Four case reports presenting new acquisitions on the association between breast and endometrial carcinoma

The occurrence of invasive cancers following a diagnosis of breast carcinoma in situ

Approximately 1 in every 600 women attending breast-screening programmes in the United Kingdom is diagnosed with breast carcinoma in situ (BCIS). However, there is little information on the occurrence of subsequent cancers (other than second breast cancers) in these women. We investigated the occurrence of invasive cancers in 12 836 women diagnosed with BCIS in southeast England between 1971 and 2003, using data from the Thames Cancer Registry. A greater than expected number of subsequent cancers was found for two sites: breast (standardised incidence ratio (SIR) 1.96; 95% confidence interval (CI) 1.79–2.14) and corpus uteri (SIR 1.42; 95% CI 1.11–1.78). For subsequent ipsilateral breast cancer in those treated with breast conservation, the excess was independent of the time since diagnosis of BCIS, whereas for subsequent contralateral breast cancer, there was a steady decline in excess over time. For subsequent uterine cancer, the excess became statistically significant only at >5 years after BCIS diagnosis, consistent with a treatment effect. This was further supported by Cox regression anaysis: the risk of subsequent uterine cancer was significantly increased in women receiving hormonal therapy compared with those not receiving it, with a hazard ratio of 2.97 (95% CI 1.84–4.80).

Prevalence of endometrial proliferation in pipelle biopsies in tamoxifen-treated postmenopausal women with breast cancer in Kuwait

OBJECTIVE

To determine the prevalence of pathologic changes in the endometrium of tamoxifen-treated asymptomatic postmenopausal patients with breast cancer.

SUBJECTS AND METHODS

Fifty postmenopausal asymptomatic breast cancer patients with positive estrogen receptor status were treated with 20 mg of tamoxifen daily for a period of 5-60 months. The control group consisted of 30 asymptomatic postmenopausal breast cancer patients who were negative for estrogen receptor and therefore did not receive tamoxifen. Endometrial biopsies were performed using Pipelle endometrial suction curette at least 5 months after the study began. The endometrium was classified as atrophic (negative finding) and proliferative or hyperplastic (positive findings). The study and control groups were compared for demographic characteristics, risk factors for endometrial cancer, histological findings and the duration of tamoxifen treatment.

RESULTS

A significantly greater prevalence of endometrial abnormalities existed among the tamoxifen-treated than control patients (76 vs. 33%, p < 0.001). The abnormal endometrial changes were further demarcated in both groups into proliferative (54 vs. 26.7%, p = 0.02) and hyperplastic (22 vs. 6.6%, p = NS). In the study group, 63.6% of hyperplastic endometrium was simple hyperplasia and 36.4% was complex/no atypia hyperplasia, while in the control group all the cases were simple hyperplasia. No endometrial cancer was detected in either group. In addition, there was a positive association between the duration of tamoxifen exposure (<1 year vs. >/=1 year) and the endometrial abnormalities (46.6 vs. 88.6%, p = 0.003; proliferative 57.1 vs. 74.1%, p = 0.015; hyperplastic 42.8 vs. 25.8%, p = NS).

CONCLUSION

The adjuvant use of tamoxifen is associated with significant time-dependent abnormal endometrial changes among patients with cancer of the breast.

Controversy about uterine effects and safety of SERMs: the saga continues

From the perspective of endometrial safety, there has been great controversy about what special management, if any, tamoxifen-treated patients should undergo. Periodic blind endometrial sampling or transvaginal ultrasound has been advocated by some. Because of the problems associated with either of these techniques alone, we recommended an approach that used transvaginal ultrasound and then proceeded to sonohysterography when the endometrial echo on transvaginal ultrasound was not reliably thin and distinct. The American College of Obstetricians and Gynecologists (ACOG), in its committee opinion, stated that patients receiving tamoxifen therapy should only have an annual pelvic exam with pap smear if they remain asymptomatic. Newer data suggest, however, that there are high- and low-risk groups that can be identified by pretreatment screening. Before tamoxifen therapy, 17% of patients have polyps. These patients have 17 times the incidence of atypical hyperplasia than those whose uterus was negative before tamoxifen therapy. Such findings call into question the validity of the only study of raloxifene where uterine safety was the primary endpoint. In that study, any woman with baseline endometrial findings other than pristinely negative (i.e., low risk) was excluded. However, other raloxifene studies without pretreatment screening show relative risk (RR) = 0.8 (95% CI = 0.2, 2.7) for endometrial carcinoma. This compares with the women over 50 years of age in the Breast Cancer Prevention Trial (National Surgical Adjuvant Breast and Bowel Project P-1) with tamoxifen when the RR = 4.01 (95% CI= 1.70, 10.90). The existence of potentially high- and low-risk groups should be taken into account in any future clinical trials looking at the endometrial safety of selective estrogen receptor modulators (SERMs).

