General Surgery #7: Peritoneal Surgery

Introduction to Peritoneal Surgery

• Peritoneal disease, which was once considered incurable, can now be treated with specific surgical techniques and a better understanding of the disease's physiopathology.
• Peritoneal surgeons must be wise and consider the benefits and disadvantages of oncological treatment and overall patient survival.

History of Peritoneal Surgery

• The concept of treating peritoneal disease began in the 1980s with Dr. Sugarbaker, who founded the International Society of Regional Cancer Therapy.
• Dr. Sugarbaker considered HIPEC (Hyperthermic Intraperitoneal Chemotherapy) as a possible addition to peritoneal surgery.

Classification of Peritoneal Tumors

• Peritoneal tumors can be classified into:
  • Benign and malignant tumors of mesothelial derivation (primary tumors of the peritoneum)
  • Lesions of the secondary Mullerian system (e.g., endometriosis)
  • Secondary cancers (e.g., peritoneal metastases from other cancers)

Pathophysiology of Peritoneal Disease

• The peritoneum has a plasma barrier that limits the penetration of chemotherapeutics.
• Peritoneal fluid circulation follows gravity and a counterclockwise pattern, with preferred implantation sites in the pelvis, diaphragm, and latero-colic spaces.
• The peritoneum and omentum have specific areas (milky spots) where the plasma barrier is less present, allowing for fluid reabsorption and carcinomatosis implantation.

Resources for Peritoneal Surgery

• The PSOGI (Peritoneal Surface Oncology Group International) is a society dedicated to peritoneal surface oncology.
• The Chicago Consensus Guidelines (2018) provide a summary of treatments for peritoneal diseases.

Assessing Peritoneal Disease

• To assess peritoneal disease, consider:
  • Presence of a primary tumor
  • Type of peritoneal disease (synchronous or metachronous)
  • Burden of peritoneal disease (can be determined radiologically or with diagnostic laparoscopy)
  • Peritoneal cancer index (PCI)

Diagnosis and Staging

• Peritoneal disease can be diagnosed incidentally, during initial symptoms, or during the workup of a primary disease.
• Diagnostic and staging exams include:
  • CT scan
  • MRI
  • PET/CT scan
  • Exploratory laparoscopy

Peritoneal Carcinomatosis Index (PCI)

• The PCI is a score used to assess the burden of peritoneal disease.
• The PCI is calculated by evaluating 12 regions of the abdomen and assigning a score based on the dimension of the carcinomatosis.

Multidisciplinary Tumor Board (MDT)

• The MDT is essential for deciding on the best course of treatment for patients with peritoneal disease.
• The MDT reviews images and decides on the best approach, considering the expertise of various specialists.

Surgery

• Principles of surgery and therapy for peritoneal disease include:
  • Completeness of cytoreduction score
  • Indications for surgery (e.g., PCI score, disease location)### Peritoneal Surgery
• Cytoreductive surgery (CRS) is the primary surgery for peritoneal disease, not a curative aimed resection.
• CRS is classified into 4 categories based on the completeness of cytoreduction score (CC-0, CC-1, CC-2, CC-3).

Surgical Candidate

• Patients must be able to tolerate long surgeries and potential multi-visceral resection.
• The extent of carcinomatosis may not be fully predictable, and surgeries can be extremely long.

Techniques

• Multi-visceral resection and peritonectomy are used to remove the peritoneum involved by the disease.
• Sugarbaker's technique: complete peritonectomy + HIPEC (hyperthermic intraperitoneal chemotherapy).
• Partial peritonectomy can be used for smaller nodules.

HIPEC

• Hyperthermic intraperitoneal chemotherapy (HIPEC) involves administering cytotoxic agents into the peritoneal cavity at an elevated temperature (41-43°C).
• Benefits of HIPEC include:
  • Damaging locally the cells, addressing minimal residual disease.
  • Allowing for better penetration of chemotherapeutic drugs into the tumor.
  • Longer direct contact between tumor cells and the chemo reduces or destroys chemoresistance mechanisms.
• HIPEC usually lasts between 30-90 minutes.

Disadvantages of HIPEC

• Risks associated with heat:
  • Hyperthermia of the patient.
  • Worsening the risk profile associated with cytoreductive surgery.
• Risks associated with chemotherapeutics:
  • Mitomycin: toxicity on the hematological system, severe neutropenia.
  • Cisplatin: acute kidney insufficiency, requires high-volume IV fluids.
  • Oxaliplatin: postoperative bleeding risk, thrombocytopenia.

Choice of Chemotherapy Agent

• Criteria for selecting a chemotherapy agent for HIPEC:
  • Hydrosoluble.
  • Active at HIPEC temperatures.
  • High molecular weight.
  • High systemic clearance.
  • High capacity of intratumor diffusion.
  • Not cell cycle specific.

HIPEC Techniques

• Open technique: uses retractors to keep the abdomen open, and a surgeon with gloved hands to wash out the abdomen.
• Closed technique: closes the abdomen, leaving the fascia exposed to chemotherapy, and uses a machine to heat and circulate the chemotherapy.

