 1
• High-dose RT to the primary tumor combined with systemic chemotherapy may improve survival in selected patients with metastatic disease at presentation 3

Follow-up

• Periodic examination of the nasopharynx and neck, cranial nerve function, thyroid function 1
• Evaluation of systemic complaints to identify distant metastasis 1
• MRI should be used to evaluate response to RT or chemoradiotherapy 1
• For T3 and T4 tumors, MRI might be used on a 6-12 month basis to evaluate the nasopharynx and base of skull for the first few years after treatment 1
• EBV serology monitoring might be useful 1

Common Pitfalls and Caveats

• Ensure adequate radiation dose (70 Gy) to the primary tumor while limiting dose to adjacent critical structures 1
• Do not compromise optimal administration of concurrent chemoradiation if induction chemotherapy is used 1
• Recognize that nasopharyngeal cancer is highly chemosensitive, and even patients with metastatic disease may achieve long-term survival with appropriate therapy 1, 3
• Intensity-modulated RT should be used when available to reduce toxicity while maintaining efficacy 2
• Consider the patient's performance status when deciding on chemotherapy regimens, particularly for metastatic disease 1