Ipsilateral irradiation for oral and oropharyngeal carcinoma treated with primary surgery and postoperative radiotherapy.

PURPOSE: The purpose was to evaluate the contralateral nodal control (CLNC) in postoperative patients with oral and oropharyngeal cancer treated with ipsilateral irradiation of the neck and primary site. Late radiation-induced morbidity was also evaluated. METHODS AND MATERIALS: The study included 123 patients with well-lateralized squamous cell carcinomas treated with surgery and unilateral postoperative irradiation. Most patients had tumors of the gingiva (41%) or buccal mucosa (21%). The majority of patients underwent surgery of the ipsilateral neck (n = 102 [83%]). The N classification was N0 in 73 cases (59%), N1 or N2a in 23 (19%), and N2b in 27 cases (22%). RESULTS: Contralateral metastases developed in 7 patients (6%). The 5-year actuarial CLNC was 92%. The number of lymph node metastases was the only significant prognostic factor with regard to CLNC. The 5-year CLNC was 99% in N0 cases, 88% in N1 or N2a cases, and 73% in N2b cases (p = 0.008). Borderline significance (p = 0.06) was found for extranodal spread. Successful salvage could be performed in 71% of patients with contralateral metastases. The prevalence of Grade 2 or higher xerostomia was 2.6% at 5 years. CONCLUSIONS: Selected patients with oral or oropharyngeal carcinoma treated with primary surgery and postoperative ipsilateral radiotherapy have a very high CLNC with a high probability of successful salvage in case of contralateral metastases. However, bilateral irradiation should be applied in case of multiple lymph node metastases in the ipsilateral neck, particularly in the presence of extranodal spread. The incidence of radiation-induced morbidity is considerably lower as observed after bilateral irradiation