Table 1.
Baseline characteristics of study patients stratified according to viral status
| Characteristics | All Patients (n=61) | EBV positive (n=26) | HPV positive (n=18) | EBV/HPV negative (n=17) | P |
|---|---|---|---|---|---|
| Age – yr | <0.001 | ||||
| Median | 54.3 | 45.2 | 57.8 | 62.3 | |
| Range | 10-83 | 10-77 | 39-83 | 40-77 | |
| Sex – no. (%) | 0.30 | ||||
| Male | 40 (65.6) | 17 (65.4) | 14 (77.8) | 9 (52.9) | |
| Female | 21 (34.4) | 9 (34.6) | 4 (22.2) | 8 (47.1) | |
| Race – no. (%) | 0.29 | ||||
| Caucasian | 45 (73.8) | 16 (61.5) | 17 (94.4) | 12 (70.6) | |
| African American | 9 (14.8) | 5 (19.2) | 1 (5.6) | 3 (17.6) | |
| Asian | 5 (8.2) | 4 (15.4) | 0 | 1 (5.9) | |
| Middle Eastern | 2 (3.3) | 1 (3.8) | 0 | 1 (5.9) | |
| Tobacco exposure – no. (%) | |||||
| Never smoked | 24 (39.3) | 18 (69.2) | 4 (22.2) | 2 (11.8) | <0.001 |
| Current and former smokers | 36 (59.0) | 7 (26.9) | 14 (77.8) | 15 (88.2) | |
| Unknown | 1 (1.6) | 1 (3.8) | 0 | 0 | |
| WHO grade – no. (%) | <0.001 | ||||
| I | 17 (27.9) | 0 | 6 (33.3) | 11 (64.7) | |
| II | 22 (36.1) | 7 (26.9) | 11 (61.1) | 4 (23.5) | |
| III | 22 (36.1) | 19 (73.1) | 1 (5.6) | 2 (11.8) | |
| EBV encoded RNA – no. (%) | <0.001 | ||||
| Positive | 26 (42.6) | 26 (100) | 0 | 0 | |
| Negative | 35 (57.4) | 0 | 18 (100) | 17 (100) | |
| p16 overexpression – no. (%) | <0.001 | ||||
| Positive | 21 (34.4) | 0 | 18 (100) | 3 (17.6) | |
| Negative | 40 (65.6) | 26 (100) | 0 | 14 (82.4) | |
| HPV DNA – no. (%) | <0.001 | ||||
| Positive | 18 (29.5) | 0 | 18 (100) | 0 | |
| Negative | 43 (70.5) | 26 (100) | 0 | 17 (100) | |
| Tumor classification – no. (%) | 0.19 | ||||
| T1 | 8 (13.1) | 4 (15.4) | 3 (16.7) | 1 (5.9) | |
| T2 | 12 (19.7) | 6 (23.1) | 4 (22.2) | 2 (11.8) | |
| T3 | 7 (11.5) | 4 (15.4) | 2 (11.1) | 1 (5.9) | |
| T4 | 30 (49.2) | 10 (38.5) | 9 (50.0) | 11 (64.7) | |
| Unknown | 4 (6.6) | 2 (7.7) | 0 | 2 (11.8) | |
| Nodal classification – no. (%) | 0.07 | ||||
| N0 | 12 (19.7) | 2 (7.7) | 5 (27.8) | 5 (29.4) | |
| N1 | 19 (31.1) | 8 (30.8) | 6 (33.3) | 5 (29.4) | |
| N2 | 21 (34.4) | 11 (42.3) | 7 (38.9) | 3 (17.6) | |
| N3 | 6 (9.8) | 4 (15.4) | 0 | 2 (11.8) | |
| Unknown | 3 (4.9) | 1 (3.8) | 0 | 2 (11.8) | |
| AJCC stage – no. (%) | 0.24 | ||||
| I | 3 (4.9) | 1 (3.8) | 1 (5.6) | 1 (5.9) | |
| II | 8 (13.1) | 4 (15.4) | 3 (16.7) | 1 (5.9) | |
| III | 13 (21.3) | 7 (26.9) | 5 (27.8) | 1 (5.9) | |
| IVA | 27 (44.3) | 8 (30.8) | 9 (50.0) | 10 (58.8) | |
| IVB | 6 (9.8) | 4 (15.4) | 0 | 2 (11.8) | |
| Unknown | 4 (6.6) | 2 (7.7) | 0 | 2 (11.8) | |
| Year of diagnosis | 0.54 | ||||
| Mean | 2001.4 | 2000.3 | 2002.7 | 2001.7 | |
| Range | 1985-2011 | 1985-2011 | 1986-2011 | 1991-2011 | |
| Radiation dose – Gy | 0.44 | ||||
| Median | 70 | 70 | 70 | 70 | |
| Range | 64.8-74.4 | 64.8-74.4 | 69.0-72.4 | 69.0-74.0 | |
| Radiation technique | 0.34 | ||||
| 2D-RT / 3D-CRT | 30 (49.2) | 15 (57.7) | 6 (33.3) | 9 (52.9) | |
| IMRT | 30 (49.2) | 11 (42.3) | 11 (61.1) | 8 (47.1) | |
| Concurrent chemotherapy – no. (%) | 0.73 | ||||
| Yes | 54 (88.5) | 24 (92.3) | 16 (88.9) | 14 (82.3) | |
| No | 5 (8.2) | 2 (7.7) | 1 (5.6) | 2 (11.8) | |
| Unknown | 2 (3.3) | 0 | 1 (5.6) | 1 (5.9) | |
| Adjuvant chemotherapy – no. (%) | 0.10 | ||||
| Yes | 17 (27.9) | 6 (23.1) | 6 (33.3) | 5 (29.4) | |
| No | 38 (62.3) | 20 (76.9) | 8 (44.4) | 10 (58.8) | |
| Unknown | 6 (9.8) | 0 | 4 (22.2) | 2 (11.8) |
Abbreviations: EBV, Epstein-Barr virus; HPV, human papillomavirus;
*P values were calculated with the use of Pearson's chi-square test for all comparisons, except age and radiation dose for which ANOVA was used, and staging (tumor, nodal, and AJCC) for which Kruskal-Wallis test was used.