Crossover trial for lipid abnormality in postmenopausal breast cancer patients during selective estrogen receptor modulators (SERMs) administrations

Comparison of effects of tamoxifen and Toremifene on hepatic function and serum lipids in breast cancer patients during adjuvant endocrine therapy

To investigate the effects of tamoxifen (TAM) and toremifene (TOR) on hepatic function and serum lipid levels in breast cancer patients receiving adjuvant endocrine therapy. The clinical data of 597 early breast cancer patients treated at the First Affiliated Hospital of Nanjing Medical University between January 2016 and December 2022 were collected. All the patients received standard adjuvant endocrine therapy with TAM or TOR after chemotherapy. Hepatic function and serum lipid data of all patients before and at 6 months and 1, 2, and 3 years after the treatment were collected retrospectively and analyzed statistically. There: no negative effect on hepatic function was observed in patients treated with either TAM or TOR. The triglyceride levels in both groups increased during treatment, and the effect of TAM on improving total cholesterol levels was stronger. Total cholesterol levels were not affected by time or treatment regimen. The low-density lipoprotein cholesterol levels decreased in both groups, and the effect was similar between groups. TAM can decrease the high-density lipoprotein cholesterol levels, whereas TOR can increase the high-density lipoprotein cholesterol levels, and there was a significant difference between groups. In the postoperative adjuvant endocrine therapy, TOR and TAM will not negatively impact the hepatic function of breast cancer patients, and TOR is better than TAM in the management of serum lipids; therefore, it may be a better choice for clinical medication.

Effects of Tamoxifen vs. Toremifene on fatty liver development and lipid profiles in breast Cancer

BACKGROUND

Tamoxifen (TAM) and Toremifene (TOR), two kinds of selective estrogen receptor modulators (SERMs), have equal efficacy in breast cancer patients. However, TAM has been proved to affect serum lipid profiles and cause fatty liver disease. The study aimed to compare the effects of TAM and TOR on fatty liver development and lipid profiles.

METHODS

This study performed a retrospective analysis of 308 SERMs-treated early breast cancer patients who were matched 1:1 based on propensity scores. The follow-up period was 3 years. The primary outcomes were fatty liver detected by ultrasonography or computed tomography (CT), variation in fibrosis indexes, and serum lipid profiles change.

RESULTS

The cumulative incidence rate of new-onset fatty liver was higher in the TAM group than in the TOR group (113.2 vs. 67.2 per 1000 person-years, p < 0.001), and more severe fatty livers occurred in the TAM group (25.5 vs. 7.5 per 1000 person-years, p = 0.003). According to the Kaplan-Meier curves, TAM significantly increased the risk of new-onset fatty liver (25.97% vs. 17.53%, p = 0.0243) and the severe fatty liver (5.84% vs. 1.95%, p = 0.0429). TOR decreased the risk of new-onset fatty liver by 45% (hazard ratio = 0.55, p = 0.020) and showed lower fibrotic burden, independent of obesity, lipid, and liver enzyme levels. TOR increased triglycerides less than TAM, and TOR increased high-density lipoprotein cholesterol, while TAM did the opposite. No significant differences in total cholesterol and low-density lipoprotein cholesterol are observed between the two groups.

CONCLUSIONS

TAM treatment is significantly associated with more severe fatty liver disease and liver fibrosis, while TOR is associated with an overall improvement in lipid profiles, which supports continuous monitoring of liver imaging and serum lipid levels during SERM treatment.

A prospective, randomized study of Toremifene vs. tamoxifen for the treatment of premenopausal breast cancer: safety and genital symptom analysis

Background

Toremifene (TOR) is a selective oestrogen receptor modulator (SERM) and has comparable efficacy to that of tamoxifen (TAM) in breast cancer patients. Herein, we compared the safety of TOR to that of TAM in the adjuvant treatment of premenopausal breast cancer.

