The effect of tamoxifen on breast tumour vascularity

As there is experimental evidence to suggest that tamoxifen may exert an anti-angiogenic effect, the present study was designed to investigate the effect of primary tamoxifen on breast tumour angiogenesis. Fifty seven patients with large operable primary breast cancers were treated with tamoxifen (20mg daily) for between three and six months prior to definitive surgery. Clinical response to treatment was assessed by serial ultrasound measurements of tumour volume and a responding tumour was defined as one in which there was a greater than 25% reduction in volume at the end of treatment. Patients underwent a wedge biopsy at diagnosis and definitive surgery on completion of tamoxifen, thus providing tumour sections before and after treatment. Microvessel counts (mvc) were performed following staining with the endothelial cell marker, antibody to Factor VIII, and changes in mvc were correlated with response.Forty three of 57 patients had tumours that responded to tamoxifen. There was no difference in pre-treatment mvc between non-responding and responding tumours. Post-treatment mvc was significantly higher in non-responding than responding tumours. There was a significant reduction in mvc in responding tumours following treatment with tamoxifen, and a significant increase in mvc was detected in non-responding tumours. A significant correlation was demonstrated between percentage change in mvc and percentage reduction in tumour volume. This is the first study to demonstrate a reduction in breast cancer angiogenesis in tumours that have responded to primary tamoxifen in the clinical setting.     

Prospective study on gynaecological effects of two antioestrogens tamoxifen and toremifene in postmenopausal women

To assess and compare the gynaecological consequences of the use of 2 antioestrogens we examined 167 postmenopausal breast cancer patients before and during the use of either tamoxifen (20 mg/day, n = 84) or toremifene (40 mg/day, n = 83) as an adjuvant treatment of stage II-III breast cancer. Detailed interview concerning menopausal symptoms, pelvic examination including transvaginal sonography (TVS) and collection of endometrial sample were performed at baseline and at 6, 12, 24 and 36 months of treatment. In a subgroup of 30 women (15 using tamoxifen and 15 toremifene) pulsatility index (PI) in an uterine artery was measured before and at 6 and 12 months of treatment. The mean (+/-SD) follow-up time was 2.3 +/- 0.8 years. 35% of the patients complained of vasomotor symptoms before the start of the trial. This rate increased to 60.0% during the first year of the trial, being similar among patients using tamoxifen (57.1%) and toremifene (62.7%). Vaginal dryness, which was present in 6.0% at baseline, increased during the use of tamoxifen (26.2%) and toremifene (24.1%). Endometrial thickness increased from baseline (3.9 +/- 2.7 mm) to 6.8 +/- 4.2 mm at 6 months (P< 0.001), and no difference emerged between the 2 regimens in this regard. Before the start of the antioestrogen regimen, the endometrium was atrophic in 71 (75.5%) and proliferative in 19 of 94 (20.2%) samples; 4 patients had benign endometrial polyps. During the use of antioestrogen altogether 339 endometrial samples were taken (159 in tamoxifen group, 180 in toremifene group). The endometrium was proliferative more often in the tamoxifen group (47.8%) than in the toremifene group (32.2%) (P< 0.0001). 20 patients had a total of 24 polyps (17 in tamoxifen and 9 in toremifene group, P< 0.05) during the use of antioestrogens. One patient in the toremifene group developed endometrial adenocarcinoma at 12 months, and one patient had breast cancer metastasis on the endometrium. Tamoxifen failed to affect the PI in the uterine artery, but toremifene reduced it by 15.0% (P< 0.05) by 12 months. In conclusion, tamoxifen and toremifene cause similarly vasomotor and vaginal symptoms. Neither regimen led to the development of premalignant endometrial changes. Our data suggest that so close endometrial surveillance as used in our study may not be mandatory during the first 3 years of use of antioestrogen treatment.     

