Clinical results of N0 tongue cancer treated with interstitial brachytherapy and management of occult cervical node metastases

One hundred patients with T1-2N0 squamous cell carcinoma of the oral tongue were treated with interstitial brachytherapy between 1962 and 1983. The patients were followed for more than two years. The cumulative 5-year survival rate was 89% in T1N0 and 66% in T2N0. The relapse-free survival rate was 88% in T1N0 and 51% in T2N0. The 2-year local control rate in the primary site was 100% in T1N0 and 73% in T2N0. Cervical node metastases developed in 41% (T1N0: 33%, T2N0: 43%) of the patients. The 5-year survival rate for patients with subsequent cervical node metastases was 42%, and 92% for patients without them (p<0.001). Twenty-seven patients also received prophylactic neck irradiation (average dose: 33.8 Gy). In these patients, the rate of subsequent cervical node metastases was 37% and the cumulative 5-year survival rate was 62%. In the group of patients without prophylactic neck irradiation, the corresponding figures were 41% and 73%. There was no statistically significant difference between the two groups. Between 1984 and 1986, 28 patients with T1-2N0 carcinoma were treated with interstitial brachytherapy. These patients were prospectively examined for the ability of chemotherapy to prevent the development of cervical node metastases. In 13 patients treated with chemotherapy (CDDP 80 mg/m2 + PEP 6 mg/m2 x 5 days), the 2-year local control rate was 90%, the incidence of cervical node metastases was 38%, and the incidence of distant metastases was 15%. In 15 patients without chemotherapy, the corresponding figures were 93%, 20% and 7%. No statistically significant difference between the two groups was found. In conclusion, the development of cervical node metastasis worsens the prognosis of patients with T1-2N0 oral tongue cancer treated with interstitial brachytherapy. The combination with prophylactic neck irradiation or chemotherapy failed to decrease the incidence of cervical node metastases or improve survival rate. (J.P.N.)