Cancer Risk Factors

According to the National Cancer Institute, a risk factor is anything that raises or lowers a person’s chance of 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.


Cancer risk factors can be divided into four groups:

  • Behavioral risk factors are things you do, such as smoking, drinking alcohol, using tanning beds, eating unhealthy foods, being overweight and not getting enough exercise. 
  • Environmental risk factors include things in the environment around you, such as UV radiation, secondhand smoke, pollution, pesticides and other toxins.
  • Biological risk factors are physical characteristics such as your gender, race or ethnicity, age and skin complexion.
  • Hereditary risk factors relate to specific mutated genes inherited from your parents. You have a higher likelihood of developing cancer if you inherit one of these mutated genes.

Most behavioral and environmental cancer risk factors can be avoided. Biological and hereditary risk factors are unavoidable, but it's important to be aware of them so you can discuss them with your doctor and get screened for cancer, if necessary.


Remember, many people who develop cancer have no known risk factors, and most people who do have risk factors don't get the disease. So, it's important to see your doctor regularly for checkups and talk to him or her about which cancer screening tests are right for you. 

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
  • Obesity or weight gain after menopause
  • Hormonal therapy
  • Inherited mutations in the BRCA1 or BRCA2 genes
  • Suspected risk factors include:
    • High-fat diet
    • Physical inactivity
    • More than one alcoholic drink per day
    • Oral contraceptives

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 Black and Latin-American women.
  • Human Papillomavirus (HPV) infection
  • Diethylstilbestrol (DES) exposure before birth
  • HIV infection
  • Weakened immune system due to organ transplant, chemotherapy or chronic steroid use


Colorectal Cancer

  • Age – most common in people over age 50
  • Personal or family history of colorectal cancer (especially a parent or sibling)
  • Personal or family history of adenomatous polyps (especially a parent or sibling)
  • 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


Endometrial Cancer (also called Uterine Cancer)


  • Increasing age
  • Increased estrogen exposure
  • 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


Lung Cancer


  • Cigarette, cigar or pipe smoking
  • Personal or family history of lung cancer
  • Recurring exposure to:
    • Radon or asbestos (especially for smokers)
    • Radiation
    • Arsenic
    • Air pollution
    • Secondhand smoke
  • Lung diseases such as tuberculosis (TB)


Ovarian Cancer


  • Age – most common in people over age 50
  • Family history of ovarian (mother, daughter, sister, grandmother, or aunt)
  • Inherited mutations in the BRCA1 or BRCA2 genes
  • Northern European and/or Ashkenazi Jewish heritage
  • Never being pregnant
  • Suspected risk factors include:
    • Fertility drugs
    • Exposure to talcum powder 
    • Hormone replacement therapy
    • Obesity


Prostate Cancer


  • Age – men 50 and older are at greater risk
  • Family history of prostate cancer (especially father, brother, or son)
  • Race – Black men have nearly twice the incidence of white men
  • Diet high in saturated fat and low in fruits and vegetables


Skin Cancer

  • Exposure to ultraviolet (UV) radiation from the sun or tanning beds
  • Fair complexion
  • Family history, especially of melanoma
  • Living in the southern states
  • Living in a sunny climate
  • Occupational exposure to:
    • Coal tar
    • Pitch
    • Creosote
    • Arsenic
    • Radium