Methods

This was a prospective randomized and open-label clinical study. Premenopausal patients with hormonal receptor (HR)-positive early breast cancer were randomly assigned (1:1) to receive TOR) or TAM treatment. The follow-up period was 1 year. The primary end point was the incidence of ovarian cysts, and secondary end points were the incidence of endometrial thickening, changes in female hormones, the incidence of fatty liver, changes in the modified Kupperman index (mKMI) and changes in quality of life.

Results

There were 92 patients in the final analysis. The incidences of ovarian cysts were 42.6% in the TOR group and 51.1% in the TAM group (p = 0.441). Forty-one patients (87.2%) in the TOR group and 36 patients (80.0%) in the TAM group experienced endometrial thickening (p = 0.348). The proportions of patients with fatty liver were 31.9% in the TOR group and 26.7% in the TAM group (p = 0.581). No significant differences in the mKMI or quality of life were observed between the two groups.

Conclusions

TOR and TAM have similar side effects on the female genital system and quality of life in premenopausal early breast cancer patients.

Trial registration

ClinicalTrials.gov NCT02344940. Registered 26 January 2015 (retrospectively registered).

Clinical significance of fatty liver disease induced by tamoxifen and toremifene in breast cancer patients

BACKGROUND AND AIM

The aim of this study was to identify the effect of selective estrogen receptor modulator (SERM) on non-alcoholic fatty liver disease (NAFLD) in Asian women.

METHODS

We retrospectively evaluated fatty liver development and/or serum alanine aminotransferase (ALT) elevation during SERM treatment in 1061 women who were diagnosed and treated with breast cancer in 2005 at Asan Medical Center.

RESULTS

45 of 618 SERM-treated patients with normal ALT at baseline experienced ALT elevation during SERM treatment. Among the 112 SERM-treated patients who underwent liver imaging test, fatty liver was observed in 47 and both fatty liver and ALT elevation developed in 16 of 102 SERM-treated patients with normal baseline ALT. The cumulative rates of ALT elevation (10.7 vs. 4.3%; P = 0.002), fatty liver (48.5 vs. 20.9%; P < 0.001), and both fatty liver and ALT elevation (17.7 vs. 7.1%; P = 0.02) at 60 months were significantly higher in the SERM group than non-SERM group. By multivariate analysis, SERM treatment increased the risk of ALT elevation (hazard ratio [HR], 2.20; P = 0.01), fatty liver development (HR, 3.59; P < 0.001), and both fatty liver and ALT elevation (HR, 4.98; P = 0.01). After discontinuation of SERM, elevated serum ALT normalized in 39 (92.9%) and there were no instances of liver-related death or progression to liver cirrhosis in patients who experienced fatty liver or ALT elevation.

CONCLUSIONS

Although SERM treatment is significantly associated with NAFLD in Asian women, considering the tolerability and reversibility of NAFLD induced by SERM, it can be continued with liver function monitoring in relevant patients.

Toremifene for breast cancer: a review of 20 years of data

Endocrine therapy is a cornerstone of medical treatment for estrogen receptor-positive breast cancer. The discovery of selective estrogen receptor modulators (SERMs) > 40 years ago represented a revolutionary advance in the treatment of breast cancer. As a therapeutic class, SERMs have either estrogenic or antiestrogenic activity, depending on the target tissue and the hormonal environment. In breast tissue, SERMs are antiestrogenic, making them a major treatment option for women with hormone-sensitive breast cancer. Toremifene citrate was developed > 20 years ago with the goal of achieving efficacy similar to that of tamoxifen and with an improved safety profile. Although studies to date have not confirmed a clear safety advantage or disadvantage for toremifene, clinical data support the efficacy and safety of toremifene for the treatment of breast cancer in postmenopausal patients. Toremifene also has a pharmacokinetic profile and metabolic pathway different from that of tamoxifen, which may provide a therapeutic advantage in certain patients. In addition, because of the selective estrogenic effects of SERMs in bone and on lipid levels along with a different side effect profile compared with the aromatase inhibitors (AIs), toremifene is a viable option to the AIs for some patients. Despite a number of clinical trials and over 500,000 patient years of use, many oncologists have limited familiarity with toremifene data. This article will examine the rationale for the use of toremifene in the treatment of women with breast cancer and review data from 20 years of clinical experience with this agent.

