Hara Masayasu, Nakanishi Hayao, Jun Qian, Kanemitsu Yukihide, Ito Seiji, Mochizuki Yoshinari, Yamamura Yoshitaka, Kodera Yasuhiro, Tatematsu Masae, Hirai Takashi, Kato Tomoyuki
Division of Oncological Pathology, Aichi Cancer Center Research Institute, 1-1 Kanokoden, Chikusa-ku, Nagoya, Aichi, 464-8681, Japan.
Clin Exp Metastasis. 2007;24(3):179-89. doi: 10.1007/s10585-007-9067-9. Epub 2007 May 9.
Peritoneal recurrence has a much lower incidence in colorectal cancer (CRC) patients than gastric cancer (GC) patients. The aim of this study is to clarify the reason for the rare peritoneal recurrence in CRC as compared with GC. The incidence and the abundance of free tumor cells in the peritoneal lavages from 102 CRC and 126 GC patients who underwent curative surgery were assessed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) with carcinoembryonic antigen (CEA) and cytokeratin 20 (CK20) as genetic markers. Prognostic significance of CEA and CK20 mRNA was also compared between CRC and GC after 2 years of follow-up by Kaplan-Meyer method with overall and peritoneal recurrence-free survival as endpoints. Positivity rate and average values of CEA and CK20 mRNA in peritoneal lavages of CRC patients, which are correlated to the depth of tumor invasion (pT category), were essentially the same as those of GC cases. Overall survival was significantly (marginally) worse in CEA mRNA (CK20 mRNA)-positive CRC patients than negatives like GC. However, peritoneal recurrence-free survival was not different between CEA (CK20) mRNA-positive and -negative CRC patients, in quite contrast to GC cases. Multivariate analysis showed that CEA mRNA was an independent prognostic factor for overall survival in GC patients, but not in CRC patients. These results suggest that the rare peritoneal recurrence in CRC patients is not due to the low incidence or the small number of intraperitoneal free cancer cells, but more likely reflects due to the low-peritoneal metastatic potential of CRC cells.
与胃癌（GC）患者相比，结直肠癌（CRC）患者腹膜复发的发生率要低得多。本研究的目的是阐明与GC相比，CRC中罕见腹膜复发的原因。通过以癌胚抗原（CEA）和细胞角蛋白20（CK20）作为基因标志物的定量逆转录-聚合酶链反应（qRT-PCR），评估了102例接受根治性手术的CRC患者和126例GC患者腹膜灌洗液中游离肿瘤细胞的发生率和丰度。通过Kaplan-Meyer方法以总生存和无腹膜复发生存为终点，对随访2年后CRC和GC患者中CEA和CK20 mRNA的预后意义也进行了比较。CRC患者腹膜灌洗液中CEA和CK20 mRNA的阳性率及平均值与肿瘤浸润深度（pT分类）相关，与GC病例基本相同。CEA mRNA（CK20 mRNA）阳性的CRC患者的总生存明显（勉强）比阴性患者差，与GC患者情况相同。然而，与GC病例形成鲜明对比的是，CEA（CK20）mRNA阳性和阴性的CRC患者之间无腹膜复发生存并无差异。多因素分析显示，CEA mRNA是GC患者总生存的独立预后因素，但不是CRC患者的独立预后因素。这些结果表明，CRC患者罕见的腹膜复发并非由于腹腔内游离癌细胞的发生率低或数量少，而更可能反映了CRC细胞的低腹膜转移潜能。
