2018-19 Section 7-Neoplastic and Inflammatory Diseases of the Head and Neck eBook

Research Original Investigation

Survival Outcomes With Adjuvant Chemotherapy in Resected Major Salivary Gland Carcinoma

Table 1. Patient and Treatment Characteristics (continued)

No. (%) of Patients a RT Alone (n = 1842)

CRT (n = 368)

P Value b

Characteristic

Histologic type Mucoepidermoid carcinoma Adenoid cystic carcinoma

898 (48.8) 131 (7.1) 676 (36.7)

134 (36.4)

14 (3.8)

Adenocarcinoma

167 (45.4) 40 (10.9)

<.001

Salivary duct carcinoma Acinic cell carcinoma

66 (3.6) 71 (3.9)

13 (3.5)

Tumor grade 2

484 (26.3) 1358 (73.7)

47 (12.8) 321 (87.2)

<.001

3

Tumor stage T1

323 (17.5) 424 (23.0) 563 (30.6) 521 (28.3)

35 (9.5) 67 (18.2) 110 (29.9) 151 (41.0)

T2 T3 T4

<.001

Unknown

11 (0.6)

5 (1.4)

Nodal stage N0

892 (48.4) 347 (18.8) 581 (31.5)

70 (19.0) 61 (16.6) 233 (63.3)

N1 N2 N3

<.001

5 (0.3) 17 (0.9)

2 (0.5) 2 (0.5)

Unknown

Margin status Negative

720 (39.1) 598 (32.5)

155 (42.1) 99 (26.9)

Microscopic residual Macroscopic residual Residual tumor NOS

36 (2.0)

9 (2.4)

.22

Abbreviations: CRT, chemoradiotherapy; NA, not applicable; NCI, National Cancer Institute; NOS, not otherwise specified; RT, radiotherapy. a Percentages have been rounded and may not total 100. b P value for 2-sided Pearson χ 2 test. c Indicates number of comorbidities.

346 (18.8) 142 (7.7)

69 (18.8) 36 (9.8)

Unknown

No. of chemotherapy agents None

1842 (100)

NA

Single

NA NA NA

206 (56.0) 122 (33.2) 40 (10.9)

NA

Multiple

Unknown but received

cluded female sex, residence in higher-income counties, and treatment inmore recent years (Table 2). Facility typewas not associated with any survival difference. Based on MVA, patients who received adjuvant CRT had worse OS compared with those who received RT alone (HR, 1.22; 95% CI, 1.03-1.44; P = .02). Additional variables associ- atedwith inferior OS underMVA included advanced age;Medi- care, other government insurance, or no insurance; a higher CD comorbidity score; submandibular tumor sites; acinic cell carcinoma; grade 3 disease; higher T and N stages; and posi- tive margins. Variables associated with improved OS under MVA were female sex and residence in higher-income coun- ties (Table 2). SubgroupMVAwas next performed ( Table 3 ). By age group, CRT appeared to have no survival improvement for patients younger than 65 years (HR, 1.39; 95% CI, 1.10-1.77) or 65 years or older (HR, 1.02; 95%CI, 0.79-1.30). In addition, we found no survival improvement with CRT for parotid (HR, 1.23; 95% CI, 1.02-1.48) or submandibular (HR, 1.13; 95% CI, 0.69-1.84)

sublingual gland (16 [0.7%]) (Table 1). Those receivingCRTwere younger male patients with good CD comorbidity scores, had more tumors of parotid gland origin with advanced T stage or N stage (mostly T3, T4, and N2 disease), and were likely to be treated at an academic institution. Overall Survival Median OS for the entire cohort was 63.7 months, with 2- and 5-year OS rates of 78.7% and 52.1%, respectively. Unadjusted 2-year OS was worse with adjuvant CRT vs RT alone (71.3% vs 80.2%), as was 5-year OS (38.5% vs 54.2%) (HR, 1.51; 95% CI, 1.29-1.76; P < .001) ( Figure 2 A). Variables associatedwithworse OS under UVA included advanced age; Medicare, other gov- ernment insurance, or no insurance; residence in urban coun- ties; and higher CD comorbidity scores. Additional variables associatedwithworseOS includedACC, adenocarcinoma, and acinic cell carcinoma compared with MEC ( Table 2 ). Higher grade, T stage, and N stage also correlated with worse OS un- der UVA. Variables associated with longer OS under UVA in-

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