Neoadjuvant chemotherapy followed by hyperthermic intraperitoneal chemotherapy for patients with colorectal peritoneal metastasis: a retrospective study of its safety and efficacy.

BACKGROUND: Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) are effective routine treatments for colorectal peritoneal metastasis (PM). However, the safety and efficacy of neoadjuvant chemotherapy (NAC) before CRS+HIPEC are poorly understood. Therefore, this study aimed to assess the perioperative safety and long-term efficacy of NAC prior to CRS+HIPEC for patients with synchronous colorectal PM.

METHODS: Patients with synchronous colorectal PM who received NAC prior to CRS+HIPEC were systematically reviewed at the China National Cancer Center and Huanxing Cancer Hospital from June 2017 to June 2019. The clinicopathologic characteristics, perioperative parameters, and survival rates of patients who underwent CRS+HIPEC with NAC (NAC group) and patients who underwent CRS+HIPEC without NAC (non-NAC group) were compared.

RESULTS: The study enrolled 52 patients, with 20 patients in the NAC group and 32 in the non-NAC group. In the NAC group, the proportion of patients with a peritoneal carcinomatosis index (PCI) score < 12 was significantly higher than that in the non-NAC group (80.0% vs 50.0%, P = 0.031), and more patients achieved complete cytoreduction (80.0% vs 46.9%, P = 0.018). The two groups had comparable grade III/IV complications and similar reoperation and mortality rates (P > 0.05). However, patients who received NAC had lower platelet counts (151.9 vs 197.7 × 109/L, P = 0.036) and neutrophil counts (4.7 vs 7.2 × 109/L, P = 0.030) on postoperative day 1. More patients survived for 2 years in the NAC group than in the non-NAC group (67.4% vs 32.2%, respectively, P = 0.044). However, the completeness of cytoreduction score (HR, 2.99; 95% CI, 1.14-7.84; P = 0.026), rather than NAC, was independently associated with overall survival (OS) in the multivariate analysis after controlling for confounding factors.

CONCLUSION: NAC administration before CRS+HIPEC can be regarded as safe and feasible for patients with colorectal PM with comparably low mortality rates and acceptable morbidity rates. Nevertheless, large-sample randomized controlled studies are needed to confirm whether the administration of NAC before CRS+HIPEC confers a survival benefit to patients.