Tuesday 25 July 2017

Disease will pose a bigger scourge in future

Pancreatic cancer poses challenges for cancer researchers Stock photo: PA News
Pancreatic cancer poses challenges for cancer researchers Stock photo: PA News

John Crown

The report of the charity Pancreatic Cancer UK provides a sobering reminder of the toll of this disease, and the likelihood that it will become an even bigger scourge in the future. Pancreatic cancer imposes tremendous personal burdens on patients and their families. It also poses challenges to health professionals and cancer researchers.

The pancreas is situated in the upper abdomen, behind the stomach, and in close connection to upper intestines. It has crucial roles in maintaining normal blood sugar levels and in assisting digestion. It produces insulin. Reduction in insulin production in the pancreas can lead to diabetes.

Cancer of the pancreas is the fourth most common cause of cancer death in Irish men (after lung, colon/rectum, and prostate) and the fifth most common in Irish women (after lung, breast, colon/rectum and ovary). About 5pc of all cancer deaths in Ireland are due to pancreatic cancer. Overall, approximately 450 to 500 Irish people lose to their lives to pancreas cancer every year.

Most pancreatic cancers are 'adenocarcinomas', cancers which arise from the cells involved in digestion. 'Neuroendocrine' cancers are a distinct, much less common subtype. They have very different treatment and a much better outlook. We will not discuss them further in this article.

The biggest risk factor, as with most cancers, is age. Pancreas cancer is rare before middle age. The average age at diagnosis is over 70. As we get better at preventing premature death from heart and circulatory disease, more people will live long enough to get pancreas cancer. Obesity increases the risk of pancreas cancer, as do diabetes and other pancreatic diseases. Thus aging populations and increasing obesity will drive increases in pancreatic cancer rates in years to come.

Smoking doubles the risk. The linkage with alcohol is less certain, but alcohol can certainly cause inflammation of the pancreas which is a risk factor for pancreas cancer.

Some cases of pancreas cancer have a hereditary component. A minority of cases occurs in patients who have well-recognised and generally uncommon cancer susceptibility conditions. Interestingly, the well-known 'BRCA mutation', the breast-ovarian cancer condition which Angelina Jolie did much to headline, also increases pancreas cancer risk.

Other patients do not have a specific cancer susceptibility condition, but do have striking family histories, with multiple relatives affected.

The best hope for pancreatic cancer cure is to cut it out before it spreads. "A chance to cut is a chance to cure" is the old surgical cliché. It is important to concentrate cases in centres of excellence to keep surgical skills high.

Sadly, most patients with pancreatic cancer will not be cured. In many cases, the disease has reached an advanced stage before it causes symptoms, and is not operable. Relapse following an apparently successful operation is also an all too frequent occurrence. Chemotherapy (anti-cancer drugs") given before or after a surgery has been shown to reduce the risk of relapse. Radiation treatment can also improve disease control.

Should we screen healthy people for the presence of pancreas cancers the way we screen women for breast and cervix cancer with mammograms and pap smears?

Routine general population screening for pancreatic cancer is not recommended in any country. It is not a proven strategy. The tests are also too intrusive, expensive and time consuming to make them practical for whole-population screening.

Some healthy people with specific risk factors might be considered for screening. Those with strong family histories or hereditary conditions might be considered. Others with some types of non-cancerous abnormalities in the pancreas such as certain types of cyst, are often offered screening with scans.

Wholly new screening technologies may become available. It is increasingly recognised that some cancers 'shed' proteins, DNA and other substances into the blood. It may in the future be possible to develop a screening blood test.

For patients who have advanced disease where an operation is not possible, chemotherapy and radiotherapy remains the mainstay of drug treatment. Both have improved, and even where cure is not possible, survival prolongation is achieved. Immunotherapy is under investigation.

Only research can help produce improvement, and there are some bright spots.

Dr Eileen O'Reilly, the brilliant Irish oncologist who heads the Pancreas Cancer Program in Memorial Sloan-Kettering Cancer Centre in New York, believes that new drugs that target DNA and the supporting 'stroma' of cancer cells offer great promise for the future.

Prof Martin Clynes and Dr Sandra Roche in DCU are growing human cancers in mice, allowing the opportunity to test new drugs. Dr Naomi Walsh, also in DCU, is studying genes that may predispose to developing the disease.

Improved government and private investment in research is needed. Before you give to a cancer charity, ask how much of your donation goes to research.

Irish Independent

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