Dose escalation for patients with locally advanced nasopharyngeal carcinoma treated with radiotherapy alone

The local control of patients with locally advanced nasopharyngeal carcinoma is still unsatisfactory. This prospective study was designed to evaluate the treatment outcomes and treatment-related complications of patients with locally advanced nasopharyngeal carcinoma treated with escalated radiation doses.

A total of 118 consecutive patients with T4 classification (1992 American Joint Committee on Cancer staging system), histology-proven nonmetastatic nasopharyngeal carcinoma were treated with radiotherapy alone between 1992 and 1997 in a medical center in southern Taiwan. Thirty-two of them were enrolled into a prospective study of dose escalation and were irradiated to a total of 81 Gy. The other 86 patients received a total of 70.2 Gy. Potentially significant patient-related and treatment-related parameters were analyzed for their prognostic significance. Radiation-related complications were recorded and analyzed.

The 5-year local progression-free rates were 61%, and 61% for patients receiving 70.2 Gy and 81 Gy, respectively (P > 0.05). The incidences of xerostomia, hearing impairment, and temporal radionecrosis were significantly higher for those receiving 81 Gy. The 5-year complication-free rates of patients receiving 70.2 Gy and 81 Gy were 14% versus 2% for xerostomia (P = 0.0070), 50% versus 30% for hearing impairment (P = 0.0198), and 91% versus 82% for temporal radionecrosis (P = 0.0400).

For patients with locally advanced nasopharyngeal carcinoma treated with radiotherapy alone, dose escalation to 81 Gy failed to show benefits on local control rate. Higher radiation doses contribute to a higher incidence of radiation-related complications.