Adjuvant trial of 12 cycles of CMFPT followed by observation or continuous tamoxifen versus four cycles of CMFPT in postmenopausal women with breast cancer: an Eastern Cooperative Oncology Group phase III study

Opportunities and challenges of long term anti-estrogenic adjuvant therapy: treatment forever or intermittently?

INTRODUCTION

Extended adjuvant (5-10 years) therapy targeted to the estrogen receptor (ER) has significantly decreased mortality from breast cancer (BC). Areas covered: Translational research advanced clinical testing of extended adjuvant therapy with tamoxifen or aromatase inhibitors (AIs). Short term therapy or non-compliance increase recurrence, but surprisingly recurrence and death does not increase dramatically after 5 years of adjuvant therapy stops. Expert commentary: Compliance ensures optimal benefit from extended antihormone adjuvant therapy.Retarding acquired resistance using CDK4/6 or mTOR inhibitors is discussed. Preventing acquired resistance from mutations of ER could be achieved with Selective ER Downregulators (SERDs), eg fulvestrant. Fulvestrant is a depot injectable so oral SERDs are sought for extended use. In reality, a 'super SERD' which destroys ER but improves women's health like a Selective ER Modulator (SERM), would aid compliance to prevent recurrence and death. Estrogen-induced apoptosis occurs in 30% of BC with antihormone resistance. The 'one in three' rule that dictates that one in three unselected patients respond to either hormonal or antihormonal therapy in BC occurs with estrogen or antiestrogen therapy and must be improved. The goal is to maintain patients for their natural lives by blocking cancer cell survival through precision medicine using short cycles of estrogen apoptotic salvage therapy, and further extended antihormone maintenance.

The molecular, cellular and clinical consequences of targeting the estrogen receptor following estrogen deprivation therapy

During the past 20 years our understanding of the control of breast tumor development, growth and survival has changed dramatically. The once long forgotten application of high dose synthetic estrogen therapy as the first chemical therapy to treat any cancer has been resurrected, refined and reinvented as the new biology of estrogen-induced apoptosis. High dose estrogen therapy was cast aside once tamoxifen, from its origins as a failed "morning after pill", was reinvented as the first targeted therapy to treat any cancer. The current understanding of the mechanism of estrogen-induced apoptosis is described as a consequence of acquired resistance to long term antihormone therapy in estrogen receptor (ER) positive breast cancer. The ER signal transduction pathway remains a target for therapy in breast cancer despite "antiestrogen" resistance, but becomes a regulator of resistance. Multiple mechanisms of resistance come into play: Selective ER modulator (SERM) stimulated growth, growth factor/ER crosstalk, estrogen-induced apoptosis and mutations of ER. But it is with the science of estrogen-induced apoptosis that the next innovation in women's health will be developed. Recent evidence suggests that the glucocorticoid properties of medroxyprogesterone acetate blunt estrogen-induced apoptosis in estrogen deprived breast cancer cell populations. As a result breast cancer develops during long-term hormone replacement therapy (HRT). A new synthetic progestin with estrogen-like properties, such as the 19 nortestosterone derivatives used in oral contraceptives, will continue to protect the uterus from unopposed estrogen stimulation but at the same time, reinforce apoptosis in vulnerable populations of nascent breast cancer cells.

Tamoxifen as the first targeted long-term adjuvant therapy for breast cancer

Tamoxifen is an unlikely pioneering medicine in medical oncology. Nevertheless, the medicine has continued to surprise us, perform, and save lives for the past 40 years. Unlike any other medicine in oncology, it is used to treat all stages of breast cancer, ductal carcinoma in situ, and male breast cancer and pioneered the use of chemoprevention by reducing the incidence of breast cancer in women at high risk and induces ovulation in subfertile women! The impact of tamoxifen is ubiquitous. However, the power to save lives from this unlikely success story came from the first laboratory studies which defined that 'longer was going to be better' when tamoxifen was being considered as an adjuvant therapy. This is that success story, with a focus on the interdependent components of: excellence in drug discovery, investment in self-selecting young investigators, a conversation with Nature, a conversation between the laboratory and the clinic, and the creation of the Oxford Overview Analysis. Each of these factors was essential to propel the progress of tamoxifen to evolve as an essential part of the fabric of society.