Weight gain after primary surgery for breast cancer - effect of tamoxifen

Summary Changes in body weight have been studied in 92 consecutive patients with primary breast cancer from the time of initial diagnosis and treatment. Sixty patients receiving tamoxifen were compared with 32 controls receiving no hormone treatment. Weight gain was seen in both groups, but was greater in the group receiving tamoxifen. Premenopausal women receiving tamoxifen had greater weight gain than postmenopausal women on tamoxifen therapy.     

p53 expression in breast and endometrium during estrogen and tamoxifen treatment of surgically postmenopausal cynomolgus macaques

Estrogens are important for both normal cell growth and malignant proliferation in the mammary gland as well as in the endometrium. Tamoxifen is a nonsteroidal antiestrogen widely used in breast cancer treatment. In recent years reports have been made of an increased risk of endometrial carcinoma during tamoxifen treatment. We used surgically menopausal cynomolgus macaques to study proliferation and p53 expression during hormonal replacement therapy (HRT) and tamoxifen treatment. Animals were treated continuously for 35 months with either conjugated equine estrogens (CEE; n = 20); medroxyprogesterone acetate (MPA; n =17); the combination of CEE + MPA (n = 13) or tamoxifen (n = 17) for 35 months. We found an increased expression of p53 in normal breast and endometrial tissue linked to CEE but not tamoxifen treatment. In the breast alveoli there was an association between proliferation measured by morphometry and p53 expression in all groups. However, in the endometrium CEE induced significantly more p53 positivity than tamoxifen, 9/20 vs. 3/17 in glands and 9/19 vs. 0/17 in stroma, respectively. If indeed longterm treatment with tamoxifen as in the present study could inactivate the tumorsuppressive function of p53, endometrial cells might thereby become more susceptible to genetic lesions associated with carcinogenesis.     

K-ras mutation in the endometrium of tamoxifen-treated breast cancer patients, with a comparison of tamoxifen and toremifene

The putative presence of a mutation in codon 12 of the K-ras gene was investigated in the endometrium of tamoxifen (TAM) and toremifene (TOR)-treated breast cancer patients. DNA was extracted from fresh cytologic samples of the endometrium in 86 TAM and 21 TOR-treated breast cancer patients. Mutations were detected by enriched PCR and an enzyme-linked mini-sequence assay (ELMA). K-ras mutation was found in 35 TAM-treated endometrial samples, and in only one TOR-treated endometrium (P<0.003). In 24 premenopausal patients, K-ras mutation was found in seven (43.8%) of 16 patients with less than 47 months of TAM treatment, while none was found in eight patients with more than 48 months of TAM treatment (P<0.03). In 62 postmenopausal-amenorrheic patients, K-ras mutation was found in three (15.8%) of 19 patients with less than 23 months of TAM treatment, while it was found in 16 (61.5%) of 26 patients with 24-47 months of TAM treatment and nine (52.9%) of 17 patients with more than 48 months of TAM treatment (P=0.002). The presence of K-ras mutation is significantly influenced by the duration of TAM treatment and menstrual status of the patients. TOR may have a lower potential genotoxicity than TAM.     

乳腺癌患者应用三苯氧胺导致的妇科并发症及其监测

三苯氧胺具有抗雌激素和雌激素的双重特性,长期持续使用可导致子宫内膜发生多种病理改变。临床应予以重视,并加以监测。本文就妇科并发症的发生和临床监测方面做一综述,以早发现、并减少并发症的发生。     

The effect of anastrozole on the pharmacokinetics of tamoxifen in post-menopausal women with early breast cancer

