[NakedScientist (OP)]

Aspirin is one of the cheapest drugs known and probably one of the oldest. Through its anti-platelet action it has prevented thousands of strokes and heart attacks and has now been shown to reduce the risk of gastro-intestinal cancers :

"A seven-year study led by Dartmouth Medical School researchers shows that a daily dose of aspirin can be effective in reducing the risk of colon adenomas - benign tumors that can develop into cancer if left in the bowel.

The study, conducted jointly by doctors and researchers from Norris Cotton Cancer Center at Dartmouth-Hitchcock Medical Center in Lebanon, NH, and at several other institutions across North America, confirms indications from non-randomized studies that low-dose aspirin may protect against cancers of the colon and rectum. The final results of the study were published in the March 6, 2003 issue of the New England Journal of Medicine.

Dr. John Baron was lead author of the article, and co-author of another report in the NEJM that also found that aspirin protected against adenomas of the colon and rectum. He noted that the findings of the two studies show that low doses of aspirin do protect against the pre-cancerous polyps, and so there is good reason to believe aspirin probably reduces rates of colorectal cancer itself. This will be particularly valuable for people who are at increased risk for cancer because they have had colon adenomas (polyps) or because they have previously been treated for colorectal cancer.

The randomized, double-blind study, conducted between 1994 and 2001, looked at over 1100 patients with previously diagnosed colorectal adenomas. Some patients received aspirin - either 81 mg or 325 mg - while others received a placebo. Interestingly, the group receiving the smaller dose of aspirin - 81-mg, or the equivalent of one baby aspirin - showed a lower incidence of recurring polyps than did those treated with the larger dose of aspirin - 325 mg or the equivalent of a standard adult aspirin.

Overall, those treated with a daily dose of baby aspirin found their risk of polyps reduced 19 percent and their risk of advanced lesions reduced by more than 40 percent.

The companion study, conducted among patients with a history of cancer of the colon or rectum, tested a regular aspirin tablet (325 mg) against placebo. It showed even larger reductions in the occurrence of adenoma - about a 35% reduction.

Although aspirin is generally a safe drug, Baron noted that it can have adverse effects for some individuals. Before people embark on a daily aspirin regimen, they should check with their doctor, he said. And, he stressed that just taking aspirin is not enough to assure freedom from colon cancer.

"Aspirin is not a magic bullet. Although the incidence was reduced, all the polyps didn't go away in our study. Regular screenings, perhaps including colonoscopies, are still important."

[Monox D. I-Fly]

gastro-intestinal cancers :

Is this what called as "stomach cancer"? Because almost two years ago a friend of mine died and the cause was said to be stomach cancer.

[chris]

The gastrointestinal tract (GI-tract) is the tube inside your body that goes from the mouth at the top to the bottom at, well, the bottom! So a cancer of the GI tract is a gatrointestinal tumour. The GI tract is divided up into different structures along its length, such as the oesophagus, stomach, small bowel, large bowel and so on. Each of these components may develop tumours, so you could say you have "stomach cancer", but this is still a form of GI tumour.

[exothermic]

Makes plenty of sense when you consider aspirin's primary MOA and the TXA2-mediated progression of cancer:

Aspirin at 81mg/day reduces the risk of atherosclerotic coronary artery disease & stroke by reducing coronary vasoconstriction and enhancing coronary vasodilation.

Aspirin facilitates endothelial prostacyclin production & localized vasodilation via the blockade of platelet thromboxane a2 production.

The downregulation by aspirin of thromboxane-induced vasoconstriction is important in the context of the ischemic-mediated oxygen supply-and-demand imbalances and reduced blood flow observed in coronary artery disease.

Several studies suggest potential involvement of TXA2S and TP in tumor progression, especially tumor cell proliferation, migration, and invasion that are key steps in cancer progression. In addition, the regulation of neovascularization by TP has been identified as a potent source of control during oncogenesis.

The thromboxane synthase and receptor signaling pathway in cancer: an emerging paradigm in cancer progression and metastasis
Cancer Metastasis Rev. Author manuscript; available in PMC 2014 Sep 25. Cancer Metastasis Rev. 2011 Dec; 30(0): 397–408. doi:  10.1007/s10555-011-9297-9 PMCID: PMC4175445
NIHMSID: NIHMS520470