The value of high adherence to tamoxifen in women with breast cancer: a community-based cohort study

Background:

Low adherence to adjuvant tamoxifen is associated with worse health outcomes but little is known about the cost-effectiveness of high adherence.

Methods:

We conducted an economic evaluation using data for all women with incident breast cancer between 1993 and 2000 who were subsequently prescribed tamoxifen in the Tayside region of Scotland. Patient-level, lifetime Markov models evaluated the impact of high vs low adherence to tamoxifen using linked prescribing, cancer registry, clinical cancer audit, hospital discharge and death records. Direct medical costs were estimated for each patient and quality-of-life weights were assigned. Recurrence information was collected by case note review and adherence calculated from prescribing records with low adherence classed below 80%.

Results:

A total of 354 (28%) patients had a recorded recurrence and 504 (39%) died. Four hundred and seventy-five (38%) patients had low adherence over the treatment period, which was associated with reduced time to recurrence of 52% (P<0.001). Time to other cause mortality was also reduced by 23% (P=0.055) but this was not statistically significant. For an average patient over her lifetime, low adherence was associated with a loss of 1.43 (95% CI: 1.15–1.71) discounted life years or 1.12 (95% CI: 0.91–1.34) discounted quality-adjusted life years (QALYs) and increased discounted medical costs of £5970 (95% CI: £4644–£7372). Assuming a willingness to pay threshold of £25 000 per QALY, the expected value of changing a patient from low to high adherence is £33 897 (95% CI: £28 322–£39 652).

Conclusion:

Patients with low adherence have shorter time to recurrence, increased medical costs and worse quality of life. Interventions that encourage patients to continue taking their treatment on a daily basis for the recommended 5-year period may be highly cost-effective.     

Breast Nurse Intervention to Improve Adherence to Endocrine Therapy Among Breast Cancer Patients in South Ethiopia

IntroductionMany women in rural Ethiopia do not receive adjuvant therapy following breast cancer surgery despite the majority being diagnosed with estrogen-receptor-positive breast cancer and tamoxifen being available in the country. We aimed to compare a breast nurse intervention to improve adherence to tamoxifen therapy for breast cancer patients.Methods and MaterialsThe 8 hospitals were randomized to intervention and control sites. Between February 2018 and December 2019, patients with breast cancer were recruited after their initial surgery. The primary outcome of the study was adherence to tamoxifen therapy by evaluating 12-month medication-refill data with medication possession ratio (MPR) and using a simplified medication adherence scale (SMAQ) in a subjective assessment.ResultsA total of 162 patients were recruited (87 intervention and 75 control). Trained nurses delivered education and provided literacy material, gave additional empathetic counselling, phone call reminders, and monitoring of medication refill at the intervention hospitals. Adherence according to MPR at 12 months was high in both the intervention (90%) and control sites (79.3%) (P = .302). The SMAQ revealed that adherence at intervention sites was 70% compared with 44.8% in the control sites (P = .036) at 12 months. Persistence to therapy was found to be 91.2% in the intervention and 77.8% in the control sites during the one-year period (P = .010).ConclusionBreast nurses can improve cost-effective endocrine therapy adherence at peripheral hospitals in low-resource settings. We recommend such task sharing to overcome the shortage of oncologists and distances to central cancer centers.     

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。     

Plasma hormone responses to tamoxifen therapy and oophorectomy

The effect of tamoxifen therapy on plasma hormones in the pre- and postmenopausal state was studied in a young patient with breast cancer. Tamoxifen therapy was carried out for metastatic disease prior to (premenopausal) and after oophorectomy (surgical menopause). Changes in luteinizing hormone, follicle-stimulating hormone, prolactin, and estrogen were noted and were corroborated with the therapy or oophorectomy. The findings support some of the previously reported changes in those hormones that were noted in conjunction with tamoxifen therapy.     

The effect of tamoxifen on the endometrium

Summary Tamoxifen is one of the most important treatments for breast cancer, especially in postmenopausal patients. It acts primarily as an anti-estrogenic agent, due to its cytoplasmic estrogen receptor binding capacity. However, it also exerts a mild estrogenic effect. Since the prolonged use of estrogen has been reported to increase the rate of benign and malignant changes in the endometrium, we evaluated whether there is a correlation between tamoxifen therapy and endometrial benign and malignant conditions. The study group comprised 95 patients with breast cancer who were treated with tamoxifen. No control group was examined. Patients underwent vaginal ultrasonography and endometrial biopsy in order to evaluate any changes in the endometrium occurring during tamoxifen therapy. Pathological changes were observed in 14 patients, 13 of whom were treated with tamoxifen for more than 12 months. Of these women, 3 were diagnosed with endometrial cancer, 3 had mild dysplasia, 3 had endometrial hyperplasia, and 4 had a benign endometrial polyp. Our findings indicate a significant correlation between long-term tamoxifen administration and endometrial proliferation. We therefore recommend that women treated with tamoxifen for more than 12 months have an annual vaginal ultrasonography and endometrial biopsy.     

