Aspirin - A New Field for Cancer Treatment?

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We live in an age where 1 in 3 people will develop cancer in their lifetime. For the majority of us it's our worst fear, according to statistics released by Cancer Research UK. New classes of drugs and treatment methods are being studied every year to combat many forms of the disease, but several studies are now claiming that a new form of treatment comes from the most commonly prescribed drug in the world.

Aspirin, or Acetyl-salicylic acid, derives from a reaction between salicylic acid and an acetyl group. 
The drug blocks the action of the Cycloxygenase (COX) enzyme by binding to serine residues near their active sites. COX converts arachidonic acid into prostaglandins, lipid-like compounds that work with other substances to cause pain and inflammation. When COX is inhibited, the body's inflammatory response is suppressed.

Cancer Explained

Quoting a publication from Yale: 
"Cancer results from the outgrowth of a clonal population of cells from tissue."*
Cancer can be caused in many ways regarding what a body is exposed to (E.g. Smoking, alcohol, unbalanced diets etc.). However, a cell can turn cancerous through either 2 fundamental pathways:

1. Genetic mutation; a series of random genetic "accidents" that can turn normal cell-growth genes (protogenes) into cancerous genes (oncogenes). Because of this randomness, no two cancers are genetically identical.
2. Tumour Viruses. That's right, some viruses can manipulate cell division control systems when integrating their foreign DNA into a host's genome.

When a cell becomes cancerous it rejects it's ability to kill itself after so many divisions. This "cell suicide" is called Apoptosis, and is a critical part in the life cycle of a cell.
When apoptosis is inhibited in a cell, it carries on dividing to form a cluster of abnormal cells referred to as a tumour. This tumour can stay within the tissue it originated from (a benign tumour) or spread to other tissues (a malignant tumour). A tumour that is malignant can invade all types of tissue - this can include organs, the circulatory system and even bones. These invasions cause all sorts of different problems that compromise the life of the suffering individual.

Aspirin treatment against Breast Cancer

Because of it's ability to suppress inflammation, Aspirin has been loosely coupled with cancer treatment in studies conducted over the last 5 years. Some researchers believe that aspirin, by blocking inflammatory chemicals that fuel cancer growth in cells, can help reduce and prevent the spread of a cancer.A recent study out of Glasgow University claims evidence that a tiny 75mg daily dose of Aspirin can increase breast cancer survival rates by nearly 60 per cent. The study consisted of 4627 women diagnosed with breast cancer, with 1000 of the women taking the aspirin every day for 10 years. Not only did the results show a 58% increase in breast cancer survival within the aspirin-prescribed group, but these participants were reported to have been less likely to die from any illness compared to the rest of the women in the study. Saying this, a latest study on aspirin treatment for breast cancer has produced results that shows that their participants were actually more likely to die on the regular aspirin dose.

Aspirin treatment against Pancreatic Cancer

Scientists at Yale University set up a research project in 2005 which was soon to be one of the largest ever studies on Aspirin's effects. Just over 1000 individuals in Connecticut hospitals were asked about doses of aspirin they had taken in the past. 362 of the patients interviewed had been newly diagnosed with pancreatic cancer, and the rest were "healthy" individuals used as a control for the study. The results of the study suggested that long term doses of aspirin had halved the risk of pancreatic cancer for many patients - people who regularly took 75-325mg doses of the drug from at least 3 years before the study was conducted had a 48% lower risk of developing pancreatic cancer. Furthermore, the results went on the show that people who had been regularly taking aspirin for 20 years before the study had a 60% lower risk of developing the cancer.
However, it is worth noting that a lot of the patients observed were taking aspirin regularly as a prescription for cardiovascular disease, or cardiovascular disease prevention. Rather than a direct link between aspirin and pancreatic cancer, CVD treatment and even genetics could play a more predominant role in this anti-cancer claim. Also, a large study conducted in 2004 went against these findings completely and produced results showing that taking aspirin could actually increase the risk of developing pancreatic cancer in women.

Aspirin treatment against Bowel/Digestive Cancer

A research team from Leiden UMC, Netherlands analysed tumour tissue from patients that suffered from colon cancer, and had undergone surgery between 2002 and 2008. As common with this type of cancer, most of the 999 patients in the study were diagnosed at the later stages of the disease.

Of these patients, 182 took a low, regular dose of aspirin. During the study 37.9% of these participants died as a result of colon cancer, whereas 48.5% of the patients who didn't use aspirin died from the cancer. These researchers believed that aspirin, by targeting COX found in gastrointestinal tract, reduced the inflammation of cancerous cells consequently reducing the spread of the cancer in the patients.                                                       

The claims that a common drug that has been around for hundreds of years can prevent or even treat cancer are certainly worth looking in to, when given the evidence of these studies. Nonetheless, for as many studies claiming aspirin is a "miracle" anti-cancer drug, there are just as many claiming the contrary. There are many crucial points surrounding this area of oncology, one being common in many other areas of the field: every cancer is different. What may work for one individual's cancer may not work as well for another's, or even prove fatal. Additionally, aspirin comes with many potential side effects. The drug causes blood platelets to become less sticky and prevents clotting, which could lead to stomach ulcers, haemorrhages or even strokes when used regularly.

For now, evidence for or against this type of treatment is inconclusive. Should anyone consider taking a regular dose of aspirin, they should first see about consulting their doctor.










Sources:

• * http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1994795/
• http://www.cancerresearchuk.org/
• http://www.labmuffin.com/2012/06/is-aspirin-mask-same-as-beta-hydroxy.html
• http://osteoarthritis.about.com/od/osteoarthritismedications/a/cyclooxygenase.htm
• http://science.education.nih.gov/supplements/nih1/cancer/guide/understanding1.htm
• http://www.dailymail.co.uk/health/article-2678610/How-aspirin-halve-risk-dying-breast-cancer-Powerful-effects-drugs-seen-women-taking-small-doses.html
• http://www.theguardian.com/science/2014/jun/26/low-dose-aspirin-risk-pancreatic-cancer
• http://www.medicalnewstoday.com/articles/274834.php
• Image of colon cancer retrieved from http://healthsciencedegree.info/colon-cancer-cells/
• Image of cancer lab retrieved from http://www.ludwigcancerresearch.org/sites/default/files/styles/lab
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