A Multi-institutional Study to Diagnose the Risk of Lymph Node Metastasis Using a CRP Genetic Polymorphism Test Kit in pT1, cN0 Thoracic Esophageal Squamous Cell Carcinoma

Background/Aim: For patients with T1a muscularis mucosae (MM) esophageal squamous cell carcinoma (ESCC) with lymphovascular invasion (LVI) or T1b submucosal (SM) ESCC, endoscopic resection is non-curative, and adjuvant treatment entailing esophagectomy or definitive chemoradiotherapy is necessary. This is because about 30% of these cases have lymph node (LN) metastasis. The purpose of this study was to test the utility of a CRP genetic polymorphism test kit for determining the risk of LN metastasis with the aim of eliminating additional invasive adjuvant therapy. Patients and Methods: This is a retrospective, multi-institutional, observational study. The CRP 1846C>T genetic polymorphisms were identified using a fully automated genotyping system. The primary end points were an 85% negative predictive value (NPV) for diagnosis of LN metastasis in pT1a (MM) and 80% NPV in pT1b (SM1) patients. Results: A total of 742 ESCC (105 pMM, 166 pSM1 and 471 pSM2-3) patients who had received esophagectomy with 2- or 3-field LN dissection at 65 institutions were enrolled. According to this test, patients with the C/C and C/T genotypes were considered to be low risk. The NPVs using this test were 82.8% in pMM and 71.7% in pSM1 patients. Conclusion: CRP 1846C>T genetic polymorphism is not a useful diagnostic indicator for determining the risk of LN metastasis; however, the possibility that CRP gene polymorphisms are involved in the mechanism of lymph node metastasis in solid tumors still remains.