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DOI: 10.1055/s-0040-1722795
Imaging of Gastric Carcinoma. Part Two: Lymph node mapping in Gastric Carcinoma
- Abstract
- Introduction
- Clinical Significance of Nodal Staging
- Anatomy
- Types of Surgery and Nodal Resection
- References
Abstract
Accurate preoperative nodal staging is critical in determining the appropriate therapy and prognosis for stomach cancer. A staging computed tomography should inform the treating surgeon about the nodal burden to decide the appropriate surgical plan or perioperative chemotherapy. Nodal staging is also a powerful predictor of the outcome of surgery and overall survival. Imaging of nodes is also important in the assessment of response following the chemotherapy. In this article, we will discuss lymphatic drainage of stomach and different nodal stations, identification of nodal stations on cross sectional imaging, and different types of surgical nodal clearance for gastric cancer.
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Introduction
Lymphatic spread is found in 74 to 88% of gastric cancers at diagnosis.[1] Nodal stage is an important determinant of the overall stage and treatment of gastric cancer. Hence, radiological nodal staging (cN) and mapping of nodal stations is an important part of gastric cancer management. In this article, we will discuss lymphatic drainage of stomach, tumor node metastasis (TNM) and Japanese Gastric Cancer Association (JGCA) nomenclature of regional and distant nodal stations, identification of each station on cross sectional imaging, and different types of surgical nodal clearance for gastric cancer.
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Clinical Significance of Nodal Staging
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Gastrectomy surgeries such as total gastrectomy and subtotal distal gastrectomy are further subdivided into D1, D1+, D2, and rarely D2+ based on the extent of dissection of distant nodal stations. Extent of nodal dissection is further determined by radiological staging. Station 10 nodes may sometimes require splenectomy, and hence, preoperative vaccination against encapsulated bacteria and a prior consent for organ removal is essential.[2]
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Nodal status is the most powerful predictors of outcome in the first 5 years after curative surgery.[3] There is a significant difference in the recurrence rate and 5-year survival rate between lymph node-negative and lymph node-positive patients.[3] [4] It has been shown that the presence of four or more involved nodes predicts worse survival outcome.[5] [6] Therefore, the American Joint Committee on Cancer (AJCC) 8th edition has emphasized this relationship between the number of involved nodes and the prognosis of gastric cancer ([Table 1]).[7]
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Evidence from studies of early gastric cancers from Japan suggest that well-differentiated cancers may metastasize more frequently to the liver and poorly differentiated tumors to lymph nodes.[8] This may explain the high rate of local recurrence with the poorly differentiated tumors.
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For early gastric cancer (tumor limited to mucosa, less than 2 cm without ulceration) minimally invasive endoscopic procedure like endoscopic mucosal resection or endoscopic submucosal dissection is feasible in selected group of patients. But 2.3 to 5% patients of early gastric cancer may harbor nodal metastases.[9] In those patients, proper gastrectomy with lymph node clearance is recommended.
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Finally, perioperative chemotherapy with (fluorouracil-leucovorin-oxaliplatin-docetaxel) regime is now considered standard of care for locally advanced and node-positive resectable gastric and gastroesophageal cancer in many centers, including ours.[10] So understaging due to inadequate information on nodal burden may lead to futile surgeries. On the other hand, overstaging may lead to unnecessary perioperative chemotherapy. Patients with heavy locoregional nodal burden (stations 1–12) should be considered for perioperative chemotherapy followed by surgery. If there are enlarged nodes at the para-aortic, aorto-caval, or mediastinal area, then the patient should be categorized as having metastatic disease and treated with palliative intent.
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Anatomy
Stomach is drained by an extensive lymphatic network. Lymph nodes are named after either the organ of drainage or the accompanying vessels. The lymphatic vessels originate in the gastric mucosa and form a submucosal and a subserosal plexus. The subserosal plexus drains into the perigastric nodes. The perigastric nodes are the sentinel group of nodes draining the stomach. The perigastric nodes ultimately drain into the retroperitoneal nodes by four lymphatic axes.
