TABLE 1.
Descriptive statistics of the study population of patients with clinically T1‐2, N0 parotid mucoepidermoid carcinoma who underwent surgical resection. National Cancer Database, 2004–2016
| Study population, N = 1,233 (%) a | Grade (%) a | p‐value b | |||
|---|---|---|---|---|---|
| Well differentiated, n = 581 | Moderately differentiated, n = 493 | Poorly differentiated, n = 159 | |||
| Age (year) | |||||
| <65 | 845 (68.53) | 417 (71.77) | 360 (73.02) | 68 (42.77) | <0.001 |
| ≥65 | 388 (31.47) | 164 (28.23) | 133 (26.98) | 91 (57.23) | |
| Sex | |||||
| Male | 479 (38.85) | 209 (35.97) | 177 (35.9) | 93 (58.49) | <0.001 |
| Female | 754 (61.15) | 372 (64.03) | 316 (64.1) | 66 (41.51) | |
| Charlson/Deyo score | |||||
| 0 | 992 (80.45) | 461 (79.35) | 405 (82.15) | 126 (79.25) | 0.48 |
| 1 | 183 (14.84) | 88 (15.15) | 67 (13.59) | (12.03–24.44) c | |
| ≥2 | 58 (4.7) | 32 (5.51) | 21 (4.26) | (01.03–07.19) c | |
| Laterality | |||||
| Right parotid gland | 626 (50.77) | 288 (49.57) | 258 (52.33) | 80 (50.31) | 0.66 |
| Left parotid gland | 607 (49.23) | 293 (50.43) | 235 (47.67) | 79 (49.69) | |
| Surgery | |||||
| Superficial parotidectomy | 717 (58.15) | 348 (59.9) | 298 (60.45) | 71 (44.65) | 0.001 |
| Total parotidectomy | 516 (41.85) | 233 (40.1) | 195 (39.55) | 88 (55.35) | |
| Facial nerve | |||||
| Preserved | 921 (74.7) | 439 (75.56) | 383 (77.69) | 99 (62.26) | <0.001 |
| Sacrificed | 312 (25.3) | 142 (24.44) | 110 (22.31) | 60 (37.74) | |
| Elective neck dissection | |||||
| Not performed | 263 (21.33) | 124 (21.34) | 108 (21.91) | 31 (19.5) | 0.81 |
| Performed | 970 (78.67) | 457 (78.66) | 385 (78.09) | 128 (80.5) | |
| Pathological T | |||||
| 1 | 784 (63.58) | 406 (69.88) | 330 (66.94) | 48 (30.19) | <0.001 |
| 2 | 354 (28.71) | 154 (26.51) | 121 (24.54) | 79 (49.69) | |
| 3 | 68 (5.52) | (01.85–04.85) c | (04.48–09.04) c | 18 (11.32) | |
| 4a | 27 (2.19) | (00.11–01.50) c | (00.98–03.70) c | 14 (8.81) | |
| Outcome of elective neck dissection | |||||
| Pathological N0 | 920 (94.85) | 448 (98.03) | 363 (94.29) | 109 (85.16) | <0.001 |
| Pathological N+ without ECE | (03.23–05.93) c | (00.76–03.42) c | (03.20–07.91) c | (06.71–18.59) c | |
| Pathological N+ with ECE | (00.29–01.48) c | (00.01–01.21) c | (00.06–01.86) c | (00.86–07.81) c | |
| Surgical margins | |||||
| Negative | 998 (80.94) | 499 (85.89) | 389 (78.9) | 110 (69.18) | <0.001 |
| Positive | 235 (19.06) | 82 (14.11) | 104 (21.1) | 49 (30.82) | |
| Lymphovascular invasion d | |||||
| Not present | 745 (96.63) | (97.67–99.83) c | (94.90–98.86) c | 77 (83.7) | <0.001 |
| Present | 26 (3.37) | (00.17–02.33) c | (01.14–05.10) c | 15 (16.3) | |
| T3‐4a, LVI, N+, ECE, and/or positive surgical margins | |||||
| Not present | 905 (73.40) | 479 (82.44) | 350 (70.99) | 76 (47.80) | <0.001 |
| Present | 328 (26.60) | 102 (17.56) | 143 (29.01) | 83 (52.20) | |
| Adjuvant radiotherapy | |||||
| Not performed | 793 (64.31) | 452 (77.8) | 308 (62.47) | 33 (20.75) | <0.001 |
| Performed | 440 (35.69) | 129 (22.2) | 185 (37.53) | 126 (79.25) | |
Abbreviations: ECE, extracapsular extension; LVI, lymphovascular invasion.
a
Percentage values add‐up vertically and may not add up to 100% due to rounding.
b
Chi‐square test.
c
This range represents 95% confidence interval. Data‐using‐agreement prohibits reporting exact number of subjects for variables with less than 10 subjects with the event so it was substituted with 95% confidence interval to convey an estimate.
d
Lymphovascular invasion variable is missing for 462 subjected because it is only available for the years 2010–2016.