[1026] Temporal Relationships between Tamoxifen Use and Endometrial Malignancies.

Deborah DeLair, Sarah Ferguson, Robert Soslow, Karuna Garg. Memorial Sloan-Kettering Cancer Center, New York, NY

Background: The development of uterine malignancies during and after the use of tamoxifen is a well-documented phenomenon. The purpose of the study was to determine if there was a correlation between the duration of tamoxifen therapy, the development of these malignancies in relation to cessation of the drug, and tumor type and/or grade. In addition, we sought to determine any recurrent morphologic features present in these tumors.
Design: All women with a history of breast cancer treated with tamoxifen who subsequently developed a uterine malignancy between 1980 and 2005 were included in the study.
Results: A total of 119 such patients were identified. The distribution of tumor type was as follows: 64 FIGO 1-2 endometrioid carcinomas (EC), 7 FIGO 3 endometrioid carcinomas, 28 serous carcinomas or mixed endometrioid and serous carcinomas, 3 clear cell carcinomas, 2 undifferentiated carcinomas, 13 carcinosarcomas (MMMT) and 2 leiomyosarcomas. There was a higher incidence of high grade tumors in patients who received tamoxifen for 5 years or more (59%), compared to those who used tamoxifen for less than 5 years (26%). Low grade tumors also appear to develop more frequently early on after the use of tamoxifen; the frequency of high grade tumors was more in cases where the interval between cessation of tamoxifen therapy and diagnosis of endometrial carcinoma was more than 1 year (58%) compared to less than 1 year (38%). In the slides available for review, a number of recurrent morphologic features were noted including prominent squamous/morular metaplasia, background polyps and/or polypoid tumors, background endometrial atrophy (also seen in endometrioid tumors) and presence of prominent ovarian stromal hyperplasia.

	FIGO 1-2 EC	FIGO 3 EC	Serous	MMMT	Others
Tamoxifen therapy duration ≥5 years	30	6	24	10	3
Tamoxifen therapy duration <5 years	33	1	5	3	4
Interval between tamoxifen cessation and EC Less than 1 year	44	2	13	8	5
Interval between tamoxifen cessation and EC 1 year and more	19	4	1	5	2

Conclusions: Patients treated with tamoxifen therapy for breast carcinomas can develop a spectrum of endometrial malignancies of all histologic subtypes. Patients who received long duration of tamoxifen therapy had a tendency to develop higher grade tumors, and these often developed later on after tamoxifen cessation. In contrast, patients who used tamoxifen for shorter time periods were more prone to developing lower grade tumors that often presented early after discontinuation of tamoxifen use, with the exception of carcinosarcomas that often presented early.
Category: Gynecologic & Obstetrics

Wednesday, March 2, 2011 1:00 PM

Poster Session VI # 147, Wednesday Afternoon