The effect of SERMs on the endometrium

Tamoxifen, the first clinically available SERM, was developed in 1966 and approved by the FDA (United States Food and Drug Administration) in 1978. It is the most prescribed antineoplastic drug in the world, with approximately 10 million women-use-years of experience. Tamoxifen has proved efficacious in all settings of breast cancer. However, in the mid-to-late 1980s, a series of letters to the editor and case reports announced an association between tamoxifen therapy in women with breast cancer and the development of endometrial carcinoma. Subsequently, in 1998, the observation of a significant 49% reduction in invasive breast cancer relative to placebo in a cohort of women at increased risk for the disease resulted in the early stopping of the National Surgical Adjuvant Breast and Bowel Project's (NSABP) P-1: Breast Cancer Prevention Trial (BCPT). Importantly, this was the first time that information became available about the effects of tamoxifen in healthy women, that is, women who did not already have breast cancer. In this healthy population, the relative risk of developing endometrial carcinoma in the tamoxifen arm was 2.54, although when stratified by age, in women over 50, the risk grew to 4.01. Thus, the risk appears to be confined to women over 50 because, in contrast, in women under 50 there was no statistically significant increase in the risk of endometrial carcinoma.

Role of exogenous and endogenous hormones in endometrial cancer: review of the evidence and research perspectives

Endometrial carcinoma is the most common cancer of the female reproductive organs in the United States. International comparisons reveal that the incidence of endometrial cancer vary widely between different countries with the highest rates observed in North America and Northern Europe, intermediate rates in Eastern Europe and Latin America, and lowest rates in Asia and Africa. International variation in endometrial cancer rates may represent differences in the distribution of known risk factors, which include obesity, postmenopausal estrogen replacement, ovarian dysfunction, diabetes mellitus, infertility, nulliparity, and tamoxifen use. Most of the risk factors for endometrial cancer can be explained within the framework of the unopposed estrogen hypothesis, which proposes that exposure to estrogens unopposed by progesterone or synthetic progestins leads to increased mitotic activity of endometrial cells, increased number of DNA replication errors, and somatic mutations resulting in malignant phenotype. Although the impact of exogenous hormone replacement was intensively studied during the last two decades, less is known about the effects of endogenous hormones in endometrial cancer. A review of available experimental, clinical, and epidemiologic data suggests that in addition to estrogens, other endogenous hormones, including progesterone, androgens, gonadotropins, prolactin, insulin, and insulin-like growth factors, may play a role in the pathogenesis of different histopathologic types of endometrial cancer.

Effect of adjuvant tamoxifen on the endometrium in women with breast cancer: a prospective study using office endometrial biopsy

PURPOSE

To determine the frequency of developing abnormal pathologic changes in the endometria of tamoxifen-treated women. To characterize the type of pathologic changes involved.

PATIENTS AND METHODS

Between October 1991 and September 1998, 159 patients initiating tamoxifen therapy for breast cancer confined to the breast and axillary lymph nodes were entered in a prospective study. In this study, office endometrial biopsies (EMBs) were obtained during the initiation of tamoxifen and at 6-month intervals for a 2-year period. Three subsequent annual EMBs were recorded for each patient, amounting to a 5-year surveillance.

