Managing nasopharyngeal carcinoma with intracavitary brachytherapy: one institution's 45-year experience

At our institution, we have been using intracavitary brachytherapy as a boost in selected cases of both primary and recurrent nasopharyngeal carcinoma. The local control, distant metastasis-free rate, overall survival, and morbidity are presented.

Between January 1, 1955, and August 2000, 576 patients with a diagnosis of nasopharyngeal carcinoma were seen at the department of radiation oncology, University of California-San Francisco, and 55 patients received intracavitary brachytherapy as one part of their treatment. All patients were treated with megavoltage external beam radiation, including 43 patients treated for initial disease and 12 for recurrence. Brachytherapy was routinely used for early cases of T1 and T2 lesions and selected cases of more advanced lesions, as well as recurrent lesions. The median age was 48 years (range 22-85 years); there were 17 women and 38 men, and 39 patients were ethnic Chinese, 13 were white, and 3 were other races. Stage at treatment (primary and recurrent) was I (n=13), II (n=18), III (n=19), and IV (n=5); 18 patients had concurrent chemotherapy. The brachytherapy applicators used were Rotterdam (n=24), balloon (n=16), ovoid (n=14), and ribbon (n=1). The dose rate was high (n=24), low (n=29), or pulsed (n=2). External beam doses ranged from 54 to 72 Gy for primary disease and 30 to 42 Gy for recurrent disease. Brachytherapy doses ranged from 5 to 7 Gy for high dose rate and 10 to 54 Gy for low dose rate.

With a median follow-up of 36 months in those who were treated for primary carcinoma, the 5-year estimate of local control was 89%, the distant metastasis-free rate was 75%, and the overall survival estimate was 86%. Recurrent patients had a median follow-up of 50 months; the 5-year estimate of local control was 64%, the distant metastasis-free rate was 100%, and the overall survival estimate was 91%. Patients with Stage I or II disease had a longer overall survival compared with those with Stage III or IV (p=0.05). There was a significant difference in the rate of distant metastases due to nodal status (N0 vs. N1-N3, p=0.02) or to overall stage (I/II vs. III/IV, p=0.005).

Intracavitary boost brachytherapy was found to be effective and well tolerated in selected cases of both primary and recurrent nasopharyngeal carcinoma.