Five versus more than five years of tamoxifen therapy for breast cancer patients with negative lymph nodes and estrogen receptor-positive tumors

The breast surgeon's role in BRCA1 and BRCA2 testing

Five percent to 10% of all women who develop breast cancer carry a hereditary mutation in the genes BRCA1 or BRCA2. Genetic testing is now clinically available, and the results of such testing can dramatically alter a patient's risks for an ipsilateral or contralateral primary breast cancer and ovarian cancer. Therefore, genetic testing will become integral in tailoring surveillance, chemoprevention, and surgical management plans for patients at risk for hereditary cancer syndromes. Such results will also impact the cancer risks for the patient's nuclear and extended family members. Surgeons will play a pivotal role in eliciting personal and family histories from patients, determining which of those histories is suggestive of a germline mutation, facilitating referrals for genetic counseling and testing, and incorporating the results of genetic testing into the patient's short- and long-term management plans.

Chemoprevention of breast cancer by tamoxifen: risks and opportunities

The antiestrogen tamoxifen is widely used in the adjuvant therapy of breast cancers in women and helps to prevent the occurrence of breast tumors in healthy women. However, epidemiological studies have shown tamoxifen treatment to be associated with a 2- to 5-fold increased risk of endometrial cancer. In rats but not in mice, long-term administration of tamoxifen results in an increase in hepatocellular carcinomas. Mechanistically, this occurs through metabolic activation of the drug, mainly by the CYP3A family, to an electrophilic species, that causes DNA damage in target tissues, and subsequently leads to gene mutations. It is controversial whether low levels of DNA damage occur in human uterine tissues, and there is no evidence that this can be causally related to the mechanisms of carcinogenesis. In healthy women, the risk:benefits for the use of tamoxifen is in part related to the risk of developing breast cancer. The results from the carcinogenicity studies in rats do not predict the likelihood that women will develop liver cancer or indeed cancers in other organs. The mechanism of endometrial cancer in women remains unresolved, but the experience with tamoxifen has highlighted the potential problems that need to be addressed in the assessment of future generations of selective estrogen receptor modulators.

Symposium overview: estrogens and antiestrogens in managing the patient with breast cancer

The prevalence of breast cancer (a hormonally driven neoplasm) in the United States, the potential health benefits of estrogen replacement therapy for postmenopausal women, and the burgeoning research focusing on selective estrogen receptor modulators (SERMs) have resulted in additional complexity in managing breast cancer. In an attempt to clarify existing data, the Society of Surgical Oncology sponsored a symposium entitled "Estrogens and Antiestrogens in Managing the Patient with Breast Cancer" at its 52nd Annual Cancer Symposium. This conference was held in March 1999 and was chaired by Dr. S. Eva Singletary, Professor of Surgery and Chief of the Surgical Breast Section at The University of Texas M. D. Anderson Cancer Center in Houston, Texas. The following is a review of the material presented by the symposium participants.

Antiaromatase agents after adjuvant tamoxifen: rationale and clinical implications

Although tamoxifen is considered standard adjuvant hormonal therapy in receptor-positive, stage I and II breast cancer, information on its optimal duration of administration has only been reported recently and, for many, the subject is still a matter of scientific debate. Data suggest that there is a time period beyond which, if tamoxifen is continued, it may become ineffective or even detrimental to the patient. Tamoxifen is usually discontinued after approximately 5 years of therapy, at which time most patients are thought to be disease free; however, some patients may harbor residual micrometastases. A fraction of these patients will have micrometastatic tumor cells that are still responsive to tamoxifen, and tamoxifen discontinuation could result in cancer cell growth. The preponderance of clinical data, however, indicate that a greater fraction of patients will have micrometastatic tumor cells that have become progressively resistant to tamoxifen. In fact, tumor cell growth could be stimulated by continued therapy with the drug. Although in some patients the micrometastatic tumor cells may have become hormonally unresponsive, in most cases (tamoxifen-responsive or tamoxifen-stimulated micrometastases), the tumor remains hormonally responsive. Therefore, the use of anti-aromatase agents to reduce the level of estrogenic stimulation and, as a result, the risk of recurrence may prove to be a valuable approach at the time of tamoxifen discontinuation. The National Surgical Adjuvant Breast and Bowel Project (NSABP) is in the final stages of developing a clinical trial (NSABP B-33) to evaluate the effect of administering 2 years of therapy with the aromatase inactivator exemestane to postmenopausal, receptor-positive patients who have completed 5 years of tamoxifen therapy and are disease free at the time of tamoxifen discontinuation.

Selective estrogen receptor modulators: structure, function, and clinical use

The sex hormone estrogen is important for many physiologic processes. Prolonged stimulation of breast ductal epithelium by estrogen, however, can contribute to the development and progression of breast cancer, and treatments designed to block estrogen's effects are important options in the clinic. Tamoxifen and other similar drugs are effective in breast cancer prevention and treatment by inhibiting the proliferative effects of estrogen that are mediated through the estrogen receptor (ER). However, these drugs also have many estrogenic effects depending on the tissue and gene, and they are more appropriately called selective estrogen receptor modulators (SERMs). SERMs bind ER, alter receptor conformation, and facilitate binding of coregulatory proteins that activate or repress transcriptional activation of estrogen target genes. Theoretically, SERMs could be synthesized that would exhibit nearly complete agonist activity on the one hand or pure antiestrogenic activity on the other. Depending on their functional activities, SERMs could then be developed for a variety of clinical uses, including prevention and treatment of osteoporosis, treatment and prevention of estrogen-regulated malignancies, and even for hormone replacement therapy. Tamoxifen is effective in patients with ER-positive metastatic breast cancer and in the adjuvant setting. The promising role for tamoxifen in ductal carcinoma-in-situ or for breast cancer prevention is evolving, and its use can be considered in certain patient groups. Other SERMs are in development, with the goal of reducing toxicity and/or improving efficacy, and future agents have the potential of providing a new paradigm for maintaining the health of women.

