A study was conducted to investigate the different types of therapy for patients diagnosed with head and neck cancer between 1998 and 2011 (Chen et al, Cancer, 2014, see table below). Study population included adults (?18 years) with confirmed diagnosis of head and neck cancer who underwent either surgical therapy alone or combined therapy (surgery + radiation + chemotherapy) . A total of 73,088 patients were included in the study, and data related to patient demographics, tumor characteristics, and type of therapy were collected.

TABLE 2. Pathologic Characteristics of Patients With Head and Neck Cancer With Adverse Features Surgery Surgery + CRT/RT N-18.299 N-54,789 % Site Oropharynx 3215 17.6 21,134 38.6 Ord cavity 10.447 57.1 19.117 34.9 Hypopharynx 912 5.0 2927 5.3 Larynx 3725 20.4 11,611 21.2 T classification T1 2697 15.9 9440 18.2 12 2499 14.8 11.669 22 5 13 2870 17.0 7631 14.7 6-434 38.0 16.825 32 5 TX 2426 143 6231 120 N classification NO 6971 413 10.295 19.9 N1 1422 84 5422 10.5 N2 4479 26.5 26.273 50.9 N3 251 1.5 1591 3.1 NX 3762 22.3 8076 15.6 Surgical margins Negative 9381 513 28,704 52 4 Positive 7870 43.0 21.148 38.6 Unknown 1048 5.7 4937 9.0 LVT No 1119 59.1 3745 59.9 LVI 773 40.9 2507 40.1 ECE No ECE 1140 12.1 3710 12.1 ECE 613 6.5 3909 12 8 Unknown 7679 81.4 22.952 75.1 Abbreviations: CAT, chemoradiation; ECE, extracapsular exteriors LVL, lymphovascular invasions RT, radiotherapy. "LV available only for patients diagnosed from 2010 through 2011. "ECE available only for patients diagnosed from 2004 through 2011