Extended adjuvant chemotherapy in endocrine non-responsive disease

INTRODUCTION AND AIMS

There is a biological rationale for expecting benefit from longer duration therapy in the subpopulation of patients with endocrine non-responsive disease. Such tumors have a rapid cell proliferation and are associated with a high risk of relapse despite adjuvant chemotherapy. Moreover, prolonged duration of chemotherapy may be particularly relevant for patients with triple negative disease to inhibit the growth of tumors that are not susceptible to the effects of endocrine therapies due to lack of steroid hormone receptors, or to the effects of anti-HER2 target treatment.

METHODS AND RESULTS

The question of duration of adjuvant chemotherapy for breast cancer has been directly addressed in several trials herein presented. Most of these were small and, therefore, unsuitable for detecting differences of modest magnitude in intrinsic biological subtypes. In addition, a number of trials examine regimens which differ in duration of therapy, but also in the drugs given. In these trials the effects of duration and choice of drug are inextricably confounded. However incremental chemotherapy strategies, compared with less extensive therapies, were more effective in past studies particularly in patients with endocrine non-responsive disease.

CONCLUSIONS

The evidence resulting from past trials indicates that conventional-dose chemotherapy for 4-6 months is an adequate option in patients whose tumors present a low or no expression of steroid hormone receptors. These tumor subtypes are part of a highly heterogeneous subgroup (e.g., basal-like, molecular apocrine, claudin-low, HER-enriched). Tailored research through international cooperation is key to solidify consensus on how to treat individual patients with endocrine non-responsive breast cancer.

Survival in patients with metastatic recurrent breast cancer after adjuvant chemotherapy: little evidence of improvement over the past 30 years

BACKGROUND

Population-based studies have shown improved survival for patients diagnosed with metastatic breast cancer over time, presumably because of the availability of new and more effective therapies. The objective of the current study was to determine whether survival improved for patients who developed distant recurrence of breast cancer after receiving adjuvant therapy.

METHODS

Adjuvant chemotherapy trials coordinated by the Eastern Cooperative Oncology Group that accrued patients between 1978 and 2002 were reviewed. Survival after distant disease recurrence was estimated for progressive time periods, and adjusted for baseline covariates in a Cox proportional hazards model.

RESULTS

Of the 13,785 patients who received adjuvant chemotherapy in 11 trials, 3447 (25%) developed distant disease recurrence; the median survival after recurrence was 20 months (95% confidence interval, 19 months-21 months). Factors associated with inferior survival included a shorter distant recurrence-free interval (DRFI), estrogen receptor-negative and progesterone receptor-negative disease, the number of positive axillary lymph nodes present at the time of diagnosis, and black race (P < .0001 for all). When the time period of recurrence was added to the model, it was not found to be significantly associated with survival for the general population with disease recurrence. Survival improved over time only in those patients with hormone receptor-negative disease with a DRFI ≤ 3 years, both among the 5 most recent and the entire trial data sets (P = .01 and P = .05, respectively).

CONCLUSIONS

In contrast to reports from population-based studies, no general improvement in survival was observed over the last 30 years for patients who developed distant disease recurrence after adjuvant chemotherapy after adjusting for DRFI. Improved survival for patients with hormone receptor-negative disease with a short DRFI suggests a benefit from trastuzumab.

The 38th David A. Karnofsky lecture: the paradoxical actions of estrogen in breast cancer--survival or death?

