Modified Appleby procedure for locally advanced pancreatic carcinoma: A primer for the radiologist

By -

 



Executive Summary

Pancreatic ductal adenocarcinoma (PDAC) remains a highly lethal malignancy with a 5-year survival rate below 10%. For tumors located in the body or neck of the pancreas that involve the celiac trunk (CTr), the prognosis is historically poor as these are often classified as locally advanced and ineligible for upfront resection. The Modified Appleby Procedure, or distal pancreatectomy with en-bloc celiac axis resection (DP-CAR), has emerged as a specialized surgical strategy offering a potential cure for selected patients who respond to induction therapy.

The procedure is highly demanding, requiring a multidisciplinary approach where diagnostic and interventional radiology are pivotal. Key takeaways include:

  • Oncological Benefit: DP-CAR can extend median overall survival to 30.9 months, compared to 9–11 months with palliative chemotherapy alone.

  • Anatomic Dependency: The procedure’s feasibility relies entirely on the presence of adequate collateral arterial flow—primarily through the pancreaticoduodenal arcade (PA) and gastroduodenal artery (GDA)—to maintain blood supply to the liver and stomach once the celiac axis is removed.

  • Radiological Rigor: Success requires precise preoperative staging (6-point checklist) and, in many cases, preoperative arterial embolization to "prime" collateral circulation.

  • Complication Management: Major morbidity rates range from 10% to 40%. Interventional radiology is the primary line of defense in managing life-threatening complications such as postpancreatectomy hemorrhage (PPH) and ischemic gastropathy.

1. Overview of the Modified Appleby Procedure (DP-CAR)

Originally described by Appleby in 1953 for gastric adenocarcinoma, the procedure was later adapted for pancreatic cancer. The "modified" version specifically refers to:

  • Components: Distal pancreatectomy (DP), splenectomy, and en-bloc resection of the celiac trunk (CTr).

  • Physiological Basis: Resection of the CTr reduces direct arterial flow to the liver and stomach. Survival of these organs depends on retrograde flow from the Superior Mesenteric Artery (SMA) through the Pancreaticoduodenal Arcade (PA) and into the Gastroduodenal Artery (GDA).

2. Patient Selection and Indications

The determination of eligibility for DP-CAR is a balance between technical feasibility and oncological benefit.

2.1 Oncological Criteria

  • Location: Tumor must be in the pancreatic body or neck without macroscopic extension into the pancreatic head.

  • Vascular Margin: The root of the CTr at the aorta must be free of macroscopic involvement to allow for a clean resection margin.

  • Treatment Response: Patients must demonstrate stability or response to induction therapy (e.g., FOLFIRINOX or gemcitabine plus nab-paclitaxel) for up to six months.

  • Exclusionary Factors: Distant metastasis, adenosquamous tumor subtypes, or rising CA 19-9 levels after induction therapy generally indicate poor outcomes.

2.2 Technical Criteria

The primary technical requirement is the preservation of the SMA and GDA. If these vessels are involved, the procedure usually requires complex arterial reconstructions that carry high morbidity and are often considered contraindications.

3. Preoperative Radiological Evaluation

Computed Tomography (CT) is the gold standard for staging, with 90% accuracy in assessing arterial involvement. MRI/DWI serves as a supplementary tool for identifying liver metastases and assessing tumor response to chemotherapy.

3.1 The 6-Point Radiological Checklist

Architects of the procedure must evaluate six specific anatomical keys to determine feasibility:

Key Point

Clinical Significance

Pancreatic/Gastric Margin

Infiltration of the posterior gastric wall or pancreatic head remnant may require extended resection.

CTr Length/Root

Involvement of the CTr root at the aorta precludes standard DP-CAR.

Left Gastric Vein (LGV)

65% drain into the Portal Vein (PV); 30% into the splenic vein. PV drainage increases risk of intraoperative injury.

Portal Vein (PV)

Posterior involvement of the left aspect of the PV often mandates segmental resection and complex reconstruction.

GDA/PA Patency

Essential for liver survival; 15% of patients with "patent" imaging have impaired flow, requiring intraoperative Doppler testing.

Vascular Variations

Replaced left hepatic arteries or celiomesenteric trunks can complicate or preclude the procedure.

4. Radiological Preparation: Preoperative Embolization

To mitigate the risk of ischemic complications, surgeons often utilize Transcatheter Arterial Embolization (TAE).

  • Rationale: Embolizing the Common Hepatic Artery (CHA) or CTr weeks before surgery stimulates the expansion of collateral pathways (PA and GDA).

  • Utility: While debated, systematic embolization is advocated by many to reduce ischemic gastropathy and liver infarction.

  • Exceptions: Preoperative embolization is unnecessary in cases of median arcuate ligament compression (which naturally primes collaterals) or specific anatomical variants where the hepatic artery arises from the SMA.

5. Postoperative Outcomes and Complications

While DP-CAR offers a curative path, it is associated with high morbidity (10–40%) and significant recurrence rates.

5.1 Survival and Recurrence

  • Median Overall Survival: Reported between 9.7 and 30.9 months.

  • Recurrence: Approximately 75% of patients experience recurrence within two years.

    • Liver: Most common site (60%).

    • Peritoneum: 40%.

    • Local Recurrence: 33%.

5.2 Common Complications

  1. Postoperative Pancreatic Fistula (PPF): The most frequent complication (10–60%). CT typically shows fluid collections or gas bubbles near the pancreatic remnant.

  2. Postpancreatectomy Hemorrhage (PPH): Occurs in 5–10% of cases. Late PPH (after 5 days) is often due to pseudoaneurysm rupture or vascular stump erosion.

  3. Ischemic Gastropathy: Impaired supply to the stomach occurs in 10–40% of cases, potentially leading to ulcers or perforation.

  4. Liver Ischemia: Insufficient flow through the GDA can cause transient liver function abnormalities, abscesses, or acute liver failure.

6. The Role of Interventional Radiology in Recovery

Interventional radiology is essential for "rescue" management, often providing minimally invasive alternatives to high-risk re-operation.

  • Percutaneous Drainage: The first-line treatment for PPF-related fluid collections.

  • TAE for Hemorrhage: The treatment of choice for delayed arterial bleeding. Metallic coils and liquid embolic agents are used to seal bleeding sites with high technical success.

  • Endovascular Stenting: Covered stents can exclude pseudoaneurysms while maintaining the patency of critical collateral vessels, reducing the risk of liver failure.

  • Venous Management: Stenting or thrombo-aspiration can address Portal Vein stenosis or thrombosis in the early postoperative phase.

Conclusion

The Modified Appleby Procedure represents an aggressive but viable surgical frontier for locally advanced pancreatic cancer. Its success is contingent upon meticulous patient selection via advanced imaging, the strategic use of preoperative embolization, and a high-volume center's ability to manage complex postoperative complications through interventional radiology.