Aromatase inhibition in male breast cancer patients: biological and clinical implications.
BACKGROUND
The role of aromatase inhibitors (AIs) and their impact on estradiol (E(2)) levels remain unknown in male breast cancer (MBC) patients.


METHODS
MBC patients with metastatic disease and those treated with AIs were selected from the breast cancer database of the Centre Antoine-Lacassagne (Nice, France). Sex hormone levels were retrospectively assessed on serum samples from our institutional serum bank.


RESULTS
Fifteen patients entered the study. Two patients (13%) had complete response, four patients (27%) had partial response, two patients (13%) had stable disease and seven patients (47%) had progressive disease. The median progression-free survival and overall survival were 4.4 months [95% confidence interval (CI) 0.1-8.6] and 33 months (95% CI 18.4-47.6), respectively. All assessable patients (n = 6) had E(2) levels less than the lower limit of the assay during AI treatment. Among them, three had partial response, one had stable disease and two had progressive disease. A large increase in follicle-stimulating hormone, luteinizing hormone and E(2) levels was observed in one responding patient at progression.


CONCLUSIONS
AIs are active in MBC patients. This activity is correlated with a significant reduction in E(2) levels. Secondary resistance is in part related to a deleterious feedback loop resulting in a significant increase in substrate for aromatization.
Doyen
J
J
Department of Medical Oncology.
Italiano
A
A
Department of Medical Oncology. Electronic address: italiano@bergonie.org.
Largillier
R
R
Department of Medical Oncology.
Ferrero
J-M
JM
Department of Medical Oncology.
Fontana
X
X
Department of Nuclear Medicine, Centre Antoine-Lacassagne, Nice, France.
Thyss
A
A
Department of Medical Oncology.
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000077384:Anastrozole; D000730:Androstadienes / Q000627:therapeutic use; D000970:Antineoplastic Agents / Q000627:therapeutic use; D001141:Aromatase / Q000378:metabolism; D047072:Aromatase Inhibitors / Q000494:pharmacology / Q000627:therapeutic use*; D018567:Breast Neoplasms, Male / Q000097:blood / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology; D002277:Carcinoma / Q000097:blood / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology; D004958:Estradiol / Q000097:blood; D006801:Humans; D000077289:Letrozole; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009570:Nitriles / Q000627:therapeutic use; D012189:Retrospective Studies; D016019:Survival Analysis; D013739:Testosterone / Q000097:blood; D016896:Treatment Outcome; D014230:Triazoles / Q000627:therapeutic use
D000730:Androstadienes; D000970:Antineoplastic Agents; D047072:Aromatase Inhibitors; D009570:Nitriles; D014230:Triazoles; D000077384:Anastrozole; D013739:Testosterone; D004958:Estradiol; D000077289:Letrozole; D001141:Aromatase; C056516:exemestane