Preoperative treatment of postmenopausal breast cancer patients with letrozole: A randomized double-blind multicenter study.
BACKGROUND
A randomized, double-blind, multicenter study was conducted to compare the anti-tumor activity of letrozole vs. tamoxifen in postmenopausal women with ER and/or PgR positive primary untreated breast cancer.


METHODS
Three hundred thirty-seven postmenopausal women with ER and/or PgR positive primary untreated breast cancer were randomly assigned once daily treatment with either letrozole 2.5 mg or tamoxifen 20 mg for four months. At baseline none of the patients were considered to be candidates for breast-conserving surgery (BCS) and 14% of the patients were considered inoperable. The primary endpoint was to compare overall objective response (CR + PR) determined by clinical palpation. Secondary endpoints included overall objective response on ultrasound and mammography and the number of patients who qualified for BCS.


RESULTS
Overall objective response rate (clinical palpation) was statistically significantly superior in the letrozole group, 55% compared to tamoxifen, 36% (P < 0.001). Secondary endpoints of ultrasound response, 35% vs. 25% (P = 0.042), mammographic response, 34% vs. 16% (P < 0.001), and BCS, 45% vs. 35% (P = 0.022) between the letrozole and tamoxifen groups, respectively, showed letrozole to be significantly superior. Both treatments were well tolerated.


CONCLUSIONS
This study shows that letrozole is more effective than tamoxifen as preoperative therapy in postmenopausal patients with ER and/or PgR positive primary untreated breast cancer and is at least as well tolerated.
Eiermann
W
W
Frauenklinik Vom, Roten Kreuz, Munich.
Paepke
S
S
Appfelstaedt
J
J
Llombart-Cussac
A
A
Eremin
J
J
Vinholes
J
J
Mauriac
L
L
Ellis
M
M
Lassus
M
M
Chaudri-Ross
H A
HA
Dugan
M
M
Borgs
M
M
D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D047072:Aromatase Inhibitors; D001943:Breast Neoplasms / Q000188:drug therapy*; D004311:Double-Blind Method; D004791:Enzyme Inhibitors / Q000627:therapeutic use; D005260:Female; D006801:Humans; D000077289:Letrozole; D008875:Middle Aged; D009570:Nitriles / Q000627:therapeutic use*; D017698:Postmenopause; D011300:Preoperative Care; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D013629:Tamoxifen / Q000627:therapeutic use*; D016896:Treatment Outcome; D014230:Triazoles / Q000627:therapeutic use*
D000970:Antineoplastic Agents; D047072:Aromatase Inhibitors; D004791:Enzyme Inhibitors; D009570:Nitriles; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D014230:Triazoles; D013629:Tamoxifen; D000077289:Letrozole