Endocrine effects of adjuvant letrozole compared with tamoxifen in hormone-responsive postmenopausal patients with early breast cancer: the HOBOE trial.
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.
Rossi
Emanuela
E
Clinical Trials Unit, National Cancer Institute of Naples, Via Mariano Semmola, 80131, Napoli, Italy.
Morabito
Alessandro
A
Di Rella
Francesca
F
Esposito
Giuseppe
G
Gravina
Adriano
A
Labonia
Vincenzo
V
Landi
Gabriella
G
Nuzzo
Francesco
F
Pacilio
Carmen
C
De Maio
Ermelinda
E
Di Maio
Massimo
M
Piccirillo
Maria Carmela
MC
De Feo
Gianfranco
G
D'Aiuto
Giuseppe
G
Botti
Gerardo
G
Chiodini
Paolo
P
Gallo
Ciro
C
Perrone
Francesco
F
de Matteis
Andrea
A
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
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