Patient Selection for HIPEC

• Exclusion criteria:
  • Advanced age (>75).
  • Comorbidities (renal disease, etc.).
  • Peritonitis or sepsis.
  • Malnutrition.
  • Extra-abdominal metastasis.
  • Massive involvement of retroperitoneum.
  • Inability to achieve complete or almost complete cytoreduction (CC-0, CC-1).

Alternatives to HIPEC

• NIPEC (normothermic intraperitoneal chemotherapy): for drugs inactivated by heat.
• EPIC (early postoperative intraperitoneal chemotherapy): uses peritoneal portal system.
• PIPAC (pressurized intraperitoneal aerosol chemotherapy): for palliative reasons, uses pressurization to increase chemotherapy penetration.
• NIPS (neoadjuvant intraperitoneal-systemic chemotherapy protocol): a bimodal therapy using IV and intraperitoneal chemotherapy.

Mesothelial Tumors

• Well-differentiated papillary mesothelioma: tends to be benign.
• Multicystic mesothelioma: borderline condition.
• Malignant mesothelioma: has a terrible prognosis if untreated.

Appendiceal Tumors

• Secondary tumors that spread to the peritoneum.
• Peritoneal metastasis varies depending on the type of tumor.
• Perforation of the appendix increases the risk of peritoneal metastasis.
• Pseudomixoma peritonei: a peculiar peritoneal tumor with a characteristic presentation, characterized by an abundant quantity of mucin.### Peritoneal Surgery
• Types of appendiceal carcinoma:
  • Low-grade tumor with disseminated mucin
  • High-grade tumor with mucin
  • High-grade tumor with signet ring cells
  • Goblet cell tumor (specific entity of the appendix, interacts with the enterochromaffin system, has neuroendocrine markers)

Pseudomixoma Peritonei

• Clinical presentation: clear diagnosis, symptoms like perforated appendix and other formations
• Macroscopic and clinical appearance: "jelly belly" appearance

Principles of Systemic Chemotherapy and Surgery

• Chemotherapy: depends on the type of cancer
• Surgery: may require multiple visceral resections (up to 7-9 times), tolerable, but dependent on patient's condition (age, general health)
• HIPEC: performed with specific dosages, may be considered for high-risk patients, extensive lymph node involvement, and specific histotypes related to metastasis

Secondary Carcinomatosis

• Depend on the type of cancer:
  • Colorectal carcinomatosis: responsive to drugs and surgery, high heterogeneity
  • Pancreaticobiliary carcinomatosis: incurable, no survival improvement with cytoreduction or HIPEC

Colorectal Carcinomatosis

• After response to generalized chemotherapy, HIPEC and surgery may be considered
• PCI (Peritoneal Cancer Index) higher than 10: may be considered for HIPEC and surgery
• Metachronous and synchronous metastasis may arise

Gastric Carcinomatosis

• Recurrence of disease after surgery: common (up to 50% of patients)
• Survival after peritoneal failure: 3-8 months
• Adjuvant therapy may extend survival time
• NOMOgrams: useful tools to understand and predict the risk of metachronous peritoneal carcinomatosis

Acute Abdomen

• Definition: sudden onset of pain, requiring prompt decision on intervention
• Causes:
  • Distension or spasm of a hollow viscus
  • Distension of the capsule of parenchymatous organs
  • Traction on the mesentery, ligaments, or peritoneum (especially parietal peritoneum)
  • Infiltration or compression of sensitive nerves
  • Irritating substances (e.g., bile) in the peritoneum

Diagnostic Tools

• Objective exam: Blumberg sign
• US: first choice, non-invasive, useful for detecting air, perforation, or obstruction
• CT scan: accurate and complete examination
• Fecal exam: useful in patients with communication problems (psychiatric, neurologic, geriatric)

Disease Approach

• Primite etiology: essential to avoid progression to peritonitis
• Main causes of acute abdomen:
  • Acute appendicitis
  • Acute cholecistitis
  • Acute pancreatitis

Appendicitis

• Definition: obstruction of the appendix lumen, leading to bacterial overgrowth, stasis, and increased pressure
• Causes:
  • Fecaliths
  • Foreign bodies
  • Tumors
  • Lymphoid hyperplasia
• Stages:
  • Minor inflammation
  • Phlegmonous appendicitis
  • Necrosis
  • Gangrene
• Complications:
  • Localized or diffuse peritonitis
  • Abscesses
  • Rarely, portal vein thrombosis
• Diagnosis:
  • Clinical evaluation
  • Laboratory tests
  • Imaging (US, CT scans)
  • Alvarado score
• Treatment:
  • Surgical (laparoscopic or open)
  • Conservative (antibiotics)
• Postoperative considerations:
  • Complications (superficial and deep surgical site infections, bowel obstruction, secondary infertility)
  • Chronic appendicitis: a controversial condition, may require elective appendectomy

Cholecystitis

• Pathophysiology: similar to appendicitis
• Risk factors:
  • Conditions causing bile stasis
  • Advanced age
  • Hormonal factors
  • Drug use
• Diagnosis:
  • Ultrasound
  • CT scan with contrast (in severe cases)
• Treatment:
  • Surgery (cholecystectomy)
  • Conservative management with antibiotics (in cases where surgery is delayed)
• Complex cases:
  • Alternative treatments (percutaneous cholecystostomy)
  • Delayed, elective cholecystectomy