Timing of Systemic Chemotherapy in Patients With Colorectal Peritoneal Carcinomatosis Treated With Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy.

BACKGROUND: Timing of systemic chemotherapy in patients with colorectal peritoneal carcinomatosis treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy is controversial. Preoperative systemic chemotherapy may offer benefits.

OBJECTIVE: The purpose of this study was to evaluate the effect of timing of systemic chemotherapy on survival.

DESIGN: This was a retrospective cohort study.

SETTINGS: The study was conducted at a tertiary referral center.

PATIENTS: Patients undergoing cytoreductive surgery and hyperthermic intraperitoneal chemotherapy from January 2004 until June 2015 were included.

MAIN OUTCOME MEASURES: The influence of patient-related, tumor-related, and treatment-related factors on survival were investigated using Cox regression models. Main outcome was overall survival.

RESULTS: A total of 280 consecutive patients underwent cytoreductive surgery and hyperthermic intraperitoneal chemotherapy. In group A, 78 patients (28%) were treated with preoperative or perioperative chemotherapy, cytoreductive surgery, and hyperthermic intraperitoneal chemotherapy. In group B, 169 patients (60%) were intentionally treated with cytoreductive surgery, hyperthermic intraperitoneal chemotherapy, and adjuvant chemotherapy. In group C, 33 patients (12%) had received their chemotherapy before peritoneal carcinomatosis was diagnosed. Median overall survival was 36.9 months (interquartile range, 20.6-79.7 mo) in group A, 43.1 months (interquartile range, 25.7-95.9 mo) in group B, and 34.0 months (interquartile range, 20.0-53.7 mo) in group C (p = 0.19). The extent of peritoneal carcinomatosis (region count of 3-5, HR = 1.58 (95% CI, 1.02-2.45), and 6-7, HR = 3.34 (95% CI, 1.66-6.72) vs 1-2 regions), a higher lymph node ratio (HR = 7.96 (95% CI, 2.16-29.31)), and cycles of systemic chemotherapy (0 cycles, HR = 2.52 (95% CI, 1.48-4.29)) and partial chemotherapy (HR = 2.15 (95% CI, 1.27-3.65) vs complete chemotherapy) were associated with poorer overall survival.

LIMITATIONS: Selection bias is present because of the retrospective design of this study.

CONCLUSIONS: Timing of systemic chemotherapy does not appear to have impact on survival in patients with colorectal peritoneal carcinomatosis undergoing cytoreductive surgery and hyperthermic intraperitoneal chemotherapy.