Drug resistance to tamoxifen during breast cancer therapy

Summary Breast cancer is the most common malignancy occurring in Western women, and is one of the leading causes of cancer mortality. The nonsteroidal antiestrogen tamoxifen has been shown to be an effective treatment for pre and postmenopausal women with all stages of the disease. Tamoxifen provides effective palliation when used to treat patients with advanced disease, and adjuvant tamoxifen therapy produces significant increases in both disease-free and overall survival (Early Breast Cancer Trialists Collaborative Group. Lancet 339:1-15, 71-85, 1992). Data from the laboratory have shown that the primary action of tamoxifen is tumoristatic rather than tumoricidal, and long-term therapy is therefore recommended. Unfortunately, many patients experience disease progression while taking tamoxifen. Some tamoxifen resistant tumors may remain sensitive to alternative endocrine therapies, while others may become refractory to any hormonal manipulation. Many models have been developedin vitro andin vivo to study the progression of breast cancer growth from tamoxifen sensitive to tamoxifen resistant. We and others have used long-term estrogen deprivation and long-term tamoxifen exposure to develop cell lines and tumors capable of growth in the presence of clinically relevant tamoxifen concentrations. Recently our laboratory has also shown that mutations in the estrogen receptor can cause an antiestrogen-occupied receptor to behave as though it were occupied by an estrogen. Breast cancer is a highly heterogeneous disease and it is likely that the mechanisms which cause tamoxifen resistant growth are equally heterogeneous. Several of the models from our laboratory and others which may contribute to an understanding of this complex phenomenon are discussed here.     

Response of metastatic breast cancer to tamoxifen withdrawal: Report of a case

This case history describes a patient with metastatic breast cancer treated sequentially with diethylstilbestrol, drug withdrawal, tamoxifen, and drug withdrawal again. An objective response was observed in all four instances. Withdrawal responses to tamoxifen exist and should be kept in mind for selected patients.     

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.     

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.     

Women's perceptions and experience of adjuvant tamoxifen therapy account for their adherence: breast cancer patients' point of view

Objective: The aim of this study on primary breast cancer patients undergoing adjuvant tamoxifen treatment was to determine how their perceptions of the treatment and their experience of side‐effects contributed to their adherence to the treatment. Methods: A consecutive series of primary breast cancer patients eligible for tamoxifen therapy were studied qualitatively by conducting semi‐structured in‐depth interviews at two French cancer centres. Results: The women aged 35–65 (N=34) were struggling with several issues involving their understanding and experience of the treatment, which have not been documented so far. These issues included confusion about the ‘hormonal’ nature and activity of tamoxifen and the etiology of the changes in their menopausal status, as well as the symbolic associations formed by patients about the paradox of taking a treatment that has aging effects but saves lives. Conclusions: This study shows the great physical burden often associated with tamoxifen treatment and brings to light women's own complex representations of the treatment and their interpretation of the side‐effects. Better communication between health‐care providers and patients should ultimately help to prevent refusal or discontinuation of tamoxifen treatment. Copyright © 2009 John Wiley & Sons, Ltd.     

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.     

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.     

Tumour excision plus continuous tamoxifen compared with modified radical mastectomy in patients over 70 years of age with operable breast cancer

Between 1985 and 1991, we randomly assigned 77 women over the age of 70 years with stage I-3a breast cancer to undergo a modified radical mastectomy or tumour excision followed by tamoxifen. Median follow-up was 45 months. Patients treated by tumour excision and tamoxifen had a significantly better survival (P = 0.04). The disease-free survival of the tumour excision and tamoxifen group was close to significantly better (P = 0.10). Only two patients in the tamoxifen group required an axillary dissection on follow-up for progressive nodal enlargement. Two patients underwent a local mastectomy for locally recurrent disease. We conclude that tumour excision followed by continous tamoxifen is an acceptable, safe alternative to a modified radical mastectomy in patients over 70 years of age.     

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.     

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.     

Adherence to cancer prevention guidelines and risk of breast cancer

Healthy eating patterns and keeping physically active are potentially more important for chronic disease prevention than intake or exclusion of specific food items or nutrients. To this end, many health organizations routinely publish dietary and lifestyle recommendations aimed at preventing chronic disease. Using data from the Canadian National Breast Screening Study, we investigated the association between breast cancer risk and adherence to two sets of guidelines specific for cancer prevention, namely the American Cancer Society (ACS) Guidelines and the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) Recommendations. At baseline, 49,613 women completed dietary and lifestyle questionnaires and height and weight measurements were taken. During a mean follow‐up of 16.6 years, 2,503 incident cases of breast cancer were ascertained. Cox proportional hazard models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the association of meeting each guideline, and number of guidelines met, with breast cancer risk. The two sets of guidelines yielded similar results. Specifically, adherence to all six ACS guidelines was associated with a 31% reduction in breast cancer risk when compared to subjects adhering to at most one guideline (HR = 0.69; 95% CI = 0.49–0.97); similarly, adherence to six or seven of the WCRF/AICR guidelines was also associated with a 31% reduction in breast cancer risk (HR = 0.69; 95% CI = 0.47–1.00). Under either classification, meeting each additional guideline was associated with a 4–6% reduction in breast cancer risk. These results suggest that adherence to cancer prevention guidelines is associated with a reduced risk of breast cancer.     

Treatment of advanced breast cancer with tamoxifen: Evaluation of the dose-response relationship at two dose levels

Summary In order to establish the optimal dose of tamoxifen in the treatment of advanced breast cancer in postmenopausal women, a randomized trial comparing 90 mg daily with the currently recommended dose of 30 mg daily was conducted. Sixty-eight patients were treated with the high dose and 75 patients with the low dose. The rate of response was 36 and 37% (p = 0.74), respectively. The time to response, duration of response, and the time to treatment failure were also identical at the two dose levels. Only a few side effects were observed, and they were equally distributed among the two treatment groups. It is concluded that a 30 mg daily dose of tamoxifen seems to be as effective as 90 mg.