title: Endocrine effects of adjuvant letrozole compared with tamoxifen in hormone-responsive postmenopausal patients with early breast cancer: the HOBOE trial.
abstract: PURPOSE We compared the endocrine effects of 6 and 12 months of adjuvant letrozole versus tamoxifen in postmenopausal patients with hormone-responsive early breast cancer within an ongoing phase III trial. PATIENTS AND METHODS Patients were randomly assigned to receive tamoxifen, letrozole, or letrozole plus zoledronic acid. Serum values of estradiol, follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone, dehydroepiandrosterone-sulphate (DHEA-S), progesterone, and cortisol were measured at baseline and after 6 and 12 months of treatment. For each hormone, changes from baseline at 6 and 12 months were compared between treatment groups, and differences over time for each group were analyzed. Results Hormonal data were available for 139 postmenopausal patients with a median age of 62 years, with 43 patients assigned to tamoxifen and 96 patients assigned to letrozole alone or combined with zoledronic acid. Baseline values were similar between the two groups for all hormones. Many significant changes were observed between drugs and for each drug over time. Namely, three hormones seemed significantly affected by one drug only: estradiol that decreased and progesterone that increased with letrozole and cortisol that increased with tamoxifen. Both drugs affected FSH (decreasing with tamoxifen and slightly increasing with letrozole), LH (decreasing more with tamoxifen than with letrozole), testosterone (slightly increasing with letrozole but not enough to differ from tamoxifen), and DHEA-S (increasing with both drugs but not differently between them). Zoledronic acid did not have significant impact on hormonal levels. CONCLUSION Adjuvant letrozole and tamoxifen result in significantly distinct endocrine effects. Such differences can explain the higher efficacy of letrozole as compared with tamoxifen.
authors.affiliation: Clinical Trials Unit, National Cancer Institute of Naples, Via Mariano Semmola, 80131, Napoli, Italy.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Rossi
authors.forename: Alessandro
authors.initials: A
authors.lastname: Morabito
authors.forename: Francesca
authors.initials: F
authors.lastname: Di Rella
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Esposito
authors.forename: Adriano
authors.initials: A
authors.lastname: Gravina
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Labonia
authors.forename: Gabriella
authors.initials: G
authors.lastname: Landi
authors.forename: Francesco
authors.initials: F
authors.lastname: Nuzzo
authors.forename: Carmen
authors.initials: C
authors.lastname: Pacilio
authors.forename: Ermelinda
authors.initials: E
authors.lastname: De Maio
authors.forename: Massimo
authors.initials: M
authors.lastname: Di Maio
authors.forename: Maria Carmela
authors.initials: MC
authors.lastname: Piccirillo
authors.forename: Gianfranco
authors.initials: G
authors.lastname: De Feo
authors.forename: Giuseppe
authors.initials: G
authors.lastname: D'Aiuto
authors.forename: Gerardo
authors.initials: G
authors.lastname: Botti
authors.forename: Paolo
authors.initials: P
authors.lastname: Chiodini
authors.forename: Ciro
authors.initials: C
authors.lastname: Gallo
authors.forename: Francesco
authors.initials: F
authors.lastname: Perrone
authors.forename: Andrea
authors.initials: A
authors.lastname: de Matteis
mesh_terms: D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D050071:Bone Density Conservation Agents / Q000008:administration & dosage; D001943:Breast Neoplasms / Q000097:blood* / Q000188:drug therapy*; D017024:Chemotherapy, Adjuvant / Q000379:methods; D019314:Dehydroepiandrosterone Sulfate / Q000097:blood; D004164:Diphosphonates / Q000008:administration & dosage; D004958:Estradiol / Q000097:blood; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007093:Imidazoles / Q000008:administration & dosage; D000077289:Letrozole; D007986:Luteinizing Hormone / Q000097:blood / Q000187:drug effects; D008875:Middle Aged; D009570:Nitriles / Q000627:therapeutic use*; D017698:Postmenopause; D011374:Progesterone / Q000097:blood; D011960:Receptors, Estrogen / Q000378:metabolism; D013629:Tamoxifen / Q000627:therapeutic use*; D013739:Testosterone / Q000097:blood; D014230:Triazoles / Q000627:therapeutic use*; D000077211:Zoledronic Acid
chemical_list: D000970:Antineoplastic Agents; D050071:Bone Density Conservation Agents; D004164:Diphosphonates; D007093:Imidazoles; D009570:Nitriles; D011960:Receptors, Estrogen; D014230:Triazoles; D013629:Tamoxifen; D013739:Testosterone; D011374:Progesterone; D004958:Estradiol; D019314:Dehydroepiandrosterone Sulfate; D000077211:Zoledronic Acid; D000077289:Letrozole; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D006854:Hydrocortisone