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Antibiotics & Cancer: No Connection or Biased Research?

When a study showed that antibiotics are associated with breast cancer, the authors did another study that appears to be an attempt to disprove their earlier results. Other studies that claim to find no association are deeply flawed. Clearly, the goals are not to find the truth or improve health. Evidence based medicine is based on intentionally flawed science.


by Heidi Stevenson

Back in 2004, a study reported in the Journal of the American Medical Association (JAMA) documented a direct relationship between breast cancer and antibiotic use.[1] After a brief flurry, the study quietly faded from the public’s—and modern medicine’s—consciousness.

This was their conclusion:

In summary, we found that increased use of antibiotics was associated with increased risk of incident and fatal breast cancer for a variety of antibiotic classes.

What makes this newsworthy is that the study has not been legitimately contradicted. In nine years, a study that demonstrates a deadly risk from one of modern medicine’s most vaunted methods is virtually ignored.

Researchers whose results go against the prevailing medical beliefs of the time—that is, they demonstrate harm from one of Big Pharma’s products or a popular, that is, money-making, procedure—tend to find that their careers go nowhere. Therefore, the authors of the study must have recognized that their careers were at risk if they let the study stand. So a year later three of them, along with two others, produced another. They used some tortured language to disguise the truth of their first study. Here’s the first sentence of their results:

Compared to non-use, antibiotic use prior to breast cancer diagnosis was not associated with a less favourable tumour profile (as measured by cancer stage, grade, and size), oestrogen receptor negative tumours, or associated with less favourable breast tumour features.[2]

Huh? Whether antibiotic use is related to “a less favourable tumour profile” has little to do with whether their use is associated with more tumors.

Their conclusion states:

Overall, we found no association between antibiotic use and breast tumour features and no dose-response gradient. However, the results are consistent with the possibility that antibiotic use may increase the risk of less favourable tumours.[2]

Dose-response gradient refers to the degree of harm or benefit of a drug in relation to how much of the drug is applied. There is no reason to presume that there is any such relationship between type or severity of a cancer and antibiotic use. It’s interesting if there is such a connection, but a lack of connection tells us nothing about whether antibiotics cause breast cancer.

Other Studies

The paucity of other studies on the topic is telling, and those that exist are deeply flawed. Cancer Research UK looked into the issue and found more recent studies that show a “slight” increase in breast cancer risk resulting from antibiotic use.[3] the implication is that a “slight” increase is not of much concern. But a slight increase of, say, one-half of one percent could amount to thousands of cases a year!

Cancer Research UK suggests that, “Antibiotics prescribed by doctors to treat bacterial infections are still very safe and effective.” That seems a rather odd statement, because it manages to completely evade the topic, whether antibiotics cause breast cancer.[3]

One study, titled “Use of Antibiotics and Risk of Breast Cancer”, claims no association.[4] However, one set of their results documented that antibiotics used to treat skin disorders were associated 1.4 times more breast cancer development. If those cases had been extrapolated so that the numbers would be equivalent to the other three types of antibiotic treatment, the results of the study would have been dramatically different, and would clearly have shown a strong association between antibiotic use and breast cancer. Nonetheless, they concluded:

In summary, we did not find convincing evidence of an increased risk of breast cancer among women exposed frequently to antibiotics.

It should come as no surprise that the study was funded entirely by the pharmaceutical firm AstraZeneca.

Another study, titled “Risk of breast cancer in relation to antibiotic use”, concluded:

We observed a dose-dependent increase in breast cancer risk in association with the antibiotic exposure up to 15 years in the past. However, the lack of temporal trends and the absence of class-specific effects suggest a non-causal relationship.[5]

So, they most assuredly did find an association between antibiotics and breast cancer, but then they found reasons to discount their findings.

Clearly, the goals of these studies were not to find the truth about antibiotics and their connection to the development of breast cancer. Their goal was simple: to whitewash the truth.


What this reveals about the goals and intentions of allopathic procedures, techniques, and drugs is, at best, disheartening. One would have thought that doctors would be particularly concerned that a primary tool in treating patients is clearly associated with a mortal disease. Yet, there’s no outcry. There’s been no related change in methods. Doctors reach for the prescription pads and push antibiotics on patients for the most flimsy of reasons every single day. And they virtually never tell their patient-victims that there may be an increased cancer risk.

Evidence-Based Medicine

This is so-called evidence-based medicine (EBM) in action. EBM is a con. As is obvious from the tortured language and twisted logic used by the authors of the initial study showing a connection between antibiotics and breast cancer used in an attempt to negate their earlier, inconvenient finding, their second study has little meaning in terms of what’s best for patients.

EBM is nothing more than a game played to give the impression that the drugs, techniques, and devices used by medicine are based on sound evidence.

Rather than honestly look at the study showing a connection between antibiotic use and breast cancer, the immediate response was an attempt to negate the results with an irrelevant study. The power of the modern medical world is so great that the authors who discovered the connection tried to show that their results were mistaken. If their goal had been to protect the public, they should have tried to find connections between antibiotics and other cancers. Instead, they abandoned their promising research.

There’s an obvious explanation for why antibiotics may be linked to breast cancer—and probably to most others*. Antibiotics attack all bacteria, not just targeted ones causing problems. They kill gut bacteria, which have evolved with us in a symbiotic relationship on which we’re absolutely dependent—and so are we. Gut bacteria are, in fact, one of the body’s most important lines of defense against illness. When we take antibiotics, we’re harming our autoimmune system. It would be surprising if there weren’t a connection between cancer and antibiotics.

Modern allopathic medicine’s proclivity for treating the body as disparate and unrelated parts is shown by the antibiotic-cancer connection to be deeply flawed. So-called evidence-based medicine plays well in this paradigm. Rather than looking at patients’ ourcomes as whole human beings, EBM is allowed to look at bits and pieces, making assumptions that an outcome in one area can be defined as good for health without considering the rest of the person. Nothing could be further from the truth.

While there may be a place for it, the fact is that the basic nature of allopathic medicine is harmful, that it must do more harm than good. Evidence-based medicine is a sham, a means of putting up a smoke-screen to hide the harm done and to give an impression of benefit that, all too often, does not exist.

*Please note that this is merely one possible method by which antibiotics can be linked to cancer. There could well be others.


  1. Antibiotic Use in Relation to the Risk of Breast CancerJAMA; Christine M. Velicer, Susan R. Heckbert, Johanna W. Lampe, John D. Potter, Carol A. Robertson, Stephen H. Taplin.
  2. Association between antibiotic use prior to breast cancer diagnosis and breast tumour characteristics (UnitedStates)Cancer Causes & Control; Christine M. Velicer, Susan R. Heckbert, Carolyn Rutter, Johanna W. Lampe, Kathi Malone; doi: 10.1007/s10552-005-0445-9.
  3. Antibiotics and Breast Cancer; Cancer Research UK.
  4. Use of Antibiotics and Risk of Breast CancerAmerican Journal of Epidemiology; L. A. García Rodríguez and A. González-Pérez; doi: 10.1093/aje/kwi087.
  5. Risk of breast cancer in relation to antibiotic usePharmacoepidemiology and Drug Safety. Tamim HM, Hanley JA, Hajeer AH, Boivin JF, Collet JP; PMID: 17943999.

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