Cancer Risk Factors

According to the National Cancer Institute, a risk factor is anything that raises or lowers a person’s chance for developing a disease. Although doctors can seldom explain why one person develops the disease and another does not, researchers have identified specific factors that increase a person’s chances of developing certain types of cancers.

Some cancer risk factors can be avoided. Others, such as inherited risk factors, are unavoidable, but it is a good idea to be aware of them.

Remember, many people who develop cancer have none of the known risk factors, and most people who do have risk factors do not get the disease. So, it is important to talk with your doctor about regular checkups and about what screening tests are right for you.

Risk Factors by Disease

Breast Cancer

• Age – most cases occur in women age 50 or older
• Family history of breast or ovarian cancer before menopause (mother, sister or daughter)
• Abnormal breast biopsy results
• Lobular or ductal carcinoma in situ or atypical hyperplasia
• First period before age 12
• Menopause after age 55
• Never being pregnant or having your first child after age 30
• Higher education and socioeconomic status
• Women in this group tend to have fewer children or start childbearing after age 30
• Obesity or weight gain after menopause
• Hormonal therapy
• Inherited susceptibility genes BRCA1 and BRCA2
• Suspected risk factors include:
  • High-fat diet
  • Physical inactivity
  • More than one alcoholic drink per day
  • Oral contraceptives

Colorectal Cancer

• Age – most common in people over age 50
• Personal or family history of colorectal cancer (father, brother son)
• Personal or family history of adenomatous polyps (father, brother son)
• Personal history of inflammatory bowel disease
• Diet high in fat (especially in red meat)
• Diet low in fiber, fruits and vegetables
• Physical inactivity
• Cigarette smoking
• Alcohol consumption
• Obesity

Prostate Cancer

• Age – men 50 and older are at greater risk
• Family history of prostate cancer
• Race – African American men have nearly twice the incidence of white men
• Diet high in saturated fat

Cervical Cancer

• First intercourse at an early age
• Multiple sex partners (either of the woman or her partner)
• Cigarette smoking
• Race – More cases occur in African American, Hispanic and American Indian women
• Human Papilloma Virus (HPV) infection
• Diethylstilbestrol (DES) exposure before birth
• HIV infection
• Weakened immune system due to organ transplant, chemotherapy or chronic steroid use

Endometrial Cancer

• Estrogen exposure and increasing age
• First period before age 12
• Menopause after age 55
• Hormonal therapy without the use of progestin
• Never being pregnant
• History of infertility
• Personal history of hereditary non-polyposis colon cancer
• Obesity
• Use of tamoxifen

Ovarian Cancer

• Family history of ovarian, breast or colon cancer
• Personal history of breast, endometrial or colon cancer
• Hereditary non-polyposis colorectal cancer
• Incessant ovulation
• Northern European and/or Ashkenazi Jewish heritage
• Living in an industrialized country
• Suspected risk factors include:
  • Prolonged use of high dose estrogen without progesterone
  • Exposure to talc or asbestos
  • High fat diet
  • Increasing age

Skin Cancer

• Exposure to ultraviolet radiation
• Fair complexion
• Family history
• Geography – living in the southern states or near the “sun belt”
• Climate – living in a sunny climate
• Occupational exposure to:
  • Coal tar
  • Pitch
  • Creosote
  • Arsenic
  • Radium