Early operable breast cancer

Early operable breast cancer is a potentially curable disease. However, a substantial number of patients are at risk for systemic recurrence and death. Breast conservation therapy (BCT) should be considered the preferred surgical option for most women with early operable breast cancer. Adjuvant systemic chemotherapy or hormonal therapy can substantially reduce, although not eliminate, the risk of recurrence and death. Neoadjuvant or primary systemic therapy (PST) in operable breast cancer slightly increases the number of women treated with breast conservation versus mastectomy. Although PST may identify women who are likely to have a better prognosis (those with a pathologic complete response), current PST strategies do not offer a survival advantage over standard adjuvant approaches. Early results of high-dose chemotherapy trials thus far have not shown any advantage over conventional dose therapy in high-risk patients with 10 or more positive lymph nodes. The role of adjuvant radiation therapy after mastectomy for all patients with high-risk early operable breast cancer is not fully defined.

Raloxifene: a review of its use in postmenopausal osteoporosis

Raloxifene is a selective estrogen receptor modulator that partially mimics the effects of estrogens in bone and the cardiovascular system, while functioning as an antiestrogen in endometrial and breast tissue. In randomised placebo-controlled studies involving postmenopausal women or patients with osteoporosis, raloxifene 60 to 150 mg/day was effective in increasing bone mineral density (BMD) over 12- to 36-month periods. At the 60 mg/day recommended dosage, increases of 1.6 to 3.4%, 0.9 to 2.3% and 1.0 to 1.6% were reported in lumbar spine, femoral neck and total hip, respectively, versus < or =0.5% with placebo. Raloxifene 60 or 120 mg/day decreased the risk of vertebral fractures over a 36-month period in postmenopausal patients with osteoporosis. Significant reductions in radiographic fracture risk versus placebo (30 and 50%) occurred regardless of whether patients had existing fractures at baseline. Although raloxifene did not affect the overall incidence of nonvertebral fractures, a reduction in the incidence of ankle fracture was reported in comparison with placebo. In postmenopausal women, raloxifene 60 mg/day significantly reduced serum levels of total and low density lipoprotein cholesterol from baseline, compared with placebo. High density lipoprotein cholesterol and triglyceride levels were unaffected. Raloxifene 60 or 120 mg/day reduced the risk of invasive breast cancer by 76% during a median of 40 months' follow-up in postmenopausal patients with osteoporosis and no history of breast cancer. A relative risk reduction of 90% was reported for estrogen-receptor positive invasive breast cancers; estrogen-receptor negative cancer risk was unaffected by raloxifene. Raloxifene was generally well tolerated in clinical trials at dosages up to 150 mg/day. Adverse events thought to be related to raloxifene treatment were hot flushes and leg cramps. Venous thromboembolism was the only serious adverse event thought to be related to raloxifene treatment and a relative risk of 3.1 compared with placebo treatment was reported in patients with osteoporosis. Vaginal bleeding occurred in < or =6.4% of raloxifene-treated women but was reported by 50 to 88% of those receiving estrogens or hormone replacement therapy (HRT). Raloxifene treatment was not associated with stimulatory effects on the endometrium.

CONCLUSIONS

Raloxifene significantly increases BMD in postmenopausal women and reduces vertebral fracture risk in patients with osteoporosis. In clinical trials, raloxifene was generally well tolerated compared with placebo and HRT, although its propensity to cause hot flushes precludes use in women with vasomotor symptoms. In particular, the lack of stimulatory effects on the endometrium and the reduction in invasive breast cancer incidence indicate raloxifene as an attractive alternative to HRT for the management of postmenopausal osteonorosis.

Chemoprevention of breast cancer

Despite a recent trend toward improvement in the U.S. breast cancer mortality rate, breast cancer incidence (182,800 new cases anticipated in 2000) and mortality figures (over 40,800 anticipated deaths) remain the highest and second highest, respectively, of all cancers in U.S. women. In 1998, the selective-estrogen-receptor-modulator (SERM) tamoxifen achieved positive results in the Breast Cancer Prevention Trial (BCPT), leading to the Food and Drug Administration (FDA) approval of tamoxifen for risk reduction in women at high risk of breast cancer (the historic first FDA approval of a cancer preventive agent). This brought about a paradigm shift in new approaches for controlling breast cancer toward pharmacologic preventive regimens, called chemoprevention. This paper presents a comprehensive clinical review of breast cancer prevention study, highlighting issues of the extensive study of tamoxifen. These issues include the record of primary tamoxifen results in several breast-cancer risk-reduction settings (primary, adjuvant, and ductal carcinoma in situ [DCIS]); critical secondary BCPT risk-benefit findings (including quality of life issues) and their effects on counseling patients on use of tamoxifen for prevention; ethic minorities; optimal tamoxifen dose/duration; and potential impact on mortality and other issues involved with potential net benefit to society. Other breast-cancer chemoprevention issues reviewed here include women at high genetic risk (especially BRCA1 mutation carriers); raloxifene in breast cancer prevention; other SERMs; SERM resistance; and new agents and combinations currently in development. Very recent developments involving PPAR-gamma ligands, COX-2 inhibitors, and RXR-ligands are discussed in the section on new drug development.

