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

Risk of Endometrial Cancer and Frequencies of Invasive Endometrial Procedures in Young Breast Cancer Survivors Treated With Tamoxifen: A Nationwide Study

Background

Although the guidelines recommend gynecological assessment and close monitoring for symptoms of endometrial cancer in postmenopausal breast cancer survivors taking tamoxifen (TAM), the risk of endometrial cancer in young breast cancer survivors has not yet been fully assessed. This study aimed to investigate the risk of developing endometrial cancer and the frequencies of gynecological examinations in young breast cancer survivors taking TAM in South Korea.

Methods

A nationwide retrospective cohort study was conducted using the Health Insurance Review and Assessment Service claims data. Kaplan–Meier analyses and log-rank tests were used to assess the probability of endometrial cancer, benign endometrial conditions, and the probability of invasive endometrial procedure. To analyze the risk of endometrial cancer and benign endometrial conditions, we used a multivariable Cox proportional hazards regression model.

Results

Between 2010 and 2015, 60,545 newly diagnosed female breast cancer survivors were included. The total person–years were 256,099 and 140 (0.23%) patients developed endometrial cancer during the study period. In breast cancer survivors aged ≥60 years [hazard ratio (HR), 5.037; 95% confidence interval (CI), 2.185–11.613], 50–59 years (HR, 4.343; 95% CI, 2.122–8.891), and 40–49 years (HR, 2.121; 95% CI, 1.068–4.213), TAM was associated with an increased risk of endometrial cancer. In subjects aged below 40 years, TAM did not significantly increase the risk of endometrial cancer. However, among the TAM subgroups, breast cancer survivors aged below 40 years [1.61 per 1,000 person–years (PY); HR, 12.460; 95% CI, 2.698–57.522] and aged 40–49 years (2.22 per 1,000 PY; HR, 9.667; 95% CI, 4.966–18.819) with TAM-related endometrial diseases showed significantly increased risks of endometrial cancer. Among the TAM subgroup with benign endometrial conditions, the ratios of the frequency of invasive diagnostic procedures to the incidence of endometrial cancer were higher in subjects under 40 than subjects aged 60 or more.

Conclusion

Young breast cancer survivors with TAM-related benign endometrial diseases are at a higher risk of developing endometrial cancer. Gynecological surveillance should be tailored to the risk of endometrial cancer in young breast cancer survivors to improve the early detection of endometrial cancer and avoid unnecessary invasive procedures.

Event-free survival following early endometrial events in breast cancer patients treated with anti-hormonal therapy: A nationwide claims data study

Tamoxifen, an anti-estrogen agent that can suppress breast cancer, has been reported to increase endometrium-related adverse events. There are no guidelines for screening tamoxifen-treated patients for endometrial disease. We analyzed nationwide claims data related to endometrial diseases to investigate patterns of endometrial disease in breast cancer patients who underwent hormonal treatment.We sourced claims data from the Health Insurance Review and Assessment Service in South Korea. Patients who made their first claim for an anti-hormonal agent between January 1, 2010 and December 31, 2012 were enrolled retrospectively. We analyzed patient characteristics and all claims related to endometrial disease, stratified by prescribed hormonal agents.Among a total of 32,496 enrolled patients, 19,603 used tamoxifen only and 10,101 were treated with an aromatase inhibitor (AI) alone. Endometrial events occurred in 15.4% (3028/19603) of the tamoxifen-only patients and 2.0% (201/10101) of the AI-only group. In patients diagnosed with breast cancer at the age of 50 or older, the hazard ratio (HR) of endometrial malignancy in the tamoxifen-only group compared to the AI-only group was 4.13 (95% CI 1.404-12.159, P = .010). The HR of curettage in the tamoxifen-only group was 31.0 (95% CI 19.668-48.831, P <.001).The occurrence of endometrial events among tamoxifen-treated breast cancer patients was higher than in patients treated with only AI, similar to previous studies. However, the HR of curettage was uniquely high, despite its invasiveness. Guidelines for screening endometrial disease and improvements of healthcare policy are required to appropriately manage high-risk patients.