During the first David A. Karnofsky Award lecture entitled "Thoughts on Chemical Therapy" in 1970, Sir Alexander Haddow commented about the dramatic regressions observed with estrogen in some breast cancers in postmenopausal women, but regrettably the mechanism was unknown. He was concerned that a cancer-specific target would remain elusive, without tests to predict response to therapy. At that time, I was conducting research for my PhD on an obscure group of estrogen derivatives called nonsteroidal antiestrogens. Antiestrogens had failed to fulfill their promise as postcoital contraceptives and were unlikely to be developed further by the pharmaceutical industry. In 1972, that perspective started to change and ICI 46,474 was subsequently reinvented as the first targeted therapy for breast cancer. The scientific strategy of targeting the estrogen receptor (ER) in the tumor, treating patients with long-term adjuvant therapy, examining active metabolites, and considering chemoprevention all translated through clinical trials to clinical practice during the next 35 years. Hundreds of thousands of women now have enhanced survivorship after their diagnosis of ER-positive breast cancer. However, it was the recognition of selective ER modulation (SERM) that created a new dimension in therapeutics. Nonsteroidal antiestrogens selectively turn on or turn off estrogen target tissues throughout the body. Patient care was immediately affected by the recognition in the laboratory that tamoxifen would potentially increase the growth of endometrial cancer during long-term adjuvant therapy. At that time, a failed breast cancer drug, keoxifene, was found to maintain bone density of rats (estrogenic action) while simultaneously preventing mammary carcinogenesis (antiestrogenic action). Perhaps a SERM used to prevent osteoporosis could simultaneously prevent breast cancer? Keoxifene was renamed raloxifene and became the first SERM for the treatment and prevention of osteoporosis as well as the prevention of breast cancer, but without an increase in endometrial cancer. There the story might have ended had the study of antihormone resistance not revealed a vulnerability of cancer cells that could be exploited in the clinic. The evolution of antihormone resistance over years of therapy reconfigures the survival mechanism of the breast cancer cell, so estrogen no longer is a survival signal but a death signal. Remarkably, remaining tumor tissue is again responsive to continuing antihormone therapy. This new discovery is currently being evaluated in clinical trials but it also solves the mystery mechanism of chemical therapy with estrogen noted by Haddow in the first Karnofsky lecture.

Locoregional Recurrence after Mastectomy: Incidence and Outcomes

BACKGROUND

Locoregional recurrences (LRR) after mastectomy may be ominous events, but incidence and outcomes data are limited by heterogeneous study populations and the time period studied. We sought to evaluate the rate of LRR at a single institution in the era of multimodality therapy, identify predictors for isolated LRR, and examine treatment strategies and outcomes of postmastectomy patients with isolated LRR.

STUDY DESIGN

In a prospective database, we identified 1,057 patients who underwent mastectomy for invasive cancer at Memorial Sloan-Kettering Cancer Center from 1995 to 1999. Predictive factors for isolated LRR were determined by univariate and multivariate analyses. Treatments and outcomes of patients with isolated LRR were reviewed. All patients with at least 2 years of followup were included. Median followup was 6 years.

RESULTS

Overall, LRR developed in 93 of 1,057 (8.8%) patients. Thirty-four (3.2%) had synchronous distant metastases. Distant recurrences developed in thirty-one (2.9%) during the followup period (median followup, 6 years). Twenty-eight patients with LRR (2.6%) remained free of distant disease during the study period. Multivariate analysis showed age less than 35 years, lymphovascular invasion, and multicentricity as major predictors for isolated LRR. In the 28 patients with isolated LRR, 24 had recurrence in the chest wall, 2 in the axilla, and 2 in more than 1 local site. Seventy-eight percent (22 of 28) of patients were rendered disease free with surgery (15 of 22), radiotherapy (13 of 22), chemotherapy (6 of 22), or hormones (9 of 22).

CONCLUSIONS

Despite widespread use of adjuvant therapies during the study period, we found an LRR rate after mastectomy of 9%. But for patients presenting with LRR without evidence of distant disease, aggressive multimodality therapy is warranted because many of these patients can be rendered disease free.

Tamoxifen--what next?