Selective estrogen receptor modulators in reproductive medicine and biology

Estrogen replacement therapy has significant potential benefits for postmenopausal women, such as improvement of menopausal symptoms and protection from osteoporosis, but it may also increase a woman's risk of breast cancer. Also, some women do not take hormone replacement therapy because of such undesirable side effects as breast tenderness and uterine bleeding. Therefore, there is much interest in the development of compounds that provide the benefits of estrogen replacement therapy without the risks and side effects. The selective estrogen receptor modulators make up one class of compounds with both estrogen agonist and antagonist activity. This review discusses the clinical indications, risks, benefits, and mechanisms of action of selective estrogen receptor modulators and related compounds.

Is there a growing role for endocrine therapy in the treatment of breast cancer?

Novel biochemical findings on the molecular mechanisms of estrogen actions may help us to understand some of the unexplained observations seen in breast cancer treatment and suggest new therapeutic opportunities. Thus, apart from the challenge of improving the clinical treatment of patients with advanced disease, results from trials in this setting may reveal new therapeutic principles that may be evaluated in the adjuvant setting. The role of endocrine therapy in metastatic as well as early breast cancer is increasing, and the possibility of improving cure rates for breast cancer by implementing therapy with novel aromatase inhibitors in the adjuvant setting is exciting. While the results from prevention trials are most interesting, suggesting the possibility of reducing breast cancer incidence in high-risk groups, more data are needed before we can decide whether such interventions are warranted in women at high risk of developing breast cancer.

Selective oestrogen receptor modifiers (SERMs) and breast cancer therapy

Antioestrogen therapy is currently receiving renewed interest for several reasons. Tamoxifen was introduced in the treatment of metastatic breast cancer more than three decades ago. The drug significantly reduces long term mortality and also reduces the risk of contralateral tumours when administered in early breast cancer. Five years of tamoxifen is now standard in adjuvant endocrine therapy, and the drug is currently being evaluated for breast cancer prevention. Despite this, several aspects regarding the pharmacology of the drug are still unclear, and the scientific rationale for dose selection has recently been challenged. Several novel antioestrogen compounds, called selective oestrogen receptor modifiers (SERMs), express selective oestrogen agonistic or antagonistic properties depending on the organ or test system evaluated. Some of these drugs, like raloxifene, do not seem to promote the development of endometrial cancer, although they still have selected oestrogen-like beneficial effects. This paper reviews the pharmacologic and the pharmacokinetic aspects of the different SERMs with particular emphasis on their potential use in therapy and prevention of breast cancer.

Altering the estrogenic milieu of breast cancer with a focus on the new aromatase inhibitors

Aromatase is a dual-enzyme complex that catalyzes the synthesis of estrogen from androgenic precursors. Although evidence implicates estrogens in the pathogenesis of breast cancer, recent findings suggest that deregulation of aromatase may be a crucial link between these hormones and this neoplasm. Whereas tamoxifen is the endocrine therapy of choice, selective inhibition of aromatase may be equally effective, and possibly less toxic, in the management of patients with hormone-responsive breast tumors.

Antiestrogens--tamoxifen, SERMs and beyond

Estrogens play a central role in reproductive physiology. The cellular effects of estrogens are mediated by binding to nuclear receptors (ER) which activate transcription of genes involved in cellular growth control. At least two such receptors, designated ERalpha and ERbeta, mediate these effects in conjunction with a number of coactivators. These receptors can directly interact with other members of the steroid receptor superfamily. A complex cross-talk exists between the estrogen-signaling pathways and the downstream signaling events initiated by growth factors, such as epidermal growth factor and insulin-like growth factors. Estrogens are also a causative factor in the pathogenesis of a variety of neoplastic and non-neoplastic diseases, including breast cancer, endometrial cancer, endometriosis, and uterine fibroids, among others. Antiestrogens, such as tamoxifen, are widely used for the treatment of breast cancer. Tamoxifen produces objective tumor shrinkage in advanced breast cancer, reduces the risk of relapse in women treated for invasive breast cancer, and prevents breast cancer in high-risk women. Although, initially developed as an antiestrogen, tamoxifen can also prevent postmenopausal osteoporosis as well as reduce cholesterol, due to its estrogen-agonist effects. Its estrogen-agonist activity, however, can lead to significant side-effects such as endometrial cancer and thromboembolic phenomena. This has led to the concept of "ideal" selective estrogen receptor modulators (SERMs), drugs that would have the desired, tissue selective, estrogen-agonist or -antagonist effects. Raloxifene is a SERM which has the desirable mixed agonist/antagonist effects of tamoxifen but does not cause uterine stimulation. "Pure" antiestrogens may provide very potent estrogen-antagonist drugs, but are likely to be devoid of beneficial effects on bone and lipids. Future drug development efforts should focus on developing superior SERMs that have a greater efficacy against ER-positive tumors and do not cause hot flashes or thromboembolism, and explore combination strategies to simultaneously target hormone-dependent as well as hormone-independent breast cancer.

Effect of time interval between breast-conserving surgery and radiation therapy on ipsilateral breast recurrence

PURPOSE

To examine the effect of the time interval (interval) between breast-conserving surgery (BCS) and the start of radiation therapy (RT) on the subsequent risk of ipsilateral breast cancer recurrence (IBR).

METHODS AND MATERIALS

We reviewed interval and a number of prognostic and treatment factors among 1,962 women treated with BCS and RT for invasive breast cancer diagnosed between January 1, 1989 and December 31, 1993 in British Columbia, Canada. Subjects were female, less than 90 years old at diagnosis, not treated with chemotherapy, not stage T4 or M1, and had survived more than 30 days from diagnosis. The cumulative incidence of IBR was estimated in four interval groups: 0-5, 6-8, 9-12, and 13+ weeks. Only 23 women had an interval of greater than 20 weeks between BCS and start of RT. To assess whether an imbalance of prognostic and treatment factors could be obscuring real differences between the interval groups, Cox proportional hazards regression analyses were conducted.

