Lymph Node Ratio Predicts for Survival in Gastric Cancer A SEER Database Analysis

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Lymph Node Ratio Predicts for Survival in Gastric
Cancer A SEER Database Analysis

• George W. Dombi, PhD1 and
• Ravi Shridhar, MD-PhD2
• 1 Epidemiology Division and
• 2 Gershenson Radiation Oncology Center
• Barbara Ann Karmanos Cancer Institute
• Detroit Medical Center
• Wayne State University
• Detroit, MI

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Gastric Cancer Epidemiology

• 870,000 new cases gastric cancer/year worldwide.
• 650,000 deaths/year worldwide, (75).
• 22,000 new cases/year in US in 2006.
• 11,430 deaths/year, (52) Lower ratio in US.
• Gastric Cancer is 14th in incidence in US.
• Worldwide top 3 cancers are lung, breast, colon.
• Top 3 deaths from cancer are lung, gastric, and
  liver.

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Gastric Cancer Epidemiology

• Location of gastric tumors are most common in the
  antrum.
• Antrum or distal stomach 40
• Fundus, cardia, GEJ 35
• Body 25

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Gastric Cancer Epidemiology

• Worldwide decline over past few decades
• 1930-1980
• Decrease from 38 to 10/100,000 men,
• Decrease from 30 to 5/100,000 women.
• Identification and treatment of Heliobacter
  pylori.
• Dietary factors
• Fresh fruits and vegetables (antioxidants)
• Introduction of refrigeration
• Less salt based preservation (includes nitrates)
• Less bacterial and fungal contamination

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Patterns of Spread

• Direct
• Omenta, pancreas, diaphragm, colon, duodenum,
  jejunum, vessels, adrenals, kidney
• Lymphatic
• Paracardial, lesser and greater curvature,
  pyloric, celiac, SMA, hepatic, splenic,
  paraaortic
• Hematogenous
• Via portal system
• Peritoneal
• Often diffuse process

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Staging Japanese

• N1 stations 1-6
• Paracardial, greater and lesser curvature,
  pyloric
• N2 stations 7-11
• Left gastric, common hepatic, splenic art and
  hilum, celiac
• N3-4 stations 12-16
• Hepatic, retropancreatic, mesenteric root, middle
  colic, paraaortic

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Gastric Cancer AJCC Staging

• T1 invasion of the lamina propria
• T2a invasion of the muscularis
• T2b invasion of the subserosa
• T3 penetration of the serosa (visceral
  peritoneum)
• T4 invasion of adjacent structures
• N1 1-6 lymph nodes
• N2 7-15 lymph nodes
• N3 gt15 lymph nodes

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Gastric Cancer AJCC Staging

• Stage IA T1 N0
• Stage IB T1 N1
• T2 N0
• Stage II T1 N2
• T2 N1
• T3 N0
• Stage IIIA T2 N2
• T3 N1
• T4 N0
• Stage IIIB T3 N2
• Stage IV T4 N1-3
• T1-3 N3
• M1

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Lymph Node Ratio

• Lymph Node ratio (LNR LN pos /LN exam)
• - LN pos number lymph nodes positive
• - LN exam number nodes examined
• Nodal ratio has become an important prognostic
  tool
• Studies showing importance of nodal ratio in
  rectal, pancreatic, and gastric cancer
• Nodal ratio in breast cancer predicts for
  survival, recurrence and who benefits from
  Radiation Therapy.
• No large US lymph node ratio gastric studies.

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Lymph Node Ratio - Italian
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Lymph Node Ratio - Italian
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Lymph Node Ratio - Japanese
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Lymph Node Ratio - Japanese
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Lymph Node Ratio - Japanese
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Lymph Node Ratio - Japanese
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Aims

• The first aim of this study was to compare three
  measures of lymph node involvement as a predictor
  of gastric cancer survival
• Number of Total nodes examined,
• Number of Total metastatic nodes, and
• Lymph Node Ratio (LNR) (metastatic nodes)/(nodes
  examined).
• The second aim was to examine the effect of
  removing 15 or more lymph nodes on survival
  outcomes for N0-N2 and 30 or more for N3

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Methods

• Data contained 13,745 cases of gastric cancer
  taken from the Surveillance, Epidemiology and End
  Results (SEER) 1990-2003 public access data
  tapes.
• Data were grouped by N0, N1, N2, and N3 stages
  (AJCC) as well as Lymph Nodes Examined, Lymph
  Nodes Positive and Lymph Node Ratio (LNR)
• (LNR LN pos /LN exam).
• Survival analysis was conducted with SAS ver 9.1
  utilizing proc lifetest for the Kaplan-Meier
  analysis and proc phreg for Cox proportional
  hazard analysis.

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Patient Characteristics
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Patient Characteristics
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Patient Characteristics
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Patient Characteristics
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Patient Characteristics
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Patient Characteristics
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Results
r0.8 Plt0.0001
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Results
r0
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Gastric Cancer Survival by Lymph Node Ratio
Groups.
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Results
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Results
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Results
AC - Adenocarcinoma
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Results
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Conclusion

• LNR is a simple, significant predictor for
  survival.
• Removing gt15 lymph nodes provided a survival
  benefit across stages N0, N1 and N2.
• LNR as a predictor of survival was nearly
  identical whether lt15 or gt15 lymph nodes were
  removed.
• LNR should be considered in the staging system.