Most patients with advanced breast cancer (ABC) ultimately die due to disease progression. Consequently, treatments for ABC are predominantly palliative in nature and, therefore, the tolerability profile of a given treatment is particularly relevant in these patients. While cytotoxic chemotherapy and endocrine therapy exhibit efficacy in hormone-sensitive, advanced disease, it is endocrine therapy that combines efficacy with minimal acute toxicity. Tamoxifen has been the chosen endocrine therapy for postmenopausal, hormone-sensitive, ABC for over 20 years. More recently, new endocrine agents with different mechanisms of action from tamoxifen have been introduced. Evidence indicates that the aromatase inhibitors anastrozole (Arimidex; AstraZeneca; Wilmington, DE), letrozole (Femara; Novartis Pharmaceuticals Corp.; East Hanover, NJ) and exemestane (Aromasin; Pharmacia Corp.; Peapack, NJ) offer superior efficacy and tolerability to tamoxifen in the first-line treatment of postmenopausal, hormone-sensitive ABC. Similarly, after tamoxifen failure, fulvestrant (Faslodex; AstraZeneca), a new estrogen receptor (ER) antagonist that downregulates the ER, is at least as effective as anastrozole, is well tolerated, and is not cross-resistant with tamoxifen. Unlike tamoxifen, fulvestrant has no known agonist effects. The sequential use of such agents may prolong the time during which endocrine therapies can be used, thereby avoiding the more acute toxicities associated with cytotoxic chemotherapy. Indeed, a series of studies has shown that this sequential use is a relevant, active, and well-tolerated option. Establishing the comparative efficacies and optimal sequences that incorporate the newer endocrine agents will be central in determining the future role of hormonal therapy in ABC; the results of this work will determine the relative place of tamoxifen in what is a rapidly changing therapeutic environment.

Dose Density in Adjuvant Chemotherapy for Breast Cancer

BACKGROUND

Dose-dense chemotherapy increases the dose intensity of the regimen by delivering standard-dose chemotherapy with shorter intervals between the cycles. This article discusses the rationale for dose-dense therapy and reviews the results with dose-dense adjuvant regimens in recent clinical trials in breast cancer.

METHODS

The papers for this review covered evidence of a dose-response relation in cancer chemotherapy; the rationale for dose-intense (and specifically dose-dense) therapy; and clinical experience with dose-dense regimens in adjuvant chemotherapy for breast cancer, with particular attention to outcomes and toxicity.

RESULTS

Evidence supports maintaining the dose intensity of adjuvant chemotherapy within the conventional dose range. Disease-free and overall survival with combination cyclophosphamide, methotrexate, and fluorouracil are significantly improved when patients receive within 85% of the planned dose. Moderate and high dose cyclophosphamide, doxorubicin, and fluorouracil within the standard range results in greater disease-free and overall survival than the low dose regimen. The sequential addition of paclitaxel after concurrent doxorubicin and cyclophosphamide also significantly improves survival. Disease-free and overall survival with dose-dense sequential or concurrent doxorubicin, cyclophosphamide, and paclitaxel with filgrastim (rhG-CSF; NEUPOGEN) support are significantly greater than with conventional schedules (q21d).

CONCLUSIONS

The delivered dose intensity of adjuvant chemotherapy within the standard dose range is an important predictor of the clinical outcome. Prospective trials of high-dose chemotherapy have shown no improvement over standard regimens, and toxicity was greater. Dose-dense adjuvant chemotherapy improves the clinical outcomes with doxorubicin-containing regimens. Filgrastim support enables the delivery of dose-dense chemotherapy and reduces the risk of neutropenia and its complications.

Randomized trial comparing six versus three cycles of epirubicin-based adjuvant chemotherapy in premenopausal, node-positive breast cancer patients: 10-year follow-up results of the French Adjuvant Study Group 01 trial

PURPOSE

To evaluate the duration and dose intensity of epirubicin-based regimens in premenopausal patients with lymph node-positive breast cancer.

PATIENTS AND METHODS

Between 1986 and 1990, 621 patients with operable breast cancer were randomly assigned to receive fluorouracil (Roche SA, Basel, Switzerland) 500 mg/m2, epirubicin (Pharmacia SA, Milan, Italy) 50 mg/m2, and cyclophosphamide (Asta Medica AG, Frankfurt, Germany) 500 mg/m2 every 21 days (FEC 50) for six cycles (6 FEC 50); FEC 50 for three cycles (3 FEC 50); or the same regimen with epirubicin 75 mg/m2 (FEC 75) for three cycles (3 FEC 75). All patients in the three arms received chest wall irradiation at the end of the third cycle.

