title: Timing of Systemic Chemotherapy in Patients With Colorectal Peritoneal Carcinomatosis Treated With Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy.
abstract: 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.
  
  
  METHODS
  This was a retrospective cohort study.
  
  
  METHODS
  The study was conducted at a tertiary referral center.
  
  
  METHODS
  Patients undergoing cytoreductive surgery and hyperthermic intraperitoneal chemotherapy from January 2004 until June 2015 were included.
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: 1 Department of Surgical Oncology, Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, the Netherlands 2 Department of Epidemiology and Biostatistics, Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, the Netherlands 3 Department of Radiology, Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, the Netherlands 4 Department of Medical Oncology and Gastroenterology, Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, the Netherlands.
authors.forename: Wijntje J
authors.initials: WJ
authors.lastname: van Eden
authors.forename: Niels F
authors.initials: NF
authors.lastname: Kok
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Jóźwiak
authors.forename: Max L
authors.initials: ML
authors.lastname: Lahaye
authors.forename: Geerard L
authors.initials: GL
authors.lastname: Beets
authors.forename: Monique E
authors.initials: ME
authors.lastname: van Leerdam
authors.forename: Henk
authors.initials: H
authors.lastname: Boot
authors.forename: Arend G
authors.initials: AG
authors.lastname: Aalbers
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage; D002277:Carcinoma / Q000473:pathology / Q000628:therapy; D017024:Chemotherapy, Adjuvant / Q000379:methods*; D015179:Colorectal Neoplasms / Q000473:pathology / Q000628:therapy; D003131:Combined Modality Therapy / Q000379:methods; D065426:Cytoreduction Surgical Procedures / Q000379:methods*; D005260:Female; D006801:Humans; D006979:Hyperthermia, Induced / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D010043:Outcome and Process Assessment, Health Care; D010534:Peritoneal Neoplasms / Q000473:pathology / Q000628:therapy; D012189:Retrospective Studies; D016019:Survival Analysis; D061665:Time-to-Treatment