Oxaliplatin HIPEC unnecessary for colorectal peritoneal carcinomatosis patients
medwireNews: Oxaliplatin-based hyperthermic intraperitoneal chemotherapy (HIPEC) after cytoreductive surgery does not improve the survival of colorectal cancer patients with peritoneal carcinomatosis, the PRODIGE 7 investigators report.
In the randomized phase III trial, overall survival (OS) did not differ significantly between the 133 patients who received HIPEC following resection and the 132 who did not, at a median of 41.7 and 41.2 months, respectively.
At the 1-year mark, 86.9% of the HIPEC group and 88.3% of the non-HIPEC group were alive, while the corresponding rates at 5 years were 39.4% and 36.7%.
François Quenet, from the Regional Cancer Institute in Montpellier, France – who presented the results at the ASCO Annual Meeting 2018 in Chicago, Illinois, USA – commented that the curative management of these patients by cytoreductive surgery alone “shows unexpected satisfactory survival results.”
He also reported on relapse-free survival, which was comparable between the HIPEC and non-HIPEC arms, at a median of 13.1 versus 11.1 months, and 1- and 5-year rates of 59.0% versus 46.1% and 14.8% versus 13.1%, respectively.
Noting that the Kaplan–Meier curves did separate a little at the beginning of follow-up, Quenet said that HIPEC perhaps delays recurrence initially, but the long-term effects are the same regardless of whether HIPEC is used or not.
The lack of a survival benefit with HIPEC was seen across all subgroups but one; patients with a peritoneal cancer index of 11–15 points, but not those with scores outside this range, appeared to derive a significant OS advantage from the use of HIPEC, with a hazard ratio of 0.437. But Quenet urged caution in interpreting this result as this was not a prespecified analysis and the sample size was small.
There was no significant difference between the study arms in terms of 30-day morbidity, with grade 3–5 complications occurring in 40.6% of HIPEC-treated participants and 31.1% of those not given HIPEC. However, HIPEC was associated with a significantly higher incidence of morbidity at 60 days, at 24.1% versus 13.6% for controls.
Speaking to the press, Quenet noted that the next steps would be to identify subgroups of patients likely to benefit from the addition of HIPEC and to investigate the role of other chemotherapeutic agents in HIPEC.
In the PRODIGE 7 trial, patients who achieved macroscopically complete resection (R0/R1) or had no more than 1 mm of residual tumor tissue (R2) were randomly assigned in the operating theater to receive or not receive HIPEC after surgery. HIPEC consisted of intraperitoneal oxaliplatin given at a dose of 460 mg/m2 (360 mg/m2 for closed procedures) over a 30-minute period together with intravenous folinic acid 20 mg/m2 and fluorouracil 400 mg/m2. All study participants received systemic chemotherapy for 6 months, either before or after surgery or at both times.
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