RESULTS

After a 131-month median follow-up, the 10-year disease-free survival (DFS) was 53.4%, 42.5%, and 43.6% (P =.05) in the three arms, respectively. Pairwise comparisons demonstrate that 6 FEC 50 was superior both to 3 FEC 50 (P =.02) and to 3 FEC 75 (P =.05). The 10-year overall survival (OS) for the 6 FEC 50 arm was 64.3%, for the 3 FEC 50 arm it was 56.6%, and for the 3 FEC 75 arm, it was 59.7% (P =.25), respectively. Pairwise comparisons demonstrate that 6 FEC 50 was more effective than 3 FEC 50 (P =.10). Cox regression analysis demonstrates that OS was significantly better in the 6 FEC 50 than in the 3 FEC 50 arm (P =.046). No severe infections (grade 3 to 4), acute cardiac toxicity, or deaths from toxicity have been observed. Only five patients developed delayed cardiac dysfunctions, and three patients developed acute myeloblastic leukemia.

CONCLUSION

After a long-term follow-up in an adjuvant setting, the benefit of six cycles of FEC 50 compared with three cycles, whatever the dose, is highly significant in terms of DFS. As regards OS, the group receiving six cycles of FEC 50 has significantly better results than the group receiving three cycles of FEC 50.

Tamoxifen ("Nolvadex"): a review

Tamoxifen has been used in the management of breast cancer for over 30 years. Since its introduction for the treatment of advanced breast cancer, its indications have increased to include the treatment of early breast cancer, ductal carcinoma in situ, and more recently for breast cancer chemoprevention. Tamoxifen has a good tolerability profile and moreover, unlike many other endocrine therapies, it is efficacious in both pre- and postmenopausal women. It is the combination of efficacy and tolerability that allows tamoxifen to maintain its position as the hormonal treatment of choice for most patients with oestrogen-receptor positive breast cancer. Ongoing studies will provide further information about the optimal duration of tamoxifen therapy and how it compares with the newer aromatase inhibitors.

Duration of adjuvant tamoxifen therapy

The benefit of using adjuvant tamoxifen to treat breast cancer has been firmly established for patients with estrogen receptor (ER)-positive tumors, regardless of age, lymph node status, or menopausal status. Uncertainty remains, however, regarding the optimal duration of tamoxifen therapy. We reviewed the findings of randomized clinical trials that directly compared alternative treatment durations. Trials comparing short-term adjuvant treatment with tamoxifen (i.e., 1-3 years) with treatments having durations of about 5 years consistently have demonstrated additional benefits stemming from the longer therapy. Trials testing 5 years of treatment with longer durations have, in the aggregate, suggested no additional benefit for the patient. Nevertheless, the number of recurrences reported to date in these trials is not large, and the results of the individual trials are heterogeneous. Furthermore, as a result of tamoxifen's "carryover" effect, duration trials require considerable follow-up before definitive results can be established. Until more definitive data become available, adjuvant treatment with tamoxifen should be limited to 5 years outside the clinical trials setting. Continued accrual of ER-positive patients to ongoing tamoxifen duration trials, including the Adjuvant Tamoxifen Treatment Offer More (aTTom) and Adjuvant Tamoxifen Longer Against Shorter (ATLAS) trials, is appropriate. Alternatively, patients who remain disease free after 5 years of tamoxifen therapy should be encouraged to participate in trials testing crossover to other hormonal interventions, including selective ER modulators or aromatase inhibitors.

Duration of adjuvant chemotherapy for breast cancer: a joint analysis of two randomised trials investigating three versus six courses of CMF

