Long-term outcomes of neo-adjuvant chemotherapy on borderline resectable oral cavity cancers: Real-world data of 3266 patients and implications for clinical practice

Background: Neo-adjuvant chemotherapy (NACT) followed by response assessment is the standard treatment algorithm for locally advanced oral cavity squamous cell carcinomas (OCSCC) in the Indian subcontinent. The 3 drug NACT regimen (Docetaxel-Cisplatin-5-FU) has shown improvement in overall survival over 2-drug regimen (Docetaxel-Cisplatin) in a phase-3 randomised study. We have analysed the 10-year outcomes with this treatment algorithm.Methods: This was an institutional review board approved retrospective analysis of a prospectively collected dataset of borderline resectable OCSCC patients who underwent NACT. Patients who became resectable after NACT underwent surgery followed by appropriate adjuvant therapy. Patients who were unresectable received definitive chemoradiation (CTRT), palliative chemotherapy, radiotherapy or best supportive care based on general condition.Results: A total of 3266 patients were included. The most common subsite was buccal mucosa and the most frequent indication was peri-tumoral edema upto zygoma. More than 2-drugs NACT was offered to 32.9% patients. Overall, 32.5% patients had a response to NACT. A total of 1358 patients were offered curative treatment, of which 929 (32%) underwent surgery and the rest underwent definitive chemo-radiation (14.8%). Patients who received more than 2-drugs NACT versus those who received 2-drugs had a 10-years OS of 21% vs 5.1% (p < 0.001). Patients who underwent surgery versus those who did not had a 10-year OS of 21.8% vs 4.1% (p < 0.001). Patients who achieved pCR had a 5-year OS of 45.3% vs 13.3% for those who did not (p < 0.001).Conclusion: NACT leads to long term survival benefit in patients of borderline resectable oral cavity cancer.