RESULTS

Median follow-up was 71 months. The crude incidence of IBR for the entire sample was 3.9%. The cumulative incidence of IBR in the 6-8, 9-12, and 13+ week groups was not statistically significantly different from the cumulative incidence of IBR in the 0-5 week group. Multivariate analyses demonstrated that patients not using tamoxifen p = 0.027) and those with grade 3 histology (p = 0.003) were more likely to recur in the breast. Interval between BCS and RT was not a statistically significant predictor of breast recurrence when entered into a model incorporating tamoxifen use and tumor grade (0-5 vs. 6-8 weeks, p = 0.872; 0-5 vs. 9-12 weeks, p = 0.665; 0-5 vs. 13+ weeks, p = 0.573).

CONCLUSIONS

We found no univariate or multivariate difference in ipsilateral breast cancer recurrence between intervals of 0 to 20 weeks from breast conserving surgery to start of radiation therapy, in a population-based, low risk group of women not receiving adjuvant chemotherapy, after controlling for other factors important in predicting ipsilateral breast cancer recurrence.

Results of two or five years of adjuvant tamoxifen correlated to steroid receptor and S-phase levels. South Sweden Breast Cancer Group, and South-East Sweden Breast Cancer Group

A Swedish cooperative trial demonstrated that 5 years of adjuvant tamoxifen was more beneficial than 2 years of tamoxifen in the treatment of postmenopausal women with estrogen receptor (ER) positive, early stage, invasive breast cancer. The main aim of the present study was to investigate the importance of progesterone receptor (PgR) and ER concentration levels for patients participating in the trial and still distant recurrence free two years after the primary operation. Subgroup analyses revealed that only patients with ER positive and PgR positive breast cancer had improved distant recurrence free survival (DRFS) by prolonged tamoxifen therapy (p = 0.0016). Patients with ER negative and PgR negative as well as ER positive and PgR negative tumors showed no significant effect of prolonged tamoxifen (p = 0.53 and p = 0.80, respectively). The percentage of ER negative and PgR positive breast cancers was too small (2.2%) for any meaningful subgroup analysis. There was a significant positive trend that the concentration level of PgR (high positive vs. low positive vs. negative) decreased the recurrence rate for those with prolonged therapy. No corresponding pattern was found for the ER content. S-phase fraction did not correlate to the recurrence rate of PgR positive breast cancers. Patients recurring during tamoxifen therapy had receptor negative tumors to a greater extent than those recurring after tamoxifen treatment. In conclusion, prolonged tamoxifen therapy for 5 years instead of 2 years was found to be beneficial for patients with ER positive and PgR positive breast cancer, whereas three extra years of tamoxifen had little or no effect for patients with ER positive but PgR negative tumors as well as for steroid receptor negative patients.

From Halsted to prevention and beyond: advances in the management of breast cancer during the twentieth century

This commentary evaluates progress made in the treatment of breast cancer during the twentieth century. Most of the period from 1900 to 1970 was governed by the 'non-science' of anecdotalism and classical inductivism and was marked by the absence of a scientific gestalt. In keeping with the Halstedian concept that breast cancer was a local disease that spread throughout the body by contiguous extension and could be cured by more expansive surgery, the disease was treated with radical surgery. In 1950, however, a new era of enlightenment began to emerge. The awareness that there was a scientific process in which hypotheses generated from laboratory and clinical investigation could be tested by means of randomised clinical trials was a seminal advance, as were findings from studies that laid the groundwork for the modern era of steroid hormone action, including identification of oestrogen receptors. Expanding knowledge regarding tumour cell kinetics, tumour heterogeneity, and technological advances related to mammography and radiation therapy were also to play a role in making possible the advances in therapy that were subsequently to occur. In the past 30 years, as a result of laboratory and clinical investigation, the Halstedian thesis of cancer surgery was displaced by an alternative hypothesis that was supported by findings from subsequent clinical trials. A new paradigm governed surgery for breast cancer, and lumpectomy followed by radiation therapy became accepted practice. A second paradigm that governed the use of adjuvant systemic therapy arose as a result of laboratory and clinical investigation. Treating patients who were free of identifiable metastatic disease with systemic adjuvant therapy because some of them might develop distant disease in the future was a revolutionary departure from prior treatment strategy and became a new exemplar. Not only did the chemotherapy favourably alter the outcome of breast cancer patients, but the anti-oestrogen tamoxifen benefited patients with all stages of the disease. Tamoxifen also reduced the incidence of contralateral breast cancer, as well as tumour in the ipsilateral breast following lumpectomy. The use of preoperative therapy was also found to enhance breast-conserving surgery in women with large tumours, although its value in other circumstances is still being defined. The observation that, as a result of tamoxifen administration, invasive and non-invasive breast cancers can be prevented in women who are at increased risk for such tumours, and the finding that pathological entities such as atypical hyperplasia, lobular carcinoma in situ (LCIS) and intraductal carcinoma (DCIS) can identify women who should be considered candidates for tamoxifen serve as a fitting capstone to the accomplishments of the twentieth century. Breast cancer prevention has now become a reality. Unfortunately, a variety of circumstances have arisen as the result of advances in the understanding and treatment of breast cancer over the last 30 years that threaten to nullify the progress that has been achieved. This distressing phenomenon may be reviewed as a 'paradox of accomplishment'. The numerous uncertainties, issues and questions that have arisen following the report of each advance in treatment, the surfeit of new information that has not yet been integrated into treatment strategies, the undesirable consequences of enhanced tumour detection, a reversion to Halstedianism and anecdotalism, and the uncertainty of therapeutic decision making resulting from the demonstration of small but statistically significant benefits, particularly in patients with good prognosis, need to be addressed. Inappropriate interpretation of those circumstances threatens to deny women with breast cancer and those at high risk for the disease the opportunity to benefit from treatments that have been proven to be of worth. Perhaps the most important accomplishment of the twentieth century relates to the change in the pro