Cyclophosphamide, methotrexate and fluorouracil adjuvant combination chemotherapy for breast cancer is currently used for the duration of six monthly courses. We performed a joint analysis of two studies on the duration of adjuvant cyclophosphamide, methotrexate and fluorouracil in patients with node-positive breast cancer to investigate whether three courses of cyclophosphamide, methotrexate and fluorouracil might suffice. The International Breast Cancer Study Group Trial VI randomly assigned 735 pre- and perimenopausal patients to receive 'classical' cyclophosphamide, methotrexate and fluorouracil for three consecutive cycles, or the same chemotherapy for six consecutive cycles. The German Breast Cancer Study Group randomised 289 patients to receive either three or six cycles of i.v. cyclophosphamide, methotrexate and fluorouracil day 1, 8. Treatment effects were estimated using Cox regression analysis stratified by clinical trial without further adjustment for covariates. The 5-year disease-free survival per cents (+/-s.e.) were 54+/-2% for three cycles and 55+/-2% for six cycles (n=1024; risk ratio (risk ratio: CMFx3/CMFx6), 1.00; 95% confidence interval, 0.85 to 1.18; P=0.99). Use of three rather than six cycles was demonstrated to be adequate in both studies for patients at least 40-years-old with oestrogen-receptor-positive tumours (n=594; risk ratio, 0.86; 95% confidence interval, 0.68 to 1.08; P=0.19). In fact, results slightly favoured three cycles over six for this subgroup, and the 95% confidence interval excluded an adverse effect of more than 2% with respect to absolute 5-year survival. In contrast, three cycles appeared to be possibly inferior to six cycles for women less than 40-years-old (n=190; risk ratio, 1.25; 95% confidence interval, 0.87 to 1.80; P=0.22) and for women with oestrogen-receptor-negative tumours (n=302; risk ratio, 1.15; 95% confidence interval, 0.85 to 1.57; P=0.37). Thus, three initial cycles of adjuvant cyclophosphamide, methotrexate and fluorouracil chemotherapy were as effective as six cycles for older patients (40-years-old) with oestrogen-receptor-positive tumours, while six cycles of adjuvant cyclophosphamide, methotrexate and fluorouracil might still be required for other cohorts. Because endocrine therapy with tamoxifen and GnRH analogues is now available for younger women with oestrogen-receptor-positive tumours, the need for six cycles of cyclophosphamide, methotrexate and fluorouracil is unclear and requires further investigation.

Locoregional failure of postmastectomy patients with 1-3 positive axillary lymph nodes without adjuvant radiotherapy

PURPOSE

To analyze the incidence and risk factors for locoregional recurrence (LRR) in patients with breast cancer who had T1 or T2 primary tumor and 1-3 histologically involved axillary lymph nodes treated with modified radical mastectomy without adjuvant radiotherapy (RT).

MATERIALS AND METHODS

Between April 1991 and December 1998, 125 patients with invasive breast cancer were treated with modified radical mastectomy and were found to have 1-3 positive axillary nodes. The median number of nodes examined was 17 (range 7-33). Of the 125 patients, 110, who had no adjuvant RT and had a minimum follow-up of 25 months, were included in this study. Sixty-nine patients received adjuvant chemotherapy and 84 received adjuvant hormonal therapy with tamoxifen. Patient-related characteristics (age, menopausal status, medial/lateral quadrant of tumor location, T stage, tumor size, estrogen/progesterone receptor protein status, nuclear grade, extracapsular extension, lymphovascular invasion, and number of involved axillary nodes) and treatment-related factors (chemotherapy and hormonal therapy) were analyzed for their impact on LRR. The median follow-up was 54 months.

RESULTS

Of 110 patients without RT, 17 had LRR during follow-up. The 4-year LRR rate was 16.1% (95% confidence interval [CI] 9.1-23.1%). All but one LRR were isolated LRR without preceding or simultaneous distant metastasis. According to univariate analysis, age <40 years (p = 0.006), T2 classification (p = 0.04), tumor size >==3 cm (p = 0.002), negative estrogen receptor protein status (p = 0.02), presence of lymphovascular invasion (p = 0.02), and no tamoxifen therapy (p = 0.0006) were associated with a significantly higher rate of LRR. Tumor size (p = 0.006) was the only risk factor for LRR with statistical significance in the multivariate analysis. On the basis of the 4 patient-related factors (age <40 years, tumor >==3 cm, negative estrogen receptor protein, and lymphovascular invasion), the high-risk group (with 3 or 4 factors) had a 4-year LRR rate of 66.7% (95% CI 42.8-90.5%) compared with 7.8% (95% CI 2.2-13.3%) for the low-risk group (with 0-2 factors; p = 0.0001). For the 110 patients who received no adjuvant RT, LRR was associated with a 4-year distant metastasis rate of 49.0% (9 of 17, 95% CI 24.6-73.4%). For patients without LRR, it was 13.3% (15 of 93, 95% CI 6.3-20.3%; p = 0.0001). The 4-year survival rate for patients with and without LRR was 75.1% (95% CI 53.8-96.4%) and 88.7% (95% CI 82.1-95.4%; p = 0.049), respectively. LRR was independently associated with a higher risk of distant metastasis and worse survival in multivariate analysis.