RESULTS

One hundred fifty-nine patients with a median age of 50 years were entered onto study. Patients were assessable if EMBs were performed at least 1 year after the initiation of tamoxifen treatment. Nine patients (5. 7%) were considered protocol violations. The remaining 111 assessable patients underwent a total of 635 EMBs (mean, 5.8 EMBs), with a median surveillance time of 36 months. Eighty-two (12.9%) of the 635 biopsies revealed tissue insufficient for diagnosis. Fourteen patients (12.6%) underwent dilation and curettage (D&C) for an abnormal EMB, persistent bleeding, or for evaluation of adnexal masses at the time of laparoscopy. Findings at D&C included complex hyperplasia (n = 1), abnormal histiocytes (n = 1), simple hyperplasia (n = 2), polyps (n = 4), endocervical polyp (n = 1), and decidualization (n = 2). Three D&Cs were negative. Three patients have undergone hysterectomy.

CONCLUSION

EMB was used to monitor the endometrium in the majority (95%) of breast cancer patients on tamoxifen in this trial, but the utility of routine EMB for screening in tamoxifen-treated women seems limited.

Uterine side effects of treatment with tamoxifen

OBJECTIVE

To assess a causal the relationship between endometrial lesions and tamoxifen therapy in patients with breast cancer.

DESIGN

Prospective longitudinal study and cross-sectional study.

SETTING

Cancer prevention unit at Basurto Hospital, Bilbao.

POPULATION AND METHODS

Three populations of breast cancer were studied: 43 before the beginning of tamoxifen; 78 after 5-72 months of tamoxifen, and 34 before tamoxifen and after 12-24 months of tamoxifen treatment (PAIRED GROUP). All of them were systematically studied with CO(2) diagnostic hysteroscopy and endometrial biopsy by the same clinician.

RESULTS

Before tamoxifen, the following endometrial lesions were detected: endometrial polyps 9.3%; endometrial cysts 16.3%; synechiae 11.6%. In the paired group the ingestion of tamoxifen shows a direct causal effect with a significant increase in endometrial polyps (11.8% vs. 29.4%; OR=13; CI=7.9-18.1), in endometrial cysts (17.7% vs. 55.9%; OR=7.5; CI=5. 9-9.1) and in synechiae (14.7% vs. 35.5%; OR=8; CI=4.7-11.3). In the group under tamoxifen for 5-72 months, one endometrial carcinoma was detected.

CONCLUSIONS

Breast cancer patients have a number of endometrial lesions before undergoing any hormonal therapy. Tamoxifen significantly increased benign endometrial lesions, usually after less than one year of treatment. No cases of endometrial carcinoma was found in our series of 34 patients with 1-2 years of tamoxifen treatment, and 1/78 in patients with 5-72 months of tamoxifen.

Gynecologic effects of tamoxifen: case reports and review of the literature

The literature regarding the gynecologic effects of tamoxifen contains very little data on the vagina and lower urinary tract. The authors present two patients receiving tamoxifen who had gynecologic surgery complications that could be associated with tamoxifen use. Both patients had poor healing which improved when the tamoxifen was discontinued. Possible explanations are given for this observation based on what is known about this unusual drug. Owing to the success of tamoxifen in breast cancer patients, its use is currently being extended to include groups of healthy women at risk for the development of breast cancer. Because the number of women receiving tamoxifen may be increasing the authors include a review of its effects, with which all health care providers caring for women should be familiar.

EM-652 (SCH 57068), a third generation SERM acting as pure antiestrogen in the mammary gland and endometrium

