What is Peutz-Jeghers syndrome?

Peutz-Jeghers syndrome (PJS) is an inherited condition that puts people at an increased risk for developing hamartomatous polyps in the digestive tract, as well as breast [2], colorectal [3], and other types of cancer. A hamartoma is a growth of normal-appearing tissue that builds up into a benign (noncancerous) tumor. However, the growth can transform into cancer over time. Cancer begins when normal cells begin to change and grow uncontrollably, forming a mass called a tumor. A tumor can be noncancerous or malignant (cancerous, meaning it can spread to other parts of the body).

The lifetime risk of cancer in people with PJS is around 93%. People with PJS also tend to develop dark blue or dark brown freckling, especially around the mouth and on the lips, fingers, or toes. Freckles generally appear in childhood and may fade with age.

The suggested criteria for a diagnosis of PJS are:

• Diagnosis of one or more hamartomatous polyps in the digestive tract, and at least two of the following:
  
  • Polyps in the small intestine
  • Characteristic freckling of the mouth, lips, fingers, or toes
  • At least one relative diagnosed with PJS

The diagnosis of PJS is also considered if someone has a family history of PJS and has the characteristic freckling. PJS may be a possible diagnosis if a person has the characteristic freckling and polyps even without a known family history.

What causes PJS?

PJS is a genetic condition. This means that the condition can be passed from generation to generation in a family. The STK11 gene (also known as the LKB1 gene) is the only gene that has been linked to PJS so far. A mutation (alteration) in the STK11 gene gives a person an increased lifetime risk of developing colorectal cancer [3] and other symptoms of PJS. It is possible that there may be other genes associated with PJS that have not yet been discovered.

How is PJS inherited?

Normally, every cell has two copies of each gene: one inherited from the mother and one inherited from the father. PJS follows an autosomal dominant inheritance pattern, in which a mutation needs to happen in only one copy of the gene for the person to have an increased risk of getting that disease. This means that a parent with a gene mutation may pass along a copy of their normal gene or a copy of the gene with the mutation. Therefore, a child who has a parent with a mutation has a 50% chance of inheriting that mutation. A brother, sister, or parent of a person who has a mutation also has a 50% chance of having the same mutation.

How common is PJS?

PJS is considered to be rare. It is estimated that one in 25,000 to one in 280,000 people will have PJS.

How is PJS diagnosed?

The diagnosis of PJS is assumed if someone meets the diagnostic criteria listed above. People who may have PJS can have a blood test to look for a mutation in the STK11 gene. If an STK11 gene mutation is found, other family members may also be diagnosed with PJS if they are tested and have the same gene mutation. However, people with PJS may not have a detectable mutation in STK11.

What are the estimated cancer risks associated with PJS?

What are the screening options for PJS or people at risk for PJS?

It is important to discuss with your doctor the following screening options, as each individual is different:

General cancer screening for people with PJS

• Upper and lower endoscopy [13] (a thin, lighted, flexible tube with a small video camera is inserted into your mouth and down your esophagus to look for tumors or other abnormalities), beginning at age 10 and repeated every two years into adulthood
• Colonoscopy [14] (the doctor inserts a thin flexible tube with a small video camera into the anus to check for abnormalities within the colon and rectum), beginning at age 10 and repeated every two years
• Endoscopic ultrasound or abdominal ultrasound [15] to screen for pancreatic cancer [4], beginning at age 30 and repeated every one to two years

Cancer screening for women with PJS

• Monthly breast self-examination and yearly clinical breast examination (examination performed by a doctor or nurse), beginning at age 20
• Mammograms [16] every two to three years, beginning at age 20, and then yearly mammograms, beginning at age 40
• Yearly gynecologic examination including Pap test [17], transvaginal ultrasound [15] (a test where a small ultrasound probe is inserted like a speculum for a pelvic examination in order to obtain better imaging of the uterus), and consideration of a uterine biopsy [18], beginning at age 20

Cancer screening for men with PJS

• Yearly testicular examination and consideration of an ultrasound [15], beginning by age 20

Screening options may change over time as new technologies are developed and more is learned about PJS. It is important to talk with your doctor about appropriate screening tests.

Learn more about what to expect when having common tests, procedures, and scans [19].

Questions to ask the doctor

If you are concerned about your risk of cancer, talk with your doctor. Consider asking the following questions of your doctor:

• What is my risk of developing colorectal cancer [3], breast cancer [2], or other types of cancer?
• How many colon polyps have I had in total?
• What type of colon polyps have I had? (The two most common kinds are hyperplastic and adenomatous.)
• What can I do to reduce my risk of cancer?
• What are my options for cancer screening?

If you are concerned about your family history and think your family may have PJS, consider asking the following questions:

• Does my family history increase my risk of colorectal cancer [3], breast cancer [2], or other types of cancer?
• Should I meet with a genetic counselor?
• Should I consider genetic testing [20]?

Additional resources

Guide to Colorectal Cancer [3]

The Genetics of Colorectal Cancer [21]

Guide to Breast Cancer [2]

The Genetics of Breast Cancer [22]

What to Expect When You Meet With a Genetic Counselor [23]

Colon Cancer Alliance
www.ccalliance.org [24]

Facing Our Risk of Cancer Empowered (FORCE)

www.facingourrisk.org [25]

National Cancer Institute
www.cancer.gov [26]

American Cancer Society
www.cancer.org [27]

CancerCare
www.cancercare.org [28]

To find a genetic counselor in your area, ask your doctor or visit the following websites:

National Society of Genetic Counselors
www.nsgc.org [29]

National Cancer Institute: Cancer Genetics Services Directory
www.cancer.gov/cancertopics/genetics/directory [30]