[Repeated radiotherapy in locally recurrent nasopharyngeal cancer]

In the period between 1993 and 2000, 20 patients with nasopharyngael cancer were re-irradiated for locally recurrent carcinomas. The median duration between primary treatment and recurrence was 30 months. Brachytherapy was the method most frequently used in 10 cases alone, and in 8 cases in combination with external beam therapy. 2 patients underwent only external beam therapy. The external irradiation was performed with CT/MRI-based treatment planning. Brachytherapy involved a high dose rate afterloading method. The cumulative dose of re-irradiation was 20-60 Gy.

After a median follow-up of 37 months the overall survival and the local control were 60% (12/20) and 58% (7/12), respectively. 7 of the 12 surviving patients are currently tumour-free. After primary irradiation xerostomy occurred in all patients as an unavoidable side-effect of the treatment. A severe (grade 3 or higher according to the Common Toxicity Criteria version 2.0) late-side effect has so far been observed in 2 cases (10%). Authors' results lie in the medial range of the data in the international literature, though the rate of radiogen side-effects in the patient group is low. Both results are assumed to be a consequence of the re-irradiation dose being lower than the value considered optimum in the recent literature.

Re-irradiation of locally recurrent nasopharyngeal cancers is an efficient treatment modality, which should be used as a combination of external beam therapy and brachytherapy. The optimum cumulative dose is about 50-60 Gy. This dose results in a 5 years survival rate of about 40% with an acceptable (30%) risk. The results of re-irradiation may be improved, if PET is used to determine the extent of the surviving tumour tissue. This can help in the choice of the proper treatment modality.