Salvage re-irradiation (rRT) for patients with locoregionally recurrent head and neck cancer (rHNC) remains challenging. A retrospective analysis was performed on 49 patients who received rRT between 2011 and 2018. The co-primary endpoint of the study was 2-year freedom from cancer recurrence rate (FCRR) and overall survival (OS), and secondary endpoints were 2-year disease-free survival (DFS), local failure (LF), regional failure (RF), distant metastases (DM), and RTOG grade 3 ≥ late toxicities. Adjuvant and definitive rRT were delivered to 22 and 27 patients, respectively. A total of 91% of patients were managed with conventional re-RT and 71% of patients received concurrent chemotherapy. The median follow-up after rRT was 30 months. The 2-year FCRR, OS, DFS, LF, RF, and DM were 64%, 51%, 28%, 32%, 9%, and 39% respectively. MVA showed that poor performance status (PS: 1–2 vs. 0) and age > 52 years were predictive of worse OS. In comparison, poor PS (1–2 vs. 0) and total dose of rRT < 60 Gy were predictive of worse DFS. Late RTOG toxicity of grade 3 ≥ was reported in nine (18.3%) patients. FCRR at 2 years after salvage rRT for rHNC was higher than other traditional endpoints and could be an important endpoint to be included in future rRT studies. rRT for rHNC at our cohort was relatively successful, with a manageable level of late severe toxicity. Replacing this approach in other developing countries is a viable option.

e18077 Background: Salvage re-irradiation (rRT) for patients with locoregionally recurrent head and neck cancer (rHNC) remains challenging. Methods: A retrospective analysis was performed on patients who received rRT between 2011 and 2018. The co-primary endpoint of the study was 2-year freedom from cancer recurrence rate (FCRR) and overall survival (OS), and secondary endpoints were 2-year disease free survival (DFS), local failure (LF), regional failure (RF), distant metastases (DM), and RTOG grade 3≥ late toxicities. Results: A total of 49 cases [nasopharygeal (n = 12); laryngeal (n = 12); oral cavity (n = 11); salivary gland (n = 9); and skin (n = 5)] were identified, adjuvant or definitive rRT were delivered to 22 and 27 patients, respectively. Various rRT fractionation schedules were used and 35/49 (71%) of patients received concurrent chemotherapy. The median follow-up after rRT was 30 months. The 2-year OS, DFS, LF, RF, and DM and FCRR were 64%, 51%, 28%, 32%, 9%, and 39% respectively. MVA showed that poor performance status (PS: 1-2 vs 0) and age > 52 years were predictive of worse OS. While, poor PS (1-2 vs 0) and total dose of rRT < 60Gy were predictive of worse DFS. Late RTOG toxicity of grade 3≥ was reported in 9(18.3%) patients. Conclusions: FCRR at 2 years after salvage rRT for rHNC was higher than other traditional endpoints and could be an important new endpoint to be included in the rRT studies. rRT for rHNC at our cohort was successful; with a manageable level of late sever toxicity.