Breast cancer is the most frequent cancer in women while it is the second cause of cancer death. Estrogens are well recognized to play the predominant role in breast cancer development and growth and much efforts have been devoted to the blockade of estrogen formation and action. The most widely used therapy of breast cancer which has shown benefits at all stages of the disease is the use of the antiestrogen Tamoxifen. This compound, however, possesses mixed agonist and antagonist activity and major efforts have been devoted to the development of compounds having pure antiestrogenic activity in the mammary gland and endometrium. Such a compound would avoid the problem of stimulation of the endometrium and the risk of endometrial carcinoma. We have thus synthesized an orally active non-steroidal antiestrogen, EM-652 (SCH 57068) and the prodrug EM-800 (SCH57050) which are the most potent of the known antiestrogens. EM-652 is the compound having the highest affinity for the estrogen receptor, including estradiol. It has higher affinity for the ER than ICI 182780, hydroxytamoxifen, raloxifene, droloxifene and hydroxytoremifene. EM-652 has the most potent inhibitory activity on both ER alpha and ER beta compared to any of the other antiestrogens tested. An important aspect of EM-652 is that it inhibits both the AF1 and AF2 functions of both ER alpha and ER beta while the inhibitory action of hydroxytamoxifen is limited to AF2, the ligand-dependent function of the estrogen receptors. AF1 activity is constitutive, ligand-independent and is responsible for mediation of the activity of growth factors and of the ras oncogene and MAP-kinase pathway. EM-652 inhibits Ras-induced transcriptional activity of ER alpha and ER beta and blocks SRC-1-stimulated activity of the two receptors. EM-652 was also found to block the recruitment of SRC-1 at AF1 of ER beta, this ligand-independent activation of AF1 being closely related to phosphorylation of the steroid receptors by protein kinase. Most importantly, the antiestrogen hydroxytamoxifen has no inhibitory effect on the SRC-1-induced ER beta activity while the pure antiestrogen EM-652 completely abolishes this effect, thus strengthening the need to use pure antiestrogens in breast cancer therapy in order to control all known aspects of ER-regulated gene expression. In fact, the absence of blockade of AF2 by hydroxytamoxifen could explain why the benefits of tamoxifen observed up to 5 years become negative at longer time intervals and why resistance develops to tamoxifen. EM-800, the prodrug of EM-652, has been shown to prevent the development of dimethylbenz(a)anthracene (DMBA)-induced mammary carcinoma in the rat, a well-recognized model of human breast cancer. It is of interest that the addition of dehydroepiandrosterone, a precursor of androgens, to EM-800, led to complete inhibition of tumor development in this model. Not only the development, but also the growth of established DMBA-induced mammary carcinoma was inhibited by treatment with EM-800. An inhibitory effect was also observed when medroxyprogesterone was added to treatment with EM-800. Uterine size was reduced to castration levels in the groups of animals treated with EM-800. An almost complete disappearance of estrogen receptors was observed in the uterus, vaginum and tumors in nude mice treated with EM-800. EM-652 was the most potent antiestrogen to inhibit the growth of human breast cancer ZR-75-1, MCF-7 and T-47D cells in vitro when compared with ICI 182780, ICI 164384, hydroxytamoxifen, and droloxifene. Moreover, EM-652 and EM-800 have no stimulatory effect on the basal levels of cell proliferation in the absence of E2 while hydroxytamoxifen and droloxifene had a stimulatory effect on the basal growth of T-47D and ZR-75-1 cells. EM-652 was also the most potent inhibitor of the percentage of cycling cancer cells. (ABSTRACT TRUNCATED)

Association between endometrial cancer and tamoxifen treatment of breast cancer

A retrospective cohort-study in 4109 breast cancer patients was undertaken to determine how tamoxifen affected the risk of endometrial cancer. Data on 1701 tamoxifen-treated women were analysed. Two thousand four hundred and eight non-tamoxifen users served as control group. The occurrence of new primary uterine cancers was assessed by computerized linkage to the Austrian Cancer Registry. Twenty-five women who subsequently developed endometrial cancer were identified. Eight uterine cancers occurred in the tamoxifen group, whereas 17 uterine cancers were found in the control group. The estimate of the relative risk (RR) showed an increased risk to develop endometrial cancer for the tamoxifen group RR 1.136 (95% CI 0.71; 1.80). Analysis of relevant confounding variables did not show any differences in the two groups. In conclusion, this retrospective study demonstrated a non-significant increased risk of endometrial cancer in women receiving tamoxifen as treatment for breast cancer. However, the magnitude of RR and the absolute number of endometrial cancer cases in this long term observation demonstrate clearly that the clinical benefit of tamoxifen therapy greatly outweighs the risk.

