New Scale Predicting Distant Recurrence in Locally Advanced Lower Rectal Cancer Patients After Neoadjuvant Chemoradiotherapy

Background/Aim: Neoadjuvant chemoradiotherapy (nCRT) for locally advanced lower rectal cancer (LALRC) is effective in preventing locoregional recurrence; however, it is less effective for preventing distant recurrence. This study aimed to evaluate a new scale for predicting distant recurrence before administering nCRT. Patients and Methods: Sixty-three patients underwent nCRT for LALRC between 2009 and 2016 at the Tokyo Women’s Medical University. Of these, 51 consecutive patients who underwent curative surgery were enrolled in this study. Patients with ≥cT3 status or cN-positive LALRC were classified into three groups before nCRT based on the neutrophil-to-lymphocyte ratio (NLR) and lymphocyte-to-monocyte ratio (LMR): high-risk, NLR ≥3.2 and LMR <5.0; intermediate-risk, NLR <3.2 and LMR ≥5.0 or NLR ≥3.2 and LMR <5.0; and low-risk, NLR <3.2 and LMR ≥5.0. Independent risk factors associated with distant relapse-free survival were analysed using the Cox proportional hazards model. Relapse-free survival from distant metastasis was evaluated using the log-rank test. Results: Patient characteristics and tumour-associated factors were not significantly different between the groups. Distant recurrence in the high-, intermediate-, and low-risk groups was 61.5%, 42.9%, and 20.8% (p=0.046), respectively. In the multivariate analysis, the new scale was an independent risk factor for distant relapse-free survival (high-risk vs. low-risk groups, p=0.004 and intermediate-risk vs. low-risk groups, p=0.055). The 3-year distant relapse-free survival rate in the high-, intermediate-, and low-risk groups was 38.5%, 56.3%, and 81.7% (p=0.028), respectively. Conclusion: A new scale combining the pre-nCRT NLR and LMR was independently associated with distant relapse-free survival. The new scale for LALRC may aid selection for total neoadjuvant chemotherapy.