xRead Articles - November 2022

Xiao et al

123

Table 1. Demographic and Clinical Information by Histology. a

MEC AC CA ANOS Ad Cy CA CA EPA SDC EMC BCA Other

Total

No. 4104 (18) 22,653 (100) Age \ 62 y 4061 (59) 2778 (70) 1194 (39) 1292 (64) 403 (49) 187 (43) 231 (41) 191 (44) 1479 (37) 11,816 (53) Age . 62 y 2864 (41) 1221 (31) 1863 (61) 731 (36) 424 (51) 246 (57) 332 (59) 247 (56) 2517 (63) 10,445 (47) Caucasian 5618 (82) 3443 (88) 2718 (88) 1678 (84) 746 (91) 367 (86) 476 (84) 394 (90) 3626 (89) 19,066 (86) African Am 946 (14) 351 (9) 292 (9) 222 (11) 51 (6) 44 (10) 57 (10) 29 (7) 291 (7) 2283 (10) Other (race) 330 (5) 131 (3) 83 (3) 94 (5) 24 (3) 15 (4) 31 (6) 17 (4) 137 (3) 862 (4) Male 3497 (50) 1631 (41) 1980 (63) 814 (40) 464 (55) 289 (66) 252 (44) 227 (51) 2659 (65) 11,813 (52) Female 3534 (50) 2392 (60) 1175 (37) 1231 (60) 374 (45) 147 (34) 321 (56) 221 (49) 1445 (35) 10,840 (48) T1 1831 (48) 999 (45) 440 (27) 326 (30) 112 (25) 65 (30) 118 (37) 82 (36) 499 (25) 4472 (38) T2 1071 (28) 828 (38) 486 (30) 307 (28) 149 (33) 65 (30) 130 (40) 85 (37) 699 (35) 3820 (32) T3 448 (12) 231 (11) 297 (18) 181 (17) 110 (24) 40 (19) 55 (17) 43 (19) 407 (20) 1812 (15) T4 447 (12) 146 (7) 411 (25) 271 (25) 80 (18) 46 (21) 20 (6) 17 (8) 392 (20) 1830 (15) Low grade 4165 (68) 1313 (85) 800 (33) 387 (65) 139 (31) 69 (21) 211 (84) 151 (79) 679 (27) 7914 (55) High grade 1939 (32) 235 (15) 1638 (67) 212 (35) 315 (69) 254 (79) 39 (16) 41 (21) 1862 (73) 6535 (45) Abbreviations: AC CA, acinar cell carcinoma; Ad Cy CA, adenoid cystic carcinoma; ANOS, adenocarcinoma not otherwise specified; BCA, basal cell adeno carcinoma; CA EPA, carcinoma ex pleomorphic adenoma; EMC, epithelial-myoepithelial carcinoma; MEC, mucoepidermoid carcinoma; SDC, salivary ductal carcinoma. a Values are presented in n (%). 7031 (31) 4023 (18) 3155 (14) 2045 (9) 838 (4) 436 (2) 573 (2) 448 (2)

Incidence data on nodal disease and occult nodal disease are presented in Tables 2 and 3 . Overall, incidence of regional metastasis was 24.4%, with salivary ductal carci noma (53.5%), adenocarcinoma NOS (45.2%), and carcinoma ex pleomorphic adenoma (26.8%) being most common. These 3 histologies also had the highest incidences of occult disease in the same order (23.6%, 19.9%, 11.8%). Epithelial myoepithelial carcinoma had the lowest incidence of nodal metastasis (6.4%). High grade significantly increased nodal disease incidence for all histopathologies (50.9% incidence vs 9.3% for low-grade disease). For occult disease, high grade did not significantly affect incidence for adenoid cystic carcinoma ( P = .361), epithelial-myoepithelial carcinoma ( P = .689), and basal cell adenocarcinoma ( P = .925). Of note, low-grade disease for all histopathologies had occult disease incidences \ 10%. Also appreciated in our nodal data is the impact of rising T stage with increased incidence of nodal disease. Regional Metastasis and Impact on Survival OS data by histology, grade, and nodal status are shown in Table 4 . Once again, high-grade disease and nodal dis ease are significantly associated with worse outcomes in most histopathologies. However, basal cell adenocarci noma did not have significantly worse outcomes with nodal disease ( P = .686) or higher-grade disease ( P = .377). Epithelial-myoepithelial carcinoma showed a 21% drop in survival with high-grade disease (relative to low grade; P = .07). Node-positive adenocarcinoma NOS had the lowest 5-year OS (29%), whereas low-grade acinar cell carcinoma had the highest (91%). OS by histology and sta ging is presented in Table 5 , showing an appreciable decrease in survival across all histologies with rising clini cal stage.

Table 2. Overall Incidence of Nodal and Occult Disease by Histology (in Percentages).

N 1

Histology

Occult Nodes

Mucoepidermoid carcinoma

20.2

9.3 4.4

Acinar cell carcinoma

10

Adenocarcinoma not otherwise specified 45.2

19.9

Adenoid cystic carcinoma

14.2 23.9 53.5

7

Carcinoma ex pleomorphic adenoma

11.8 23.6

Salivary ductal carcinoma

Epithelial-myoepithelial carcinoma

4.8 9.4

1.5 6.3

Basal cell adenocarcinoma

Total

24.4

10.2

Predictors of Regional Metastasis Univariate and multivariate logistic regression analyses are shown in Table 6 . Age, sex, ethnicity, T stage, and grade were entered into regression analysis for each histology, but only significant predictors of nodal metastasis are shown ( P .05) in Table 6 . High grade and high T stages (T3 and T4) had the highest odds ratios (ORs) for nodal disease in univari ate analysis. In multivariate analysis, age was a significant pre dictor only for mucoepidermoid carcinoma, showing lesser likelihood of nodal disease (OR, 0.697; 95% confidence inter val [95% CI], 0.555-0.874). Male sex was significantly predic tive only in adenocarcinoma NOS (OR, 1.329; 95% CI, 1.009 1.75). Otherwise, high T stage and high grade remained the only independent predictors of nodal disease for other histo pathologies. High grade was most predictive of disease for mucoepidermoid carcinoma, acinar cell carcinoma, adenocarci noma NOS, and carcinoma ex pleomorphic adenoma. In