Cytoreduction & HIPEC

What is peritoneal carcinomatosis?

Peritoneal carcinomatosis is the spread of malignant cells throughout the peritoneum — the thin serous membrane that lines the inside of the peritoneal cavity and covers intra-abdominal organs. It creates multiple small or larger disease deposits on peritoneal surfaces.

Historically considered terminal disease with median survival of only 6–12 months on systemic chemotherapy alone, since the 1990s — thanks to the work of Paul Sugarbaker and the Peritoneal Surface Oncology Group International (PSOGI) — the modern approach has gradually emerged. Today, in selected patients, Cytoreductive Surgery (CRS) — with or without complementary HIPEC — achieves long-term survival and, in certain histologies, even cure.

Cytoreduction is the principal prognostic factor

According to current literature and international guidelines, the most important survival factor in peritoneal disease is the quality of cytoreduction — not HIPEC. Complete cytoreduction (CC-0 or CC-1) is the prerequisite for any favorable outcome.

Cytoreductive Surgery is an extensive and technically demanding procedure during which all macroscopically visible disease is removed from peritoneal surfaces and affected organs. It includes a combination of:

• Peritonectomies — removal of affected peritoneal surfaces: abdominal wall, diaphragm (right/left), lesser omentum, pelvic peritoneum.
• Organ resections — total or partial splenectomy, cholecystectomy, bowel resections (rectosigmoidectomy, right/left colectomy), gastrectomy, hysterectomy/salpingo-oophorectomy in gynecologic origins (if required).
• Removal of previous scar from midline laparotomy or trocar sites, umbilectomy or hepatic metastasectomies when required.
• Complete omentectomy — removal of the greater omentum, consistently involved in peritoneal disease.

The procedure is performed through a midline laparotomy, typically lasts 4–8 hours (cytoreductive phase only), and requires a team of experienced surgeons, specialized anesthetic management, and Intensive Care Unit support.

The role of HIPEC: when it is added and when it is not

HIPEC is a complementary, not mandatory technique. It involves intraperitoneal delivery of heated chemotherapy solution (typically 41–43°C) immediately after the cytoreductive phase and before abdominal closure. Duration is 30–90 minutes depending on protocol.

The principle of action is based on two mechanisms:

1. Pharmacokinetic advantage. Intraperitoneal delivery achieves chemotherapy concentrations on peritoneal surfaces significantly higher than intravenous routes, with limited systemic absorption (due to the "plasma-peritoneal barrier").
2. Hyperthermia. Elevated temperature is thought to enhance drug penetration and effect, and has direct cytotoxic action on cancer cells.

However, in recent years the clinical significance of HIPEC has been rigorously reassessed based on data from large randomized trials. The critical finding: HIPEC does not replace cytoreduction, and its value depends decisively on the underlying disease.

In which cases is it applied?

Indications vary significantly by underlying disease and extent of peritoneal involvement. The decision is made by a multidisciplinary oncology team (MDT) after complete imaging and clinical workup.

Other potential indications under evaluation: primary sarcomas (desmoplastic small round cell tumor — DSRCT), neuroendocrine tumors (NETs), and prophylactic HIPEC in high-risk patients (e.g., T4 colorectal cancer with perforation). These indications remain under clinical research and are not recommended in general practice.

The PCI and CC scores

Assessment of peritoneal disease and the success of cytoreduction relies on two internationally recognized scoring systems.

Peritoneal Carcinomatosis Index (PCI)

Introduced by Sugarbaker, it is the fundamental tool for assessing the extent of peritoneal disease. The abdomen is divided into 13 anatomical regions (9 abdominal + 4 small bowel). Each region receives a score 0–3 (Lesion Size Score — LS) based on lesion size:

Total: 0 to 39. The lower the PCI, the better the prognosis. Indication thresholds differ by disease: in colorectal cancer the cut-off for CRS+HIPEC is typically PCI ≤ 15–20, while in pseudomyxoma cytoreduction may be attempted even at higher PCI.

Completeness of Cytoreduction (CC) Score

Evaluates the result of cytoreduction at the end of surgery:

Long-term survival is achieved mainly in CC-0 / CC-1. If complete cytoreduction is not feasible, continuation of the procedure is usually avoided, as incomplete cytoreduction (CC-2/CC-3) provides no oncologic benefit and HIPEC has no role.

How suitability is determined

Patient selection is the most critical success factor. Evaluation is performed by a multidisciplinary oncology team. Factors considered:

• Type and histology of primary disease — different approach and indications for each malignancy.
• Extent of peritoneal disease (PCI) — calculated preoperatively with CT/MRI and confirmed intraoperatively. Diagnostic laparoscopy often precedes for accurate assessment.
• Feasibility of complete cytoreduction — predicted from disease distribution. Certain locations (e.g., extensive small bowel/mesenteric involvement, hepatic hilum) may make CC-0 impossible.
• Absence of extensive extraperitoneal disease — multiple hepatic metastases, pulmonary metastases, or extensive lymph node disease are usually contraindications.
• Patient performance status (PS 0–1) — adequate cardiac, renal, hepatic, and respiratory function required.
• Age and comorbidities — age per se is not a contraindication, but comorbidities are carefully evaluated.
• Response to prior systemic therapy — particularly important in ovarian and colorectal cancer.
• Molecular/biological characteristics — e.g., BRAF/RAS mutation status, MSI/MSS in colorectal cancer, per current guidelines.

How the operation is performed

CRS+HIPEC is one of the most extensive oncologic procedures. It follows a defined sequence:

PIPAC, EPIC and newer approaches

Beyond conventional CRS+HIPEC, modern peritoneal oncology offers additional options, each with a specific role:

Postoperative care and risks

Recovery after CRS±HIPEC is longer than typical surgery and requires coordinated multidisciplinary care:

• First 24–48 hours (ICU): close monitoring of hemodynamic, respiratory, renal, and hepatic function. Management of any complications.
• Days 3–7 (ward): gradual return of bowel function, progressive feeding (liquids to soft diet), mobilization, drain management.
• Days 7–14 (ward): full feeding, drain removal, discharge preparation.
• Weeks 1–6 (home): progressive return to daily activities. Avoid heavy lifting and strenuous exercise.
• First oncologic follow-up: 4–6 weeks after surgery, with pathology review and planning of adjuvant systemic therapy if indicated.
• Long-term surveillance: every 3 months for the first 2 years, every 6 months until year 5, annually thereafter. Includes clinical exam, tumor markers, CT, and endoscopy as appropriate.

Common complications

In specialized centers, mortality is 1–5% and major morbidity 20–35%. The most common complications include:

• Anastomotic leak — 5–10%, the most serious surgical complication.
• Bleeding and thromboembolic events.
• Renal dysfunction — mainly when cisplatin is used during HIPEC.
• Respiratory complications — pleural effusions, atelectasis, pneumonia.
• Hematologic complications — leukopenia, thrombocytopenia from intraperitoneal chemotherapy.
• Delayed return of bowel function (ileus).
• Infections — wound or intra-abdominal.

Frequently asked questions