Meta-analysisindependent cross-checkabstract checked★ key study I-CAN-119 in-depth review

Weakened immunity raises cancer risk

Incidence of cancers in people with HIV/AIDS compared with immunosuppressed transplant recipients: a meta-analysis.

Overview

Grulich AE et al.. Lancet 2007 · PMID 17617273 · DOI 10.1016/S0140-6736(07)61050-2

People with HIV/AIDS or on transplant drugs had higher rates of 20 of 28 cancer types.

Does the study support the specific claim? No · Methodological quality: high

Study explained simply

What did the researchers want to find out?: Compare cancer in two immune-deficient groups.
How was the study done?: Meta-analysis of cohorts.
How many people, animals or samples were studied?: ~476,000 people.
What was actually found?: Many cancers more frequent.
How large was the observed effect?: e.g. Hodgkin SIR 11.03.
What do the results mean in everyday life?: The immune system helps keep cancer in check.
What are the study's limitations?: Mainly infection-related cancers.
What does it say about Elawady's specific claim?: Contradicts the claim.
Do the results apply to Germany and Europe?: High.
What can explicitly not be concluded from this study?: Immune control of every cancer type.

Do people with HIV/AIDS and immunosuppressed transplant recipients have similar patterns of increased cancer incidence?

Study design: Meta-analysis – Meta-analysis of population-based cohort studies
Population: People with HIV/AIDS (n=444,172) and solid-organ transplant recipients (n=31,977)
Country: International
Period: Published 2007
Sample size: 7 HIV/AIDS and 5 transplant cohorts
Inclusion and exclusion criteria: Population-based cohort studies

Results: 20 of 28 cancer types significantly increased in both groups, mostly cancers with an infectious cause; e.g. Hodgkin lymphoma SIR 11.03 (8.43-14.4) HIV and 3.89 (2.42-6.26) transplant; liver cancer 5.22 and 2.13; stomach cancer 1.90 and 2.04. Most common epithelial cancers not increased.
Absolute risks: not reported
Authors' conclusion: Similar patterns suggest immune deficiency, rather than other risk factors, is responsible for the increased risk.

SIR CIs log-symmetric (recalculated).

Shows that the immune system does control many cancers (especially virus-driven ones): when immunity falls, these cancers rise.

Most common epithelial cancers were not increased, so immune control is cancer-type specific.

High.

Strong human evidence for immune control of cancer, contradicting 'the immune system does not fight cancer'.

Multidimensional assessment
Multidimensional assessment
Authenticity of the source	verified
Methodological quality	high
Risk of bias	some concerns
Precision of results	moderate
Directness	indirect
Reproducibility	replicated
Consistency with the overall evidence	consistent
Regional transferability	high
Adequacy of the interpretation (by the archive)	not applicable