title: Five or more years of adjuvant endocrine therapy in breast cancer: a meta-analysis of published randomised trials.
abstract: Five years of adjuvant hormonal therapy is the standard of care in early breast cancer (BC) expressing oestrogen receptors (ER+). Prolonged duration of adjuvant endocrine therapy is implemented to prevent recurrence and death; in particular, its carryover effect may prevent very late events. This meta-analysis compares the efficacy of 5 years of hormonal therapy alone with that of additional years of hormonal therapy, in patients with early BC. Randomised trials comparing 5 years versus more than 5 years of hormonal therapy in BC were identified by electronic searches of PubMed, EMBASE, ISI Web of Science and the Cochrane Central Register of Controlled Trials. Meta-analysis was performed using the fixed- or random-effects models. The primary endpoints were overall survival (OS), BC-specific survival (BCSS) and relapse-free survival (RFS) reported as odds ratios (ORs) and 95 % confidence interval (CI). Eight trials, including 29,138 patients, were identified. Overall, in ER+ BCs, extended endocrine therapy beyond 5 years of tamoxifen significantly improved OS (OR, 0.89; 95 % CI 0.80-0.99; P = 0.03), BCSS (OR, 0.78; 95 % CI 0.69-0.9; P = 0.0003) and RFS (OR 0.72; 95 % CI 0.56-0.92; P = 0.01) compared with 5 years of hormonal therapy alone. Loco-regional and distant relapses were reduced by 36 and 13 %, respectively. Compared with 5 years of tamoxifen, additional adjuvant endocrine therapy reduced risk of death and relapse of ER+ BC by ~10 and 30 %, respectively. This strategy should be considered in patients free of disease after 5 years of hormonal therapy.
authors.affiliation: Division of Medical Oncology, Department of Medical Oncology, Azienda Ospedaliera Treviglio, Piazzale Ospedale 1, 24047, Treviglio, BG, Italy. faupe@libero.it
authors.forename: Fausto
authors.initials: F
authors.lastname: Petrelli
authors.forename: Andrea
authors.initials: A
authors.lastname: Coinu
authors.forename: Mary
authors.initials: M
authors.lastname: Cabiddu
authors.forename: Mara
authors.initials: M
authors.lastname: Ghilardi
authors.forename: Veronica
authors.initials: V
authors.lastname: Lonati
authors.forename: Sandro
authors.initials: S
authors.lastname: Barni
mesh_terms: D018931:Antineoplastic Agents, Hormonal / Q000008:administration & dosage*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D017024:Chemotherapy, Adjuvant; D003131:Combined Modality Therapy; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D009364:Neoplasm Recurrence, Local / Q000188:drug therapy / Q000473:pathology; D016032:Randomized Controlled Trials as Topic; D011960:Receptors, Estrogen / Q000378:metabolism; D013629:Tamoxifen / Q000008:administration & dosage*
chemical_list: D018931:Antineoplastic Agents, Hormonal; D011960:Receptors, Estrogen; D013629:Tamoxifen