Cancer therapy aspirin stops cancerous tumors

Cancer therapy: Aspirin could slow down tumor growth

21/03/2012

Acetylsalicylic acid (ASA) can slow the growth of tumors and reduce the risk of cancer. This was discovered by British scientists around Peter M. Rothwell from the University of Oxford as part of a meta-study. However, the better known as aspirin drug also has side effects that are not negligible.

Wonder weapon aspirin for cancer?
It sounds too good to be true: Aspirin by day can not only drive away a headache, it can also prevent cardiovascular disease and cancer, according to a metastatic study. Rothwell and his colleagues analyzed numerous data leading to a new evaluation of the general purpose product. In three studies published in the prestigious trade journals „The Lancet“ and „Lancet Oncology“ The researchers confirm that aspirin appears to reduce cancer risk.

For the study, scientists first analyzed 51 studies in which more than 80,000 subjects participated. The researchers wanted to review the drug's claimed effects on cardiovascular disease. For this purpose, the study participants were randomly assigned to either a group who received aspirin for several years or assigned to the comparison group who took active placebos. Rothwell and his team then re-analyzed the studies to see if aspirin prevented cancer, and if so, when.

The result of the evaluation showed that the risk of dying from cancer was reduced by 40 percent after five years when Aspirin was taken daily. After three years, the groups receiving the drug were found to have 25 percent less cancer. This was true for both men and women.

Statistical context still needs to be verified in reality
As pleasing as the results may seem, it is initially only a static connection. Not much is known about the exact mechanism of action behind it. The practical results are largely based on mouse models in the Petri dish. From this it could be deduced that aspirin primarily responds to two enzymes. Cox-1 and Cox-2 act as a signal to form so-called prostaglandins - hormone-like substances - in the cell. These prostaglandins are extremely important for tumors because they make them grow faster. When the Cox enzymes are inhibited by aspirin, fewer prostaglandins are present for the cancer cells. The result: tumor growth is slowed down. „We are currently testing which people are best protected from cancer by Cox inhibitors and who is most susceptible to side effects such as gastrointestinal bleeding, "explains Prof. Cornelia Ulrich, director of the National Center for Tumor Diseases and scientist at the German Cancer Research Center. „Simply giving it to all aspirin does not make sense. Among other things, our genes determine how great the benefit really is. "

Aspirin has numerous side effects
Even an all-purpose remedy such as aspirin is not without side effects. The list in the leaflet is long: In addition to nausea and vomiting, it can cause heartburn and stomach pain. Likewise, allergic reactions and shortness of breath may occur in asthmatics. Serious side effects such as heavy bleeding are not often the case, because the drug will be taken over a longer period, explain the British scientists. The risk of life-threatening bleeding increases in the first three years, but then decreases again. Nevertheless, Rothwell and his colleagues believe that the benefits of aspirin outweigh the side effects. Cornelia Ulrich disagrees „I would limit it to risk groups.“

The intake of aspirin leads to the liquefaction of the blood, since the coagulation-promoting effect of the platelets is inhibited. This mechanism not only appears to protect against stroke and myocardial infarction, but also contributes to the reduction of cancer risk. The price, however, is an increased bleeding tendency. Especially gastric bleeding can be triggered by aspirin.

Aspirin has been shown to be used successfully in the treatment of colon polyps, which are considered to be a precursor to cancer. Patients who have had colonic polyps at the age of 60 and over may be able to reduce their risk by about half by using aspirin. People with precursors of oesophageal or stomach cancer may also benefit from taking the product.

Metastasis is also limited by aspirin
Rothwell and his colleagues found that aspirin reduced metastasis by 30 to 40 percent, far from the tumor. „This has already been shown in animal studies, and now we see evidence in humans too, "explains Rothwell. „Metastasis via the platelets is likely to play a role in this. "The researchers therefore recommend that doctors stop taking the drug during cancer therapy and consider whether it can be given as a supplement to the treatment.

Critical voices call for further studies
Cornelia Ulrich is less euphoric: „On the other hand, the results of the study may also be somewhat too positive. Perhaps the patients from the trials were more likely to have side effects with the doctor, so on that occasion a cancer was detected and treated early. Another possibility is that aspirin causes tumors and their precursors to bleed more quickly and thus be found better. "However, the expert confirms that inhibitors of the enzyme Cox-2 could soon be used for cancer therapy and that studies are already in progress. „However, aspirin is inconvenient prior to surgery as it increases the likelihood of bleeding.“ Alternative means could then be better suited.

Prof. Bernd Mühlbauer, Chief of Clinical Pharmacology at the Bremen Medical Center and board member of the German Medical Association's Drug Commission, is critical of the study results: „All data on aspirin and cancer comes from studies that are actually investigating cardiac and vascular effects; because the distortion potential is great. A good study looking directly at the impact of aspirin on cancer would be desirable from independent bodies such as the Ministry of Research or the WHO. "(Ag)

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Picture: Rainer Sturm