Antibiotic Use Linked with Breast Cancer Risk

Yahoo! News ^ | Mon Feb 16, 2004 | Reuters

[Aracelis]

NEW YORK (Reuters Health) - The use of antibiotics appears to be associated with an increased risk of breast cancer and fatal breast cancer, according to the results of a new study reported in this week's issue of the Journal of the American Medical Association.

However, the investigators add that although a relationship has been found, their findings do not prove that antibiotic use is the cause of breast cancer in these women and they note that other factors may be involved.

Earlier reports have suggested a link between antibiotics and increased cancer risk, lead author Dr. Christine M. Velicer of the University of Washington, Seattle and colleagues note.

The effects of these drugs on the microorganisms normally found in the intestines and the way estrogen is processed, as well as their effects on the immune system and on inflammation, have been suggested as possible ways antibiotics may influence the development of cancer.

To further investigate a possible relationship, Velicer's group evaluated data collected for 2266 women with primary, invasive breast cancer between 1993 and 2001, and 7953 randomly selected women without breast cancer who were enrolled in the same health plan.

"We found that increasing cumulative days of antibiotic use and increasing cumulative number of antibiotic prescriptions were associated with increased risk of incident breast cancer, after controlling for age and length of enrollment," they report.

When compared with women with no history of antibiotic use, women with cumulative antibiotic use for 1 to 500 days had a 2.5-fold increase risk of breast cancer. "Increasing cumulative days of antibiotic use was also associated with death due to breast cancer, controlling for age, length of enrollment, and ever use of postmenopausal hormones," they write.

The investigators stress, however, that "it cannot be determined from this study whether antibiotic use is causally related to breast cancer, or whether indication for use, overall weakened immune function, or other factors are pertinent underlying exposures."

"This observation is potentially worrisome in that antibiotic exposure is common and sometimes nonessential," Drs. Roberta B. Ness and Jane A. Cauley of the University of Pittsburgh comment in an accompanying editorial. "Thus, if real, the risk of breast cancer attributable to the use of antibiotics could be large and partially preventable."

The study provides more questions than answers, they add.

Both the authors and editorialists agree that the clinical implications of the study are unclear and than more studies are needed to explore the relationship between antibiotic use and cancer risk.

SOURCE: Journal of the American Medical Association, February 18, 2004.

[Aracelis]

Don't panic yet, researchers have not demonstrated a link specifically between antibiotics and breast cancer, only that there seems to be some connection.

[Henrietta]

It's like that Joe Jackson song:

Everything gives you cancer
Everything gives you cancer
There's no cure, there's no answer
Everything gives you cancer

Don't touch that dial
Don't try to smile
Just take this pill
It's in your file

Don't work hard
Don't play hard
Just plan for
The graveyard

Everthing gives you cancer

[TASMANIANRED]

I would be willing to bet that every woman in this study has teeth. Since there is 100% correlation then having teeth must cause breast cancer.

I wonder if this study eliminated other factors that could also be implicated in breast cancer like first pregnancy abortion.

[Aracelis]

I wonder if this study eliminated other factors

The report states the researchers are looking into other factors, including estrogen chemistry and immune system response.

[Sacajaweau]

What about the bovine additives. It is my understanding that the cows developed infections (and I believe they were mammary gland infections). The cows were given tons of antibiotics and there was a "subdued" warning about the possible consequences of milk from these cows.

[sharpee]

My wife died of this disease three years ago. Nothing she did would indicate what could have caused it. I hope that they can find a cause to prevent others from going through what she went through.

[tiki]

It could also mean that people with a lot of infections get breast cancer more often.

[Lizavetta]

I wonder if this study eliminated other factors that could also be implicated in breast cancer like first pregnancy abortion.

There's also a link between high-fat and/or high sugar diets (but not necessarily being overweight), and deficiencies in certain vitamins and minerals. I've also heard that pot use in one's youth is a factor as well.

But since science has been politicized and certain big donors (sugar lobby, beef industry, etc.) would be implicated, the truth will never come from government.

[Maynerd]

I am very sorry to hear about your loss.

It's a very tough disease and physicians don't have a good test for confidently detecting it early. Mammograms are at best marginally helpful.

[Aracelis]

I'm terribly sorry you and your wife had to suffer through this disease...

[NotJustAnotherPrettyFace]

I really wish this article would have stated the class of antibiotics used in this study. There is the -cillin family such as penicillin/ampicillin, there are the -mycin family such as erethromycin, there is bactrim, there is cipro.....

[Aracelis]

I imagine we will find out in short order.

[FITZ]

I think people do have to wonder whatever they consume will likely have some effect on the cells in their body. Antibiotics circulate and whatever they do to bacteria, they are likely doing something to normal cells.

[NotJustAnotherPrettyFace]

OK, I was curious enough to go to the AMA website and try to find the article published in JAMA. It was found here (.pdf format): Antibiotic Use in Relation to the Risk of Breast Cancer

The study involved women using tetracyclines and macrolides (I had to read all the way to page 4 [out of 9 pages] to find that out ;-). I found out here that Macrolides represented almost 20 percent of antibiotic sales in 2000 and are expected to retain this share over time.

Examples of macrolides and lincosamines:
Generic name/Trade name
Azithromycin* Zithromax®
Clarithromycin* Biaxin®
Clindamycin Cleocin®
Dirithromycin Dynabac®
Erythromycin E-mycin®, Ery-tab®, Benzamycin®
Lincomycin Lincocin®
Troleandomycin Tao®

[Yaelle]

Interesting. Back when I was about 12, I got put on tetracyclines for face breakouts! It was a daily dosage! And what about all those antibiotics they make you take for prevention, such as when you go into the hospital for a birth or a surgery, and they want to try and prevent infection before one starts?

[Aracelis]

Hmmm...macrolides inhibit protein synthesis.

[Sandy]

People who tend to get sick tend to get sick. Amazing.

[heylady]

I usually use the analogy that most women have worn blue jeans so blue jeans must cause breast cancer.

These studies are amusing. I had no family history, didn't drink, smoke, use antibiotics or have an abortion. I had children early in life and breast fed all 4 of them and yet I still got breast cancer.