Is postoperative adjuvant chemoradiotherapy necessary for high-risk oropharyngeal squamous cell carcinoma?

BACKGROUND: High-risk factors for recurrence of head and neck squamous cell carcinoma after surgical resection include involvement of ≥ 2 regional lymph nodes, extracapsular spread, and microscopic involvement of resected mucosal margins. Adjuvant chemoradiotherapy is thought to improve postoperative locoregional control and survival. In this paper, we evaluate the efficacy of adjuvant therapy for high-risk oropharyngeal squamous cell carcinoma (OPSCC) (i.e., with ≥ 2 lymph nodes, positive extracapsular spread, or positive margins).
METHODS: This is a retrospective analysis of 45 high-risk OPSCC patients who underwent surgery without adjuvant therapy (n = 19), with radiotherapy (n = 17), or with chemoradiotherapy (n = 9).
RESULTS: The median follow-up period was 41.0 months. Radiotherapy patients showed a trend toward longer overall survival than patients without adjuvant therapy [hazard ratio (HR) = 0.32, p = 0.176]. However, overall survival for the chemoradiotherapy group seemed to be the same as that for the no adjuvant therapy group (HR = 0.79, p = 0.779). Multivariate analysis found that the relative risk of recurrence for patients without adjuvant therapy compared with any adjuvant therapy was 3.02 (p = 0.101). The relative recurrence risk in radiotherapy patients was 0.95 compared with that in chemoradiotherapy patients (p = 0.971). However, pathological T-stage was significantly associated with disease-free survival for high-risk OPSCC.
CONCLUSIONS: Although the current study uses data from a small retrospective sample of patients, our results suggest that the addition of chemotherapy to radiotherapy may not be necessary as an adjuvant therapy for all high-risk OPSCC. A novel prognostic factor, such as pathological T-stage, should be considered for selecting those patients with high-risk OPSCC who would benefit from adjuvant therapy.