Clinicopathologic study of 56 patients with endometrial cancer during or after adjuvant tamoxifen use for their breast cancers

Effects of tamoxifen on the endometrium and its mechanism of carcinogenicity

This study was conducted to clarify the clinicopathological characteristics of tamoxifen-associated endometrial carcinomas and its mechanisms of carcinogenesis. Seven patients with tamoxifen-associated endometrial carcinomas (TAM group) and 28 with sporadic endometrioid adenocarcinomas (EMC group) were included in the study. The clinicopathological factors, such as FIGO stage, histological type, grade, lymph node metastases, vascular invasion and the coexistence of hyperplasia, were investigated in both groups. The protein expression of p53, PTEN, hMLH1 and hMSH2 was investigated by immunohistochemistry. Microsatellite instability (MSI), k-ras and p53 mutation were also examined. In the TAM group, the histological types included five endometrioid, one endometrioid combined with serous and one clear cell type. The rates of coexistence with hyperplasia (five of seven cases) and vascular invasion (four cases) were significantly higher in the TAM group. The rates of stage III/IV (four cases) and lymph node metastasis (three cases) tended to be higher in the TAM group. Although there were no significant differences in PTEN, hMLH1 and hMSH2 expression between the two groups, p53 mutation was more frequent in three out of five cases (60%) in the TAM group compared with 2 of 15 cases in the EMC group (13.3%). No significant differences were observed concerning MSI and k-ras mutation in either group. These results suggested that TAM-associated endometrial carcinomas have overlapping biological characteristics of type I and type II endometrial carcinomas. This might explain the somewhat worse prognosis of these tumors than sporadic endometrioid carcinomas.

Long-term follow-up of postmenopausal breast cancer patients following discontinuation of tamoxifen therapy

BACKGROUND

There is a need to evaluate the extent of endometrial pathologies that might develop in postmenopausal breast cancer patients following discontinuation of tamoxifen (TAM) therapy.

METHODS

The medical records of 153 postmenopausal breast cancer patients who remained untreated following discontinuation of tamoxifen therapy were evaluated for various clinical features, for endometrial thickness measurements, as detected by transvaginal ultrasonography, and for various endometrial pathologies detected. The last endometrial thickness measurement performed before discontinuation of tamoxifen was compared with endometrial thickness measured following discontinuation of tamoxifen.

RESULTS

Patients were followed for 37.5+/-31.3 months. There was a gradual and significant decrement of endometrial thickness measured at the last ultrasonographic study performed before cessation of tamoxifen, compared to that observed in all four ultrasonographic studies performed following discontinuation of tamoxifen (P=0.001). Endometrial thickness gradually and significantly decreased in correlation with the time intervals of the four ultrasonographic studies performed following discontinuation of tamoxifen (P=0.001). Overall, 40 hysteroscopies were performed in 38 (24.8%) patients. No tissue was obtained in 18 (11.8%) patients. Overall endometrial pathologies were diagnosed in 22 (14.4%) patients. Benign endometrial polyps were the most frequent endometrial pathology recovered: 17 (11.1%) patients. No endometrial malignancy was diagnosed. The rate of endometrial pathologies considerably decreased with the extension of time following discontinuation of tamoxifen therapy.

CONCLUSIONS

Long-term follow-up of postmenopausal breast cancer patients who remained untreated following discontinuation of TAM therapy did not reveal any malignant endometrial pathology. Only few benign endometrial pathologies were diagnosed, which became fewer in time.

Aromatase inhibitors reverse tamoxifen induced endometrial ultrasonographic changes in postmenopausal breast cancer patients

OBJECTIVE

Aromatase inhibitors may decrease endometrial thickness in breast cancer patients previously having short-term tamoxifen treatment. There is a necessity to find out if aromatase inhibitors can also decrease endometrial thickness in patients previously treated with long-term tamoxifen treatment.

METHODS

Prospective comparison of the last ultrasonographic endometrial thickness measurement taken before discontinuation of long-term tamoxifen treatment in 36 postmenopausal breast cancer patients, with further measurements, performed following aromatase inhibitors administration.

RESULTS

There was a significant decrement of endometrial thickness, following 36.2 +/- 16.8 months of tamoxifen treatment, from a mean value of 9.1 +/- 5.8 mm, measured at the last ultrasonographic measurement performed before discontinuation of tamoxifen treatment, down to a mean value of 6.0 +/- 5.0 mm, measured following 5.8 +/- 5.8 months of aromatase inhibitors therapy (P = 0.001). A second ultrasonographic measurement performed in 8 patients following of additional 7.5 +/- 4.0 months of aromatase inhibitors treatment revealed further decrement of mean endometrial thickness to 4.8 +/- 2.1 mm (P = 0.002 compared to baseline). In 28 patients (77.8%), endometrial thickness was reduced following the administration of aromatase inhibitors, in four patients (11.1%) there was no change in endometrial thickness and four (11.1%) patients demonstrated an increase of endometrial thickness.

CONCLUSIONS

Aromatase inhibitors may reverse endometrial thickening induced by long-term tamoxifen treatment in postmenopausal breast cancer patients.

Comparison of uterine malignancies that develop during and following tamoxifen therapy

OBJECTIVES

There is a greater than 7-fold increased risk of uterine cancer in women with breast cancer exposed to tamoxifen. The objective of this study was to determine the percentage of women who developed uterine cancer more than 12 months after discontinuing tamoxifen (past users) and to compare their clinical and pathologic features with those of women who developed uterine cancer while on tamoxifen therapy or within 12 months of stopping therapy (recent users).

METHODS

All women with a diagnosis of uterine cancer at Memorial Sloan-Kettering Cancer Center between 1980 and June 2004 with a past history of breast cancer treated with tamoxifen were identified. Clinical and pathologic data were obtained through retrospective chart review.

RESULTS

There were 106 women identified with a history of breast cancer treated with tamoxifen preceding their diagnosis of uterine cancer. Thirty-nine (37%) developed uterine cancer more than 12 months after discontinuing tamoxifen. The median time until developing uterine cancer in past users was 33 months (range, 13-22). There were no significant differences in age at breast cancer diagnosis, body mass index, parity, stage of breast cancer, modality of breast cancer treatment, or duration of tamoxifen therapy between past and recent users of tamoxifen. Women who were past users of tamoxifen had significantly more FIGO (International Federation of Gynecology and Obstetrics) grade 3 and non-endometrioid histologic subtypes (P = 0.009; P = 0.007).

CONCLUSIONS

More than one third of women treated with tamoxifen develop uterine cancer more than 12 months after discontinuing therapy. These women are at greater risk of developing moderately to poorly differentiated tumors, which is a known poor prognostic factor. Therefore, women with a past history of tamoxifen therapy should have continued surveillance after completion of tamoxifen to ensure early diagnosis of uterine cancer.