Basic Science applied to medicine

1. The trouble with the world is that the stupid are cocksure and the intelligent are full of doubt
-Bertrand Russell
INTRODUCTION
● 2nd most common cause of death in US
● Many malignancies are preventable
● Survival rates are improving
● Prevention is better than cure
● 2 approaches
○ Risk factor reduction
■ Tobacco
■ Alcohol
■ Obesity
■ Inactivity
■ Unsafe sex
■ Urban air pollution
■ Contaminated injections
○ Screening of high risk population
TOBACCO USE
● Most easily preventable cause of cancer
● Accounts for 20 % of all cancer related deaths
● A/W malignancies of
○ Lung
○ Oral cavity
○ Pharynx
○ Larynx
○ Leukemia
○ Esophagus
○ Pancreas
○ Liver
○ Stomach
○ Bladder
● Mechanism of oncogenesis
○ Delivers carcinogens directly to tissues
○ Causes irritation and inflammation
- Created with love
by Dr. Eashan Srivastava

2. The trouble with the world is that the stupid are cocksure and the intelligent are full of doubt
-Bertrand Russell
○ Interferes with the body's natural protective barriers
ENVIRONMENTAL EXPOSURES
1. Excess sun exposure, artificial ultraviolet radiation
a. Risk factors for BCC, SCC, Melanoma
b. Mechanism
i. Ultraviolet radiation causes genetic mutations
ii. Interferes with the cutaneous immune system
c. Recommendations for sun/ultraviolet protection
i. Applicable to high-risk characteristics such as
1. Fair skin
2. Large number of nevi
3. Positive family history
ii. Limit the time spent in the sun 10 AM to 4 PM
iii. Wear hats/sunglasses
iv. Use sunscreen
2. Air pollution
a. Diesel exhaust
b. Particulate matter
c. A/w CA Lung
d. Radon​​ = Component of indoor air pollution
e. Arsenic
i. In drinking water
ii. A/w CA Bladder
PHYSICAL ACTIVITY
● Physical activity is protective in
○ CA Breast
○ CA colon
○ Endometrial and prostate cancer
● Mechanisms
○ Reduction in circulating levels of insulin, hormones, and other growth factors
- Created with love
by Dr. Eashan Srivastava

3. The trouble with the world is that the stupid are cocksure and the intelligent are full of doubt
-Bertrand Russell
○ Improved immune function
OBESITY
● Esophageal adenocarcinoma
● Gastric CA
● Colorectal CA
● HCC
● CA endometrial
● Ovarian CA
● Breast cancers
● Meningioma
● Thyroid CA
● Bladder CA
● Mechanism
○ Obesity creates an inflammatory environment
DIET
1. Dietary fat
a. No clear link between total fat intake and colon or breast cancer
b. Reports suggest that a diet low in animal fat may be protective against colorectal
cancer
2. Red meat
a. Increased risk of colon cancer
3. Fruits and vegetables
a. a/w reduction in cancer
b. Weak association
4. Dairy
a. Association with ovarian cancer is uncertain
5. Fiber
a. A/w reduced colorectal cancer risk
6. Omega-3 fatty acids and dietary fish
a. A/w decreased incidence of colorectal cancer
- Created with love
by Dr. Eashan Srivastava

4. The trouble with the world is that the stupid are cocksure and the intelligent are full of doubt
-Bertrand Russell
7. Dietary patterns
a. Mediterranean diet (ie, high intake of fruits, vegetables, nuts, legumes, whole
wheat bread, fish, and olive oil)= Lower risk of cancer
b. Western diet (Ultra-processed foods) = A/w colorectal CA
8. VITAMINS AND MICRONUTRIENTS
a. In theory, antioxidants should reduces CA risk
b. Vitamin A, C, D, E = No evidence of benefit
c. Selenium = No evidence
d. Calcium
i. Linked to reduced risk of colorectal cancer
ii. a/w an increased risk of prostate cancer
e. Folate and other B vitamins
i. Widely present in green, leafy vegetables, fruits, cereals and grains
ii. Role is uncertain
ALCOHOL
● A/w CA
○ Oropharynx
○ Esophagus
○ Larynx
○ Rectum
○ Breast
○ HCC
INFECTIONS
● HPV
○ CA cervix
○ Other anogenital cancers
○ SCC of the head and neck
● HBV and HCV
○ HCC
● HTLV-I
- Created with love
by Dr. Eashan Srivastava

5. The trouble with the world is that the stupid are cocksure and the intelligent are full of doubt
-Bertrand Russell
○ Adult T-cell leukemia
● HIV
○ Kaposi sarcoma
○ non-Hodgkin lymphoma
● HHV-8
○ Kaposi sarcoma
○ Primary effusion lymphoma
● EBV
○ Burkitt lymphoma
● H pylori
○ CA stomach
○ MALT lymphomas
● Liver flukes
○ Cholangiocarcinoma
○ HCC
● Strategies to prevent transmission
○ Screening of blood products
○ ANC screening
○ Use of sterile disposable needles
○ Regulation of tattooing
○ HPV vaccination
○ ART has been shown to reduce the incidence of AIDS-related lymphoma
○ HepB vaccination
CHEMOPREVENTION
1. Breast cancer
a. Tamoxifen
i. Selective estrogen receptor modulator (SERM)
ii. Estrogen agonist and antagonist properties
iii. ER+ breast cancer
iv. Risk
1. Endometrial cancer
2. Thromboembolic events
b. Raloxifene
- Created with love
by Dr. Eashan Srivastava

6. The trouble with the world is that the stupid are cocksure and the intelligent are full of doubt
-Bertrand Russell
i. Alternative to tamoxfene
c. Aromatase inhibitors
i. Anastrozole, letrozole, and exemestane
ii. Inactivating aromatase
2. Prostate cancer and 5-alpha reductase inhibitors
a. Finasteride
i. Reduces incidence of CA prostate
ii. But do not have a favorable risk-benefit profile for the chemoprevention of
prostate cancer in healthy men
3. Aspirin
a. Effective in reducing colorectal cancer risk
b. Decreases the synthesis of prostaglandins
4. Metformin
a. a/w reduced incidence of several types of cancer in patients with type 2 diabetes
b. Pancreatic, liver, breast, colon and prostate
5. Statins
a. No convincing evidence
- Created with love
by Dr. Eashan Srivastava