Leiomyosarcoma of the uterus in a woman on adjuvant tamoxifen therapy

Etiology and pathogenesis of uterine leiomyomas: a review

Uterine leiomyomas, or fibroids, represent a major public health problem. It is believed that these tumors develop in the majority of American women and become symptomatic in one-third of these women. They are the most frequent indication for hysterectomy in the United States. Although the initiator or initiators of fibroids are unknown, several predisposing factors have been identified, including age (late reproductive years), African-American ethnicity, nulliparity, and obesity. Nonrandom cytogenetic abnormalities have been found in about 40% of tumors examined. Estrogen and progesterone are recognized as promoters of tumor growth, and the potential role of environmental estrogens has only recently been explored. Growth factors with mitogenic activity, such as transforming growth factor- (subscript)3(/subscript), basic fibroblast growth factor, epidermal growth factor, and insulin-like growth factor-I, are elevated in fibroids and may be the effectors of estrogen and progesterone promotion. These data offer clues to the etiology and pathogenesis of this common condition, which we have analyzed and summarized in this review.

[Uterine sarcoma in patients receiving tamoxifen therapy. Apropos of 2 cases]

INTRODUCTION

Tamoxifen--a non steroidal triphenylethyl compound--in addition to having antiestrogenic properties may provoke weak estrogenic effects, the well known "paradoxical effects" on the female genital tractus. Concern has been raised about prolonged tamoxifen treatment and subsequent occurrence of endometrial adenocarcinoma; subsequent attention has been drawn through high risk histologic subtypes including poorly differentiated patterns and uterine sarcomas.

EXEGESIS

We report two cases of uterine sarcoma arising in postmenopausal women taking tamoxifen, 20 mg daily during 38 and 42 months, for breast carcinoma: one leiomyosarcoma and one endometrial stromal sarcoma; both cases were asymptomatic and detected by pelvic sonography.

CONCLUSION

Further studies will be required to establish if there is a relationship between long term tamoxifen exposure and highly aggressive types of cancer of the uterine corpus exhibiting adverse histologic features such as uterine sarcomas. There is no consensus regarding uterine surveillance of women receiving tamoxifen. We advocate an annual gynecologic examination plus imaging by means of transvaginal ultrasonography.

Controversies regarding tamoxifen and uterine carcinoma

An increasing number of cases of endometrial cancer in women receiving tamoxifen have been reported but most are from non-randomized studies and case reports. In the last year, there have been no further results either confirming or disproving an association between tamoxifen and endometrial cancer from randomized controlled studies in breast cancer patients and those participating in chemopreventative trials with tamoxifen. Several papers have examined the possible mechanisms behind tamoxifen's endometrial effects.

Tamoxifen and the female genital tract

Ugwumadu AHN, Carmichael P, Neven P. Tamoxifen and the female genital tract. Int J Gynecol Cancer 1998; 8: 6-15. Tamoxifen was originally developed by Imperial Chemical Industries (England) (ICI) in 1966 as an anti-estrogenic contraceptive. Ironically, it found a role in the treatment of anovulatory infertility, but its most important application to date is in adjuvant hormonotherapy for breast cancer. Tamoxifen has a complex and poorly understood mix of estrogenic and anti-estrogenic properties with variable and contrasting effects on hormone-sensitive target tissues, such as the endometrium. This article reviews the gynecologic lesions associated with tamoxifen therapy and discusses the merits and acceptability of endometrial surveillance tests and the role of progestogens.