Selective estrogen receptor modulators: a new category of therapeutic agents for extending the health of postmenopausal women

Selective estrogen receptor modulators are a new category of therapeutic agents that bind with high affinity to estrogen receptors and mimic the effect of estrogens in some tissues but act as estrogen antagonists in others. Tamoxifen, a triphenylethylene derivative, was the first clinically available selective estrogen receptor modulator. It is a potent antiestrogen in the breast, and its use in breast cancer patients has made it the most prescribed antineoplastic drug worldwide. It has estrogen-like activity on bone metabolism, and it also reduces cholesterol. However, its ability to produce proliferation, polyp formation, and even carcinomas in the endometrium is well known. A new selective estrogen receptor modulator, raloxifene, a benzothiopene derivative, has a clinical profile similar to that of tamoxifen. However, both preclinical and clinical studies reveal that, unlike tamoxifen, it is a pure antiestrogen in the uterus. It has recently been approved by the Food and Drug Administration for prevention of osteoporosis in postmenopausal women. This report reviews pertinent preclinical and currently available clinical studies about this new selective estrogen receptor modulator and discusses clinical applicability.

Sonographic evaluation of the uterus in postmenopausal women receiving tamoxifen: characterization of mid-uterine abnormalities

BACKGROUND

Tamoxifen is known to exert agonist estrogenic effects on the uterus. Its use in postmenopausal women has also been associated with various endometrial and uterine abnormalities that can be detected by endovaginal sonography.

OBJECTIVE

To study postmenopausal patients receiving tamoxifen who were referred for evaluation following the detection of abnormal uterine findings by endovaginal sonography.

METHODS

Fifty-two women treated with tamoxifen for breast cancer who were found to have an abnormal uterine sonogram constituted the study population. Uterine sonograms were reviewed and clinical and sonographic data were correlated with the results of the histologic examinations.

RESULTS

Forty-five women demonstrated a thickened mid-uterine structure. Of these, in thirty-nine patients (87%) either no tissue of scant fragments of normal endometrium were obtained on curettage, and six women (13%) had endometrial hyperplasia. Seven women had fluid loculation lined by thin endometrium. Their subsequent histologic examination was normal. The sonograms of the women who demonstrated an appearance of a thickened endometrium but no neoplasia, characteristically demonstrated hyperechogenic cystic area with no midline echo.

CONCLUSIONS

Among 52 postmenopausal patients receiving tamoxifen presented with an abnormal uterine sonogram, 39 (75%) women were found to have a thick mid-uterine structure resembling a thickened endometrium without histologic evidence of neoplasia. This phenomenon can be characterized by typical sonographic features, and may be differentiated from other uterine abnormalities.

The effects of tamoxifen treatment on the endometrium

OBJECTIVE

To investigate the association between tamoxifen and endometrial cancer.

BACKGROUND

Tamoxifen is a nonsteroidal antiestrogenic drug that has been used successfully for 15 years in the treatment of all stages of breast carcinoma. In light of the positive results, several studies are now being conducted to test prolonged tamoxifen treatment as a prophylaxis against breast cancer in high-risk women. Although tamoxifen was thought to have only a few side effects, reports indicate that it is associated with an increased incidence of proliferative and neoplastic changes in the endometrium. As the current trend is to administer tamoxifen for prolonged periods and for more indications, the detrimental effects on the endometrium have vast implications.

METHODS

Review of the current literature.

RESULTS

Tamoxifen treatment is associated with an increased incidence of proliferative and neoplastic changes in the endometrium, with a 1.3 to 7.5 relative risk of developing endometrial carcinoma.

CONCLUSIONS

The results of tamoxifen treatment in breast carcinoma override the risk of developing endometrial carcinoma. Any vaginal bleeding in women treated with tamoxifen should be investigated carefully and promptly. In the future it may be necessary to advise these women to undergo routine uterine cavity examination.