Thirty-four post-menopausal women with early breast cancer who had received 20 mg tamoxifen once daily as adjuvant therapy for at least 10 weeks participated in a randomized, double-blind, parallel-group, multicentre trial. The primary aim of the trial was to determine the effect of anastrozole upon tamoxifen pharmacokinetics, with secondary aims of assessing the tolerability of the two drugs in combination and whether or not tamoxifen had any effect upon the oestradiol suppression seen with anastrozole. Patients were randomized to receive either 1 mg anastrozole (16 patients) or matching placebo (18 patients) once daily on a double-blind basis for 28 days. No significant difference (P = 0.919) was observed in serum tamoxifen concentrations between the anastrozole and placebo groups during the trial. The serum concentration of oestradiol was significantly suppressed (P < 0.0001) in patients co-administered anastrozole compared with placebo in the presence of tamoxifen, confirming that anastrozole remained an effective suppressant of oestradiol in the presence of tamoxifen. The combination of tamoxifen and anastrozole was well tolerated, with very little difference in side-effects reported between anastrozole and placebo. In conclusion, the results of this study confirm that anastrozole does not affect the pharmacokinetics of tamoxifen when the two drugs are given in combination to post-menopausal women with early breast cancer. In addition, the oestradiol suppressant effects of anastrozole appear unaffected by tamoxifen. © 1999 Cancer Research Campaign     

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.     

Baseline breast tissue characteristics determine the effect of tamoxifen on mammographic density change

Tamoxifen prevents recurrence of breast cancer and is also approved for preventive, risk-reducing, therapy. Tamoxifen alters the breast tissue composition and decreases the mammographic density. We aimed to test if baseline breast tissue composition influences tamoxifen-associated density change. This biopsy-based study included 83 participants randomised to 6 months daily intake of placebo, 20, 10, 5, 2.5, or 1 mg tamoxifen. The study is nested within the double-blinded tamoxifen dose-determination trial Karolinska Mammography Project for Risk Prediction of Breast Cancer Intervention (KARISMA) Study. Ultrasound-guided core-needle breast biopsies were collected at baseline before starting treatment. Biopsies were quantified for epithelial, stromal, and adipose distributions, and epithelial and stromal expression of proliferation marker Ki67, oestrogen receptor (ER) and progesterone receptor (PR). Mammographic density was measured using STRATUS. We found that greater mammographic density at baseline was positively associated with stromal area and inversely associated with adipose area and stromal expression of ER. Premenopausal women had greater mammographic density and epithelial tissue, and expressed more epithelial Ki67, PR, and stromal PR, compared to postmenopausal women. In women treated with tamoxifen (1–20 mg), greater density decrease was associated with higher baseline density, epithelial Ki67, and stromal PR. Women who responded to tamoxifen with a density decrease had on average 17% higher baseline density and a 2.2-fold higher PR expression compared to non-responders. Our results indicate that features in the normal breast tissue before tamoxifen exposure influences the tamoxifen-associated density decrease, and that the age-associated difference in density change may be related to age-dependant differences in expression of Ki67 and PR.     

Association between endometrial cancer and tamoxifen treatment of breast cancer

A retrospective cohortstudy in 4109 breast cancer patients was undertaken to determine how tamoxifen affected the risk of endometrial cancer. Data on 1701 tamoxifentreated women were analysed. Two thousand four hundred and eight nontamoxifen users served as control group. The occurrence of new primary uterine cancers was assessed by computerized linkage to the Austrian Cancer Registry. Twentyfive 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 nonsignificant 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.     

The Stockholm trial on adjuvant tamoxifen in early breast cancer

Summary The paper presents interim results of an on-going randomized trial of adjuvant tamoxifen (40 mg daily for 2 years) versus no endocrine adjuvant therapy in postmenopausal women with early breast cancer. A total of 1407 patients were included in the study between November 1976 through June 1984. Estrogen receptor (ER) data were available on 1184 patients (84%). The median follow-up was 53 months. Adjuvant tamoxifen increased the recurrence-free interval (P<0.01) but had no significant effect on overall survival. Treatment failures were reduced by 25% (P<0.01) and deaths by 7% (P>0.05). Tamoxifen mainly decreased the frequency of loco-regional recurrence whereas distant metastases were less affected. The treatment effect was independent of tumor stage but was significantly related to the estrogen receptor (ER) content of the primary tumor. Tamoxifen appeared ineffective among ER negative patients, and the greatest effect was seen among those with high levels of ER. The results indicate that the main mechanism of action of adjuvant tamoxifen is similar to that suggested in advanced disease, i.e. an interaction with the estrogen receptor.     