Differences in estrogen and progesterone receptor expression in endometrial polyps and atrophic endometrium of postmenopausal women with and without exposure to tamoxifen

Postmenopausal women who use tamoxifen present with an increased incidence of endometrial alterations, such as polyps and hyperplasia, in addition to a higher risk of malignant endometrial neoplasms. Among these endometrial changes, polyps are the most common, with a pathogenesis associated with hormonal influence. The objective of this study was to compare the expression of estrogen receptors (ERs) and progesterone receptors (PRs) in endometrial polyps from tamoxifen users with that in endometrial polyps and the atrophic endometrium of postmenopausal tamoxifen non-users. Among women undergoing surgical hysteroscopy, 84 tamoxifen users with benign endometrial polyps were selected. This group was compared to 84 samples of atrophic endometrium and to 252 benign polyps from postmenopausal women who were not treated with tamoxifen. The expression of ER/PR was assessed by immunohistochemical analysis, according to the percentage of stained cells, intensity of nuclear staining and final score. The polyps from tamoxifen users exhibited a higher expression of ER and PR in the glandular epithelium and stroma compared to the atrophic endometrium (P<0.0001). Compared to the polyps from women not treated with tamoxifen, tamoxifen users exhibited a higher PR expression in the epithelium (P=0.0014) and stroma (P=0.0056), with no difference in the expression of ER. In conclusion, endometrial polyps frequently exhibit an increase in ER expression, regardless of tamoxifen use. High levels of PR expression appear to be consistent with the estrogen agonist effects of tamoxifen.

Gynecologic effects of arzoxifene in postmenopausal women with osteoporosis or low bone mass

OBJECTIVE

The aim of this study was to report the gynecologic safety findings from the Generations trial, a phase 3 study of the selective estrogen receptor modulator (SERM), arzoxifene.

METHODS

A predefined objective of the trial was to evaluate the effects of arzoxifene on the genital tract. Gynecologic examinations were performed yearly, and further gynecologic assessment, including endometrial biopsy, was performed in a predefined subset of women and in those who developed vaginal bleeding.

RESULTS

Overall, 9,354 women were randomized (4,678 to placebo, 4,676 to arzoxifene 20 mg/d). There were 13 adjudicated cases of endometrial cancer (placebo, 4 cases; arzoxifene, 9 cases: P = 0.165) and 6 cases of endometrial hyperplasia (placebo, 2 cases; arzoxifene, 4 cases). Endometrial thickness, assessed at 24- and 36-month transvaginal ultrasounds in a subset of women, increased slightly in women assigned to arzoxifene compared with baseline and women in placebo. At the last measurement, 3 (1.7%) women assigned to placebo and 21 (10.2%) assigned to arzoxifene had an endometrial thickness greater than 5 mm (P < 0.001 for difference between treatment groups). Endometrial polyps were more common in women treated with arzoxifene (n = 37) than in women treated with placebo (n = 18; P < 0.05). Vulvular and vaginal inflammation, including mycotic infections, and vaginal discharge were reported more frequently in women treated with arzoxifene than in women treated with placebo, as were urinary tract infections.

CONCLUSIONS

Gynecologic events were generally more common in women treated with arzoxifene than in women treated with placebo. The gynecologic effects of arzoxifene seem to differ from those of raloxifene, although both SERMs have a benzothiophene structure. Although all SERMs influence cells through the estrogen receptor, they need to be evaluated independently in terms of their effects on various tissues, including the genital tract.

Are endometrial polyps true cancer precursors?

OBJECTIVE

The purpose of this study was to assess whether endometrial polyps (EMPs) represent cancer precursors.

STUDY DESIGN

Age standardized incidence ratios (SIRs) of histologically verified endometrial cancers (EmCas) were estimated in women with EMPs and in women with uterine leiomyomata, which is a condition that is unrelated to endometrial carcinogenesis. SIRs were calculated as the ratio of observed to expected EmCas based on age-specific incidence rates for female Montreal residents during the same period.