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Nodes along left inferior phrenic artery (left subdiaphragmatic pedicle)
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Nodes along left gastric, splenic, and common hepatic arteries (celiac pedicle)
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Infrapyloric nodes and nodes along root of superior mesenteric artery (superior mesenteric pedicle)
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Nodes along the hepatoduodenal ligament and posterior aspect of pancreatic head (retro-pancreatic pedicle)
Due to the presence of extensive perigastric lymphatic networks, even early mucosa-confined tumors can have lymphatic spread at diagnosis.[11]
Gastric Nodal Stations
Gastric nodes are described in 23 nodal stations, stations 1 to 20, and stations 110 to 112 ([Table 2]). Generally, stations 1 to 12 are considered regional nodes both by AJCC and the JGCA. However, JGCA considers the superior mesenteric vein lymph node (station 14v) to be regional, but the AJCC considers it as a distal node. Also, if the tumor of the proximal third of stomach involves the esophagus, then the infradiaphragmatic, paraesophageal, and supradiaphragmatic lymph nodes (stations 19, 20, 110 and 111) are also considered regional nodes.[12] All of these stations are considered distant nodal stations by the AJCC. For carcinomas arising in the remnant stomach with a gastrojejunostomy, jejunal lymph nodes adjacent to the anastomosis are included in regional lymph nodes as well.
There are some specific distal nodal sites that are typical for gastric carcinoma and some other upper abdominal malignancies. Metastasis can manifest as an enlarged supraclavicular node (Virchow node), periumbilical node (Sister Mary-Joseph node), or left axillary node (Irish node). The Virchow node is one of the left supraclavicular lymph nodes that is adjacent to the junction of the thoracic duct and left subclavian vein. Gastric and other upper abdominal malignancies have a propensity to metastasize to these nodes. Presence of hard and enlarged nodes in the left supraclavicular fossa is historically described as Troisier sign and is suggestive of abdominal malignancy[13] ([Fig. 1]).
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Radiological Anatomic Mapping
On cross-sectional imaging, most nodal stations can be identified by accompanying vascular pedicles. [Fig. 2] shows the locations of the nodal stations on diagrams and [Figs. 3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17]–[18] demonstrated the nodal stations on contrast-enhanced CT ([Figs. 2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17]–[18]).
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Lymph Node Morphology
Lymph nodes are considered pathological when
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Perigastric nodes (stations 1–6) with short axis diameter >6 mm
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Extra-perigastric nodes (stations 7, 8, 9, and 11) with short axis diameter >8 mm
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Lymph nodes with rounded or irregular shape
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Absent fatty hilum
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Heterogeneous enhancement
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Types of Surgery and Nodal Resection
Complete surgical resection of the tumor and draining nodes with a negative resection margin is the only curative treatment for gastric carcinoma. The primary objective of surgery is to excise the primary tumor with clear longitudinal and circumferential resection margin of at least 5 cm (R0 resection), adjacent organ resection as required, resection of associated lymph nodes, and then safely restoring intestinal and biliary continuity. Various types of surgical resection are performed based on the size and location of the primary tumor.
Types of Gastrectomy
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Total gastrectomy, for diffuse tumors, large distal tumors, and the tumor involving body or lesser curvature of stomach
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Esophagogastrectomy for tumors involving cardia and gastroesophageal junction (with epicenter located greater than 2 cm into the proximal stomach)
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Distal subtotal gastrectomy for tumors limited to distal stomach
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Proximal gastrectomy with transhiatal excision of lower mediastinal lymph node (below the level of inferior pulmonary vein) for gastroesophageal junction tumor infiltrating less than 3 cm into the lower esophagus.[14]
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Types of Lymphadenectomy
D1 lymphadenectomy is when all N1 nodes (perigastric nodes closest to the primary tumor) are removed en bloc with the stomach and D2 lymphadenectomy is when all N1 and N2 (distant perigastric nodes and nodes along main arteries supplying stomach) are systematically removed en bloc with stomach. Since gastric cancer commonly remains localized to stomach and adjacent lymph nodes, D2 lymphadenectomy has a survival benefit. Overall, D2 has lower locoregional recurrence and gastric cancer-related death rates, but it has higher postoperative mortality, morbidity, and reoperation rates compared with D1 surgeries.[15] Originally, to ensure full nodal clearance along the splenic artery, a routine en bloc resection of spleen and distal pancreas used to be performed. But spleen preserving D2 resection technique is currently performed in most higher centers as it can reduce morbidity significantly. According to Sano et al total gastrectomy for proximal tumors which has not involved greater curvature of stomach, splenectomy should be avoided.[2] The extent of D1 and D2 resection is given below.
