Objectives: Early progression, defined as a disease-free interval (DFI) of less than 6 months after completion of adjuvant platinum-based chemoradiotherapy (CRT), leads to poor outcomes in locally advanced oral cavity squamous cell carcinoma (OCSCC). However, appropriate biomarkers for predicting early progression remain unknown.
Methods: In this study, 346 patients with OCSCC, who underwent curative surgical resection and platinum-based adjuvant CRT at the Taipei Veterans General Hospital (202 patients, training cohort) and Chung Shan Medical University Hospital (144 patients, validation cohort) were enrolled. The clinical-pathological variables were compared using the χ2 test. Cox proportional-hazards analyses were performed for DFIs. Survival was estimated using the Kaplan-Meier method and log-rank tests, and a scoring system for predicting early progression was established.
Results: One-fifth (20.5%, 71/346) of all patients experienced progression within 6 months. Each of the independent factors for the DFI in the training cohort, including pT3-4, extracapsular spread, and perineural invasion, were assigned a score of one point to establish a scoring system. The 6-month DFIs of the low-risk (score 0-1), intermediate-risk (score 2), and high-risk (score 3) groups were 97.8%, 78.7%, and 35.7% and 88.2%, 77.6%, and 42.1% in the training and validation cohorts, respectively. If the cutoff level was ≥2 or <2, the sensitivity/specificity/area under the curve for the training and validation cohorts were 94.4%/56.1%/0.837, and 73.3%/56.6%/0.703, respectively.
Conclusions: The established scoring system effectively predicted early progression after adjuvant CRT for locally advanced OCSCC.
Keywords: Oral cavity squamous cell carcinoma; adjuvant chemoradiotherapy; early progression; predictive markers.