RESULTS

Of 1467 women with EMPs, 125 (8.5%) had EmCa. Of 1138 patients with uterine leiomyomata, 133 (11.7%) had EmCa. The SIRs of EmCa for women with EMPs (odds ratio, 8.0; 95% confidence interval, 6.6-9.5) were significantly lower than that in women with leiomyomata (odds ratio, 19.1; 95% confidence interval, 16.0-22.6). Abnormal uterine bleeding was the main reason for evaluating patients with EMP with or without associated EmCa.

CONCLUSION

The findings of higher EmCa incidence are consistent with enhanced detection opportunity rather than with the endometrial cancer precursor potential of EMPs.

Endometrial safety: a key hurdle for selective estrogen receptor modulators in development

Selective estrogen receptor modulators (SERMs) have the ability to provide mixed functional estrogen receptor (ER) agonist or antagonist activity, depending on the target tissue. Tamoxifen, the first SERM available for clinical use, is regarded as a highly effective agent for the prevention and treatment of breast cancer. However, tamoxifen exhibits ER agonist activity in the uterus and is associated with an increased risk of endometrial hyperplasia and malignancy. Endometrial safety has been an important consideration in the clinical development of SERMs, with improved benefit-risk profiles. Raloxifene, which is currently approved for the prevention and treatment of postmenopausal osteoporosis and for the prevention of breast cancer, seems to have neutral effects on the uterus. Promising results have been observed with the targeted development of newer and more tissue-specific SERMs, many of which are under investigation for postmenopausal osteoporosis. Of the newer SERMs in development, lasofoxifene has been shown to reduce fracture risk and decrease the incidence of breast cancer but has been associated with an increased incidence of vaginal bleeding, endometrial thickening, and endometrial polyps. Lasofoxifene and ospemifene have shown beneficial effects on the vaginal epithelium. Phase 3 clinical data have shown that bazedoxifene is effective in preventing and treating postmenopausal osteoporosis, without adverse effects on the endometrium or breast. Arzoxifene has been evaluated in phase 3 trials for postmenopausal osteoporosis and has been studied for the treatment of uterine malignancies but is no longer in clinical development. Further investigation of newer SERMs is warranted to more clearly define the endometrial safety of these agents.

Selective estrogen receptor modulators (SERMs) for uterine leiomyomas

BACKGROUND

Uterine fibroids are benign tumors that arise from individual smooth muscle cells of the uterus. Selective estrogen receptor modulators (SERMs) are ER ligands that act as estrogens in some tissues, while blocking estrogen action in others. There have been many clinical studies of various SERMs for uterine fibroid. However, their effectiveness is controversial.

OBJECTIVES

To evaluate the evidence for the effectiveness and safety of selective estrogen receptor modulators in women with uterine fibroids.

SEARCH STRATEGY

We searched The Cochrane Library, MEDLINE, the Register of Chinese trials developed by the Chinese Cochrane Centre, and the Chinese Med Database, Chinese Biomedical Disc (CBMDisc 1978 to July 2004); VIP (1989 to October 2005)); China National Knowledge Infrastructure (CNKI 1994 to 2003) in October 2005. We hand searched a number of journals, and searched reference lists, databases of ongoing trials and the Internet.

SELECTION CRITERIA

We included randomized controlled studies of selective estrogen receptor modulators versus other forms of medical therapy or placebo in women in the reproductive age (18 to 45 years old) with confirmed uterine fibroid.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed trial quality. As the studies identified were not sufficiently similar and not of sufficient quality, we did not do a meta-analysis but summarized the data in a narrative format.

MAIN RESULTS

Three studies involving 215 participants were included, trial size varied from 25 to 100. Comparison interventions included no treatment, Poly vitamins, and leuprolide acetate depot plus raloxifene versus leuprolide plus placebo tablet. There was a tendency towards fibroid reduction with selective estrogen receptor modulators (SERMs), although this was not significant in all studies. All three studies mentioned adverse reactions but no detailed data were acquired in the included studies.

