Patterns of Regional Lymph Node Recurrence after Surgery for Intrahepatic Cholangiocarcinoma and Combined Hepatocellular-Cholangiocarcinoma: A Retrospective Analysis in a Single Institution

Abstract

<h3>Purpose/Objective(s)</h3> The overall incidence of cholangiocarcinoma (CCA) has increased progressively worldwide over decades. CCAs are highly aggressive, which renders a dismal prognosis with high recurrence rates after dissection and disappointing 5-year survival rate (7%-20%). Surgical resection remains the mainstay of potentially curative therapy for intrahepatic CCA (iCCA) or combined hepatocellular carcinoma (HCC)-CCA. Most patients develop recurrent disease after surgery and extrahepatic recurrence was found in 40% patients. Postoperative radiotherapy (RT) has been considered an adjuvant treatment modality. However, no consensus has been reached regarding to the clinical target volume (CTV) of RT. We aim to investigate the patterns of regional recurrence after surgery for iCCA and combined HCC-CCA to give insights on CTV delineation. <h3>Materials/Methods</h3> Medical records of iCCA and combined HCC-CCA patients who underwent surgery at Cancer Hospital of Chinese Academy of Medical Sciences between 2010 to 2019 were retrospectively reviewed. Patients were included in this study if they 1) had been pathologically diagnosed with iCCA or combined HCC-CCA; 2) underwent surgical resection; and 3) had been diagnosed with first recurrent event in regional LNs. Patients were excluded if they had adjuvant radiotherapy. All available follow-up imaging studies were thoroughly reviewed. Patterns of recurrence were categorized as local (intrahepatic), regional (regional LNs) and distant failure. Regional failures as first site of recurrence were further evaluated. <h3>Results</h3> A total of 53 patients were included in analysis, 42 of which had iCCA and 11 had combined HCC-CCA. The median age was 59 years (35-70) for all patients. The proportion of patients with history of hepatitis B and elevated AFP was higher in combined HCC-CCA group than in iCCA group. 67.9% patients underwent R0 resection and the median number of dissected LNs is 5 (0-31). Hepatic hilar is the most common recurrent region for both groups followed by portal vein-vena cava (high risk stations). Recurrence rates at left gastric, paracardial, diaphragmatic, common hepatic, celiac trunk and superior mesenteric artery are similar and moderate (medium risk stations). There is much less recurrence at other LN regions with likelihood less than 10% (low risk stations). A total of 20.8% patients had skip metastases. 13.2% patients had recurrence at medium risk stations without recurrence at high-risk stations and 7.6% patients had recurrence at high and low risk stations without recurrence at medium risk stations. A figure of 3-dimentional distribution of recurrent LNs was created. A standard patient was selected and all recurrent LNs were contoured on her CT images according to relationship between LNs and vessels. <h3>Conclusion</h3> This study created a LN recurrence map of surgically resected iCCA and combined HCC-CCA patients, which might be helpful for radiation oncologists in CT-guided delineation of postoperative CTV.