Early recurrence risk: aromatase inhibitors versus tamoxifen

Aromatase inhibitors (AIs) are becoming the hormonal treatment of choice for postmenopausal women with early breast cancer. Large, well-controlled clinical studies have established the efficacy and safety of initial adjuvant therapy with letrozole or anastrozole versus the previous standard of 5 years of adjuvant tamoxifen and support using an AI (exemestane, anastrozole or letrozole) following tamoxifen for 2-3 years (early 'switch' treatment) or 5 years (extended adjuvant treatment). Reducing recurrence risk is a primary goal of adjuvant hormonal therapy. There is an early peak of recurrences 2 years after surgery; most are distant metastases rather than local or regional events. Therefore, treatment strategies such as initial therapy with AIs, which reduce early distant recurrence events, can be expected to improve long-term survival outcomes. Switching to an AI following 2-3 years of initial adjuvant tamoxifen is an effective option for patients unable to begin treatment with an AI.

Effects of toremifene and tamoxifen on lipid profiles in post-menopausal patients with early breast cancer: interim results from a Japanese phase III trial

OBJECTIVE

Toremifene and tamoxifen have been used for adjuvant therapy in post-menopausal patients with breast cancer in Japan. Dyslipidemias are common in post-menopausal women. However, limited data are available on the effects of these agents on lipid profiles in Japanese patients. The Japan Toremifene Cooperative Study Group has been conducting a Phase III randomized trial of post-menopausal patients with breast cancer. One of its secondary endpoints is to confirm the effects of these agents on serum lipid profiles.

METHODS

The subjects were post-menopausal Japanese patients who had undergone surgery for early breast cancer. Toremifene or tamoxifen was administered for 2 years. Lipid levels were measured before and up to 24 months after initiation.

RESULTS

Compared with baseline, at 24 months, the toremifene group (n = 123) showed significantly decreased total cholesterol (P < 0.001) and low-density lipoprotein cholesterol levels (P < 0.001), and significantly increased high-density lipoprotein cholesterol levels (P < 0.001). Their triglyceride levels were not affected (P = 0.677). The tamoxifen group (n = 120) also showed significantly decreased total cholesterol (P < 0.001) and low-density lipoprotein cholesterol levels (P < 0.001); no significant changes occurred in high-density lipoprotein cholesterol (P = 0.297) or triglyceride levels (P = 0.120).

CONCLUSIONS

Distinct differences between two selective estrogen receptor modulators on lipids were observed. Toremifene improved lipid profiles, particularly as an enhancer of high-density lipoprotein cholesterol. To a large extent, tamoxifen improved low-density lipoprotein cholesterol levels. The impact of these improved lipid profiles on the risk of cardiovascular diseases needs further confirmation.

Apolipoprotein E4 allele influences the response of plasma triglyceride levels to tamoxifen in breast cancer patients

BACKGROUND

Apolipoprotein E4 (APOE4) allele is an important risk factor for breast cancer and affects clearance of chylomicron remnants. Tamoxifen therapy increases serum triglyceride levels and sometimes inducing severe hypertriglyceridemia in breast cancer patients.

METHODS

Thirty-three women with breast cancer were recruited to examine the APOE polymorphism and fasting plasma lipid profiles before and after tamoxifen treatment for 6 months.

RESULTS

We found that plasma lipid profiles changed in accordance with the APOE4 allele after tamoxifen treatment for 6 months. Especially plasma triglyceride levels significantly decreased in the APOE4-positive patients (p=0.025), while there was no change in APOE4-negative patients (p=0.189). The total plasma cholesterol levels were reduced in APOE-4 positive patients after 6-month tamoxifen treatment (p=0.014). The levels of plasma low density lipoprotein cholesterol and high density lipoprotein cholesterol significantly decreased in both APOE4-negative and APOE4-positive patients.

CONCLUSIONS

These findings indicate that the effects of tamoxifen on plasma triglyceride levels are modified by APOE polymorphism. Breast cancer patients with APOE4 allele have low plasma triglyceride levels when receiving tamoxifen therapy. Therefore, we suggest that APOE gene polymorphism is a critical validation before tamoxifen treatment in breast cancer patients.

