[The status analysis of diagnosis and treatment of synchronous peritoneal carcinomatosis from colorectal cancer in China: a report of 1 003 cases in 16 domestic medical centers].

Objective: To analyze the status of domestic surgical treatment of synchronous peritoneal carcinomatosis from colorectal cancer in China. Methods: Clinicopathological data of patients who underwent surgery from October 2003 to October 2018 in 16 domestic medical centers was retrospectively analyzed. Excel database was created which covered 77 fields of 7 parts: baseline information of patients, laboratory tests, imaging tests, chemoradiotherapy information, intra-operative findings, postoperative pathology and follow-up data. The Wilcoxon rank-sum test was used for comparison of the measurement data between groups. The χ(2) test was used for comparison of the categorical data between groups. The survival curve was calculated by the Kaplan-Meier method. Results: Of the 1 003 patients, there were 575 male and 428 female patients with the age of (58.5±14.1) years (range: 18 to 92 years). In a total of 920 patients, the carcinoma of sigmoid colon was performed in 292 cases (31.8%) with the highest ratio. The proportion of patients with liver metastasis and lung metastasis were 27.9% (219/784) and 8.3% (64/769). Preoperative detection of carcino-embryonic antigen level was the most common method in China (87.74%, 880/1 003), and the positive rate was 64.5% (568/880). The correct rate of preoperative imaging tests was 40.7% (280/688). The ratio of peritoneal carcinomatosis index (PCI) scores between 0 and 10 was the highest (59.6%, 170/285). Two hundred and sixty-two (27.0%) patients were performed by totally laparoscopic operation in 971 patients. The resection of primary tumor was performed in 588 of the 817 patients (72.0%). In a total of 457 cases, 253 (55.4%) patients were performed cytoreduction which group scored completeness of cytoreduction (CCR) 0. The postoperative hyperthermic intraperitoneal chemotherapy was implemented in 70 of the 334 cases (21.0%). Among 1 003 cases, 562 cases (56.03%) had complete follow-up data and the median overall survival was 15 months. The primary tumor resection and the CCR scores were affected by the PCI scores. The patients underwent primary tumor resection (187/205 vs . 26/80, χ(2)=105.085, P= 0.000) and the patients were performed cytoreduction which scored CCR 0 or CCR 1 (162/204 vs . 8/78, Z= -10.465, P= 0.000) had significant difference between the groups of PCI<20 and ≥20. There was a close correlation between the surgical method and the CCR scores ( Z= -3.246, P= 0.001).When the maximum degree of tumor reduction was planned, most surgeons would choose laparotomy. The overall survival time was longer in patients with primary tumor resection ( P= 0.000). The median survival time was 18.6 months in the group of primary tumor resection. Conclusions: It is difficult to diagnose the synchronous peritoneal carcinomatosis from colorectal cancer before the operation. Primary tumor resection has an obvious effect to prolong the survival time. It is necessary to standardize the treatment of peritoneal metastasis.