Flooding the peritoneal cavity with heated chemotherapy during surgical resection of a form of metastatic colorectal cancer (CRC) does not improve survival over surgery alone and may increase complication rates, a French trial demonstrates.

Peritoneal carcinomatosis is a metastatic tumor that spreads to the peritoneum and occurs in approximately 20% of patients with CRC. The usual treatment is surgical resection, which can be lengthy owing to the large numbers of tumor nodules across the peritoneal surfaces.

Some centers also use hyperthermic intraperitoneal chemotherapy (HIPEC), in which chemotherapy heated to 43ºC is delivered to the peritoneal cavity while the patient is still under anesthesia. Introduced about 15 years ago, this approach has been adopted in many centers and has become the standard of care in some countries.

Commenting on the new results, ASCO expert Andrew Epstein, MD, said that the study is "very important" and "a particularly excellent example about how less is more, which is something we've seen in other studies at this meeting."

Epstein told that the use of HIPEC in the United States is "variable" it is accepted and "even the standard of care in some places" but not in others. However, he commented that its use is "ill-defined" and there have been no data "to demonstrate what the additional benefit of HIPEC is, and that's why this [study] is critical."

ASCO Chief Medical Officer Richard L. Schilsky, MD, agreed, saying that the lack of consistency in the use of HIPEC "underscores the success of Dr. Quenet and colleagues in completing this study."

He said, "There is not equipoise on this in the surgical community. There are surgeons in the US who are fervent believers in HIPEC, and there are others who are true skeptics."

Study Details

Presenting the study, Quenet noted that without treatment, the median survival of patients with peritoneal carcinomatosis is less than six months; this rises to 16 months with modern systemic chemotherapy alone.

Some previous studies have suggested that median survival can increase to 40 months with surgery plus HIPEC, at a cure rate of 16%. To determine the contribution of HIPEC to those outcomes, the Partenariat de Recherche en Oncologie Digestive (PRODIGE 7) study enrolled 265 patients with stage IV CRC with isolated peritoneal carcinomatosis from 17 centers across France.

Between 2008 and 2014, all patients underwent complete surgical resection with a margin of 1 mm or less and were randomly assigned during the procedure to HIPEC with oxaliplatin (n = 133) or no HIPEC (n = 132).

Both groups, which were stratified by centers and degree of macroscopic resection, also received perioperative neoadjuvant systemic chemotherapy for 6 months.

The median age of the patients was 60 years, and the two treatment groups were well balanced regarding their baseline characteristics. The 30-day postoperative mortality rate was the same in both groups, at 1.5%. The 30-day morbidity rates also did not differ.

However, the rate of grade 3 to 5 complications at 60 days was significantly higher in the HIPEC group than in patients who did not have HIPEC, at 24.1% vs. 13.6% (P = .030).