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(A) Total gastrectomy
D0: Any lymphadenectomy less than D1
D1: Stations 1–7
D1+: D1 + stations 8a, 9, 11p
D2: D1 + Stations 8a, 9, 10, 11p, 11d, 12a
For tumors invading the esophagus: D1+ includes 110 and D2 includes 19, 20, 110, and 111.
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(B) Distal gastrectomy
D0: Any lymphadenectomy less than D1
D1: Stations 1, 3, 4sb, 4d, 5, 6, 7
D1+: D1 + stations 8a, 9
D2: D1 + stations 8a, 9, 11p, 12a
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Nodal mapping in CT – What the Surgeon Wants to Know
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T-status of the tumor; location, relation with the surrounding structures
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Presence of enlarged or suspicious lymph node in perigastric area
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Presence of enlarged or suspicious lymph nodes in para-aortic, aortocaval, mediastinal, and left supraclavicular nodes
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Comparison of pre- and postchemotherapy nodal burden before surgery
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Conflict of Interest
None declared.
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References
- 1 Ferlay J, Soerjomataram I, Dikshit R. et al Cancer incidence and mortality worldwide: sources, methods and major patterns in GLOBOCAN 2012. Int J Cancer 2015; 136 (05) E359-E386
- 2 Sano T, Sasako M, Mizusawa J. et al Stomach Cancer Study Group of the Japan Clinical Oncology Group. Randomized controlled trial to evaluate splenectomy in total gastrectomy for proximal gastric carcinoma. Ann Surg 2017; 265 (02) 277-283
- 3 Hochwald SN, Kim S, Klimstra DS, Brennan MF, Karpeh MS. Analysis of 154 actual five-year survivors of gastric cancer. J Gastrointest Surg 2000; 4 (05) 520-525
- 4 Kim DY, Seo KW, Joo JK. et al Prognostic factors in patients with node-negative gastric carcinoma: a comparison with node-positive gastric carcinoma. World J Gastroenterol 2006; 12 (08) 1182-1186
- 5 Gunji Y, Suzuki T, Hori S. et al Prognostic significance of the number of metastatic lymph nodes in early gastric cancer. Dig Surg 2003; 20 (02) 148-153
- 6 Ichikura T, Tomimatsu S, Okusa Y, Uefuji K, Tamakuma S. Comparison of the prognostic significance between the number of metastatic lymph nodes and nodal stage based on their location in patients with gastric cancer. J Clin Oncol 1993; 11 (10) 1894-1900
- 7 Amin MB, Edge S, Greene F. et al, eds. AJCC Cancer Staging Manual. 8th ed. New York: Springer 2017
- 8 Roukos DH, Kappas AM. Perspectives in the treatment of gastric cancer. Nat Clin Pract Oncol 2005; 2 (02) 98-107
- 9 Sasako M, McCulloch P, Kinoshita T, Maruyama K. New method to evaluate the therapeutic value of lymph node dissection for gastric cancer. Br J Surg 1995; 82 (03) 346-351
- 10 Al-Batran S-E, Homann N, Pauligk C. et al FLOT4-AIO Investigators. Perioperative chemotherapy with fluorouracil plus leucovorin, oxaliplatin, and docetaxel versus fluorouracil or capecitabine plus cisplatin and epirubicin for locally advanced, resectable gastric or gastro-oesophageal junction adenocarcinoma (FLOT4): a randomised, phase 2/3 trial. Lancet 2019; 393 (10184) 1948-1957
- 11 Roviello F, Rossi S, Marrelli D. et al Number of lymph node metastases and its prognostic significance in early gastric cancer: a multicenter Italian study. J Surg Oncol 2006; 94 (04) 275-280 , discussion 274
- 12 Japanese Gastric Cancer Association. Japanese classification of gastric carcinoma: 3rd English edition. Gastric Cancer 2011; 14 (02) 101-112
- 13 Som PM, Curtin HD, Mancuso AA. Imaging-based nodal classification for evaluation of neck metastatic adenopathy. AJR Am J Roentgenol 2000; 174 (03) 837-844
- 14 Kumamoto T, Kurahashi Y, Niwa H. et al True esophagogastric junction adenocarcinoma: background of its definition and current surgical trends. Surg Today 2020; 50 (08) 809-814
- 15 Songun I, Putter H, Kranenbarg EM-K, Sasako M, van de Velde CJH. Surgical treatment of gastric cancer: 15-year follow-up results of the randomised nationwide Dutch D1D2 trial. Lancet Oncol 2010; 11 (05) 439-449
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Publication History
Article published online:
02 March 2021
© 2021. Indian Society of Gastrointestinal and Abdominal Radiology. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial-License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/).
