Selection strategy for complete cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy among patients with gastric cancer with peritoneal metastasis / 中国肿瘤临床

ABSTRACT

Objective: To construct a predictive model to assess the completeness of cytoreduction (CC) and help guiding selection for cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy (CRS+HIPEC) in patients with gastric cancer with peritoneal metastasis (GCPM). Methods: GCPM patients treated with CRS+HIPEC at Beijing Shijitan Hospital were enrolled in this study. The major clinicopathologic and therapeutic characteristics were compared between those with complete CRS (CCRS) and incomplete CRS (ICRS). A nomogram based on a Logistic regression model was constructed for predicting the risk of ICRS. The nomogram was evaluated using area under receiver operating characteristic curve (AUC) and validated using the bootstrap resampling method. The probability of CCRS was predicted using the nomogram. Results: Among the included 125 patients with GCPM, 52 had CC0 cytoreduction and 73 had CC1-3 cytoreduction. The median overall survival (mOS) was 30.0 (95% CI 16.8-43.3) months in the CC0 group, which was significantly longer than the mOS of 7.3 (95% CI 5.8-8.8) months in the CC1-3 group (P<0.001). As there were no significant differences in OS among the CC1, CC2, and CC3 groups, CC0 patients were included in the CCRS group and CC1-3 patients were included in the ICRS group. Multivariate Logistic regression demonstrated that the time of peritoneal metastasis development (OR=14, 95% CI 2.0-97.9, P= 0.008), preoperative tumor markers (TM) (OR=6.5, 95% CI 2.1-37.8, P=0.037), and peritoneal cancer index (PCI) (OR=1.5, 95% CI 1.3-1.8, P<0.001) were independent predictive factors for ICRS. The AUC of the nomogram was 0.985. Internal validation displayed good accuracy and consistency between the predictions and the actual observations. The cutoffs of PCI, with the probability of CCRS set at ≥ 50%, were ≤16, ≤12, ≤10, and ≤5 for synchronous GCPM with normal TM, synchronous GCPM with abnormal TM, metachronous GCPM with normal TM, and metachronous GCPM with abnormal TM, respectively. Conclusions: Complete CRS+HIPEC improves the survival of some patients with GCPM. A selection strategy based on PCI combined with the time of peritoneal metastasis development and TM may be a practical way for selecting patients with GCPM eligible for CCRS.