Tamoxifen in high-risk premenopausal women with primary breast cancer receiving adjuvant chemotherapy. Report from the Danish Breast Cancer co-operative Group DBCG 82B Trial

Following modified radical mastectomy, pre- and perimenopausal (amenorrhoea for < 5 years) patients with stage II or III breast cancer received CMF (cyclophosphamide 600, methotrexate 40, 5-fluorouracil 600 mg/m2 intravenously (i.v.) every 4 weeks, 9 cycles). The effect on recurrence-free survival (RFS) and overall survival (OS) of the addition of adjuvant tamoxifen (TAM) to adjuvant chemotherapy was examined by randomisation either to no additional treatment (n = 314), or concurrently TAM 30 mg daily for 1 year (n = 320). 40% had positive, 12% negative and 48% unknown receptor status. One year after surgery 21% versus 35% (CMF + TAM versus CMF) were still menstruating (P < 0.01). With a median follow-up of 12.2 years there was no difference in RFS (10-year RFS 34% versus 35%, P = 0.81) or OS (45% versus 46%, P = 0.73). In a Cox proportional hazards model, tumour size, number of metastatic lymph nodes, frequency of metastatic nodes in relation to total number of nodes removed, degree of anaplasia, age, and menostasia within the first year after operation were significant independent prognostic factors for RFS, and the same factors except age for OS. No significant interactions with TAM were seen. Thus, in this group of pre- and perimenopausal high-risk early breast cancer patients with heterogeneous receptor status given CMF i.v., concurrent TAM for 1 year did not improve the outcome. These results do not exclude that receptor positive patients may benefit from adjuvant TAM for longer periods given sequentially to chemotherapy.

The Potential of SERMs for Reducing the Risk of Coronary Heart Disease

Selective estrogen receptor modulators (SERMs) represent a growing class of compounds that act as either estrogen receptor agonists or antagonists in a tissue-selective manner. Preclinical and clinical studies have shown that estrogen has favorable effects on serum lipids and might affect processes at the blood vessel wall to inhibit atherosclerosis. SERMs with the appropriate selectivity profile offer the opportunity to dissociate these favorable cardiovascular effects of estrogen from its unfavorable stimulatory effects on the breast and uterus. This article reviews the data from both animal and human studies that document the cardiovascular effects of SERMs and discusses the clinical implications of these results.

Tamoxifen and endometrial pathologies: a prospective study

OBJECTIVE

The purpose of this study was to prospectively follow a group of women with breast cancer, on tamoxifen, for the development of endometrial pathologies.

MATERIALS AND METHODS

Eighty women with breast cancer, on tamoxifen, were prospectively followed every 6 months with pelvic examination, Pap smear, vaginal ultrasound, and endometrial biopsy.

RESULTS

Nine women were lost to follow-up prior to initiation of treatment and 4 refused biopsies, leaving 67 patients for evaluation. Fifty (74.6%) of the 67 patients were already on tamoxifen for a mean duration of 15.8 +/- 16.6 months and had a baseline benign, unremarkable endometrium at the time of entry into the study. The total duration of treatment was 32.5 +/- 19.6 months (median 30 months). The mean age of the patients was 51.7 +/- 9.9 years (median 52 years). Of the patients, 56.7% were postmenopausal. Sixty-three patients had a benign endometrium (mean age 51.8 +/- 10.1 years, mean duration 33.1 +/- 19.6 months). Two patients had simple hyperplasia (mean age 43.5 years, duration 28.5 +/- 33.2 months), 1 patient had complex hyperplasia with atypia (age 57 years, duration 13 months), and another patient developed adenocarcinoma (grade 3) after 22 months. These 4 patients had abnormal vaginal bleeding. Seven patients developed endometrial polyps (mean age 54.0 +/- 8.5 years, duration 36 +/- 24.2 months). The mean endometrial thickness for patients with histologically unremarkable and abnormal endometrium was not significantly different (7.6 +/- 3.9 vs 8.8 +/- 5.0 mm, respectively) (median 7.0 mm for both groups). No endometrial thickness cutoff point reached statistical significance. The patient who developed endometrial cancer had a thickness of only 3 mm.

CONCLUSION

All patients who developed an abnormal endometrium had abnormal vaginal bleeding. There was no correlation between endometrial thickness and endometrial pathology; thus the value of routine screening remains controversial.

The Molecular Pharmacology of SERMs

Estrogen-containing medicines have been used successfully for the past 50 years for the treatment of conditions associated with menopause. Although initially considered a reproductive hormone, millions of years of clinical exposure to estrogen(s) have indicated that its influence extends to a variety of target tissues not generally considered to be involved in reproduction. Specifically, estrogen has positive actions in the skeleton, the cardiovascular system and possibly the central nervous system, activities that combine to have a positive impact on mortality and morbidity. However, despite the medical benefits afforded by estrogen replacement therapy, the number of women who initiate or remain on therapy for longer than one year is relatively small. This is due in part to the fear that estrogens increase the risk for breast cancer. Consequently, it was realized several years ago that novel estrogen receptor modulators were needed, which would retain the beneficial effects of estrogens in most target organs but be inactive in the breast. Although the perfect tissue-selective estrogen remains to be identified, progress in this direction has been made. In the past year, for example, we have seen selective estrogen receptor modulators (SERMs) enter into the clinic for the prevention of osteoporosis. Compounds of this class, which function as estrogens in the skeletal system but oppose estrogen action in the breast, are the first step in developing the perfect hormone replacement therapy. This review summarizes the complex pharmacology of the SERMs and illustrates how they differ mechanistically from estradiol, the physiological ligand of the estrogen receptor.

