How I ended up in a high-risk pancreatic cancer screening clinic

Pancreatic cancer is a scary disease. The pancreas (like the brain) is in a difficult to access space.  It is removed from other anatomical structures so that it does not produce symptoms that lead to early detection.  In medical school they taught us two presentations – waking up with painless jaundice and depression.  The painless jaundice is more of a specific give away than the depression. In either case, prognosis at the time of diagnosis is poor and has not improved significantly in the past decades (1,2,7).

I think about discussions I used to have over lunch with several specialists. Our typical group consisted of 3 GI docs, 1 or 2 Infectious Disease docs, a nephrologist and me.  We usually talked about movies but one day it turned to pancreatic cancer.  The question became – if you could screen for it would you?  This discussion happened back in the 1990s and the consensus at that time was no.  One of the pieces of evidence offered was the poor prognosis after surgical intervention – irrespective of the time of diagnosis.

I personally know 10 people who were diagnosed with pancreatic cancer. Four of them are on the paternal side of my family and one is a first degree relative – my sister. My earliest recollection of the disease was visiting my paternal aunt who lived a few blocks from my family.  Back in the 1950s, there was no useful imaging and diagnoses typically depended on exploratory surgery and direct tissue sampling. People who lived in remote areas did not travel to large referral centers to see specialists. You lived and died based on the skill of local physicians – some who had surgical training but were not technically general surgeons. Blood banking also did not exist and my father and uncle had to donate blood for my aunt. Nine of the 10 people I have known with pancreatic cancer are deceased some of them within weeks to months of the diagnosis.  My sister has been a trail blazer.  After a fortuitous diagnosis while being scanned for gallbladder disease, pancreatic cancer was diagnosed and she underwent radiation therapy, chemotherapy, a Whipple procedure, and maintenance therapy with a poly (ADP-ribose) polymerase (PARP) inhibitor.  She saw an oncologist who recommended genetic testing and discovered she had an ATM gene variant. The genetic counselor she was seeing at the time recommended that all her siblings get tested for the same gene and to see if their children also needed to be tested.

ATM stands for “ataxia telangiectasia mutated.”  Ataxia telangiectasia (AT) is a hereditary degenerative ataxia that occurs in 1 in 20K to 100K live births (3,4).  Gait problems and truncal instability occurs in the first decade of life followed by progressive ataxia. Telangiectasias starts at about age 5 and are most evident in the conjunctive but can occur at various sites on the body. Immunodeficiency is noted with frequent respiratory infections.  Humoral and cell mediated immunity are affected as evidenced by decreased immunoglobulins and lymphocytopenia. AT is also associated with an increased frequency of cancers beginning with hematological malignancies in childhood and different malignancies as adults (6).  Lifespan with AT is decreased but is now more than 25 years with supportive measures. 

The mutations causing AT were discovered as mutations in the ATM gene in the late 20^th century.  The ATM gene is located on chromosome 11, and the gene product is a serine-threonine kinase involved in DNA repair (5). Like most human genes there are a large number of mutations and single nucleotide polymorphisms (SNPs).  Those mutations associated with AT are insertions, deletions, missense, and truncations.  These mutations can lead to absence or loss of function ATM protein.  In my case the lab report read:

 

Variant Details:

ATM, Exon 10, c.1564_1565del (p.Glu522Ilefs*43), heterozygous, PATHOGENIC

This sequence change creates a premature translational stop signal (p.Glu522Ilefs*43) in the ATM gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in ATM are known to be pathogenic (PMID: 23807571, 25614872).

This premature translational stop signal has been observed in individual(s) with breast cancer and ataxia-telangiectasia (PMID: 9000145, 9463314, 10330348, 10817650, 12497634, 21965147, 27083775).

