胃癌术前分期的现状及其对术前精准分期的思考

Present status of preoperative staging and contemplation on preoperative precision staging for gastric cancer

胃癌的术前分期旨在施行手术前，能正确判断肿瘤浸润深度（T分期）、淋巴结转移范围（N分期）及其有无远处转移（M分期），从而为患者制定最佳的治疗方案。传统的胃癌术前分期主要采用影像学诊断技术，如内镜超声、CT扫描、核磁共振、腹腔镜探查等。目前，对胃癌术前TNM分期的准确率普遍达到70%～85%，正确的术前分期有助于临床判断患者的治疗结果及预后，具有重要的临床意义。按照＂精准医疗＂的理念，做到胃癌术前精准分期，除应用影像学诊断技术外，必须联合基于疾病的基因组学、蛋白组学、代谢组学等分子信息分析或分子病理分型等方法，将肿瘤影像形态学与分子生物学特征结合起来，并与临床和病理诊断等资料一起综合进行判断，为患者量身设计最佳诊断与治疗方案，以实现对患者的个体化诊疗。迄今，医学界已为此作出了大量的研究，诸如分子影像诊断技术、外周血循环肿瘤细胞（CTCs）与循环肿瘤DNA（ctDNA）、肿瘤靶向治疗分子靶标与胃癌分子病理分型等，本文就术前如何应用这些技术，进一步了解胃癌的分子生物学特性等作初步探讨。

The aim of the preoperative staging of gastric cancer was to evaluate the depth of tumor infiltration（T-stage）, the extent or number of metastasized lymph nodes （N-stage）, and distant metastasis （M-stage）before surgery, to develop an optimal therapeutic scheme for the patients with gastric cancer. Traditional methods of preoperative staging for gastric cancer are usually imaging diagnostic techniques, such as endoscopic ultrasonography （EUS）, CT scan, magnetic resonance imaging （MRI）and laparoscopic exploration. At present, the accuracy of preoperative TNM staging of gastric cancer can generally reach 70% to 85% with significant clinical benefit. The accurate preoperative staging for cancer patients can have a major role in determining the final clinical outcome and in predicting the prognosis. According to the concept of ＂ precision medicine＂, to achieve ＂ preoperative precision staging of gastric cancer＂, the application of imaging diagnostic techniques must be combined with the analysis of individual genetic information or tumor molecular pathological classification, which should be based on research of the disease genomics, proteomics and metabolomics. In this article, we provide a review of results on preoperative staging of gastric cancer in recent years, and we also discuss how to think about the ＂ preoperative precision staging of gastric cancer＂ , with special emphasis on the potential of molecular imaging techniques, circulating tumor cells （CTCs）or circulating tumor DNA （ctDNA）, molecular targets for tumor targeting therapy and molecular pathological classification, etc. in judging bio-molecular behavior of gastric cancer before surgery.