What happens in pancreatic cancer, exactly?

What is it?

Pancreatic cancer is a type of cancer that affects the pancreas. The pancreas is a glandular organ near the stomach. Before nutrients can be absorbed from our food our body has to break them down. The pancreas produces digestive enzymes that do this, and releases them to the small intestine. The pancreas also produces the hormone insulin, which helps sugar move inside our cells so that our cells can use it as an energy source. The most common form of pancreatic cancer affects the cells that produce digestive enzymes.

There are rarely any symptoms in the early stages of pancreatic cancer. When they do emerge, they include things like weight loss, stomach pain, and yellow-ish skin. By the time of diagnosis, the cancer has often spread to other parts of the body. This, combined with the aggressive nature of this type of cancer, makes the prognosis of the disease particularly bad. After being diagnosed with the type that affects the digestive enzyme cells, adenocarcinoma, 75% of people die within a year, and 95% die within five years.

About 1.5% of the US population get pancreatic cancer during their lifetime. It is most common in people over 70, and very rare in those under 40. It is also more common in developed countries.

What causes it?

About 5-10% of pancreatic cancer cases have a genetic component. Most cases, however, are due to lifestyle factors such as smoking, obesity and diabetes, and sheer bad luck.

What happens during it?

Normal cells do their job in the tissue, maybe divide a few times, and when they’re no longer needed, they die. In cancer this system goes wrong. Cells start to divide uncontrollably, and in the worst case, these cells can travel in the bloodstream to other parts of the body and harm vital organs. The cells don’t care about the body’s signals that tell them to stop reproducing. This is because the DNA, the instructions for the cell’s behavior, has been mutated in a critical manner. Mutations in some genes will lead to this unresponsiveness, while mutations in others can lead to other attributes that promote cancer cell growth. Normal cells, for example, can only divide so many times, because non-coding strands in the ends of their DNA become shorter and shorter with every division. Ultimately  they run out and the cell wouldn’t be able to divide without harming the coding part of DNA. Cancer cells have a way of rebuilding the lost part of the non-coding strand after dividing, which is why they can, in principle, divide endlessly.

Pancreatic cancer is so bad because it spreads to other organs so easily. Even patients in the first stage of the disease have a survival rate of only 30%. In comparison, first-stage breast cancer patients have a survival rate of nearly 100%. This is thought to be attributable to a gene called ATCD. It is active in the vast majority of pancreatic cancer cases, and it plays a key role in regulating the tumor’s progression from  kind of just being there to sending cells around the body to invade other organs. ATCD is thought to do this by promoting the development of cancer stem cells: a small number of cells inside the tumor that make the tumor grow and spread.

The pancreas is important, but it isn’t absolutely vital given the advances of modern medicine. Dysfunction of the liver is more fatal, and people with pancreatic cancer usually die from liver failure as the cancer spreads there.

How can it be treated?

Removing the tumor surgically is the only cure for pancreatic cancer. Unfortunately, it has often already spread in such a way that this isn’t possible.

Chemotherapy and radiotherapy can also be used to slow down the illness. The DNA of dividing cells is more vulnerable than in others and these therapies take advantage of that. They are effective because cancer cells divide far more frequently than normal cells, but this mechanism is also why these therapies damage healthy cells, as some amount of division is going on in our bodies all the time.

While the research is only in its beginning, the discovery of the role of ATCD gives hope that we could be looking at more advanced and efficient interventions for pancreatic cancer in the future.

 

 

Sources: en.wikipedia.org/wiki/Pancreatic_cancer, http://www.medicalnewstoday.com/articles/288104.php, https://www.sciencedaily.com/releases/2015/01/150115102649.htm, http://www.cancerresearchuk.org/about-cancer/type/pancreatic-cancer/treatment/the-stages-of-pancreatic-cancer, en.wikipedia.org/wiki/Cancer, http://www.cancer.org/cancer/breastcancer/detailedguide/breast-cancer-survival-by-stage

 

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