Long-term outcomes in oral cavity squamous cell carcinoma with adjuvant and salvage radiotherapy after surgery

OBJECTIVE Early-stage oral cavity squamous cell carcinoma (OCSCC) represents a heterogeneous group of patients, and locoregional recurrence rates are as high as 25% with surgery alone. Radiotherapy (RT) is typically reserved as part of salvage multimodality therapy after salvage surgery because it is generally thought that there is no significant detriment to salvage therapy. Our aim was to examine outcomes for recurrent OCSCC treated with salvage surgery and radiation and compare them to outcomes for patients treated with adjuvant postoperative RT upfront. METHODS We identified 425 patients with OCSCC treated with postoperative RT at our institution. The 5-year rates of local failure, locoregional failure (LRF), survival, and distant metastasis (DM) were the main outcome measures. We performed a landmark analysis and examined the same outcomes in the adjuvant versus salvage cohorts using Cox proportional hazards and Fine-Gray competing risk method. RESULTS The adjuvant cohort had higher tumor (T) (P