Is Long-term Use of Benzodiazepines a Risk for Cancer?

[Felonious Monk]

A large study of the population in Taiwan reveals that long-term use of benzodiazepine drugs, commonly prescribed for anxiety, significantly increases the risk for brain, colorectal, and lung cancers. The research, published open-access in the journal Medicine, also identifies the types of benzodiazepines that carry the greatest cancer risk.

Benzodiazepines are a group of central nervous system depressants that are commonly prescribed in the general population. Public health research reveals that approximately six to ten percent of US adults were prescribed a benzodiazepine in 2010 and that, in some countries, as many as forty-two percent of the elderly use these drugs.

Clonazepam, brand name Klonopin, was found to carry the greatest cancer risk.
Clonazepam, brand name Klonopin, was found to carry the greatest cancer risk.

There has been debate in the research over the risk for cancer posed by the long term use of benzodiazepines. Animal studies have reported a relationship between the use of these drugs and thyroid cancer, breast cancer, and liver cancer. While the relationship is not yet definitive, some researchers point out that the risk may be unnecessary as “there is no persuasive evidence for benefits from long term use.”

In this study, researchers use the Taiwanese National Health Insurance system to gather information about benzodiazepine use and cancer risk. They found that certain benzodiazepines carried a greater risk than others.

Namely, clonazepam (Klonopin), lorazepam (Ativan), alparazolam (Xanax), bromazepam (Lexotan), zolpidem (Ambien), and zopiclone (Lunesta) were found to have a high risk for cancer while chlordiazepoxide (Librium), diazepam (Valium), medazepam (Azepamid), oxazepam (Serax), and nitrazepam (Mogadon) did not have a significant association with cancer.

Clonazepam (Klonopin) was found to be the most dangerous, carrying a fifteen percent higher risk for cancer than all other benzodiazepine drugs.

The research also revealed that benzodiazepines exposure increased the overall cancer risk up to 21%, specifically for brain 98%, colorectal 25%, lung 10%, esophagus 59%, prostate 36%, bladder 39%, liver 18%, pancreas 41% and other cancers 27%.

This article is published open-access and can be read in full here →
http://journals.lww.com/md-journal/...k_for.7.aspx?WT.mc_id=EMxALLx20100222xxFRIEND


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Iqbal, Usman, Phung-Anh Nguyen, Shabbir Syed-Abdul, Hsuan-Chia Yang, Chih-Wei Huang, Wen-Shan Jian, Min-Huei Hsu, Yun Yen, and Yu-Chuan Jack Li. "Is long-term use of benzodiazepine a risk for cancer?." Medicine94, no. 6 (2015).

--Justin Karter, News Editor

http://www.madinamerica.com/2016/03/is-long-term-use-of-benzodiazepine-a-risk-for-cancer/

 

[Crankinit]

Good thing my doctor refuses to write me anything other than valium :/

 

[neversickanymore]

I would not be surprised in the slightest to see chronic benzo use be clearly associated with autoimmune diseases, chronic neurological pain, and possibly chronic fatigue.


Do we think the actual benzo chemicals are causing the increased risk for cancer or is that we are circumventing a more complex system and in doing so we are ending up with this?

 

[sigmond]

I remember reading about possible links to dementia and stomach cancer but cannot find anything at the moment. Came across this;

We did not find an association between long term use of BZRD and risk of cancer, except for what is likely explained by residual confounding.
Our results differ from the cohort study by Kripke et al. who reported an overall hazard ratio of 1.35 for cancer when comparing users and non-users of hypnotics [13].

Kripke et al. were able to account for some lifestyle factors that were not covered by our data sources. However, their study was seriously hampered by some infelicitous choices in the design [35], in particular that the authors defined non-users of hypnotics as individuals with no hypnotic prescriptions throughout the entire follow-up period.

We mimicked this bias in our case–control study by excluding unexposed cases or controls who redeemed BZRD prescriptions after the index date, which produced exactly the same risk estimate as in the study by Kripkeet al. [13].

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3635606/

Nitrazepam

Benzodiazepine use for more than one to six months at prescribed doses is associated with an increased risk of the development of ovarian cancer.^[76] Fifteen epidemiologic studies have shown hypnotic drug use is associated with increased mortality, mainly due to increased cancer deaths in humans.

The cancers included cancers of the brain, lung, bowel, breast, and bladder, and other neoplasms. Not only are benzodiazepines associated with an increased risk of cancer, but the benzodiazepine receptor agonist Z-drugs also are associated with cancer in humans in these studies.

Initially, FDA reviewers did not want to approve the Z-drugs due to concerns of cancer, but ultimately changed their minds and approved the drugs despite the concerns. The data show the trial subjects receiving hypnotic drugs had an increased risk of developing cancer.

The review author concluded, "the likelihood of cancer causation is sufficiently strong now that physicians and patients should be warned that hypnotics possibly place patients at higher risk for cancer."^[77]

(more links contained in quotes)

 

[SixBuckets]

[FONT=Arial, Verdana, Tahoma, sans-serif]We also observed that benzodiazepines exposure increased the overall cancer risk up to 21%, specifically for brain 98%, colorectal 25%, lung 10%, esophagus 59%, prostate 36%, bladder 39%, liver 18%, pancreas 41% and other cancers 27%.

[/FONT]

[FONT=Arial, Verdana, Tahoma, sans-serif]I don't think this is phrased very well - It sounds like the percentages given are the relative risk of those cancers if you take benzodiazepines, but I think the authors meant to convey the effect on the baseline absolute risk (so the percentage is the amount of change the benzodiazepines had on your odds of developing cancer). This is actually much less dramatic than those numbers make it sound. For example, the absolute risk of brain cancer is only about 0.5 per 10,000 and things that are generally considered acceptably safe like CT scans increase relative risk by 200%, so a 98% increase in brain cancer risk from taking benzodiazepines is actually not that huge.[/FONT]