MUC1 expression in primary breast cancer: the effect of tamoxifen treatment

This was a non-randomised single institution retrospective study. Forty-six banked frozen tumour specimens were obtained from a group of patients who had undergone 3 weeks of neoadjuvant treatment with tamoxifen between biopsy and surgery. Fifty-one comparison specimens were randomly selected from a group of concomitantly treated primary breast cancer patients who did not receive neoadjuvant tamoxifen. Specimen selection was not based on prognostic factors: hormone receptor status, patient age, or menopausal status. MUC1 expression and cell cycle distribution were assessed by flow cytometry. S-phase fraction of MUC1 positive and MUC1 negative cells were compared. A lower percentage of cells expressed MUC1 following 3-week tamoxifen treatment 18.2% versus 28.5% (p=0.03, Mann-Whitney) and lower levels of MUC1 expression were seen following tamoxifen treatment 31,519 molecules/cell versus 39,387 (p=0.04, Mann-Whitney). MUC1 positive cells, irrespective of treatment group, had a greater proportion of cells in S-phase of the cell cycle 27.9% versus 16.8% (p=0.0004, Mann-Whitney) and demonstrated more cases of aneuploidy 80.65% versus 42.6% (p<0.0001). MUC1 levels in primary tumours treated neoadjunctively with 3 weeks of tamoxifen were lower than a comparison group which did not receive tamoxifen. MUC1 should be explored further as an intermediate biomarker for assessment of treatment and prognosis.     

Randomized clinical trial of tamoxifen plus sequential CMF chemotherapy versus tamoxifen alone in postmenopausal women with advanced breast cancer

Summary Eighty-eight postmenopausal women with metastatic breast cancer, in whom estrogen receptors (ER) were positive or unknown, were treated on a controlled trial to determine the effectiveness of tamoxifen and to assess the therapeutic advantage of sequentially adding low-dose cyclophosphamide-methotrexate-5-fluorouracil (CMF) chemotherapy in tamoxifen responders. Patients with known ER negative status were not studied. After the initial 12-week treatment with tamoxifen alone, 60% of ER positive patients achieved complete or partial response as did 35% in whom ER were unknown. Response status further improved in 18% randomized to continue tamoxifen alone vs 31% in whom CMF was added to tamoxifen. There were no statistically significant differences in time to the development of progressive disease or survival between the ER positive and ER unknown patients or between the tamoxifen and tamoxifen plus CMF groups. We conclude that inability to determine ER status should not prejudice against the use of tamoxifen in postmenopausal patients with advanced breast cancer. No benefit has been demonstrated from the addition of CMF chemotherapy in tamoxifen responders. Address for reprints: J.H. Glick, M.D., Hospital of the University of Pennsylvania, 3400 Spruce St., Philadelphia, PA 19104.     

The incidence of hepatocellular carcinoma in US white women with breast cancer after the introduction of tamoxifen in 1977

Summary It has been hypothesized that hepatocellular carcinoma might be a long-term adverse effect of tamoxifen therapy. Data from nine population-based cancer registries in the United States were used to investigate time trends in the incidence of hepatocellular carcinoma in white women previously diagnosed with invasive breast cancer during 1974–1987 and followed until 1989. Of particular interest were the rates after 1977, the year tamoxifen was licensed by the FDA. Compared to rates in all white women, no increased risk of hepatocellular carcinoma was found in women most likely to have received tamoxifen - those 50 years of age or more at diagnosis of breast cancer and diagnosed after 1977. These results suggest that tamoxifen does not cause a large increase in the incidence of hepatocellular carcinoma within the first decade after use. However, smaller and/or later increases in the risk for hepatocellular carcinoma are possible and warrant continued monitoring of women treated with tamoxifen.     