AUTHORS' CONCLUSIONS

There is no evidence from the limited number of studies that SERMs reduce the size of fibroids or improve clinical outcomes. Further studies are required to establish evidence of benefit of SERMs in treating women with uterine fibroids.

Selective estrogen receptor modulators (SERMs) for uterine leiomyomas

BACKGROUND

Uterine fibroids are benign tumors that arise from individual smooth muscle cells of the uterus. Selective estrogen receptor modulators (SERMs) are ER ligands that act as estrogens in some tissues, while blocking estrogen action in others. There have been many clinical studies of various SERMs for uterine fibroid. However, their effectiveness is controversial.

OBJECTIVES

To evaluate the evidence for the effectiveness and safety of selective estrogen receptor modulators in women with uterine fibroids.

SEARCH STRATEGY

We searched The Cochrane Library, MEDLINE, the Register of Chinese trials developed by the Chinese Cochrane Centre, and the Chinese Med Database, Chinese Biomedical Disc (CBMDisc 1978 to July 2004); VIP (1989 to October 2005)); China National Knowledge Infrastructure (CNKI 1994 to 2003) in October 2005. We hand searched a number of journals, and searched reference lists, databases of ongoing trials and the Internet.

SELECTION CRITERIA

We included randomized controlled studies of selective estrogen receptor modulators versus other forms of medical therapy or placebo in women in the reproductive age (18 to 45 years old) with confirmed uterine fibroid.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed trial quality. As the studies identified were not sufficiently similar and not of sufficient quality, we did not do a meta-analysis but summarized the data in a narrative format.

MAIN RESULTS

Three studies involving 215 participants were included, trial size varied from 25 to 100. Comparison interventions included no treatment, Poly vitamins, and leuprolide acetate depot plus raloxifene versus leuprolide plus placebo tablet. There was a tendency towards fibroid reduction with selective estrogen receptor modulators (SERMs), although this was not significant in all studies. All three studies mentioned adverse reactions but no detailed data were acquired in the included studies.

AUTHORS' CONCLUSIONS

There is no evidence from the limited number of studies that SERMs reduce the size of fibroids or improve clinical outcomes. Further studies are required to establish evidence of benefit of SERMs in treating women with uterine fibroids.

Changes in the sonographic appearance of the uterus after discontinuation of tamoxifen therapy

OBJECTIVE

The purpose of this study was to assess the duration of sonographically detected changes in the endometrium of women with a history of tamoxifen use.

METHODS

Patients with breast cancer who had a history of tamoxifen use and documented pelvic sonographic studies were identified by means of clinic databases in both the Section of Gynecological Oncology and the Section of Obstetrical and Gynecological Ultrasound, University of Chicago, between January 1, 1996, and March 30, 2004. Of the 99 patients who met study criteria, 34 had discontinued tamoxifen use before the sonographic evaluation. Each patient's age, gravity and parity, weight, ethnicity, duration and dose of drug use, interval from drug discontinuation until sonographic evaluation, and uterine pathologic findings were reviewed. Endometrial thickness as assessed by pelvic sonography was examined in relation to duration of tamoxifen use and time from discontinuation of the drug. Statistical analysis was performed with linear regression and mixed effect linear regression models.

RESULTS

Endometrial thickness increased with increasing duration of tamoxifen use at a rate of 0.75 mm/y. The mean endometrial thickness after approximately 5 years of tamoxifen use was 12 mm (range, 6-21 mm). After discontinuation of tamoxifen, endometrial thickness decreased by 1.27 mm/y.

CONCLUSIONS

Endometrial thickness as measured by pelvic ultrasound examination increases with the duration of tamoxifen use. After discontinuation of the drug, the measured thickness decreases but at a very slow rate.