Suppression of Estrogenic Activity by Medroxyprogesterone Acetate in Tamoxifen-treated Patients after Surgery for Breast Cancer to Reduce the Risk of Endometrial Cancer Development

BACKGROUND: Postoperative adjuvant tamoxifen (TAM) therapy in breast cancer patients may lead, albeit rarely, to endometrial cancer. Preventive measures are urgently needed. METHODS: The study subjects were postmenopausal women who had undergone surgery for breast cancer. The control group (n=10) received no further therapy. Patients who had completed adjuvant TAM therapy were assigned to a medroxyprogesterone acetate (MPA;400 mg/day orally for 4 weeks) group (n =15) or no MPA treatment group (no MPA group)(n=15). Uterine cervix cytodiagnosis was performed after completing the TAM therapy(initial), and 4(4-week)and 16(16-week)weeks later. The serum 17beta-estradiol (E2) and progesterone concentrations were measured initially and at 4 weeks. The karyopyknotic index (KPI), eosinophilic index (EI) and maturation index (MI) were calculated from Papanicolaou-stained specimens. RESULTS: The background parameters showed no biases. There were no differences in the PKI or El between the no MPA and MPA groups. However, regarding the MI, after 4 weeks in the MPA group, the intermediate cells were significantly increased, while the superficial cells tended to be significantly decreased. Regarding the percent change from the initial value, after 4 weeks in the MPA group, the KPI and superficial cells were significantly decreased, and the intermediate cells were significantly increased. The estrogen activity level and the progesterone concentration were significantly lower in the MPA group compared with the no MPA group. CONCKLUSIONS: The MPA administration clearly lowered the estrogenic activity, indicating that MPA therapy should be effective in reducing the risk of TAM-associated endometrial cancer.

Saline infusion sonohysterography

Saline infusion sonography enhances endovaginal ultrasound examination of the uterine cavity. It is easily and rapidly performed at minimal cost. It is well tolerated by patients and virtually devoid of complications. It can prevent further invasive diagnostic procedures in some patients and optimize the preoperative triage process for those patients who will require therapeutic intervention.

Tamoxifen and Endometrial Cancer

Tamoxifen is commonly used in the management of patients with breast cancer. Clinical trials of tamoxifen involving over 75,000 patients demonstrate an improved recurrence-free and overall survival benefit in both pre- and post-menopausal women. Large-scale trials also are evaluating the role of tamoxifen as a chemopreventive agent in women considered to be at high risk for developing breast cancer based on family history. Endometrial cancer is an uncommon complication of tamoxifen therapy. Since the majority of these cancers will be detected at an early stage when they are highly curable, however, the overall benefit of tamoxifen treatment in breast cancer patients outweighs this risk. All women receiving tamoxifen who have a uterus should undergo regular gynecologic examinations.

Gynecologic effects of tamoxifen and the association with endometrial carcinoma

Tamoxifen has been used as an adjuvant therapy for breast cancer for nearly two decades. The benefits of adjuvant tamoxifen therapy in prolonging disease-free and overall survival have been shown in randomized clinical trials. Despite this, some developing evidence suggests that tamoxifen causes a 2- to 3-fold increase in endometrial cancer. This paper reviews the reports of endometrial carcinoma in tamoxifen-treated patients. Two hundred fifty cases of endometrial carcinoma are reported, but only one case is identified in a premenopausal woman. When documented, 77% (n=127) of the cases are good-grade (grade 1 or 2) and 80% (n=125) are stage-I disease. Since the distribution of good grade (79%) and stage I (74%) from the Surveillance, Epidemiology and End Results (SEER) data are comparable, concerns about more aggressive or late-stage disease appear to be unwarranted. The modest increase in the incidence of early-stage, good-grade endometrial carcinoma described during tamoxifen therapy suggests that it would be unreasonable to institute an aggressive detection strategy of endometrial biopsies. This approach would only lead to further detection bias and would not be cost-effective. Physicians should ensure that patients do not have pre-existing endometrial cancer prior to adjuvant tamoxifen therapy for breast cancer and, furthermore, they should educate patients about signs and symptoms of early endometrial carcinoma and when reported these should be followed up with a gynecologic examination.

Gynaecologic effects of tamoxifen

Tamoxifen, an estrogen antagonist, is widely used as adjuvant therapy in patients with breast cancer. Its efficacy in increasing survival and reducing recurrence rates has been demonstrated in several European and American studies. However, its effects appear to be tissue specific. Tamoxifen exerts an estrogen effect (agonist) on the endometrium, myometrium and vagina. An increase in uterine cancer has been confirmed in several placebo-controlled clinical trials. Due to the widespread use of this drug, it is timely to review the gynecologic effects of tamoxifen.

