Predicting Radiotherapy Necessity in Tongue Cancer Using Lymph Node Yield

Purpose: In patients with head and neck cancer and a single metastatic lymph node (pN1), the value of lymph node yield (LNY) remains controversial in determining the prognosis and identifying patients who require radiotherapy. This study evaluated the role of LNY in predicting the adequacy of neck dissection, need for adjuvant radiotherapy, and survival in patients with pN1 oral tongue squamous cell carcinoma.

Materials and methods: The authors implemented a retrospective cohort study. The predictor variable was LNY. The outcome variables were 5-year disease-specific survival and the need for adjuvant radiotherapy. Other study variables were age, gender, tumor stage, pathologic grade, growth pattern, tobacco and alcohol habits, and time frame. Descriptive and bivariate statistics were computed, and a P value less than .05 was considered statistically significant.

Results: The sample was chosen from among 2,792 patients who were histopathologically diagnosed as having oral squamous cell carcinoma and underwent surgical treatment from June 1996 through December 2012. One hundred forty-one patients treated at the Department of Oral and Maxillofacial-Head and Neck Oncology of the Beijing Stomatological Hospital (Beijing, China) were screened for the study. Receiver operating characteristics curve analysis identified that a cutoff (LNY, 20; area under the curve, 0.708; 95% confidence interval, 0.625-0.781; sensitivity and specificity, 64.94 and 70.31%, respectively; P = .0001) could best discriminate patients into 2 groups according to need for adjuvant radiotherapy. Interestingly, subgroup analyses showed that patients who underwent adjuvant radiotherapy had notably better 5-year disease-specific survival than those who did not undergo radiotherapy if the LNY was smaller than 20 (58.0 vs 21.0%; P = .021). However, there was no significant association for 5-year disease-specific survival between the low and high LNY groups (49.2 vs 58.7%; P = .363).

Conclusions: An LNY smaller than 20 at levels I to III predicted a benefit from adjuvant radiotherapy in patients with tongue cancer who had pN1 neck status without other adverse histopathologic features.