Table 1 Demographic characteristics of patients with newly diagnosed p16-negative oropharyngeal squamous cell carcinoma receiving concurrent chemoradiotherapy
|  | Total N = 3942 | Pre-CCRT PET-CT N = 1663 | No Pre-CCRT PET-CT N = 2279 | P value | |||
|---|---|---|---|---|---|---|---|
n | (%) | n | (%) | n | (%) | ||
Sex | |||||||
 Male | 3633 | (92.2) | 1528 | (91.9) | 2105 | (92.4) | 0.5774 |
 Female | 309 | (7.8) | 135 | (8.1) | 174 | (7.6) |  |
Age (years) | |||||||
 Mean (SD) | 55.0 | (10.3) | 54.8 | (10.0) | 55.2 | (10.5) | 0.2550 |
 Median (Q1–Q3) | 54 | (48–61) | 54 | (47–61) | 54 | (48–61) |  |
 ≤ 40 | 230 | (5.8) | 88 | (5.3) | 142 | (6.2) | 0.2600 |
 41–50 | 1166 | (29.6) | 514 | (30.9) | 652 | (28.6) |  |
 51–60 | 1517 | (38.5) | 637 | (38.3) | 880 | (38.6) |  |
 61–70 | 700 | (17.8) | 298 | (17.9) | 402 | (17.6) |  |
 > 70 | 329 | (8.3) | 126 | (7.6) | 203 | (8.9) |  |
AJCC clinical stages | |||||||
 I–II | 422 | (10.7) | 168 | (10.1) | 254 | (11.1) | 0.0111 |
 III–IVA | 3520 | (89.3) | 1495 | (89.9) | 2025 | (88.9) |  |
Clinical T stages | |||||||
 T1–T2 | 1813 | (46.0) | 789 | (47.4) | 1024 | (44.9) | 0.1180 |
 T3–T4 | 2129 | (54.0) | 874 | (52.6) | 1255 | (55.1) |  |
Clinical N stages | |||||||
 N0–N1 | 1251 | (31.7) | 475 | (28.6) | 776 | (34.1) | 0.0003 |
 N2–N3 | 2691 | (68.3) | 1188 | (71.4) | 1503 | (65.9) |  |
Differentiation | |||||||
 Well | 273 | (4.6) | 91 | (5.5) | 182 | (8.0) |  < 0.0001 |
 Moderate | 2399 | (40.1) | 1007 | (60.6) | 1392 | (61.1) |  |
 Poor | 1270 | (21.2) | 565 | (33.9) | 705 | (30.9) |  |
Platinum cumulative dose, mg | |||||||
 Mean (SD) | 542.4 | (430.7) | 533.2 | (420.2) | 549.6 | (438.6) | 0.4215 |
 Median (Q1–Q3) | 450.0 | (300.0—650.0) | 450.0 | (300.0–650.0) | 450.0 | (300.0–700.0) |  |
CCI scores | |||||||
 Mean (SD) | 0.7 | (1.2) | 0.6 | (1.2) | 0.7 | (1.2) | 0.3871 |
 Median (Q1–Q3) | 0 | (0–1) | 0 | (0–1) | 0 | (0–1) |  |
 0 | 2578 | (65.4) | 1096 | (65.9) | 1482 | (65.0) | 0.3818 |
 1 | 747 | (18.9) | 322 | (19.4) | 425 | (18.6) |  |
 2+ | 617 | (15.7) | 245 | (14.7) | 372 | (16.3) |  |
Diagnosis year | |||||||
 2008–2010 | 945 | (24.0) | 308 | (18.5) | 637 | (28.0) |  < 0.0001 |
 2011–2014 | 1161 | (29.5) | 448 | (26.9) | 713 | (31.3) |  |
 2015–2018 | 1836 | (46.6) | 907 | (54.5) | 929 | (40.8) |  |
Hospital volume | |||||||
 High patient volume | 2547 | (64.6) | 1106 | (66.5) | 1441 | (63.2) | 0.0336 |
 Low patient volume | 1395 | (35.4) | 557 | (33.5) | 838 | (36.8) |  |
 Mean follow-up time, months (SD) | 40.3 | (34.8) | 52.5 | (33.1) | 50.2 | (36.0) |  |
 All-cause death |  | 2485 | (63.0) | 1014 | (61.0) | 1471 | (64.5) |