Randomised comparison of 5 years of adjuvant tamoxifen with continuous therapy for operable breast cancer. The Scottish Cancer Trials Breast Group

Evidence that tamoxifen preserves bone density in late postmenopausal women with breast cancer

Tamoxifen, which is used for treating breast cancer, exhibits estrogenic and antiestrogenic characteristics, depending on the tissue. In the human breast it acts as an antiestrogen, whereas estrogenic effects have been reported on endometrium and bone. The purpose of this study was to determine whether tamoxifen (TAM) prevents bone loss in elderly, postmenopausal women. Bone mineral density of the lumbar spine (SBD) was measured in elderly women (at least 10 years after menopause) 5 years after stage I or II breast cancer (n = 111). The results showed that SBD in untreated patients (n = 74) was significantly lower (p < 0.05) than SBD in patients (n = 37) treated with TAM over 5 years. In a subgroup of patients (n = 24) with positive estrogen receptor status, changes in SBD 12 months after discontinuation of 5-year TAM therapy were measured and compared with the changes of extended TAM treatment over a sixth year. Twelve months after withdrawal of 5-year TAM medication (n = 11) bone density decreased significantly (- 4.8+/-2.5%; p > 0.05), whereas in the group of women (n = 13) receiving extended TAM medication (20 mg) for an additional 12 months, SBD ( + 1.9+/-3.5 %) was maintained during the observation period, and was significantly higher when compared with the group of untreated patients (p <0.05). We conclude that tamoxifen has a preventive effect on trabecular bone loss at the lumbar spine, when compared to age-matched data and to untreated women with breast cancer in the late menopause. Our data give evidence of benefits to bone density provided by prolonged administration in patients after breast cancer and at risk of osteoporosis.

Hormonal treatment of endometrial cancer

This article summarizes the endocrine background of women with endometrial cancer at both peripheral and tissue levels, and the current status of clinical trials of hormonal, cytotoxic, and combination regimens. Because significant advances in systemic therapy are required to improve the prognosis of endometrial cancer, recommendations for future clinical investigations will be based on these recent biologic observations.

Early stopping of a clinical trial when there is evidence of no treatment benefit: protocol B-14 of the National Surgical Adjuvant Breast and Bowel Project

Although several randomized clinical trials in the 1980s indicated a benefit from the use of tamoxifen in the treatment of early-stage breast cancer, questions have remained regarding the optimal duration of drug administration. In 1982, the National Surgical Adjuvant Breast and Bowel Project (NSABP) initiated a randomized trial to compare 5 years of tamoxifen to placebo among breast cancer patients with estrogen receptor-positive tumors and no evidence of axillary node involvement. By 1987, evidence of a substantial benefit for tamoxifen led the NSABP to extend this trial to determine whether longer duration tamoxifen therapy would be additionally beneficial. This study randomized patients who had completed 5 years of tamoxifen free of breast cancer recurrence or other events to either tamoxifen or placebo for an additional 5 years. By 1994, 1172 women had entered the study and accrual was closed. In late 1995, the trial was terminated on the basis of interim findings indicating that a benefit for continuing tamoxifen would not be realized. The closure has prompted controversy among cancer researchers, because there are currently at least three tamoxifen duration trials in progress, whereas results from two other studies evaluating 5-year duration therapy versus longer therapy were recently published. Here, we provide details of the statistical rationale contributing to our decision to recommend early closure of the study. We then consider other possible approaches to assessing the appropriateness of early termination in the face of evidence against a benefit, including Bayesian methods, which can be used to incorporate a range of prior beliefs regarding the efficacy of a treatment with accruing information from the trial. We also briefly discuss results of the other published studies.

