Genes Behind Pancreatic Cancer

Pancreatic cancer is the third most common cause of cancer-related deaths in the United States, with over 43,000 deaths expected in 2017.¹ While most pancreatic cancers are sporadic, approximately 10% of pancreatic cancers appear to have a familial component.²

Familial Pancreatic Cancer (FPC) is defined as families that have > 2 affected individuals who are first-degree relatives of each other. FPC can also include families with > 3 affected individuals on the same side of the family, even if they are not first-degree relatives of each other.

Germline mutations in BRCA1, BRCA2, PALB2, ATM, p16, PRSS1, STK11, and the mismatch repair genes (Lynch syndrome) are associated with a significantly increased risk of pancreatic cancer; however, these genes have a low penetrance for pancreatic cancer, and often the family history is more notable for other cancers.

Despite what appears to be an autosomal dominant mechanism for inheritance, a genetic mutation leading to pancreatic cancer is found only 10% of seemingly hereditary cases.

Several large-volume centers have begun to study screening for pancreatic cancer in high-risk patients, and consensus-based guidelines have been published.³  Candidates for screening may include:

1) First-degree relative of an affected individual in a FPC family

2) First-degree relative of an affected individual in a family with > 2 pancreatic cancers

3) BRCA2, PALB2, p16, ATM, and mismatch repair gene mutation carriers with affected first-degree relatives

4)  BRCA2 mutation carriers with 2 affected relatives, even if no first-degree relative is affected

5) All Peutz-Jegher’s syndrome (STK11 mutation) patients regardless of their family history

6) All PRSS1 mutation carriers

Consensus guidelines recommend pancreatic cancer screening in high-risk individuals at age 50, with the exception being PRSS1 mutation carriers who start screening at age 40.

The goals of pancreatic cancer screening include:

1)  Detection and treatment of precancerous lesions (i.e., high grade multifocal pancreatic intraepithelial neoplasms, or high-grade dysplasia within an intraductal papillary mucinous neoplasm).

2) The detection and treatment of a T1N0M0 cancer.

3) Detection of any resectable pancreatic carcinoma.

Detection of these early pancreatic cancers or pre-malignant lesions is dependent on our ability to identify and screen high-risk individuals before the onset of symptoms.  Current tools for pancreatic cancer screening include Magnetic Resonance Imaging (MRI) with MR Cholangiography (MRCP) and endoscopic ultrasound (EUS.)

MRI has the benefit of being a non-invasive test, but is sometimes limited by the patient’s ability to lie still for the duration of the study. 

EUS is a more invasive examination which requires anesthesia, but offers an opportunity to sample any abnormalities that may be detected on examination.

Emerging data suggest that MRCP may be more effective in detecting cystic lesions of the pancreas, while EUS may be more sensitive to detect small solid lesions.⁴ Computer tomography (CT scan), abdominal ultrasound, and endoscopic retrograde cholangiopancreatography are not generally used in pancreatic cancer screening.

For further information on pancreatic cancer screening studies, or to arrange a consultation please visit  http://www.mountsinai.org/profiles/aimee-lucas or  http://labs.icahn.mssm.edu/lucas

Amiee Lucas, MD  Professor of Medicine – Gastroenterology  Mt. Sinai Hospital

References

1. Society AC. Cancer Facts & Figures 2017. Atlanta: American Cancer Society 2017.

2. Klein AP, Hruban RH, Brune KA, et al. Familial pancreatic cancer. Cancer J 2001;7:266-73.

3. Canto MI, Harinck F, Hruban RH, et al. International Cancer of the Pancreas Screening (CAPS) Consortium summit on the management of patients with increased risk for familial pancreatic cancer. Gut 2012.

4. Harinck F, Konings IC, Kluijt I, et al. A multicentre comparative prospective blinded analysis of EUS and MRI for screening of pancreatic cancer in high-risk individuals. Gut 2015.

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