Heated Intraperitoneal Chemotherapy (HIPEC) is an advanced multi-step surgical intervention performed in combination with cytoreductive surgery (CRS), also known as tumor debulking. The primary goal of HIPEC is to eradicate microscopic cancer cells that remain scattered across the peritoneum (the tissue lining the abdominal wall and organs) after all visible tumors have been surgically removed.

By circulating a heated chemotherapy solution (typically between 41°C and 43°C or 105.8°F to 109.4°F) throughout the abdominal cavity for 60 to 90 minutes, HIPEC delivers concentrated anticancer medication directly to malignant cells. The combination of heat (hyperthermia) and localized chemotherapy enhances drug penetration and drug toxicity against tumor cells while sparing the rest of the body from the severe systemic side effects associated with intravenous administration.

The HIPEC procedure takes place immediately following cytoreductive surgery (CRS) under general anesthesia. Once all visible tumors are resected, surgical cannulas (inflow and outflow tubes) and thermal probes are placed in the peritoneal cavity. The surgical team can perform HIPEC using an open technique (Coliseum technique) or a closed technique (where the abdominal skin is temporarily closed). The heated chemotherapy solution is circulated through a specialized hyperthermic perfusion machine at 41-43°C for 60 to 90 minutes. The surgeon manually redistributes the fluid continuously in open procedures or gently massages the abdomen in closed procedures to ensure uniform thermal and drug exposure across all peritoneal surfaces. After the perfusion time is complete, the chemotherapy solution is completely drained, the abdomen is thoroughly irrigated with room-temperature sterile saline, surgical reconstructions or anastomoses are completed, abdominal drains are inserted, and the incision is closed.

Evidence-based clinical advantages of combining cytoreductive surgery with HIPEC include:

• Targeted Local Delivery: Achieves high local concentrations of chemotherapy in direct contact with cancer cells while maintaining low systemic plasma levels.
• Hyperthermic Synergism: Thermal enhancement significantly increases cytotoxicity and cellular absorption of chemotherapy agents.
• Mechanical Washout: Continuous fluid circulation helps break down microscopic fibrin deposits that may harbor malignant cells.
• Improved Progression-Free Survival: Clinical trials (such as the landmark OV21/van Driel trial in ovarian cancer) demonstrate significant improvements in progression-free and overall survival in selected patient cohorts.
• Palliative Fluid Control: Effectively controls malignant ascites (fluid accumulation in the abdomen) in advanced peritoneal malignancies.

Recovery from cytoreductive surgery and HIPEC requires a structured, multi-phase rehabilitation process due to the extensive nature of the surgery:

• Hospital Stay: Typically 7 to 14 days, starting with 1 to 3 days in the Intensive Care Unit (ICU).
• Gastrointestinal Function: Intestinal motility usually returns within 5 to 7 days; temporary nasogastric tube drainage and parenteral nutrition may be required.
• Physical Activity: Early ambulation begins on post-operative day 1 or 2 to prevent deep vein thrombosis (DVT) and pulmonary complications. Full physical recovery takes 8 to 12 weeks.
• Return to Work: Patients typically resume light duties within 6 to 8 weeks and full daily activities within 3 to 4 months, depending on baseline physical status and supplemental systemic chemotherapy schedules.

HIPEC is indicated for primary peritoneal malignancies and secondary peritoneal carcinomatosis, including:

• Pseudomyxoma Peritonei (PMP): A rare mucinous neoplasm usually originating in the appendix.
• Malignant Peritoneal Mesothelioma (MPM): A primary malignancy of the peritoneal membrane.
• Advanced Epithelial Ovarian Cancer: FIGO Stage III disease, either during primary interval debulking or recurrent disease settings.
• Appendiceal Adenocarcinoma: Colorectal-type appendiceal cancers with peritoneal spread.
• Colorectal Cancer with Peritoneal Metastases: Select cases with limited peritoneal involvement and controlled extra-abdominal disease.
• Gastric Cancer with Peritoneal Involvement: Select clinical protocols or trials evaluating narrow peritoneal burden.

Pre-procedure preparation involves a rigorous multidisciplinary evaluation. Diagnostic staging includes high-resolution CT scans of the chest, abdomen, and pelvis, abdominal MRI, or PET-CT, and often a diagnostic laparoscopy to calculate the Peritoneal Cancer Index (PCI) score. Laboratory evaluations include comprehensive metabolic panels, complete blood count, coagulation profiles, and baseline tumor markers (CEA, CA 125, CA 19-9). Cardiac and pulmonary clearance tests (echocardiogram, pulmonary function testing) are performed to ensure tolerance for prolonged general anesthesia and fluid shifts. Patients undergo nutritional optimization, deep vein thrombosis prophylaxis planning, bowel preparation, and pre-operative counseling regarding potential stoma creation and ICU recovery.

Major risks and potential complications include intra-abdominal abscess, bowel perforation or anastomotic leak, prolonged paralytic ileus, post-operative hemorrhage, acute kidney injury (AKI) from chemotherapeutic nephrotoxicity or fluid shifts, hematological toxicity (neutropenia, thrombocytopenia), deep vein thrombosis (DVT) or pulmonary embolism (PE), pleural effusion or pulmonary complications, wound infection or dehiscence, and organ failure requiring prolonged ICU support. Minor side effects include transient fatigue, nausea, appetite loss, and mild abdominal discomfort during initial healing.

Clinical Patient Journey for HIPEC

1. Pre-Operative Evaluation and Workup

Patients undergo extensive staging, including high-resolution cross-sectional imaging (CT or MRI scans), diagnostic laparoscopy, and cardiopulmonary clearance to assess performance status and determine the Peritoneal Cancer Index (PCI) score.

2. Cytoreductive Surgery (CRS) Phase

In the operating room under general anesthesia, surgical oncologists perform radical debulking to remove all visible macroscopic peritoneal tumors from abdominal organs and membranes.

3. HIPEC Perfusion Phase

Specialized perfusion cannulas are placed in the abdomen. A heated sterile chemotherapy solution is circulated continuously through an automated hyperthermic perfusion circuit for 60 to 90 minutes at controlled temperatures.

4. Lavage, Reconstruction, and Closure

The chemotherapy fluid is drained, the abdominal cavity is flushed with sterile saline, necessary organ reconstructions or bowel anastomoses are completed, and surgical drains are placed prior to incision closure.

5. Inpatient Recovery and Monitoring

The patient recovers in the Intensive Care Unit (ICU) or specialized surgical step-down unit for 1 to 3 days, followed by 7 to 10 days on a surgical ward, focusing on gastrointestinal recovery, pain management, and physical rehabilitation.

6. Long-Term Follow-Up

Routine outpatient evaluation includes physical examinations, tumor marker blood tests, and periodic surveillance imaging every 3 to 6 months to monitor disease response and recurrence.