Introduction: Process-related measures have been proposed as quality metrics in head and neck cancer care. However, there is limited data demonstrating association of these metrics and patient survival. A recent single-institution study identified four key quality metrics that were associated with increased overall survival (OS), disease-specific survival (DSS), and disease-free survival (DFS). This proposed “clinical care signature” included elective neck dissection with lymph node yield of 18 or more, no unplanned surgery within 14 days, no unplanned 30-day readmission, and referral for adjuvant radiotherapy for stage III or IV disease. The aim of this study was to evaluate the association of these key quality metrics with survival in a multi-institutional patient cohort.
Methods: An IRB approved multicenter retrospective cohort of patients treated with primary surgical resection for oral cavity squamous cell carcinoma at six tertiary care centers between 1/2005 and 1/2015 was queried to identify patients in whom quality metrics could be evaluated. Baseline patient and pathologic characteristics and compliance with predetermined quality metrics was evaluated. Association between compliance of these quality metrics with OS, DSS, and DFS was evaluated using Cox proportional hazards models.
Results: From the database of 1282 patients from 6 institutions, 773 patients from 3 institutions were included in the study. Compliance with quality metrics was high with 507 (65.6%) meeting all quality metrics, 240 (31.1%) had a single unfavorable quality metric, and only 26 (3.4%) had two or more unfavorable metrics. Five-year OS rate of the total patient population was 0.62 (95% CI: 0.58-0.66), with median of 100.1 months (95% CI: 83.1-120.4 months). Five-year DFS rate was 0.50 (95% CI: 0.46-0.54), with median of 59.6 months. Five-year DSS rate was 0.78 (95% CI: 0.74-0.81), median was not reached. On multivariate analysis, patients with two or more unfavorable process metrics of the clinical care signature had significantly worse OS (HR 1.77, 95% CI: 1.02-3.07), DFS (HR 2.18, 95% CI: 1.33-3.59), and DSS (HR 3.15, 95% CI: 1.58-6.28) than patients with one or less unmet quality metric. On univariate analysis, unplanned surgery within 14 days (HR 1.76, 95% CI: 1.16-2.68) and unplanned readmission within 30 days (HR 1.87, 95% CI: 1.20-2.91) were significantly associated with worse OS, with unplanned surgery also significantly associated with worse DSS (HR 2.12, 95% CI: 1.22-3.68). Patients who received a referral for adjuvant radiotherapy for stage III or IV disease had significantly better DFS than patients who did not receive a referral (HR 0.48, 95% CI: 0.33-0.69).
Discussion: In this study, patients with two or more unfavorable clinical care signature quality metrics experienced a worse OS, DFS, and DSS. Compliance with quality metrics across participating institutions was high, and in this population an elective neck dissection was not significantly associated with OS, DFS, or DSS.
Conclusions: Process-related quality metrics were able to identify patients with worsened outcomes. In this cohort, patients with two or more unfavorable key quality metrics were shown to have worsened survival.