title: Physical activity and survival after breast cancer diagnosis: meta-analysis of published studies.
abstract: Published data have shown that physical activity (PA) has a positive role on the primary prevention of breast cancer risk. However, the role of PA on breast cancer outcome has been controversial with inconsistent data. The lack of a meta-analysis that addresses that issue prompted the current report. A comprehensive literature search identified eight studies, of which two studies were excluded. The remaining six studies (12,108 patients with breast cancer) were included in this meta-analysis. Pre-diagnosis PA reduced all causes mortality by 18% but had no effect on breast cancer deaths. Post-diagnosis PA reduced breast cancer deaths by 34% (HR=0.66, 95% CI, 0.57-0.77, P<0.00001), all causes mortality by 41% (HR=0.59, 95% CI, 0.53-0.65, P<0.00001), and disease recurrence by 24% (HR=0.76, 95% CI, 0.66-0.87, P=0.00001). Breast cancer mortality was reduced by pre-diagnosis PA in women with body mass index (BMI)<25 kg/m2, while post-diagnosis PA reduced that risk among those with BMI≥25 kg/m2. On the other hand, post-diagnosis PA reduced all causes mortality regardless of the BMI. The analysis showed that post-diagnosis PA reduced breast cancer deaths (HR=0.50, 95% CI, 0.34-0.74, P=0.0005), and all causes mortality (HR=0.36, 95% CI, 0.12-1.03, P=0.06) among patients with estrogen receptor (ER)-positive tumor, while women with ER-negative disease showed no gain. The current meta-analysis provides evidence for an inverse relationship between PA and mortality in patients with breast cancer and supports the notion that appropriate PA should be embraced by breast cancer survivors.
authors.affiliation: Oncology Center, International Medical Center, PO Box 2172, Jeddah, 21451, Kingdom of Saudi Arabia, ezzibrahim@imc.med.sa.
authors.forename: Ezzeldin M
authors.initials: EM
authors.lastname: Ibrahim
authors.forename: Abdelaziz
authors.initials: A
authors.lastname: Al-Homaidh
mesh_terms: D001943:Breast Neoplasms / Q000401:mortality*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans
references.citation: Br J Cancer. 2004 Jun 1;90(11):2138-41
references.pmid: 15150561
references.citation: J Clin Oncol. 2008 Aug 20;26(24):3958-64
references.pmid: 18711185
references.citation: BMC Med Res Methodol. 2005 Apr 25;5:14
references.pmid: 15850485
references.citation: Cancer Epidemiol Biomarkers Prev. 2008 Feb;17(2):379-86
references.pmid: 18250341
references.citation: JAMA. 2005 May 25;293(20):2479-86
references.pmid: 15914748
references.citation: Breast Cancer Res Treat. 1990 Oct;16(3):205-14
references.pmid: 2085672
references.citation: Eur J Cancer Prev. 2002 Aug;11 Suppl 2:S94-100
references.pmid: 12570341
references.citation: BMJ. 1997 Sep 13;315(7109):629-34
references.pmid: 9310563
references.citation: Stat Med. 1998 Dec 30;17(24):2815-34
references.pmid: 9921604
references.citation: JAMA. 2003 Sep 10;290(10):1377-9
references.pmid: 12966131
references.citation: Control Clin Trials. 1986 Sep;7(3):177-88
references.pmid: 3802833
references.citation: Ann Intern Med. 1997 Nov 1;127(9):820-6
references.pmid: 9382404
references.citation: Cancer. 1998 Aug 1;83(3 Suppl):621-8
references.pmid: 9690525
references.citation: Cancer. 1996 Dec 15;78(12):2465-70
references.pmid: 8952552
references.citation: Epidemiology. 2007 Jan;18(1):137-57
references.pmid: 17130685
references.citation: Cancer. 2006 Oct 15;107(8):1777-85
references.pmid: 16967443
references.citation: Cancer Epidemiol Biomarkers Prev. 2004 Jul;13(7):1163-72
references.pmid: 15247127
references.citation: Cancer. 2003 Apr 1;97(7):1746-57
references.pmid: 12655532
references.citation: Cancer Epidemiol Biomarkers Prev. 2003 Aug;12(8):721-7
references.pmid: 12917202
references.citation: Public Health Rep. 1985 Mar-Apr;100(2):131-46
references.pmid: 3920712
references.citation: Cancer Res. 2004 Apr 15;64(8):2923-8
references.pmid: 15087413
references.citation: Cancer Causes Control. 1996 Nov;7(6):605-25
references.pmid: 8932921
references.citation: Br J Sports Med. 2008 Aug;42(8):636-47
references.pmid: 18487249
references.citation: Obes Rev. 2002 Feb;3(1):5-8
references.pmid: 12119660
references.citation: J Womens Health Gend Based Med. 1999 Dec;8(10):1265-72
references.pmid: 10643834
references.citation: Br J Cancer. 1985 Dec;52(6):885-91
references.pmid: 4074640
references.citation: Diabetes Care. 1997 Jan;20(1):26-31
references.pmid: 9028689
references.citation: Med Sci Sports Exerc. 2001 Jun;33(6 Suppl):S530-50; discussion S609-10
references.pmid: 11427781
references.citation: Prev Chronic Dis. 2005 Apr;2(2):A16
references.pmid: 15888227
references.citation: Cancer Epidemiol Biomarkers Prev. 2009 Jan;18(1):87-95
references.pmid: 19124485
references.citation: Epidemiology. 1995 May;6(3):311-7
references.pmid: 7619942
references.citation: J Clin Oncol. 2007 Jun 10;25(17):2345-51
references.pmid: 17557947