SynthesisBritish journal of anaesthesia2025
Effects of opioids on tumour growth and metastasis in animal models: a systematic review.
Synthesis in British journal of anaesthesia, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 4 papers, 1 of them a synthesis that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
4 citing papers in PubMed, 1 synthesis or guideline pooled it.
- Opioid use and the risk of cancer incidence and mortality: a systematic review.Cancer metastasis reviews · 2025Pooled it
- Crosstalk Between Opioids and the Anti-Tumour Immune Checkpoint Axis.Current oncology (Toronto, Ont.) · 2026Review
- Effects of Extended-Release Liposomal Bupivacaine on Postoperative Mechanical and Thermal Hypersensitivity in C57BL/6 Mice (Mus musculus).Journal of the American Association for Laboratory Animal Science : JAALAS · 2026Article
- Regular use of pharmaceutical opioids and subsequent risk of cancer: a prospective cohort study and Mendelian randomization analysis.EClinicalMedicine · 2025Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
5 authors.
Funding
Abstract
backgroundThe International Agency for Cancer Research monographs recently classified opium consumption as carcinogenic to humans, with sufficient evidence for carcinogenicity in the larynx, lung, and urinary bladder and limited evidence in the oesophagus, pancreas, stomach, and pharynx. This causes concerns of a potential cancer-promoting effect in the same organs associated with the use of pharmaceutical opioids.
methodsWe performed a systematic review (registered in the Open Science Framework: osf.io/xyg9p) of the published in vivo preclinical literature to determine whether the effects of opioids on tumour growth and metastasis are organ specific. We investigated whether the opioid category (agonist, antagonist, or peptide), organ of origin of the cancer cells, site of tumour measurement, immune status of rodents, opioid dose, or duration of opioid exposure was associated with reported cancer outcomes.
resultsA total of 118 studies, representing 168 experiments, were included. Most animal experiments (94/168, 56%) reported an anti-cancer effect of opioids and 31 (18%) reported a pro-cancer effect. Of the assessed parameters, opioid category (P<0.001) and opioid dose (P=0.0056) were the only factors significantly associated with the reported cancer outcome. In studies testing morphine, experiments showing a cancer-promoting effect predominantly administered low doses of morphine (the proportion of studies using low-dose morphine was 65% among those reporting pro-cancer outcomes vs 8% among those reporting anti-cancer outcomes).
conclusionsWe found no relationship indicative of an organ-specific, cancer-promoting effect of opioids.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.