Meta-analysiscited by the Tayebat archiveabstract only checked★ key study A-CHM-10 standard review
Chemotherapy-related thinking problems are small on average
Meta-analysis of cognitive functioning in breast cancer survivors previously treated with standard-dose chemotherapy.
Overview
Jim HS et al.. J Clin Oncol 2012 · PMID 22927526 · DOI 10.1200/JCO.2011.39.5640
Breast-cancer survivors performed slightly worse in two of eight areas of thinking.
Does the study support the specific claim? Partly · Methodological quality: moderate
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Pool studies on cognition after chemo.
- How was the study done?
Meta-analysis.
- How many people, animals or samples were studied?
17 studies, 807 patients.
- What was actually found?
Small deficits in verbal and visuospatial ability.
- How large was the observed effect?
g -0.19 and -0.27.
- What do the results mean in everyday life?
Most survivors are only mildly affected, some more.
- What are the study's limitations?
Heterogeneous studies.
- What does it say about Elawady's specific claim?
Limits 'persistent decline'.
- Do the results apply to Germany and Europe?
High.
- What can explicitly not be concluded from this study?
Individual risk.
Scientific in-depth review
1. Full reference
- Authors
- Jim HS, Phillips KM, Chait S, Faul LA, Popa MA, Lee YH, Hussin MG, Jacobsen PB, Small BJ
- Journal
- J Clin Oncol
- Year
- 2012
- Identifier
- PMID 22927526 DOI 10.1200/JCO.2011.39.5640 · PMC3462044
- Verification
- verified (PMID in archive was wrong, corrected) – PubMed E-utilities efetch, 2026-10-25
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
Authors' disclosures of potential conflicts of interest and author contributions are found at the end of this article. | Grants: NCI NIH HHS
2. Research question
Cognitive functioning >=6 months after standard-dose chemotherapy for breast cancer.
3. Study design and population
- Study design
- Meta-analysis – Systematic review and meta-analysis
- Population
Breast cancer survivors
- Country
Multinational (studies pooled)
- Period
Literature to search date (not stated in abstract)
- Sample size
17 studies, 807 patients
- Inclusion and exclusion criteria
Studies of chemotherapy-treated breast cancer patients >=6 months post-treatment
4. Methods and endpoints
- Exposure / intervention
Standard-dose chemotherapy
- Comparator
Non-cancer controls, no-chemo patients, or pre-chemo baseline
- Endpoints
Eight cognitive domains
- Statistical methods
Hedges g random effects
5. Actual results
- Results
Deficits only in verbal ability (g=-0.19; P<.01) and visuospatial ability (g=-0.27; P<.01). Age, education, time since treatment and endocrine therapy did not moderate effects.
- Absolute risks
not applicable (standardised mean differences)
- Authors' conclusion
On average, deficits are small in magnitude and limited to verbal and visuospatial ability.
6. Strengths
- Systematic search with paired raters
- Multiple comparison types
7. Weaknesses
- Heterogeneous designs
- Small total sample
8. Risk of bias
- Orienting tool
- AMSTAR 2
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
- Rationale
Search and dual screening reported; risk-of-bias assessment of primary studies not described in abstract.
9. Assessment of the statistical interpretation
Effect sizes g -0.19 and -0.27 are small by convention.
10. Relevance to the specific claim
Quantifies chemo-related cognitive effects as small on average.
11. Independent contrary findings
Itself limits the magnitude.
12. Transferability to Germany and Europe
High.
13. Overall methodological judgement
Best evidence in the archive's list on chemo-brain; supports existence but limits magnitude.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified (PMID in archive was wrong, corrected) |
| Methodological quality | moderate |
| Risk of bias | some concerns |
| Precision of results | moderate |
| Directness | direct |
| Reproducibility | partly replicated |
| Consistency with the overall evidence | mixed |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | essentially correct but incomplete |
14. Open questions
Subgroups at higher risk.
15. Linked fact checks
- Chemotherapy causes persistent cognitive decline ('chemo fog'). – Studies with mixed or unclear results
Use by the Tayebat archive
Note: according to the archive, the studies were compiled by the archive operators. Whether Dr. Elawady himself cited this study is not established.
- What the archive says about the study
'Chemo fog' confirmed by Ahles and Jim's meta-analysis (persistent cognitive decline).
- A. What was actually studied?
Pooled cognitive outcomes.
- B. What did the authors find?
Small deficits in two domains.
- C. What conclusions do the authors themselves draw?
Deficits are small and limited.
- D. What does the archive derive from it?
Confirms chemo fog.
- E. Is this derivation scientifically justified?
Partly: it confirms a measurable effect, but the authors stress it is small and limited; 'persistent cognitive decline' overstates the average finding.
- Adequacy of the interpretation (by the archive)
- essentially correct but incomplete