Abstract 2828: The prognostically significant immunological indices for patients who underwent curative resection of pulmonary metastases of colorectal cancer
Authors: Okazaki Yuki , Shibutani Masatsune , Wang En , Nagahara Hisashi , Fukuoka Tatsunari , Iseki Yasuhito , Kashiwagi Shinichiro , Tanaka Hiroaki , Maeda Kiyoshi , Hirakawa Kosei , Ohira Masaichi 
Published: July 2021

Abstract
Background: In recent years, it has been revealed that the immunological state of the host affects with the effect of cancer treatments. The neutrophil-to-lymphocyte ratio (NLR) as a systemic inflammatory marker and the density of tumor-infiltrating lymphocytes (TILs) at cancer microenvironment have been reported to be useful prognostic indices in various cancers, including colorectal cancer (CRC). The aim of this study is to evaluate the prognostic significance of immunological indices in patients who underwent curative resection of pulmonary metastases of CRC.
Patients and Methods: The medical records of 17 patients who underwent potentially curative resection for pulmonary metastases of CRC were retrospectively reviewed. The correlation between the relapse-free survival (RFS) or the overall survival (OS) after curative resection of pulmonary metastases of CRC and the clinicopathological factors, NLR or TILs were evaluated. The NLR was calculated from the blood sample which was obtained within 2 weeks before pulmonary resection by dividing the absolute neutrophil count by the absolute lymphocyte count. According to the receiver operating characteristic (ROC) curve analysis, patients with an NLR of ≥ 2.5 were classified as high-NLR group. The density of TILs was examined by immunohistochemistry of pulmonary metastatic tumor sample, by staining anti-CD3 and anti-CD8 antibody. The number of CD3+TILs and CD8+TILs at the border of tumor was counted in a randomly selected field at a magnification of ×400. The mean of the values obtained in five different areas was used. According to the ROC curve analysis, the patients with the number of CD3+TILs ≥ 31 were classified as high- CD3+TILs group and patients with the number of CD8+TILs ≥ 21 were classified as high- CD8+TILs group.
Results: The RFS and OS after resection of pulmonary metastases were significantly worse in the high-NLR group than in the low-NLR group (p=0.001, p=0.003, respectively). The RFS after resection of pulmonary metastases was significantly better in the high-CD3+TILs group than in the low-CD3+TILs group (p=0.041). Multivariate analysis revealed that the number of pulmonary metastases and the NLR before resection of pulmonary metastases were independent prognostic factors of the RFS (p=0.007, p=0.002, respectively) and the NLR before resection of pulmonary metastasis was the independent prognostic factor of the OS (p=0.009).
Conclusion: The immunological indices such as the NLR and the density of TILs, may have prognostic significance in patients who underwent curative resection of pulmonary metastases of CRC.
Citation Format: Yuki Okazaki, Masatsune Shibutani, En Wang, Hisashi Nagahara, Tatsunari Fukuoka, Yasuhito Iseki, Shinichiro Kashiwagi, Hiroaki Tanaka, Kiyoshi Maeda, Kosei Hirakawa, Masaichi Ohira. The prognostically significant immunological indices for patients who underwent curative resection of pulmonary metastases of colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2828.