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

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CHERAGHLOU ET AL .

FIGURE 2 Survival associated with adjuvant therapy for propensity-score matched cohort by patient risk group. Note: The late-stage without adverse feature group did not have sufficient numbers to include in this analysis

3.1 | Early-stage disease without adverse features The most common T classification among patients with early-stage disease without adverse features was 1 (67.7%; Table 1). The primary treatment used for this group was sur- gery without adjuvant therapy (83.0%), with 17.0% receiving adjuvant radiotherapy and 0.1% receiving adjuvant chemora- diotherapy. The 5-year survival rate in this group was 93.7% (SE 0.9). The 5-year survival rates for patients who did and did not receive adjuvant therapy were 93.0% (SE 2.2) and 93.8% (SE 1.0), respectively. The addition of adjuvant radiotherapy to the postoperative treatment of this group was not associ- ated with improved survival on univariate, multivariate, or propensity-score matched analyses. Survival curves for propensity-score matched cohorts are presented in Figure 2.

The addition of adjuvant therapy to the postoperative treatment of this group was not associated with a survival benefit on univariate analysis. However, on both multivariate (hazard ratio [HR] 0.744; P 5 .001; Table 2) and propensity- score matched analyses (HR 0.744; P 5 .004), treatment with surgery and adjuvant therapy was associated with improved survival compared to surgery alone. In the matched group, the 5-year survival rate was 80.9% (SE 1.4) among patients who received surgery only and 84.5% (SE 1.3) among those who received surgery followed by adjuvant therapy (Figure 2). On multivariate analysis of patients posi- tive for specific adverse features, adjuvant therapy was asso- ciated with improved survival for intermediate/high-grade tumors (HR 0.771; P 5 .013) but not for margin-positive (HR 0.847; P 5 .271) or adenoid cystic (HR 0.900; P 5 .666) tumors (Figure 3). Patients with late-stage disease without adverse features com- prised the smallest group of the sample (n 5 118; Table 1). Most patients were white (64.4%) with no comorbidities (83.9%) and had private insurance (50.8%). The most com- mon histologic subtype was mucoepidermoid (34.8%). Treat- ment in this group was primarily surgery without adjuvant therapy (58.5%), with 39.8% receiving adjuvant radiotherapy and 1.7% (n 5 2) receiving adjuvant chemoradiotherapy. The 5-year survival rate in this group was 80.6% (SE 4.3). 3.3 | Late-stage disease without adverse features

3.2 | Early-stage disease with adverse features

Among patients with early-stage disease with adverse fea- tures, there were approximately the same number of T1 (51.4%) as T2 (48.6%) cases (Table 1). Sixty-eight percent had intermediate/high-grade tumors. The majority were treated with surgery and adjuvant radiotherapy (54.1%), with 2.9% receiving adjuvant chemoradiotherapy and 43.0% receiving surgery without adjuvant therapy. Among these patients, the 5-year survival rate was 83.8% (SE 0.8).

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