Postoperative radiation therapy for cervical lymph node metastases from an occult squamous cell carcinoma

One hundred thirteen patients with cervical metastases from a squamous cell carcinoma and no evidence of the primary tumor were treated for cure by surgery and routine large-field postoperative irradiation. Patients were staged according to the 1987 American Joint Committee on Cancer (AJCC) classification. There were 24 N1, 54 N2, 29 N3, and 6 Nx lesions. One hundred four patients underwent cervical lymph node dissection and 9 had adenectomy. All patients received postoperative external beam therapy to the entire naso-oro-pharyngo-larynx and all cervical lymphatics. The overall nodal failure rate was 13.7%. Nodal failure was significantly correlated with N staging (P = .01) and with the number of histologically involved nodes (P = .05). NOdal failure was 21% when nodes were initially fixed versus 7.5% when they were not (P = .07) and 18% when there was extracapsular spread versus 4.3% when the capsule was intact (P = .11). Eleven patients (9.7%) developed a subsequent primary lesion. In 3 patients (2.6%), this primary was located in the previously irradiated area and, in 2 cases, under the anterior block of lateral fields. Metastases occurred in 18 patients (16%). The five-year overall survival rate was 38%. Survival was correlated with N staging (P less than .02), nodal fixation (P = .05), extracapsular spread (P = .01) and loosely with the number of histologically involved nodes (P = .08). On the contrary, histological differentiation did not influence the local control rate, nor the development of metastases or subsequent primary lesions. Large-field prophylactic radiation therapy appears to be effective in preventing the emergence of initially occult primary lesions. However, control of disease in the neck and survival remain disappointing in patients with advanced nodal disease, even after combined surgery and radiation therapy.