NAR Score validation in TNT (Total Neoadjuvant treatment) for locally advanced rectal cancer
ILAN DANIEL PERROT ROSENBERG,
Chile
PO-1322
Abstract
NAR Score validation in TNT (Total Neoadjuvant treatment) for locally advanced rectal cancer
Authors: ILAN DANIEL PERROT ROSENBERG1,2, José Antonio Solís Campos1,2, Gabriel Lazcano Alvarez1, Gabriel Veillon Contreras1,2, Benjamin Tudela Staub2,1, Jorge Olivares Gonzalez1
1Universidad de Valparaiso, Radiotherapy, Valparaiso, Chile; 2Hospital Carlos Van Buren, Radiation Oncology, Valparaiso, Chile
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Purpose or Objective
A current management for locally advanced rectal cancer is neoadjuvant radio – chemotherapy and total neoadjuvant treatment (TNT) is one possible approach. The purpose of this study is to analyze the oncological outcomes in survival and the impact of pathologic response in TNT using the NAR Score
Material and Methods
We performed a retrospective cohort study including all locally advanced rectal cancer patients treated with TNT with a curative intention between 2017-2019, receiving 25 Gy in 5 Gy daily fractions followed by FOLFOX Chemotherapy and surgery. Pre-operative and post-operative biopsies were analyzed calculating NAR score for each patient. Survival analysis was performed using the Kaplan Meier method. The study was approved by the local ethics committee.
Results
49 patients were identified. 4 patients cT2 (8.2%); 34 cT3 (69.4%) and 11 cT4 (22.4%). All patients completed radiotherapy with a 7-day median duration (ICR 5-7). 98% received at least 1 cycle of chemotherapy, median of 3 cycles (ICR 3-4). Median interval between radiotherapy and surgery 115 days (ICR 99-144). 6 patients (10%) operated within 12 weeks. 34 surgical biopsies were retrieved. 10 patients ypT0 (29.4%); 3 ypT1 (8.8%); 7 ypT2 (20.6%); 11 ypT3 (32.4%); 3 ypT4 (8.8%); 27 ypN0 (79.4%); 4 ypN1 (11.8%) and 3 ypN2 (8.8%). 9 patients showed pathologic complete response (18.4%). Cohort Overall Survival 75.5% within a 32 month follow up period. Median NAR score was 8.4. Considering response to TNT patients with low NAR (<8.4) had 100% Overall survival, while high NAR patients (>8.4) showed 60% overall survival. (p=0.002).
Conclusion
In conclusion, our TNT results are comparable to the ones found in the international literature. Although initially validated in extended concomitant neo adjuvant radio chemotherapy trials, we demonstrated NAR score still shows prognostic significance in the context of TNT.