In order to appreciate how the ATM protein works – a brief review of cell biology is in order.  Cells reproduce according to a cell cycle with various components. The protein components and cell signaling of that cycle were discovered in the past 40 years.  The cell cycle has checkpoints designed to stop the cycle and repair any DNA that is discovered as defective along the way. ATM is one of the proteins that modulates that process.  Functional ATM protein means that it is less likely that damaged DNA is passed along in new cell lines and that reduces the risk of cancer.  ATM mutations are associated with increase risk for pancreatic, ovarian, breast, and prostate cancer and as previously noted – malignancies associated with AT.  That is the mile high version of checkpoint and checkpoint proteins.  If you want a more detailed explanation, put it in the comments section and I will add more.

This mechanism is interesting to consider when thinking about genomic versus environmental effects. Peak incidence for new diagnoses of pancreatic cancer occurs during the 70s. If you have a defective DNA repair mechanism – is this the time where those defects accumulate to the point of creating malignancy?  How is your history of avoiding carcinogens like alcohol and tobacco smoke relevant to that probability?  What about the protective effects of antioxidants and exercise? At some point does a partially functional ATM protein protect against cancer or is the fully functional protein required?

The referral process in my own primary care clinic went smoothly when I told my internist about my sister’s diagnosis. I got an online appointment with a genetic counselor and when the results came back – she told me there was a 10-15% chance of pancreatic cancer and one clinic that did risk surveillance at Mayo.  She asked me if I was interested and why.  She also advised me that there are currently loopholes in the law that allow some companies to discriminate against you based on genetic testing. After discussing what those companies did – I told her I was not concerned about it and she made the referral.  I met with the gastroenterologist who headed the clinic, signed up for additional research protocols, had an MRI scan and just completed an upper GI endoscopy with ultrasound (US).  The ultrasound device is in the head of the gastroscope and it needs to be positioned in various areas of the stomach and duodenum to visualize the entire pancreas. The US procedure was also set up to proceed with a fine needle biopsy of the pancreas – but no lesions were noted and no biopsy was necessary. If a biopsy is required it is done through the wall of the stomach or duodenum.  Current screening is on an annual basis and the orders have already been placed for next year.

Getting back to the answer to the question posed in the title - it comes down to genes. One of the cultural myths in the US is that you always bear some level of responsibility for your disease. Recall any discussion about this with friends or family: “Did you hear that your classmate died last week from X?”  The next question or comment is likely to be – “well he (smoked, drank, never exercised, was obese, didn’t take care of himself, never saw a doctor, etc.”). There always must be an explanation for your old classmate dying prematurely and it is rarely biological.  Even though everybody in town with the same risk factors – outlived him by 20 years.  The stark reality is that it does not take a risk factor-based analysis. All it takes is a gene (or many genes) that code for the disease either directly or indirectly.

 

George Dawson, MD, DFAPA

 

References:

1:  Armstrong SA, Schultz CW, Azimi-Sadjadi A, Brody JR, Pishvaian MJ. ATM Dysfunction in Pancreatic Adenocarcinoma and Associated Therapeutic Implications. Mol Cancer Ther. 2019 Nov;18(11):1899-1908. doi: 10.1158/1535-7163.MCT-19-0208. PMID: 31676541; PMCID: PMC6830515.

2:  Klein AP. Pancreatic cancer epidemiology: understanding the role of lifestyle and inherited risk factors. Nat Rev Gastroenterol Hepatol. 2021 Jul;18(7):493-502. doi: 10.1038/s41575-021-00457-x. Epub 2021 May 17. PMID: 34002083; PMCID: PMC9265847.

The risk of death from pancreatic cancer rises dramatically with age from <2 deaths per 100,000 person-years for individuals in the USA aged 35–39 years to >90 deaths per 100,000 person-years for individuals aged >80 years.

3:  Subramony SH, Xia G. Disorders of the cerebellum, including the degenerative ataxias.  In:  Neurology in Clinical Practice (7^th edition). RB Daroff, J Jancovic, JC Mazziotta, SL Pomeroy (eds). Elsevier, London, 2016.  p: 1468-1469.