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References
- 1 Ferlay J, Soerjomataram I, Dikshit R. et al Cancer incidence and mortality worldwide: sources, methods and major patterns in GLOBOCAN 2012. Int J Cancer 2015; 136 (05) E359-E386
- 2 Sano T, Sasako M, Mizusawa J. et al Stomach Cancer Study Group of the Japan Clinical Oncology Group. Randomized controlled trial to evaluate splenectomy in total gastrectomy for proximal gastric carcinoma. Ann Surg 2017; 265 (02) 277-283
- 3 Hochwald SN, Kim S, Klimstra DS, Brennan MF, Karpeh MS. Analysis of 154 actual five-year survivors of gastric cancer. J Gastrointest Surg 2000; 4 (05) 520-525
- 4 Kim DY, Seo KW, Joo JK. et al Prognostic factors in patients with node-negative gastric carcinoma: a comparison with node-positive gastric carcinoma. World J Gastroenterol 2006; 12 (08) 1182-1186
- 5 Gunji Y, Suzuki T, Hori S. et al Prognostic significance of the number of metastatic lymph nodes in early gastric cancer. Dig Surg 2003; 20 (02) 148-153
- 6 Ichikura T, Tomimatsu S, Okusa Y, Uefuji K, Tamakuma S. Comparison of the prognostic significance between the number of metastatic lymph nodes and nodal stage based on their location in patients with gastric cancer. J Clin Oncol 1993; 11 (10) 1894-1900
- 7 Amin MB, Edge S, Greene F. et al, eds. AJCC Cancer Staging Manual. 8th ed. New York: Springer 2017
- 8 Roukos DH, Kappas AM. Perspectives in the treatment of gastric cancer. Nat Clin Pract Oncol 2005; 2 (02) 98-107
- 9 Sasako M, McCulloch P, Kinoshita T, Maruyama K. New method to evaluate the therapeutic value of lymph node dissection for gastric cancer. Br J Surg 1995; 82 (03) 346-351
- 10 Al-Batran S-E, Homann N, Pauligk C. et al FLOT4-AIO Investigators. Perioperative chemotherapy with fluorouracil plus leucovorin, oxaliplatin, and docetaxel versus fluorouracil or capecitabine plus cisplatin and epirubicin for locally advanced, resectable gastric or gastro-oesophageal junction adenocarcinoma (FLOT4): a randomised, phase 2/3 trial. Lancet 2019; 393 (10184) 1948-1957
- 11 Roviello F, Rossi S, Marrelli D. et al Number of lymph node metastases and its prognostic significance in early gastric cancer: a multicenter Italian study. J Surg Oncol 2006; 94 (04) 275-280 , discussion 274
- 12 Japanese Gastric Cancer Association. Japanese classification of gastric carcinoma: 3rd English edition. Gastric Cancer 2011; 14 (02) 101-112
- 13 Som PM, Curtin HD, Mancuso AA. Imaging-based nodal classification for evaluation of neck metastatic adenopathy. AJR Am J Roentgenol 2000; 174 (03) 837-844
- 14 Kumamoto T, Kurahashi Y, Niwa H. et al True esophagogastric junction adenocarcinoma: background of its definition and current surgical trends. Surg Today 2020; 50 (08) 809-814
- 15 Songun I, Putter H, Kranenbarg EM-K, Sasako M, van de Velde CJH. Surgical treatment of gastric cancer: 15-year follow-up results of the randomised nationwide Dutch D1D2 trial. Lancet Oncol 2010; 11 (05) 439-449