title: [Colorectal cancer prevention by flavonoids].
abstract: BACKGROUND
  Valid, sustained and safe clinical means of colorectal cancer prevention are still lacking, but they are urgently needed to lower the incidence of colorectal cancer. Dietary factors and phytochemicals such as flavonoids play an important role for prevention.
  
  
  METHODS
  A selective search of the literature using PubMed was performed with the following key words: flavonoids, cancer, therapy, colorectal cancer focused on clinical queries. Results of clinical studies including the authors' own were compared.
  
  
  RESULTS
  In vivo and in vitro studies with animals, cell cultures and subcellular components provide ample evidence for antimutagenic and anticarcinogenic effects of flavonoids as shown for multiple biological and molecular endpoints. Isoflavonoids in vitro have been shown to induce proliferation of breast cancer cells. Epidemiologic trials (cohort, case-control and cross-sectional studies) yielded inconsistent results for flavonoid protection. Systematic reviews and meta-analyses support the protective role of tea flavonoids on adenoma incidence. An interventional pilot study with sustained flavonoid supplementation was shown to reduce the rate of neoplasia in patients with resected colorectal cancer.
  
  
  CONCLUSIONS
  Selected flavonoids possess antimutagenic and anticarcinogenic properties and could reduce the incidence of colorectal neoplasias as shown in epidemiologic trials. Randomized controlled clinical studies with flavonoid intervention are necessary to provide evidence for their role in colorectal cancer prevention.
authors.affiliation: Privat-Praxis Innere Medizin und Gastroenterologie, Marienhospital Darmstadt, Darmstadt, Germany. h.p.hoensch@t-online.de
authors.forename: Harald
authors.initials: H
authors.lastname: Hoensch
authors.forename: Elke
authors.initials: E
authors.lastname: Richling
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Kruis
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Kirch
mesh_terms: D000236:Adenoma / Q000517:prevention & control* / Q000601:surgery; D000818:Animals; D016588:Anticarcinogenic Agents / Q000008:administration & dosage*; D016587:Antimutagenic Agents / Q000008:administration & dosage*; D015179:Colorectal Neoplasms / Q000517:prevention & control* / Q000601:surgery; D005419:Flavonoids / Q000008:administration & dosage*; D006801:Humans; D009364:Neoplasm Recurrence, Local / Q000517:prevention & control; D014407:Tumor Cells, Cultured / Q000187:drug effects
chemical_list: D016588:Anticarcinogenic Agents; D016587:Antimutagenic Agents; D005419:Flavonoids
references.citation: Am J Clin Nutr. 2009 Mar;89(3):905-12
references.pmid: 19158208
references.citation: Free Radic Biol Med. 2004 Aug 1;37(3):287-303
references.pmid: 15223063
references.citation: Aliment Pharmacol Ther. 2004 Mar 1;19(5):497-510
references.pmid: 14987318
references.citation: Cancer Epidemiol Biomarkers Prev. 2010 Jan;19(1):148-58
references.pmid: 20056634
references.citation: Gastroenterology. 2008 Apr;134(4):1224-37
references.pmid: 18395100
references.citation: Int J Gastrointest Cancer. 2005;35(3):187-95
references.pmid: 16110120
references.citation: Int J Cancer. 2009 Dec 15;125(12):2945-52
references.pmid: 19530252
references.citation: Nat Rev Cancer. 2009 Jun;9(6):429-39
references.pmid: 19472429
references.citation: Drug Dev Res. 2008 Nov 1;69(7):460-471
references.pmid: 19884979
references.citation: World J Gastroenterol. 2008 Apr 14;14(14):2187-93
references.pmid: 18407592
references.citation: Cancer Epidemiol Biomarkers Prev. 2008 Nov;17(11):3020-5
references.pmid: 18990744
references.citation: Am J Clin Nutr. 2009 May;89(5):1441-52
references.pmid: 19339391
references.citation: Br J Nutr. 2010 Feb;103(3):429-36
references.pmid: 19732470
references.citation: Int J Cancer. 2008 Aug 1;123(3):660-3
references.pmid: 18338754
references.citation: J Natl Cancer Inst. 2010 Apr 21;102(8):529-37
references.pmid: 20371762
references.citation: Cancer Epidemiol Biomarkers Prev. 2007 Apr;16(4):684-93
references.pmid: 17416758
references.citation: Am J Epidemiol. 2006 Oct 1;164(7):644-51
references.pmid: 16923774
references.citation: Mol Nutr Food Res. 2009 Oct;53(10):1211-25
references.pmid: 19764065
references.citation: Planta Med. 2008 Oct;74(13):1608-24
references.pmid: 18855307
references.citation: Cochrane Database Syst Rev. 2009 Jul 08;(3):CD005004
references.pmid: 19588362
references.citation: J Nutr. 2000 Aug;130(8S Suppl):2073S-85S
references.pmid: 10917926
references.citation: Cancer Epidemiol Biomarkers Prev. 2006 Aug;15(8):1555-8
references.pmid: 16896049
references.citation: Cancer Epidemiol Biomarkers Prev. 2008 Jun;17(6):1344-53
references.pmid: 18559549