CDKN2A and metastatic neoplasm: Patients included in this study all underwent bilateral neck dissection and adjuvant therapy according to the pathological results, therefore, occult metastatic disease did not lead to undertreatment; however, had the same patient collective been treated non-surgically, 18.8% of p16-negative and 8.8% of p16-positive patients would have received treatment with an underlying underestimation of their metastatic disease burden.