The effects of atamestane and toremifene alone and in combination compared with letrozole on bone, serum lipids and the uterus in an ovariectomized rat model

We compared the effects of atamestane (ATA) and toremifene (TOR) alone and in combination, with letrozole (LET) on bone, serum lipids and the uterus in ovariectomized (OVX) rats after 16 weeks of treatment. Compared to OVX controls lumbar vertebral and femoral BMD as well as mechanical strength and trabecular bone volume were significantly greater in animals given ATA, TOR or ATA + TOR. The effects of ATA were not reversed by the androgen receptor blocker, flutamide (FLT). Serum cholesterol, low-density lipoprotein cholesterol and triglycerides were reduced by TOR and ATA + TOR whereas they remained unchanged in animals receiving ATA, ATA + FLT, and LET. The uterine epithelium in OVX animals was equally stimulated by TOR and ATA + TOR and unaffected by ATA or LET. Intact animals had significant atrophy of the uterine epithelium when receiving ATA. In summary, TOR alone or in combination with ATA had a predictable stimulatory effect on bone and the uterine epithelium while reducing key parameters of lipid metabolism. In contrast, ATA but not LET had an unexpected stimulatory effect on the OVX rat's bone and this was not reversed by the anti-androgen FLT leaving this finding unexplained for now. ATA is distinct from LET on end-organ function and this favorable profile makes clinical testing of this steroidal aromatase inhibitor of interest in the clinical setting.

Cardiovascular Health and Aromatase Inhibitors

Cardiovascular disease is the most frequent cause of death in North American women, and so death resulting from cardiovascular disease, rather than from malignancy, is not uncommon in breast cancer patients. This may be a consequence of the shared risk factors for developing breast cancer and cardiovascular disease, as well as the difficulty of managing cancer patients at higher risk for developing cardiovascular disease. Recently, much attention has focused on understanding the cardiovascular risk factors associated with breast cancer therapies. Tamoxifen has a lowering effect on serum lipids and is reported to decrease the risk of myocardial infarction but to increase the risk of thromboembolic events. Current data indicate that aromatase inhibitors (AIs) are not associated with an increased risk of thromboembolic or cerebrovascular events. Reports of a greater incidence of hypercholesterolaemia when AIs are compared head-to-head with tamoxifen may be a result of the intrinsic lipid-lowering effects of tamoxifen therapy and may be confounded by differences in data collection among trials. The incidence of cardiovascular events associated with AIs in large trials has been reported to be higher in trials comparing AIs with tamoxifen; comparisons within the MA.17 trial, which evaluated an AI versus placebo, did not show increases in hypercholesterolaemia or in cardiovascular events with the AI. When treating breast cancer patients, oncologists should consider the same positive lifestyle changes that are proposed to lower the risk of cardiovascular disease in patients who do not have breast cancer. Moreover, physicians should assess cardiovascular risk, and monitor and treat patients already diagnosed with or at risk for coronary heart disease, according to established guidelines.

Toremifene: an evaluation of its safety profile

Toremifene has been in clinical use for 8 years for the treatment of advanced hormone-sensitive breast cancer and the adjuvant treatment of early breast cancer. More than 350,000 patient treatment years have accumulated, sufficient to allow evaluation of its longer-term safety profile in comparison with tamoxifen and, where possible, with raloxifene and aromatase inhibitors. We reviewed all preclinical and clinical safety data from 1978 to 2004 and comparative clinical safety data between October 1995 and the end of 2004. Secondary endometrial cancer incidence was lower with toremifene than with tamoxifen and was similar to that with raloxifene. It is speculated that toremifene may unmask existing endometrial tumors rather than induce new events. The risk of stroke, pulmonary embolism, and cataract may be lower with toremifene than with tamoxifen and the risk of pulmonary embolism and deep vein thrombosis lower than with raloxifene. Beneficial estrogen agonistic effects were equivalent to those of tamoxifen regarding bone mineral density and superior regarding lipid profiles.