Titre : | Association between marijuana use and risk of cancer: A systematic review and meta-analysis (2019) |
Auteurs : | M. GHASEMIESFE ; B. BARROW ; S. LEONARD ; S. KEYHANI ; D. KORENSTEIN |
Type de document : | Article : Périodique |
Dans : | JAMA Network Open (Vol.2, n°11, November 2019) |
Article en page(s) : | e1916318 ; 15 p. |
Langues: | Anglais |
Discipline : | PAT (Pathologie organique / Organic pathology) |
Mots-clés : |
Thésaurus mots-clés CANNABIS ; FACTEUR DE RISQUE ; CANCER ; USAGE REGULIER ; PATHOLOGIE ORGANIQUE ; EPIDEMIOLOGIE ; MORBIDITE |
Résumé : |
Importance: Marijuana use is common and growing in the United States amid a trend toward legalization. Exposure to tobacco smoke is a well-described preventable cause of many cancers; the association of marijuana use with the development of cancer is not clear.
Objective: To assess the association of marijuana use with cancer development. Data Sources: A search of PubMed, Embase, PsycINFO, MEDLINE, and the Cochrane Library was conducted on June 11, 2018, and updated on April 30, 2019. A systematic review and meta-analysis of studies published from January 1, 1973, to April 30, 2019, and references of included studies were performed, with data analyzed from January 2 through October 4, 2019. Study Selection: English-language studies involving adult marijuana users and reporting cancer development. The search strategy contained the following 2 concepts linked together with the AND operator: marijuana OR marihuana OR tetrahydrocannabinol OR cannabinoid OR cannabis; AND cancer OR malignancy OR carcinoma OR tumor OR neoplasm. Data Extraction and Synthesis: Two reviewers independently reviewed titles, abstracts, and full-text articles; 3 reviewers independently assessed study characteristics and graded evidence strength by consensus. Main Outcomes and Measures: Rates of cancer in marijuana users, with ever use defined as at least 1 joint-year exposure (equivalent to 1 joint per day for 1 year), compared with nonusers. Meta-analysis was conducted if there were at least 2 studies of the same design addressing the same cancer without high risk of bias when heterogeneity was low to moderate for the following 4 cancers: lung, head and neck squamous cell carcinoma, oral squamous cell carcinoma, and testicular germ cell tumor (TGCT), with comparisons expressed as odds ratios (ORs) with 95% CIs. Results: Twenty-five English-language studies (19 case-control, 5 cohort, and 1 cross-sectional) were included; few studies (n = 2) were at low risk of bias. In pooled analysis of case-control studies, ever use of marijuana was not associated with head and neck squamous cell carcinoma or oral cancer. In pooled analysis of 3 case-control studies, more than 10 years of marijuana use (joint-years not reported) was associated with TGCT (OR, 1.36; 95% CI, 1.03-1.81; P = .03; I² = 0%) and nonseminoma TGCT (OR, 1.85; 95% CI, 1.10-3.11; P = .04; I² = 0%). Evaluations of ever use generally found no association with cancers, but exposure levels were low and poorly defined. Findings for lung cancer were mixed, confounded by few marijuana-only smokers, poor exposure assessment, and inadequate adjustment; meta-analysis was not performed for several outcomes. Conclusions and Relevance: Low-strength evidence suggests that smoking marijuana is associated with developing TGCT; its association with other cancers and the consequences of higher levels of use are unclear. Long-term studies in marijuana-only smokers would improve understanding of marijuana's association with lung, oral, and other cancers. Key points: Question: What is the association between marijuana use and cancer development in adults with at least 1 joint-year exposure (equivalent to 1 joint per day for 1 year)? Findings: This systematic review and meta-analysis identified 25 English-language studies assessing marijuana use and the risk for developing lung, head and neck, urogenital, and other cancers. In meta-analyses, regular marijuana use was associated with development of testicular germ cell tumors, although the strength of evidence was low; evidence regarding other cancers was insufficient. Meaning: Sustained marijuana use may increase the risk for testicular cancer, but overall, the association of marijuana use and cancer development remains unclear. |
Domaine : | Drogues illicites / Illicit drugs |
Sous-type de document : | Méta-analyse / Meta-analysis ; Revue de la littérature / Literature review |
Refs biblio. : | 71 |
Affiliation : | Northern California Institute of Research and Education, San Francisco, CA, USA |
Lien : | https://doi.org/10.1001/jamanetworkopen.2019.16318 |
Accueil