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e-Poster Display Session

435P - Hypnotics and risk of cancer: A meta-analysis of observational studies


22 Nov 2020


e-Poster Display Session


Cancer Prevention

Tumour Site


Tzu Rong Peng


Annals of Oncology (2020) 31 (suppl_6): S1407-S1415. 10.1016/annonc/annonc368


T.R. Peng

Author affiliations

  • Pharmacy, Taipei Buddhist Tzu Chi General Hospital, 23142 - New Taipei City/TW


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Abstract 435P


The association between hypnotic drugs and risk of cancer remains controversial. Therefore, we performed a meta-analysis to investigate this association.


Pubmed and Embase were searched systematically were searched to identify publications up to May 2020. The Newcastle-Ottawa scale for observational studies was used to assess the quality of studies. All included studies were evaluated by two reviewers independently; any discrepancies were resolved through discussion.


A total of 28 observational epidemiological studies including 22 case-control studies and 6 cohort studies with 340,614 hypnotics users and 1,828,057 non-users were included in the final analyses. Hypnotics (benzodiazepines and Z-drugs) use was significantly associated with an increased risk of cancer (odds ratio [OR] or relative risk [RR] 1.17; 95% confidence interval 1.09–1.26) in a random-effects meta-analysis of all studies. Subgroup meta-analyses by various factors such as study design, type of case-control study, study region, and methodological quality of study showed consistent findings. Also, a significant dose-response relationship was observed between the use of hypnotics and the risk of cancer.


This meta-analysis revealed association between use of hypnotics drugs and risk of cancer. However, a high heterogeneity was observed among identified studies and results were inconsistent in some subgroups. Randomized control trials are needed to confirm the results in future.

Clinical trial identification

Editorial acknowledgement

This study was supported by grants from the Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation (TCRD-TPE-109-18).

Legal entity responsible for the study

The author.


Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation.


The author has declared no conflicts of interest.

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