Gastric Cancer Epidemiology

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Gastric Cancer Epidemiology

• Suminori Kono, MD, PhDProfessor of Preventive
  MedicineKyushu Univ School of MedicineFukuoka
  812-8582, Japanskono_at_phealth.med.kyushu-u.ac.jp

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Learning Objectives

• Understand descriptive features
• Learn protective and risk factors
• Learn ways of interpreting epidemiological
  observation

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Reading Materials

• Kono S, Hirohata T. Nutrition and stomach cancer.
  Cancer Causes Control 1996 7 41-55.
• World Cancer Research. Food, nutrition and the
  prevention of cancer a global perspective.
  Washington, DC American Institute for Cancer
  Research, 1997.

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Descriptive Features of Gastric Cancer

• 1) Second most common cancer
• 2) Dramatic decline worldwide
• 3) Wide variation in incidence
• 4) Altered risk among migrants
• 5) Male-to-female ratio 1.5 to 2.0

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Histological Types

• Intestinal typemore frequent in males and at
  older ages
• Diffuse typelittle difference between sexes and
  more frequent at younger ages
• Intestinal typeenvironmental cancer (?)

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5-year Relative Survival Rates

• Japan (1987-89) 48 US (1986-91)
  19
• Denmark (1983-85) 19
• Source Hanai A. Jpn J Cancer Clin 1998 44 49-59

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Screening for Gastric Cancer

• Nationwide screening in Japan
• Barium X-ray method
• No randomized controlled trial
• Benefit in case-control studies

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Smoking and Gastric Cancer

• Japanese physicians study
• Cigarettes/day RR (95 CI)
• Never/past 1.0
• 1-19 1.7 (1.1-2.6)
• 20 1.8 (1.1- 3.0)
• Adjusted for age and alcohol use

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Alcohol Use and Gastric Cancer

• Generally, no association between alcohol use and
  gastric cancer.
• Exceptionally, increased risk in relation to a
  heavy use of red wine and vodka drinking

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Helicobacter pylori and Gastric Cancer
prospective studies

• Study (year) Population RR (95
  CI)Parsonnet, et al. HMO subscribers 3.6
  (1.8-7.3)(1991) in USA Nomura, et
  al. Japanese men 6.0 (2.1-17.3)(1991) in
  HawaiiForman, et al. British men 2.8
  (1.0-8.0)(1991)

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Helicobacter pylori and Gastric Cancer current
interpretation

• A definite cause of gastric cancer
• African enigma
• No sex difference in H. pylori

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Dietary Factors and Gastric Cancer

• Protective Factor
• Convincing Vegetables and fruits,
  refrigerators
• Probable Vitamin C
• Possible Carotenoids, allium compounds, whole
  grain cereals, green tea
• Risk Factor
• Convincing None
• Probable Salt/salting
• Possible Starch, grilled meat and fish

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Vegetables and Fruits

• Many case-control studiesdecreased risk
  associated with high consumption
• Few prospective studies less consistent
  association
• Antioxidant micronutrients postulated
  constituents

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Vitamin Supplements Randomized Controlled Trial

• Country Supplements Relative risk
• China beta-carotene 0.84 vitamin E
• Finland beta-carotene 1.25 vitamin E 1.25

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Salt and Salted Foods

• Many case-control studies increased risk with
  salt intake, use of table salt, or salty foods.
• 1 of 2 prospective studies increased risk with
  salted fish.
• High salt intake promoted chemically-induced
  gastric carcinoma in rats. (Jpn J Cancer Res
  1983 74 28-34)

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Green Tea and Gastric Cancer

• Area Comparison RR (95 CI)
• Nagoya (Jpn) 4 cups vs. less 0.6 (n.s.)Saga
  (Jpn) 10 cups vs. less 0.3 (0.1-0.7)Shanghai U
  se of strong tea 0.3 (0.1-0.7)Shanghai
  M 3kg/yr vs 0 0.8 (0.6-1.3)
  F 1.2kg/yr vs 0 0.8 (0.5-1.4)Shanghai 4
  batches vs 0 0.5 (0.3-0.9)Hawaii 2 cups
  vs. 0 1.5 (0.9-2.3)
• Per day. Prospective study of Japanese men.

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Nitrate, Nitrite, and N-nitroso Compounds in
Gastric Carcinogenesis