Uterine neoplasms in patients treated with tamoxifen

Since 1985, when Killackey originally described three cases of endometrial carcinoma in patients receiving tamoxifen, there have been several reports confirming or denying the relationship between tamoxifen and endometrial carcinoma. Our study of 15 patients treated for breast carcinoma with tamoxifen found that papillary serous carcinoma was the most common tumor in this group of patients. Several other retrospective studies reported a high incidence of high-grade endometrioid adenocarcinoma or high-risk variants of endometrial carcinoma in patients receiving tamoxifen.

Unusual ultrasonographic appearance of the uterus in patients receiving tamoxifen

Tamoxifen is widely used as adjunctive therapy for patients with breast cancer and has been suggested as protection against the development of breast cancer in women at risk on the basis of heredity. It is a nonsteroidal estrogen antagonist, but like all antagonists it has some agonistic properties. Its administration should result in atrophic changes in the endometrium, but paradoxically some reports have found hyperplasia and even carcinomas developing prospectively in patients on tamoxifen therapy. Increasingly, endovaginal ultrasonography is being used for endometrial assessment in a wide variety of patients. This report is the first description of an unusual ultrasonographic finding in the uteri of some patients receiving tamoxifen. Initially believed to be endometrial in location, when viewed after fluid instillation (sonohysterogram) the heterogenous bizarre ultrasonographic appearance was actually found to represent small subendometrial sonolucencies in the proximal myometrium. Because none of these patients were clinically bleeding and all had inactive endometria on biopsy, it seems prudent not to overinterpret ultrasonography findings in patients receiving tamoxifen who have not had fluid-enhanced assessment.

What do we know and what don't we know about tamoxifen in the human uterus

Since its introduction in the early seventies, the list of indications for the use of the antiestrogen tamoxifen has been continuously expanded. Tamoxifen is now used for the treatment of metastatic breast cancer and for long-term and often indefinite administration as an adjuvant therapy. Large clinical trials in three countries are now evaluating the efficacy of tamoxifen as a preventive agent. However, tamoxifen therapy has been associated with an increased incidence of endometrial carcinoma. Laboratory and clinical data available to date on this controversial issue can be summarized as follows: a) Tamoxifen can have an estrogenic effect on endometrium in the presence of low estrogen levels. b) Tamoxifen treatment is probably associated with an increased incidence of endometrial cancer; however, this association appears to be linked to higher tamoxifen doses (40 mg/d). d) It is not known whether tamoxifen causes or allows the identification of occult endometrial carcinoma. e) At the present time there is evidence for a tumor promoting effect of tamoxifen on endometrial cancer at a dose of 20 mg per day. f) Replacement of tamoxifen by 'pure' antiestrogens or coadministration of progestins with tamoxifen do not appear to offer benefit unless clinical trials demonstrate a reduced incidence of endometrial problems. g) Patients must be evaluated for pre-existing endometrical carcinoma before starting tamoxifen therapy. f) Close followup of long-term tamoxifen patients with endometrial biopsies is recommended with individuals who experience symptoms.

Fourteenth Gaddum Memorial Lecture. A current view of tamoxifen for the treatment and prevention of breast cancer

Tamoxifen has been found to be a safe and effective treatment for all stages of breast cancer. Long term tamoxifen therapy is associated with some rare, but potentially serious, side effects so patients should be carefully monitored. However, long term tamoxifen therapy is also associated with a number of physiological benefits over and above its tumouristatic action. These benefits include a decrease in the development of contralateral breast cancer, the maintenance of bone density in postmenopausal women and a decrease in cardiovascular disease. The successful application of tamoxifen to treat breast cancer has increased enthusiasm to test its worth to prevent breast cancer. Although there are individual requests by patients for tamoxifen to prevent breast cancer, individual treatment is inappropriate. Tamoxifen can only be adequately evaluated as a preventive in randomized, double-blind clinical trials. These trials are in place and physicians should encourage women to participate and establish a new therapeutic option as rapidly as possible.