Cost-effectiveness of MR imaging and core-needle biopsy in the preoperative work-up of suspicious breast lesions

PURPOSE

To assess the clinical and economic consequences of the use of preoperative breast magnetic resonance (MR) imaging and core-needle biopsy (CNB) to avert excisional biopsy (EXB).

MATERIALS AND METHODS

A decision-analytic Markov model was constructed to compare MR imaging, CNB, and EXB without preoperative testing in a woman with a suspicious breast lesion. Stage-specific cancer prevalence, tumor recurrence, progression rates, and MR imaging and CNB sensitivity and specificity were obtained from the literature. Cost estimates were obtained from the literature and from the Medicare fee schedule.

RESULTS

EXB without preoperative testing was associated with the greatest quality-adjusted life expectancy, followed by MR imaging and CNB; life expectancies were 17.409, 17.405, and 17.398 years, respectively. EXB resulted in the greatest lifetime treatment cost ($31,438), followed by MR imaging ($29,072) and CNB ($28,573). Results were robust over a wide range of cancer prevalence, stage distribution, tumor progression rates, and procedure and treatment costs. Incremental cost-effectiveness ratios showed that preoperative testing was cost-effective, but the choice between MR imaging and CNB was highly dependent on the accuracy of each test and to patient preferences.

CONCLUSION

Preoperative testing of most suspicious breast lesions was cost-effective. More precise estimates of MR imaging and CNB test performance characteristics are needed. Until those are available, patient preferences should inform individual decisions regarding preoperative testing.

Health-related quality of life and tamoxifen in breast cancer prevention: a report from the National Surgical Adjuvant Breast and Bowel Project P-1 Study

PURPOSE

This is the initial report from the health-related quality of life (HRQL) component of the National Surgical Adjuvant Breast and Bowel Project Breast Cancer Prevention Trial. This report provides an overview of HRQL findings, comparing tamoxifen and placebo groups, and advice to clinicians counseling women about the use of tamoxifen in a prevention setting.

PATIENTS AND METHODS

This report covers the baseline and the first 36 months of follow-up data on 11,064 women recruited over the first 24 months of the study. Findings are presented from the Center for Epidemiological Studies-Depression Scale (CES-D), the Medical Outcomes Study 36-Item Short Form Health Status Survey (MOS SF-36) and sexual functioning scale, and a symptom checklist.

RESULTS

No differences were found between placebo and tamoxifen groups for the proportion of participants scoring above a clinically significant level on the CES-D. No differences were found between groups for the MOS SF-36 summary physical and mental scores. The mean number of symptoms reported was consistently higher in the tamoxifen group and was associated with vasomotor and gynecologic symptoms. Significant increases were found in the proportion of women on tamoxifen reporting problems of sexual functioning at a definite or serious level, although overall rates of sexual activity remained similar.

CONCLUSION

Women need to be informed of the increased frequency of vasomotor and gynecologic symptoms and problems of sexual functioning associated with tamoxifen use. Weight gain and depression, two clinical problems anecdotally associated with tamoxifen treatment, were not increased in frequency in this trial in healthy women, which is good news that also needs to be communicated.

Breast cancer screening, diagnosis, and treatment

The incidence of breast cancer in US women remains disturbingly high, and unfortunately primary care physicians still frequently encounter patients in whom the disease is suspected or, even worse, confirmed. Fortunately, however, the body of knowledge surrounding the disease has grown dramatically during the past decade, and major advances have been made in the understanding of breast cancer risk, prevention, diagnosis, and treatment. Controversies persist, particularly those concerning the screening of younger women, but consensus now exists regarding many clinical issues relevant to primary care practice. Although multidisciplinary subspecialty expertise must be made available to all women with known or suspected breast cancer, the primary care physician has an important role to play when dealing with patients with this condition. The following article focuses on what primary care practitioners need to know to expertly contribute to the diagnosis, counseling, and initial treatment of women with this disease.

Current status of tamoxifen use: An update for the surgical oncologist

The surgical oncologist is frequently responsible for the screening and diagnosis of women with breast cancer. In this pivotal role, they are often the first to discuss treatment options, including nonsurgical interventions, with breast cancer patients. Recent long-term clinical trial data provide support for the use of tamoxifen to prevent breast cancer in women at high risk of the disease. A breast cancer risk assessment can help identify women at higher than average risk for the disease, who may be appropriate candidates for chemoprevention. It is important for the surgical oncologist to understand the current indications and evidence regarding the use of tamoxifen for breast cancer prevention and treatment as they counsel their patients on available options.

Patients with early stage invasive cancer with close or positive margins treated with conservative surgery and radiation have an increased risk of breast recurrence that is delayed by adjuvant systemic therapy

PURPOSE

The association between a positive resection margin and the risk of ipsilateral breast tumor recurrence (IBTR) after conservative surgery and radiation is controversial. The width of the resection margin that minimizes the risk of IBTR is unknown. While adjuvant systemic therapy may decrease the risk of an IBTR in all patients, its impact on patients with positive or close margins is largely unknown. This study examines the interaction between margin status, margin width, and adjuvant systemic therapy on the 5- and 10-year risk of IBTR after conservative surgery and radiation.