Endometrial lesions causing uterine bleeding in postmenopausal women receiving raloxifene

It is generally accepted, that raloxifene administration does not have adverse effects on the uterus. We report the cases of two relatively young postmenopausal patients, who presented with vaginal bleeding, due to endometrial pathology, approximately 1 year after the initiation of raloxifene administration. The women were 43 and 44 years old, and received 60 mg/day of oral raloxifene for 11.5 and 10.5 months, respectively. In both cases, raloxifene was given for osteoporosis prevention in the absence of vasomotor symptoms. The first patient underwent Pipelle-biopsy and hysteroscopy with histopathology revealing simple endometrial hyperplasia. The second patient underwent hysteroscopy with removal of an endometrial polyp, with no histopathological signs of malignancy. Continuation of raloxifene administration was decided in both cases, and follow-up did not reveal any sign of recurrence. Uterine bleeding may rarely occur in postmenopausal women under raloxifene therapy. Patients should be encouraged to report bleeding or spotting and appropriate diagnostic and therapeutic management should follow as in any other case.

Third generation aromatase inhibitors may prevent endometrial growth and reverse tamoxifen-induced uterine changes in postmenopausal breast cancer patients

BACKGROUND

Tamoxifen may induce uterine abnormalities of clinical concern. Our aim was to compare early uterine changes occurring in postmenopausal breast cancer patients treated in first-line with tamoxifen or third generation aromatase inhibitors. We also assessed the effect of aromatase inhibitors on tamoxifen-induced uterine changes.

PATIENTS AND METHODS

Seventy-seven consecutive postmenopausal breast cancer patients scheduled to start endocrine treatment were included in this prospective study. Transvaginal ultrasonography (TVUS) was carried out before and after 3 months of therapy. No interventions were done on pre-existing asymptomatic uterine abnormalities seen on baseline sonography.

RESULTS

After 3 months of therapy, tamoxifen significantly increased endometrial thickness and uterine volume. Additionally, tamoxifen induced endometrial cysts and polyps, and increased the size of pre-existing fibroids. In contrast, aromatase inhibitors did not stimulate endometrial growth and were not associated with endometrial pathologies seen under tamoxifen. Furthermore, aromatase inhibitors decreased endometrial thickness and uterine volume in patients previously treated with tamoxifen.

CONCLUSIONS

Our study demonstrates that tamoxifen induces uterine abnormalities from as early as 3 months of therapy. In contrast, these abnormalities are not seen in patients on aromatase inhibitors. Furthermore, our data indicate that tamoxifen therapy followed by an aromatase inhibitor may lead to a reduction in endometrial pathologies associated with tamoxifen.

Osteopenia and osteoporosis in women with breast cancer

Osteopenia and osteoporosis are prevalent in women. Epidemiologic studies show that the risk of breast cancer is greater in postmenopausal women with higher bone mineral density (BMD). Standard treatments for breast cancer such as adjuvant chemotherapy or hormonal therapy can increase bone loss, and hence may increase the risk of osteoporosis. Premenopausal women treated with standard adjuvant chemotherapy frequently develop permanent ovarian failure, or early menopause. Ovarian failure is associated with accelerated bone loss, and bisphosphonates may mitigate this bone loss in women treated with adjuvant chemotherapy. Tamoxifen preserves BMD in postmenopausal women; however, in premenopausal women tamoxifen may increase bone loss. Anastrazole, an aromatase inhibitor, is approved for adjuvant treatment of postmenopausal women with early-stage, estrogen receptor-positive breast cancer. With a follow-up duration of less than 5 years, anastrazole-treated women experience increased fractures relative to those treated with tamoxifen. The management of osteopenia and osteoporosis in women with breast cancer generally does not differ from women without breast cancer. Adequate dietary calcium and vitamin D intake, encouraging weight-bearing exercise, and counseling about the relationship between smoking and alcohol and bone loss are all prudent recommendations for overall health and may lessen bone loss and the risk of subsequent osteoporosis. BMD should be measured in women with chemotherapy-induced ovarian failure, and in those on aromatase inhibitors. Bisphosphonates reduce the bone loss associated with chemotherapy-induced ovarian failure, and clinical trials evaluating third-generation bisphosphonates in women with chemotherapy-induced ovarian failure are underway. As many women with breast cancer will be long-term survivors, increasing recognition of maintaining skeletal health is important.