TITLE:
Short-term Femara (letrozole) treatment and suppression of Ki67 expression in postmenopausal endometrial carcinoma
AUTHORS:
Lloyd H. Smith, Gary Leiserowitz, Guibo Xing, John Bishop
KEYWORDS:
Endometrial Carcinoma; Aromatase Inhibitor; Letrozole; Ki67
JOURNAL NAME:
Open Journal of Obstetrics and Gynecology,
Vol.3 No.3,
May
8,
2013
ABSTRACT: Objective: To determine if short-term treatment with
Femara (letrozole) induces measurable reduction in tumor Ki67 expression in
postmenopausal women with FIGO grade 1 and 2 endometrial carcinoma. Methods: In
this non-randomized prospective study, 12 patients were given Femara
(letrozole) 2.5 mg daily for approximately 3 weeks prior to planned hysterectomy
for FIGO grade 1 or 2 endometrial carcinoma. A group of 12 demographically
similar patients were enrolled as no-treatment controls. Ki67 expression in
tumor cells was quantitated by immunohistochemistry with mechanical scanning
within the initial endometrial biopsy and compared to that in the hysterectomy
specimen for each patient in the treatment and control groups. Results: The
treatment and control groups were similar in age, tumor grade and FIGO stage. When
“aromatase inhibitor responsiveness” was defined as proportionate decline in
Ki67% stained tumor cells of at least 70% between the pre-treatment endometrial
biopsy and post-treatment hysterectomy specimens, 5 of 12 patients were found
to be “responsive” in the treatment group with none of the controls fulfilling
these criteria. Conclusion: Femara (letrozole) 2.5 mg daily for approximately
3 weeks induced a significant reduction in tumor cell Ki67 expression among 5
of 12 (41%) postmenopausal women with FIGO grade 1 or 2 endometrial
carcinoma. We postulate that Ki67 may be a useful marker during aromatase
inhibitor medical treatment of patients with endometrial cancer who are not
candidates for surgical treatment.