METHODS AND MATERIALS

A series of 1,262 patients with clinical Stage I or II breast cancer were treated by breast-conserving surgery, axillary node dissection, and radiation between March 1979 and December 1992. The median follow-up was 6.3 years (range 0.1-15.6). The median age was 55 years (range 24-89). Clinical size was T1 in 66% and T2 in 34%. Seventy-three percent of patients were node-negative. Only 5 % of patients had tumors that were EIC-positive. Forty-one percent had a single excision, and 59% had a reexcision. The final margins were negative in 77%, positive in 12%, and close (< or = 2 mm) in 11%. The median total dose to the tumor bed was 60 Gy with negative margins, 64 Gy with close margins, and 66 Gy with positive margins. Chemotherapy +/- tamoxifen was used in 28%, tamoxifen alone in 20%, and no adjuvant systemic therapy in 52%.

RESULTS

The 5-year cumulative incidence (CI) of IBTR was not significantly different between patients with negative (4%), positive (5%), or close (7%) margins. However, by 10 years, a significant difference in IBTR became apparent (negative 7%, positive 12%, close 14%, p = 0.04). There was no significant difference in IBTR when a close or positive margin was involved by invasive tumor or DCIS. Reexcision diminished the IBTR rate to 7% at 10 years if the final margin was negative; however, the highest risk was observed in patients with persistently positive (13%) or close (21%) (p = 0.02) margins. The median interval to failure was 3.7 years after no adjuvant systemic therapy, 5.0 years after chemotherapy +/- tamoxifen, and 6.7 years after tamoxifen alone. This delay to IBTR was observed in patients with close or positive margins, with little impact on the time to failure in patients with negative margins. The 5-year CI of IBTR in patients with close or positive margins was 1% with adjuvant systemic therapy and 13% with no adjuvant therapy. However, by 10 years, the CI of IBTR was similar (18% vs. 14%) due to more late failures in the patients who received adjuvant systemic therapy.

CONCLUSION

A negative margin (> 2 mm) identifies patients with a very low risk of IBTR (7% at 10 years) after conservative surgery and radiation. Patients with a close margin (< or = 2 mm) are at an equal or greater risk of IBTR as with a positive margin, especially following a reexcision. A margin involved by DCIS or invasive tumor has the same increased risk of IBTR. A reexcision of an initially close or positive margin that results in a negative final margin reduces the risk of IBTR to that of an initially negative margin. A close or positive margin is associated with an increased risk of IBTR even in patients who are EIC-negative or receiving higher boost doses of radiation. The median time to IBTR is delayed; however, the CI is not significantly decreased by adjuvant systemic therapy in patients with close or positive margins-the 5 year results in these patients underestimate their ultimate risk of recurrence.

Development of a new prevention maintenance therapy for postmenopausal women

In spring 1998, breast cancer prevention emerged from being a concept to being a reality. The National Surgical Adjuvant Breast and Bowel Project prevention trial showed that tamoxifen reduced breast cancer by 45% in high-risk women between the ages of 35 and 75. Additionally, an evaluation of 10,550 patients randomized to osteoporosis trials of placebo versus raloxifene demonstrated a 50% reduction in the incidence of breast cancer in woman taking raloxifene. For the future, a Study of Tamoxifen Against Raloxifene (STAR) is ongoing in high-risk postmenopausal women. This chapter describes the biological rationale for the current clinical advances.

Is axillary lymph node dissection indicated for early-stage breast cancer? A decision analysis

PURPOSE

Axillary lymph node dissection (ALND) has been a standard procedure in the management of breast cancer. In a patient with a clinically negative axilla, ALND is performed primarily for staging purposes, to guide adjuvant treatment. Recently, the routine use of ALND has been questioned because the results of the procedure may not change the choice of adjuvant systemic therapy and/or the survival benefit of a change in adjuvant therapy would be small. We constructed a decision model to quantify the benefits of ALND for patients eligible for breast-conserving therapy.

METHODS

Patients were grouped by age, tumor size, and estrogen receptor (ER) status. The model uses the Oxford overviews and three combined Cancer and Leukemia Group B studies. We assumed that patients who did not undergo ALND received axillary radiation therapy and that the two procedures are equally effective. All chemotherapy combinations were assumed to be equally efficacious.

RESULTS

The largest benefits from ALND are seen in ER-positive women with small primary tumors who might not be candidates for adjuvant chemotherapy if their lymph nodes test negative. Virtually no benefit results in ER-negative women, almost all of whom would receive adjuvant chemotherapy. When adjusted for quality of life (QOL), ALND may have an overall negative impact. In general, the benefits of ALND increase with the expected severity of adjuvant therapy on QOL CONCLUSION: Our model quantifies the benefits of ALND and assists decision making by patients and physicians. The results suggest that the routine use of ALND in breast cancer patients should be reassessed and may not be necessary in many patients.

A Retrospective Study of Breast Cancer Patients Treated with Quadrantectomy without Radiation Therapy

BACKGROUND: Radiation therapy after breast-conserving surgery (BCS) reduces the risk of local recurrence. However, whether radiation therapy is necessary forall patients undergoing BCS remains unclear. METHODS: In order to determine the selection criteria for patients who can safely omit radiation therapy and to confirm the survival benefit of quadrantectomy without radiation therapy, we reviewed 107 patients who underwent quadrantectomy without radiation therapy between February 1988 and July 1995. RESULTS: The 5-year overall survival, disease-free survival and cumulative local recurrence rates were 93.7%, 80.7% and 12.1% respectively. There were no significant differences of 5-year overall survival (94.0% vs 94.1%) and disease-free survival rates (83.1% vs 70.0%) between patients with or without tamoxifen. The 5-year cumulative local recurrence rate of patients with tamoxifen, however, tended to be lower (p = 0.0810) than that of patients without tamoxifen. The 5-year cumulative local recurrence rate of the patients aged 45 or less was significantly higher than that of patients aged from 45 to 55 years and those over 55 (p= 0.0090 and 0.0089, respectively). In ER positive patients, the 5-year cumulative local recurrence rate of patients with tamoxifen tended to be lower (p= 0.0791) than that of patients without tamoxifen. CONCLUSION: The survival rate of quadrantectomy without radiation therapy wasacceptable. While the risk of local recurrence following quadrantectomy withoutradiation therapy is substantial, radiation therapy following quadrantectomy might not be necessary in elderly ER positive women receiving adjuvant tamoxifen therapy.

