Pancreatic Cancer: Family History and Genetics
Dr. Fay Kastrinos, Director of the Muzzi Mirza Pancreatic Cancer Prevention and Genetics Program, recently asked readers to send her questions about the role of genetics and family history in pancreatic cancer. What follows is the first in a three-part series of the most popular questions with Dr. Kastrinos’ answers.
What are the main causes of developing pancreatic cancer? What is the average person’s risk of developing pancreatic cancer in his or her life?
The majority (up to 90%) of patients diagnosed with pancreatic cancer have developed the disease because of “sporadic” causes. This means the cancers developed from environmental factors (such as toxins from cigarette smoke) that randomly caused abnormalities in pancreas cells and led to uncontrolled growth. Such factors are encountered throughout one’s life and act over a long period of time. In these “sporadic” cases of pancreatic cancer, there is no identifiable inherited gene involved and in an average person’s life, the risk of developing pancreatic cancer is 1% or less.
Does having a family history of pancreatic cancer increase risk? When should a person suspect that pancreatic cancer might run in the family?
Up to 10% of all pancreatic cancers appear to have an inheritable cause where there are multiple relatives in the family with pancreatic cancer or multiple other cancers.
Individuals who have a family history of pancreatic cancer have a considerably increased risk of developing pancreatic cancer.
An increase in an individual’s risk of developing pancreatic cancer is closely tied to the number of family members affected with pancreatic cancer and the relationships among at-risk individuals. Having multiple first-degree relatives with pancreatic cancer (first-degree relatives include parents, brothers, sisters, and children) increases the risk of non-affected family members developing the disease.
This risk has been estimated to be 4 times greater in individuals with one first-degree relative with pancreatic cancer; 6.4-times greater in individuals with two first-degree relatives with pancreatic cancer pancreatic cancer; and 32-times greater in individuals with three or more first-degree relatives with pancreatic cancer.
Is genetic evaluation for pancreatic cancer available? Who is genetic evaluation appropriate for?
In evaluating a patient for a possible inherited cause of pancreatic cancer, it is important to determine whether pancreatic cancer in the family is:
- diagnosed in multiple relatives in the same side of the family, or
- there are multiple other cancers in the family known to be associated with inherited cancer syndromes for which genetic testing may be appropriate.
In situations where there are multiple first and second degree relatives with pancreatic cancer in the absence of other known, genetic cancer syndromes, the term Familial Pancreatic Cancer may be appropriate.
The specific gene abnormality responsible for causing Familial Pancreatic Cancer has not yet been identified. Therefore, there is currently no genetic testing for those individuals who have multiple family members diagnosed with pancreatic cancer and no other cancer diagnoses.
However, genetic evaluation and testing may be appropriate in some families with pancreatic cancer and other types of cancers. There are several genetic conditions where family members develop different types of cancers and are associated with an increased risk of pancreatic cancer.
Which genetic conditions have genetic testing?
The following genetic conditions have an elevated risk for certain cancers, including pancreatic cancer, and genetic testing is available:
- Hereditary breast and ovarian cancer syndrome: available testing for abnormalities in the BRCA genes. The condition can effect every generation and is associated with cancers of the prostate and melanoma, in addition to breast and ovaries.
- Peutz-Jeghers Syndrome: available testing for abnormalities in the STK11/LKB1 gene. Patients with this condition often have multiple polyps in the small intestine and colon and can have freckling of the lips or in the mouth. Family members in every generation can be affected. Patients are at increased risk of also developing cancers of the breast, ovaries, uterus, and testicles.
- Hereditary Pancreatitis: available testing for abnormalities in the PRSS1 gene. Multiple family members have history of pancreatitis (inflammation of the pancreas often requiring hospitalizations) and often manifests at a young age. It affects every generation and can lead to a high incidence of cancer 30-40 years after the onset of repeated attacks of pancreatitis.
- Familial atypical multiple mole melanoma (FAMMM): available testing for abnormalities in the CDKN2A gene. The condition is characterized by multiple moles, atypical moles, and multiple melanomas. Every generation can be affected and there is a strong family history of melanoma.
- Lynch syndrome (previously referred to as Hereditary Non-Polyposis Colorectal Cancer or HNPCC): available testing for abnormalities in mismatch repair genes MLH1, MSH2, MSH6, PMS2, EPCAM. The condition is associated with an increased risk of many types of cancer, particularly cancers of the colon and rectum as well as the uterus and ovaries in women. People with Lynch syndrome can often be affected by cancer at young ages (younger than 60 years) and have multiple cancer diagnoses. The condition can affect every generation. In addition to pancreatic cancer, other less common cancers include those of the stomach, small intestine, liver, gallbladder ducts, upper urinary tract, and brain.
What should I consider before receiving genetic evaluation?
Determining whether the relatives of a patient with pancreatic cancer are at increased risk is not simple. Talking to someone with experience in hereditary cancer syndromes such as a genetic counselor, geneticist, gastroenterologist, or oncologist is often helpful. If a person is considering genetic evaluation and testing, it is important to speak with the appropriate health care provider (genetic counselor or doctor) qualified to interpret and explain the test results before they proceed with testing. It is important for people to understand and carefully weigh the benefits and risks of genetic testing before these tests are done and to be able to interpret the results for other family members.
Variability in insurance coverage for testing may exist and can be addressed during consultation. Often, genetic testing may be most appropriate in those patients affected by cancer and options can be discussed during routine cancer related care.
We offer genetic counseling and screening here as part of the Muzzi Mirza Pancreatic Cancer Prevention and Genetics Program. We assess a person’s individual risk based on a full genetic evaluation including family history of pancreatic cancer and other cancers, genetic screening, and other indicators. From there, our team compiles a personalized surveillance plan. If you would like more details about what our program involves, please visit our Participating in the Program page.