4:  Rothblum-Oviatt, C., Wright, J., Lefton-Greif, M.A. et al. Ataxia telangiectasia: a review. Orphanet J Rare Dis 11, 159 (2016). https://doi.org/10.1186/s13023-016-0543-7

5:  ATM serine/threonine kinase [ Homo sapiens (human) ]

Gene ID: 472, updated on 12-Mar-2023

https://www.ncbi.nlm.nih.gov/gene/472

6:  Hsu F, Roberts NJ, Childs E, et al. Risk of Pancreatic Cancer Among Individuals With Pathogenic Variants in the ATM Gene. JAMA Oncol. 2021;7(11):1664–1668. doi:10.1001/jamaoncol.2021.3701

“The cumulative risk of pancreatic cancer among individuals with a germline pathogenic ATM variant was estimated to be 1.1% (95%CI, 0.8%-1.3%) by age 50 years; 6.3%(95%CI, 3.9%-8.7%) by age 70 years; and 9.5%(95%CI, 5.0%-14.0%) by age 80 years. Overall, the relative risk of pancreatic cancer was 6.5 (95%CI, 4.5-9.5) in ATM variant carriers compared with noncarriers.”

7:  Trikudanathan G, Lou E, Maitra A, Majumder S. Early detection of pancreatic cancer: current state and future opportunities. Curr Opin Gastroenterol. 2021 Sep 1;37(5):532-538. doi: 10.1097/MOG.0000000000000770. PMID: 34387255; PMCID: PMC8494382.

8:  Oh SY, Edwards A, Mandelson MT, Lin B, Dorer R, Helton WS, Kozarek RA, Picozzi VJ. Rare long-term survivors of pancreatic adenocarcinoma without curative resection. World J Gastroenterol. 2015 Dec 28;21(48):13574-81. doi: 10.3748/wjg.v21.i48.13574. PMID: 26730170; PMCID: PMC4690188.

9:  Overbeek KA, Goggins MG, Dbouk M, Levink IJM, Koopmann BDM, Chuidian M, Konings ICAW, Paiella S, Earl J, Fockens P, Gress TM, Ausems MGEM, Poley JW, Thosani NC, Half E, Lachter J, Stoffel EM, Kwon RS, Stoita A, Kastrinos F, Lucas AL, Syngal S, Brand RE, Chak A, Carrato A, Vleggaar FP, Bartsch DK, van Hooft JE, Cahen DL, Canto MI, Bruno MJ; International Cancer of the Pancreas Screening Consortium. Timeline of Development of Pancreatic Cancer and Implications for Successful Early Detection in High-Risk Individuals. Gastroenterology. 2022 Mar;162(3):772-785.e4. doi: 10.1053/j.gastro.2021.10.014. Epub 2021 Oct 19. PMID: 34678218.

10:  Søreide K, Ismail W, Roalsø M, Ghotbi J, Zaharia C. Early Diagnosis of Pancreatic Cancer: Clinical Premonitions, Timely Precursor Detection and Increased Curative-Intent Surgery. Cancer Control. 2023 Jan-Dec;30:10732748231154711. doi: 10.1177/10732748231154711. PMID: 36916724; PMCID: PMC9893084.

"The overall poor prognosis in pancreatic cancer is related to late clinical detection. Early diagnosis remains a considerable challenge in pancreatic cancer. Unfortunately, the onset of clinical symptoms in patients usually indicate advanced disease or presence of metastasis."

11:  National Center for Biotechnology Information. ClinVar; [VCV000127340.60], https://www.ncbi.nlm.nih.gov/clinvar/variation/VCV000127340.60 (accessed March 19, 2023).

Graphics:

I drew that genogram of my immediate family using EDraw Max.  I am one of the two siblings that tested positive for the ATM variant. My other siblings have not been tested.