Heated Intraperitoneal Chemotherapy (HIPEC) for Recurrent Ovarian Cancer

Ovarian cancer is most often diagnosed at an advanced stage. Treatment options at this point are varied, but the process is generally long and difficult. Surgery combined with chemotherapy is the standard approach. However, recurrence is an important event that worsens the course of the disease.

Published on 13 November 2024 in The Lancet Oncology , the phase III CHIPOR trial showed that adding hyperthermic intraperitoneal chemotherapy (HIPEC) may significantly improve survival in recurrent platinum-sensitive ovarian cancer. This article examines CHIPOR's details and the potential implications of this treatment approach.

Hyperthermic Intraperitoneal Chemotherapy (HIPEC) delivers chemotherapy directly into the abdomen and heats the drugs to increase their efficacy. During surgery, chemotherapy heated to 40-42°C is circulated through the abdominal cavity to target remaining microscopic tumor cells. HIPEC is generally used for advanced or recurrent intra-abdominal cancers, particularly ovarian and gastric cancers.

Key Findings of the CHIPOR Study

Conducted at 31 centers in France, Belgium, Spain, and Canada, CHIPOR was a large study carried out at centers with high surgical expertise . It enrolled patients with epithelial ovarian cancer recurring at least 6 months after initial platinum-based chemotherapy. After second-line platinum-based chemotherapy, participants were randomized to complete cytoreductive surgery with or without HIPEC.

Cytoreductive surgery is a procedure that aims to minimize tumor burden by removing as much cancerous tissue as possible.

Treatment Protocol:

• In the HIPEC group, cisplatin at 75 mg/m² was administered during surgery for 60 minutes at 41ºC ± 1ºC.
• The groups were stratified by factors such as performance status, platinum-free interval, and PARP inhibitor use after surgery.

A Marked Improvement in Overall Survival

Data from a median follow-up of 6.2 years showed a significant increase in overall survival with HIPEC:

• Overall Survival: Median survival in patients receiving HIPEC was 54.3 months , compared with 45.8 months without HIPEC—a difference of approximately 10 months.
• Risk Reduction: HIPEC reduced the risk of death by 27% (HR = 0.73; 95% CI = 0.56–0.96; P = 0.024).

These findings suggest that HIPEC could be a promising option for patients with platinum-sensitive recurrent ovarian cancer.

Adverse Effects and Safety Profile

Alongside HIPEC's survival benefit, treatment-related adverse effects were observed. Serious adverse effects were more frequent in the HIPEC group, particularly within the first 60 days after surgery (49% vs 27%). The most common included:

• Anemia: 23% (HIPEC group) and 14% (control group)
• Electrolyte Disturbances: 14% (HIPEC group) and 1% (control group)
• Renal Failure: 10% (HIPEC group) and 1% (control group)

However, these toxicities were described as manageable with precautions taken at expert centers during HIPEC.

Who Is Best Suited to HIPEC?

The researchers emphasized that CHIPOR's findings align with those of the earlier OVHIPEC-1 study and that HIPEC may play an important role in improving survival in advanced ovarian cancer. It is particularly recommended for the following groups:

• Platinum-Sensitive Recurrence: Patients without recurrence for 6 months or longer after initial platinum-based treatment.
• After Complete Cytoreduction: Cases in which all tumor tissue has been surgically removed.

However, treatment should be delivered only at centers experienced in toxicity management, with suitable supportive care such as protective thiosulfate.

Conclusion: A New Standard for Ovarian Cancer?

CHIPOR showed that HIPEC may improve overall survival in recurrent ovarian cancer and that its toxicities can be managed. However, it requires advanced surgical and medical oncology expertise. Whether HIPEC should enter routine clinical practice will become clearer with long-term data from further studies.

These promising results reinforce the importance of individualized approaches to ovarian cancer. HIPEC in carefully selected patients at expert centers could reshape treatment standards.