Neoadjuvant chemotherapy followed by definitive chemoradiation in technically unresectable oral cavity squamous cancers

e18073 Background: Definitive Chemoradiation has dismal outcomes in very advanced oral cavity cancers. Surgical resection is the preferred modality of treatment . NACT followed by assessment for surgery is the standard algorithm used in technically unresectable oral cavity squamous cancers. Patients who are not amenable for surgery or not willing for the same are subjected to definitive Chemoradiation. There is very limited data about the outcomes of these patients and hence we have performed this analysis. Methods: This is an institutional review board approved retrospective analysis of a prospectively collected dataset of borderline resectable oral cavity squamous patients who received NACT. Adults patients with an eastern co-operative oncology group (ECOG) performance status (PS) 0-2 who were deemed as technically unresectable in a multi-disciplinary clinic (MDC) were included. These patients received 2-3 cycles of NACT (3-weekly) and underwent a response assessment. Depending on response and general condition, they were re-assessed in MDC and further therapy was decided. Patients who were not amenable to surgery and not willing for the and considered for definitive Chemoradiation were included in this analysis. Overall survival (OS) was calculated from date of diagnosis to date of death. Kaplan-meier method was used for estimation of 5 years OS. Impact of response to neoadjuvant chemotherapy on overall survival was calculated using log-rank method. Results: A total of 429 patients were analysed of which 387 (90.2%) were males The median age was 40 years (IQR; 40-54 years). The baseline ECOG PS was 0 in 163 (38%), 1 in 257 (59.9%) and 2 in 9 (2.1%) patients. The clinical stage at presentation was IVA in 257 (59.9%) patients and IVB in 172 (40.1%). The neoadjuvant regimen received were TPF regimen in 162 (37.8%) patients and two drug Taxane- Platinum regimen in the rest. The response rate to neoadjuvant therapy was 35.9% (N=154). Three thirty nine patients had an event with a median survival of 10 months (95%CI-;8.6-11.4). The five year survival was 15.6 % (Standard error 2%), while the 10 year OS was 9.6% (standard error 2.6%). On multivariate analysis, the only factor impacting the OS was response to neoadjuvant chemotherapy (HR: 0.54, 95% CI; 0.43-0.69; P=0.000). Conclusions: Neoadjuvant Chemotherapy followed by definitive Chemoradiation (who are not amenable for surgical resection or not willing) leads to dismal outcomes and further strategies to improve the outcomes are warranted.