Serum cholesterol reduction with tamoxifen

Summary The serum cholesterol levels of 123 consecutively and newly diagnosed women with Stage I and II breast cancer taking tamoxifen were compared with a control group of 81 consecutively newly diagnosed women with Stage I and II breast cancer who were not taking a hormonal treatment or supplement. Other factors that were evaluated were age, menopausal status, tumor size, weight, height, Quetelet index, and smoking and alcohol intake history.The mean cholesterol change in patients on tamoxifen (34.2 ± 3.6 mg/dl) was significantly greater than controls (1.0 ± 4.1 mg/dl) (P<0.001). Serum cholesterol fell by more than 10 mg/dl in 72.9% of women on tamoxifen vs. 35.1% of controls and by more than 40 mg/dl in 39.9% of women on tamoxifen vs. 12.6% of controls. Multivariate analysis revealed that tamoxifen administration (P<0.0001), initial cholesterol level (P = 0.001), and age (P = 0.04) were significant factors in producing a decrease in serum cholesterol.The administration of tamoxifen as adjuvant therapy to women with newly diagnosed breast cancer resulted in a significant fall in serum cholesterol. This effect of tamoxifen on the serum cholesterol may prove to be an additional benefit in the form of reduced cardiovascular risk in these women.     

Endometrial mesodermal mixed tumor occurring after tamoxifen treatment: Report on a new case and review of the literature

Background:Anti oestrogenic treatment is widely used for breastcancer treatment and prevention of recurrence. Because of concomitantestrogenic effects, tamoxifen exerts carcinogenic properties on theendometrium. Although secondary endometrial cancers usually present as pureadenocarcinomas, other types of rare tumors have also been reported. Patients and methods:Herein we describe the clinical,pathological as well as therapeutic aspects of a new case of endometrialmesodermal mixed tumor occurring after long-term tamoxifen therapy. Results:The present case occured five years after cessation ofa five years tamoxifen treatment. The patient failed to respond to doxorubicinand cyclophosphamide when combined to 5-fluorouracil (5-FU), but she reachedcomplete response when the same two drugs were used with carboplatin,suggesting the potential usefullness of platinum derivatives. Conclusions:A longer latency period might be observed forendometrial mesodermal mixed tumors as compared to adenocarcinomas and couldjustify a prolonged clinical and ultrasonographic follow-up of patients duringand after tamoxifen treatment. When indicated, chemotherapy might require theuse of platinum derivatives in this particular type of secondary tumor.     

An alpha-fetoprotein-derived peptide reduces the uterine hyperplasia and increases the antitumour effect of tamoxifen

Tamoxifen (Tam) is effective for the treatment and prevention of breast cancer. However, it has toxic drawbacks and has limited-duration utility because, over time, human tumours become refractory to Tam. Recently, a new nontoxic peptide, alpha-fetoprotein-derived peptide (AFPep) has been proposed for the treatment and prevention of breast cancer. The purpose of this paper is to determine whether combining AFPep with Tam would increase efficacy and reduce toxicity in experimental models of breast cancer. Low doses of AFPep and Tam were more effective in combination than either agent alone against breast cancer growth in cell culture, in tumour-xenografted mice, and in carcinogen-exposed rats. alpha-Fetoprotein-derived peptide interfered with Tam-induced uterine hyperplasia in immature mice, and showed no toxic effects. Unlike Tam, AFPep did not inhibit binding of oestradiol (E(2)) to oestrogen receptor (ER). Thus, these two agents utilise different mechanisms to interfere with ER functionality, yet work cooperatively to reduce breast cancer growth and alleviate Tam's troubling toxicity of uterine hyperplasia and appear to be a rational combination for the treatment of ER-positive breast cancer.