Improved outcomes in adjuvant radiotherapy for oral cavity carcinoma at an academic center: a matched-pair analysis.

OBJECTIVES/HYPOTHESIS: Our objective was to evaluate for outcomes differences for patients with oral cavity squamous cell carcinoma (OCSCC) who underwent primary surgical resection at an academic center (AC), followed by postoperative radiation therapy either at the AC or at a nonacademic radiation treatment center (non-AC).
DESIGN: Secondary analysis of a retrospective cohort of patients with previously untreated upper aerodigestive tract SCC who underwent surgery followed by adjuvant therapy at an AC from 2002 to 2012. Fifty-three matched pairs of OCSCC patients surgically treated at the AC, but receiving adjuvant radiation at either an AC or a non-AC, were evaluated for differences in clinicopathologic variables, radiation treatment metrics, and survival outcomes. The main outcome measures were overall survival, disease-specific survival, and locoregional control rates.
RESULTS: Matched pairs were closely comparable in TNM (tumor, node, metastasis) stage, age, and gender. There were no significant between-groups differences in demographic and clinicopathologic variables except for smoking status (never smokers 43.3% for AC vs. 20.8% for non-AC; P=0.037). Non-AC OCSCC patients received a significantly lower total radiation dose (P=0.0004) and lower radiation fractional dose (P=0.0002) than their AC matched-pair counterparts. AC treatment was associated with improved overall survival (P=0.005), disease-specific survival (P=0.019), and locoregional control (P=0.016). AC treatment was an independent predictor of overall survival on multivariate analysis (P=0.044), after adjustment for clinicopathologic differences between groups.
CONCLUSIONS: Improved survival for combined modality treatment of OCSCC at the AC was noted on multivariate analysis. Differences in key radiation treatment metrics could explain survival differences noted in this study. LEVEL OF EVIDENCE: 4.