Scoping Review and Meta-Analysis Suggests that Cannabis Use May Reduce Cancer Risk in the United States.
Clark et al.·Cannabis and cannabinoid researchImpact 2.5
GemischtGRADEModerat10 Zitate
Stichprobek = 34 Studien n = 24 Pat.
Dauerunklar
KontrolleKein Cannabis-Konsum
EndpunktRelatives Krebsrisiko
Verblindungunklar
DesignMeta-Analyse
”Kernaussage
Nicht-signifikanter Trend zu reduziertem Krebsrisiko insgesamt (RR=0,90, p>0,06); nach Ausschluss von Selektions- und Performance-Bias signifikant reduziertes Risiko (RR=0,86, p<0,017); Kopf-Hals-Karzinome zeigten signifikante Risikoreduktion (RR=0,83), aber hohe Heterogenität und niedrige Konfidenz in den Ergebnissen.
Zusammenfassung
Scoping Review mit Meta-Analyse zu Cannabis-Gebrauch und Krebs-Risiko in den USA; k=34 Studien (50 Datenpunkte mit Risiko-Ratios). Gesamt-RR=0,90 (p>0,06, nicht signifikant, hohe Heterogenität I²=72,4%). Nach Entfernung von Studien mit hohem Selektions-/Performance-Bias: RR=0,86 (p<0,017, Hedges g=0,66; N=24 Datenpunkte), aber weiterhin hohe Heterogenität (I²=74,9%). Hodentumor: einziger Krebs-Typ mit RR>1 (RR=1,12, p=0,3, nicht signifikant). Kopf-Hals-Karzinome: negative Assoziation (RR=0,83, p<0,05, Hedges g=0,55). Daten konsistent mit negativer Assoziation zwischen Cannabis-Gebrauch und nicht-testikulären Krebsarten, aber niedrige Konfidenz wegen hoher Heterogenität.
P
PopulationErwachsene in den USA mit verschiedenen Krebserkrankungen – gepoolte Daten aus 34 Studien, N=50 auswertbare Datenpunkte
I
InterventionCannabis-Konsum (verschiedene Formen)
C
KontrolleKein Cannabis-Konsum
O
OutcomeNicht-signifikanter Trend zur Risikoreduktion im Gesamtpool (RR=0,90, p>0,06); nach Bias-Bereinigung signifikante Risikoreduktion (RR=0,86, p<0,017); Kopf-Hals-Tumoren: RR=0,83, p<0,05; Hodentumoren: RR=1,12 (n.s.)
Vertrauen in die Evidenz
Sehr niedrigNiedrigModeratHoch
Moderat
Dritte von vier GRADE-Stufen, die Effektschätzung ist wahrscheinlich verlässlich.
Introduction:Cannabis smoke contains carcinogens similar to tobacco, in addition to compounds with antitumor activity. Cannabis use reduces the risk of obesity and cannabinoids inhibit chronic inflammation, known causes of cancer. The net effect of Cannabis use on cancer risk is not known. Objective: To examine the association between Cannabis use and cancer risk in the United States. Methods: Identify and analyze published data on cancer risk in Cannabis users. Results: A total of 55 data points, consisting of risk ratios of cancer in Cannabis users and nonusers, were identified from 34 studies. Of these, 5 did not contain data essential for inclusion in the meta-analysis. The remaining data showed a nonsignificant trend to an association with reduced risk (relative risk [RR]=0.90, p>0.06, N=50) although heterogeneity is high (I(2)=72.4%). Removal of data with high risk of selection bias (defined as those from North Africa and those that failed to adjust for tobacco) and data with high risk of performance bias (defined as those with fewer than 20 cases or controls among Cannabis users) resulted in an RR <1.0 (RR=0.86, p<0.017, N=24) and large effect size (Hedges g=0.66), but did not decrease heterogeneity (I(2)=74.9). Of all cancer sites, only testicular cancer showed an RR value >1, although this was not significant and had a negligible effect size (RR=1.12, p=0.3, Hedges g=0.02). Following removal of testicular cancers the remaining data showed a decrease in risk (RR=0.87, p<0.025, N=41). Cancers of the head and neck showed a negative association with cancer risk (RR=0.83, p<0.05), with a large effect size (Hedges g=0.55), but high heterogeneity (I(2)=79.2%). RR did not reach statistical significance in the remaining cancer site categories (lung, testicular, obesity-associated, other). The data are consistent with a negative association between Cannabis use and nontesticular cancer, but there is low confidence in this result due to high heterogeneity and a paucity of data for many cancer types.