Telomere Length and Breast Cancer Prognosis: A Systematic Review.
Telomeres ensure genome integrity during replication. Loss of telomeric function leads to cell immortalization and accumulation of genetic alterations. The association of telomere length (TL) with breast cancer prognosis is examined through a systematic review. Electronic databases (MEDLINE, EMBASE, CENTRAL), from inception to December 2015, and relevant reviews were searched. Studies that evaluated TL (blood and/or tumor) in association with breast cancer survival or prognostic factor were included. Thirty-six studies met inclusion criteria. Overall risk of bias was critical. Eight studies reported survival outcomes. Overall, there was a trend toward an association of longer telomeres with better outcomes (tumor, not blood). Of the 33 studies reporting associations with prognostic factors, nine adjusted for potential confounders. Among the latter, shorter telomeres were associated with older age (blood, not tumor), higher local recurrence rates (normal tissue), higher tumor grade (tumor), and lower physical activity (blood), which were reported in one study each. TL was not associated with molecular subtype (blood, one study), family history (tumor, one study), chemotherapy (blood, three of four studies), and stress reduction interventions (blood, two of two studies). Although major methodologic differences preclude from drawing conclusive results, TL could be a valuable breast cancer prognostic marker. Cancer Epidemiol Biomarkers Prev; 26(1); 3-10. ©2016 AACR.
Axe Oncologie, Centre de Recherche du CHU de Québec-Université Laval, Québec, Canada.|Centre de Recherche sur le Cancer, Université Laval, Québec, Canada.|Département de Médecine Sociale et Préventive, Faculté de Médecine, Université Laval, Québec, Canada.
Kaoutar
K
Ennour-Idrissi
Axe Oncologie, Centre de Recherche du CHU de Québec-Université Laval, Québec, Canada.|Centre de Recherche sur le Cancer, Université Laval, Québec, Canada.|Département de Médecine Sociale et Préventive, Faculté de Médecine, Université Laval, Québec, Canada.|Centre des Maladies du Sein Deschênes-Fabia, Hôpital du Saint-Sacrement, Québec, Canada.
Elizabeth
E
Maunsell
Axe Oncologie, Centre de Recherche du CHU de Québec-Université Laval, Québec, Canada. Caroline.Diorio@crchudequebec.ulaval.ca.|Centre de Recherche sur le Cancer, Université Laval, Québec, Canada.|Département de Médecine Sociale et Préventive, Faculté de Médecine, Université Laval, Québec, Canada.|Centre des Maladies du Sein Deschênes-Fabia, Hôpital du Saint-Sacrement, Québec, Canada.
Caroline
C
Diorio
D001943:Breast Neoplasms / Q000235:genetics* / Q000401:mortality* / Q000628:therapy; D005260:Female; D005819:Genetic Markers; D006801:Humans; D064887:Observational Studies as Topic; D011237:Predictive Value of Tests; D011379:Prognosis; D012189:Retrospective Studies; D016615:Telomere / Q000235:genetics* / Q000473:pathology; D059506:Telomere Shortening / Q000235:genetics*; D016896:Treatment Outcome
D005819:Genetic Markers