Possible respect of patient quality of life--without reducing survival expectancy--in breast cancer treatment

The treatment of breast cancer by some doctors in all countries and all in some does not concern itself with quality of life considerations. Partial breast cancer surgery is possible in cases of neither voluminous nor central tumors, and surgery can also be partial after pre-surgical chemotherapy reduction. The apoptotic test for cytostatic choice should assist in obviating toxicities which are minor for the physician, i.e., alopecia, cardiac lesion, etc, but which are major for the patient. Cytostatics will be useless in treatment if they are not apoptogenic. Hormonal treatment may, when there are estrogen receptors involved, be advantageously combined with chemotherapy. In estrogen receptors absence, growth factor receptors should be considered, as there is a possible indication of somatostatin analogs (instead of hormones, which are useless). Quality of life is mainly determined by the partial character of the surgery, hence by the volume and localization of the tumor. Cancer screening allows diagnosis when tumors are smaller as opposed to those which are the object of spontaneous diagnosis. We even propose screening of dysplasias and their biological treatment between 40 and 50 years--hormonal if the specific cells carry hormone receptors, and based on somatostatin analogs if they carry growth factor receptors.

The Role of Hormonal Therapy in Breast Cancer

This review reassesses the role of hormonal therapy in breast cancer specifically the sequential or concurrent use of endocrine therapy and the combined use of chemotherapy with endocrine therapy. In advanced disease the sequential use of hormone therapies is generally recommended rather than the combined use of various hormonal agents, though combination hormonal therapy offers advantages in certain subsets of patients. The efficacy of combined chemo-endocrine therapy is questionable. Chemotherapy with estrogenic recruitment is an attractive but still experimental concept. However, in an adjuvant setting there is evidence that combined chemo-endocrine therapy causes a significant increase in disease-free and/or overall survival, particularly in postmenopausal patients with estrogen receptor(ER)-positive tumors. While hormonal treatment strategies have clearly benefitted from randomized studies, data regarding optimal endocrine therapy are still insufficient.

Controversies regarding tamoxifen and uterine carcinoma

An increasing number of cases of endometrial cancer in women receiving tamoxifen have been reported but most are from non-randomized studies and case reports. In the last year, there have been no further results either confirming or disproving an association between tamoxifen and endometrial cancer from randomized controlled studies in breast cancer patients and those participating in chemopreventative trials with tamoxifen. Several papers have examined the possible mechanisms behind tamoxifen's endometrial effects.

Inhibition of 7,12-dimethylbenz[a]anthracene-induced rat mammary tumor growth by aryl hydrocarbon receptor agonists

The antitumorigenic activities of 6-methyl-1,3,8-trichlorodibenzofuran (6-MCDF), 8-methyl-1,3,6-trichlorodibenzofuran (8-MCDF) and 6-cyclohexyl-1,3,8-trichlorodibenzofuran (6-CHDF) were investigated in the 7,12-dimethylbenz[a]anthracene (DMBA) rat mammary tumor model. At doses of 5, 10 or 25 mg/kg/week, both 6-MCDF and 8-MCDF significantly inhibited mammary tumor growth and at the 5 mg/kg/week dose >50% growth inhibition was observed. In contrast, 6-CHDF was inactive at the 5 mg/kg/week dose and the structure-antitumorigenicity relationships (6-MCDF/8-MCDF > 6-CHDF) correlated with structure-antiestrogenicity (rat uterus) studies and the relative binding affinities of these compounds for the aryl hydrocarbon receptor (AhR). The antitumorigenic activity of 6-MCDF or 8-MCDF in the mammary was not accompanied by any significant changes in liver/body weight ratios, liver morphology or induction of hepatic CYP1A1-dependent activity which is one of the most sensitive indicators of exposure to AhR agonists. RT-PCR and Western blot analysis of mammary tumor mRNA and protein extracts, respectively, confirmed the presence of AhR suggesting that AhR-mediated signaling pathways are functional in rat mammary tumors. These results define a relatively non-toxic group of AhR agonists which exhibit potent antitumorigenic activity in the DMBA-induced rat mammary tumor model (<1 mg/kg/day), and therefore represent a new class of indirect-acting antiestrogens which have potential for clinical treatment of mammary cancer.