Strategy based on neoadjuvant chemotherapy (NAC) for locally advanced rectal cancer and the new predictive marker for its response; the lymphocyte ratio before and after NAC.

Background
In the era of neoadjuvant therapy for locally advanced rectal cancer (LARC), we reported the benefit of NAC for low-risk LARC. Also, we reported that NAC could omit lateral lymph node dissection in patients without LLN with 7mm and larger. On the other hand, more intensive treatment should be considered for high-risk patients. To achieve the maximum effect of neoadjuvant therapy, the predictive marker is essential, but not evident so far. In this session, we introduce the new predictor for its response.
Patients and Methods
A total of 95 patients with LARC who underwent curative surgery between 2008 and 2019 were analyzed to investigate the predictive marker for Dworak’s tumor regression grade (TRG).
Results
TRG 1/2/3/4 were recognized in 41/30/19/9 patients, respectively. In multivariate analyses, ycN and Lymphocyte ratio before and after NAC were independent predictive marker for TRG (p = 0.005 and p = 0.044, respectively). Of 42 patients with both ycN0 and Lymratio ≥ 0.918, 23 patients (54.7%) had good response to NAC. On the other hand, only 5 patients (14.7%) had good response in 34 patients with one of these and 19 without these markers had no good response.
Conclusion
Lymratio would be a potential predictor for good response to NAC.