[Effectiveness of prophylactic irradiation of the cervical lymphatics in malignant tumors of the nasopharynx].

The effectiveness of prophylactic irradiation of areas of the neck commonly involved in metastatic spread was studied in 276 patients with nasopharyngeal malignancies who were followed up during 5 and more years. The analysis was carried using such criteria as the decrease in the frequency of recurrent regional metastases, distant metastases and increase in 5-year survival. The absorbed doses ranged 45-50 Gy. The procedure was followed by a decrease in the frequency of regional metastases (3.4% versus 32.7% in untreated patients). The frequency of distant metastases decreased nearly by half (19.5% versus 31.7%). Five-year survival rates increased significantly from 49 to 65.5%. This relationship was recorded for all histological types of tumors. Application of prophylactic irradiation in doses of 45-50 Gy prevents local subclinical metastasis development in most patients.