BIO 108- Ch. 12 Cancer Prevention

Cancer Prevention

• more than ½ of all cancer deaths could be prevented

• avoid environmental agents and behaviors which cause cancer

• if already exposed to cancer-causing agent, block subsequent events required for the progression to malignancy

Avoid Cancer-Causing Agents: Agents: Tobacco

• Tobacco: #1 cause of preventable deaths, 30% of all cancer deaths

Protect Against Solar Radiation: What can you do?

• UV radiation protection

• regulation of physical/chemical carcinogens

  • radiation: less than 5% of all cancers

  • chemicals: less than 5% of all cancer deaths

    • OSHA (1970): occupational health and safety administration

      • problems:

        • EPA bans asbestos

Environment

• Environmental Protection Agency (EPA)

  • Exceptions:

    • people who live near toxic chemical site

    • people who live/work in old buildings: asbestos

    • people who take prescription drugs to treat chronic health issues

    • public water supply problems: example - Flint, MI

  • Example: Hormone Replacement Therapy (HRT)

    • Beneficial Effects:

      • Strengthens bones

      • decreases colon cancer risk

      • reduces menopause symptoms

    • adverse effects:

      • increases breast cancer risk

      • increases heart attacks

      • increases strokes

      • increases blood clots

      • increases ovarian cancer risk

• Control of Infectious Agents

  • avoid behaviors that expose you to infectious agents

  • vaccinations

  • testing/treatments

Eat a Healthy Diet

• fruits and vegetables

• limit fat/red meat consumption

• reduce use of high temperature cooking

• reduce pesticide contamination

• exercise

• vitamins: anti-oxidants

Are Vitamins Beneficial?

• important note: Vitamin A can increase lung cancer risk in smokers

• randomized trial (7 years) in Finland

  • results show now protective effect, but statistically increase lung cancer cases in men given Vitamin A, result confirmed in US studies

Dietary Fiber

• Indigestible (not digested) portion of plant foods

• reported double fiber intake associated with 40% reduction in colon cancer incidence

• whole grains are very beneficial

Coffee

• May be associated with a reduces risk of endometrial and liver cancers

  • study: American journal of clinical nutrition, 2022

    • results from 19 previously published studies, 40,000 people

    • coffee drinkers: 13% lower risk of endometrial cancer compared to non-coffee drinkers

    • the more coffee people drank, the lower their cancer risk

  • study: hepatology communications, 2022

    • patient data and responses from 200,000 East Asian participants ages 20-89

    • coffee drinkers: 31% decreased risk of hepatocellular carcinoma

• bioactive compounds in coffee (chlorogenic acids and polyphenols: antioxidant, anti-inflammatory properties. No difference between regular or decaf (endometrial cancer)

Limit Sugary Beverages

• Study (cancer epidemiology 2022): 30 year study with 900,000 participants

• results: drinking 2 or more sugar sweetened beverages/day associated with colorectal and kidney cancer mortality

Practice Good Dental Hygiene

• gum disease:

  • 45% more likely to develop colorectal cancer

  • 43% increased esophageal cancer risk 52% increase stomach cancer risk

  • 18% increase breast cancer risk

• prevention:

  • brush teeth for 2 minutes twice a day

  • floss teeth daily

  • see a dentist at least twice per year

Preventative Prescription Drugs

• tamoxifen

• oral contraceptives

Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)

• Example: aspirin and colon cancer

• 1990s study: test anti-inflammatory drugs (Celebrex, Vioxx, bextra)

• Issues: stomach/intestinal ulcers, vomiting, renal problems, increased risk of heart attack and stroke

  • Vioxx recalled

Maintain a Healthy Body Weight

• 2003 American Cancer Society Study

  • obesity linked to a wide variety of cancers

Obesity

• obesity-related cancers: colon, rectum, esophagus, gallbladder, kidney, liver, ovary, pancreas, stomach, uterus, multiple myeloma, breast cancer (postmenopausal women)

  • a growing epidemic of obesity in US since 1980