Adjuvant therapy for resectable breast cancer

The breast cancer mortality rate is falling, most likely because of a combination of early detection, refined surgical and radiation therapy techniques, and improved systemic therapy efficacy. The proper integration and application of these treatment modalities present evolving challenges for clinicians. Systemic therapy, in particular, is changing rapidly with the advent of new chemotherapy drugs, new classes of agents, and new therapeutic regimens. The most recent studies suggest that optimal outcomes are possible through the broad but appropriate use of hormone therapy and chemotherapy to prevent relapse and possibly prevent second primary tumors. The choice of therapy for patients remains a matter for careful consideration and discussion in each individual case.

S-phase fraction combined with other patient and tumor characteristics for the prognosis of node-negative, estrogen-receptor-positive breast cancer

Women with estrogen-receptor (ER)-positive breast cancer and no axillary lymph-node involvement are considered to have excellent overall prognosis. However, this population is not homogeneous with regard to risk of recurrence; in fact, some of these patients have a prognosis no better than that of many women with ER-negative tumors or positive axillary nodes. Consequently, better tumor markers and better use of those currently available are needed to distinguish patients who would benefit from more aggressive therapy from those for whom such therapy is unnecessary. A well-defined cohort of over 4000 breast cancer patients from National Surgical Adjuvant Breast and Bowel Project (NSABP) Protocol B-14 who had ER-positive tumors and no axillary lymph-node involvement was analyzed to ascertain the usefulness of tumor cell S-phase fraction for prognosis. The significance of clinical tumor size, patient age at surgery, ER and progesterone receptor (PgR) expression, and nuclear grade was also explored. Statistical methods based on smoothing splines were used to relate treatment failure and mortality rates to patient and tumor characteristics. Models for 5- and 10-year disease-free survival (DFS) and overall survival were developed and summarized. The attenuation of the prognostic importance of covariates over time was investigated. After other characteristics were accounted for, a strong association was found between S-phase fraction and DFS, as well as survival. Tumor size, patient age at surgery, and PgR status were also significantly associated with outcome. The diversity of risk in the B-14 population was more extreme than is generally recognized. The prognostic capabilities of S-phase, tumor size, and PgR status were sharply attenuated as the time from surgery increased.

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.

North American Adjuvant Breast Cancer Trials

The National Cancer Institutes in the United States and Canada sponsor Cooperative Groups to perform randomized trials in distinct subsets of patients with early breast cancer. In women with low-risk ductal carcinoma in situ (DCIS), ongoing studies are evaluating the role of adjuvant breast irradiation. For those with low-risk, node-negative invasive tumors, efforts have been directed to improving the efficacy of tamoxifen, while in high-risk patients the focus has been on improving chemotherapy. The roles of dose intensity and dose density have been evaluated at dose levels requiring either G-CSF or stem cells. More recently, the introduction of taxanes into adjuvant regimens has been a major area of investigation. Following treatment with doxorubicin-cyclophosphamide (AC), patients have been randomized to receive paclitaxel or no further therapy in INT 0148 and NSABP B-28 and to receive docetaxel in NSABP B-27. For women with 4-9 involved nodes, sequential treatment A(doxorubicin)-T(paclitaxel)-C(cyclophosphamide) with G-CSF is being compared to AC x 4 followed by high-dose chemotherapy with stem cell support. Cooperative Group trials have been critical in defining the standard of care in the past, and successful completion of these new trials is essential for further progress against breast cancer.

Tamoxifen and risk of large bowel cancer in women with breast cancer

BACKGROUND

The increasingly consistent association between estrogen replacement therapy and colorectal cancer suggests that the anti-estrogen tamoxifen may also be associated with large bowel cancer incidence.

METHODS

Women with new diagnoses of breast cancer were identified from the Surveillance Epidemiology and End Results (SEER) Program, a set of geographically defined, population based cancer registries representing approximately ten percent of the U.S. population. Of 85,411 women with local or regional breast cancer diagnosed from 1983-90, 14,984 women were reported to have received hormonal therapy and 70,427 were not known to have received hormonal therapy. Subsequent cancer diagnoses were identified in this cohort beginning 6 months after initial breast cancer diagnosis until death, or December 31, 1994. Multivariate Cox proportional hazards models were used to estimate the risk of developing colorectal cancer and other second cancers according to hormonal therapy use.

RESULTS

Over the follow-up period 793 colorectal, 2,648 contralateral breast, 506 endometrial, 250 ovarian, 98 gastric, and 1,765 other cancers were identified in the study cohort. While overall there was no association between hormonal therapy use and colorectal cancer (relative risk (RR) 1.09, 95% confidence interval (CI) 0.88-1.35), in the period five or more years after diagnosis, risk was increased significantly by about 50% (95% CI 1.00-2.15). As expected, based upon clinical trials data, cancers of the contralateral breast were significantly decreased, and cancers of the uterine endometrium were significantly increased. No other meaningful associations were observed. When women were excluded for whom hormonal therapy might represent therapy other than tamoxifen (premenopausal women and those who received chemotherapy), this did not meaningfully alter these estimates.

CONCLUSIONS

The results of this large population based cohort study suggest that tamoxifen therapy may modestly increase risk of large bowel cancer in women, but only after 5 years following initiation of breast cancer therapy.