Endometrial changes in postmenopausal women treated with tamoxifen for breast cancer

OBJECTIVE

To evaluate whether risk factors, other than tamoxifen, can be identified for the development of endometrial pathologies in postmenopausal breast cancer patients treated with tamoxifen.

DESIGN

A cross-sectional study.

SETTING

Department of Obstetrics and Gynaecology and Oncology Clinic, Sapir Medical Center, Kfar Saba, Israel.

SUBJECTS

77 asymptomatic postmenopausal women, treated with tamoxifen for breast cancer. Of these, 55 had no endometrial tissue and 22 had endometrial tissue obtained by biopsy.

MAIN OUTCOME MEASURES

Demographic characteristics, health habits, risk factors, vaginal ultrasonographic evaluations of endometrial thickness and texture, and histologic evaluations of endometrial biopsies.

RESULTS

Overall, there was a high rate (29%) of endometrial pathological change among the 77 asymptomatic postmenopausal women. There were no significant statistical differences in the features tested between the two groups.

CONCLUSION

It is impossible to predict which postmenopausal women will develop pathological endometrial changes after treatment with tamoxifen and thus a routine periodic endometrial sampling-follow up is suggested for all postmenopausal women being treated with this agent.

An unusual type of endometrial cancer, related to tamoxifen?

Tamoxifen, which is increasingly being used in breast cancer patients, has been associated with an elevated frequency of endometrial carcinoma. To our knowledge not a single case of uterine serous papillary carcinoma (USPC) has been documented during tamoxifen treatment. No conclusions as to a causal relationship are yet being made, but if it is due to tamoxifen, we should advise a strategy for prevention, because this subtype is not as curable as endometrioid carcinoma.

Endometrial carcinoma in tamoxifen-treated breast cancer patients

Tamoxifen is an important agent for the treatment of breast cancer. Occasionally the drug, which is an antiestrogen, has agonistic estrogenic activity. The authors describe three new cases of endometrial carcinoma developing in breast cancer patients taking tamoxifen and stress the necessity of carefully monitoring the uterine cavity under tamoxifen treatment.

Oncogenic potential of tamoxifen on endometria of postmenopausal women with breast cancer--preliminary report

Tamoxifen (TAM), a nonsteroidal antiestrogen, is used for pre- and postmenopausal patients with breast cancer. Recent reports suggest that TAM may cause endometrial neoplasia. This study is designed to evaluate the oncogenic potential of low-dose TAM on the endometrium. Initially, endometrial screening of patients with breast cancer who had received TAM therapy for at least 12 months was conducted. Seventy patients were interviewed and office endometrial biopsies were obtained from thirty-eight patients. Seven (18%) had hyperplastic changes, ranging from simple hyperplasia through complex hyperplasia with atypia. The following prospective study was conducted: after breast surgery and prior to initiation of TAM therapy, an office endometrial sampling was obtained as a control. After initiation of TAM therapy, biopsies were repeated every 4 to 6 months as long as the patients remained asymptomatic. Nineteen patients were interviewed. Twelve patients were biopsied and followed from 3 to 15 months. One patient refused additional biopsies. Eleven patients had repeat biopsies after initiation of TAM. New hyperplastic changes were found in 3/11 (27%) patients. The preliminary results of this study (although with a small number of patients) indicate that TAM may have some neoplastic effect on the endometrium of postmenopausal patients with breast cancer. This study is still in progress. Additional prospective studies are warranted before a significant correlation between TAM and endometrial neoplasia is confirmed.

Tamoxifen-associated endometrial carcinoma in postmenopausal breast cancer patients

Tamoxifen citrate, a nonsteroidal antiestrogen with agonistic properties, is prescribed as an adjuvant to surgery in the treatment of breast cancer. Recent reports have suggested that tamoxifen has an estrogenic property and may be implicated in the development of endometrial carcinomas. Seven new cases are reported to the existing literature in which endometrial carcinomas developed in postmenopausal women on tamoxifen therapy for breast carcinomas.