Abstract 405P
Background
Neoadjuvant chemoradiotherapy (NACRT) is a standard treatment for patients with clinical stage II/III rectal cancer. Recently, neoadjuvant rectal (NAR) score was suggested as an independent prognostic factor after NACRT for rectal cancer. The aim of this study was to evaluate the prognostic value of NAR score in patients with locally advanced rectal cancer (LARC) who received NACRT followed by surgery.
Methods
We performed a unicentric, retrospective, consecutive case series analysis of the patients with LARC who received NACRT followed by surgical resection between January of 2016 and December of 2019. NAR scores were calculated using the equation [5ypN-3(cT-ypT)+12]2/9.61 and classified as low (<8), intermediate (8-16) and high (>16). Clinicopathological data and survival outcomes were analyzed and correlations between NAR-score and disease-free survival (DFS) were performed with the Kaplan-Meier method and compared by log-rank test.
Results
A total of 110 patients were analyzed, 58.2% male and 41,8% female patients, with a median age of 65 years old (36-83) at the time of diagnosis. The median NAR score was 8.4 (0-65.1). Considering the NAR score classification, 35 (38.5%) had low, 52 (57.2%) had intermediate and 23 (25.3%) had high NAR score. The median observation period was 32.3 months (4.7-62.7). Higher NAR score was associated with higher tumor regression grade (TRG) (p<0.001) and higher ypTNM stage (p<0.001). The 5-year DFS was 81% for low, 71% for intermediate and 41% for high NAR score groups. For high NAR score group the median DFS was 4.17 years (95% C.I 0.53 – 7.82). A statistically significant difference in DFS was observed between the three NAR groups (p=0.002), but there was no significant difference in DFS stratifying according to the TRG classification (p=0.229).
Conclusions
Our results suggested that NAR score could be useful in predicting DFS following NACRT and surgery for LARC. TRG is a histological measure of score tumor response to NACRT and is associated with survival outcomes in literature. However, in our study there was no association between TRG and DFS. Although our data suggest that NAR score might be a predictor of DFS further studies are needed.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.