CONCLUSION

LRR after mastectomy is not only a substantial clinical problem, but has a significant impact on the outcome of patients with T1 or T2 primary tumor and 1-3 positive axillary nodes. Patients with risk factors for LRR may need adjuvant RT. Randomized trials are warranted to determine the potential benefit of postmastectomy RT on the survival of patients with a T1 or T2 primary tumor and 1-3 positive nodes.

Estimates of the likely prophylactic effect of tamoxifen in women with high risk BRCA1 and BRCA2 mutations

The development of breast cancer control strategies in women at high genetic risk of breast cancer is an important issue. The likely benefit of chemopreventive approaches is of particular interest. Tamoxifen tends to be more effective in both prevention and treatment of oestrogen receptor positive tumours than oestrogen receptor negative. In this study, we combine the oestrogen-receptor specific effects of tamoxifen from randomized preventive or therapeutic trials with the oestrogen receptor status of tumours in BRCA1 and BRCA2 mutation positive women from published tumour surveys to obtain estimates of the likely effect of tamoxifen administration in mutation carriers. We used a simple two-stage procedure to estimate the benefit as a weighted average of the effect on oestrogen receptor positive tumours and oestrogen receptor negative, and using a more complex hierarchical modelling approach. Using the simple procedure and deriving the estimates of benefit from both primary prevention and therapeutic trials, we obtain an estimated reduction in risk of breast cancer from administration of tamoxifen in BRCA1 mutation positive women of 13% (RR=0.87, 95% CI 0.68--1.11). The corresponding estimated reduction in BRCA2 mutation positive women was 27% (RR=0.73, 95% CI 0.59--0.90). Using the more complex models gave essentially the same results. Using only the primary prevention trials gave smaller estimates of benefit in BRCA1 carriers but larger estimates in BRCA2, in both cases with wider confidence intervals. The benefit of prophylactic use of tamoxifen in BRCA1 mutation carriers is likely to be modest, and the effect in BRCA2 mutation carriers somewhat greater.

Adjuvant chemotherapy for tumors of one centimeter or less: the law of diminishing returns

The role of adjuvant chemotherapy in treatment of breast cancers of 1 cm or less is controversial. Careful consideration must be given to the overall risk of recurrence and death and to the absolute benefit of adjuvant chemotherapy, given that risk. Studies in this group of patients indicate that their overall survival rate is 90% to 99%. The absolute benefit of chemotherapy in this setting is most likely 1% or less. Adjuvant chemotherapy has significant toxicities, including cognitive dysfunction, early menopause, leukemia, and even death. Following a realistic and detailed discussion between patient and oncologist, some patients may choose chemotherapy. However, for the majority of patients with breast cancers of 1 cm or less, the minimal benefit of adjuvant chemotherapy does not justify the risk of the treatment.

What is the ideal duration of adjuvant therapy for primary breast cancer: are four cycles of cyclophosphamide and doxorubicin enough?

For 25 years we have known that adjuvant chemotherapy improves both disease-free and overall survival for many of our patients with primary breast cancer. We also know that these therapies have significant toxicities and are not always effective. We have therefore focused a great deal of effort into maximizing the effectiveness of adjuvant chemotherapy and defining just how much chemotherapy, with respect to both dose and duration, is necessary to achieve this maximum benefit. In our attempt to define these parameters through clinical trials, we have been faced with many options, and we may not yet have defined an optimal regimen of chemotherapy, or an optimal duration. Although many physicians in the United States consider four cycles of cyclophosphamide and doxorubicin as "standard of care" for patients with primary breast cancer, many feel that both choice of regimen and duration of treatment remain controversial. The reasons for this uncertainty and lack of clarity are complex, and they are addressed in this review.

Systemic treatment after sentinel lymph node biopsy in breast cancer: who, what, and why?

SLNB, although subject to numerous technical problems, has nonetheless shown great promise in predicting the status of the remaining axillary lymph nodes. The growing use of SLNB has presented the opportunity of using immunohistochemical and molecular markers to detect occult micrometastases. These micrometastases may be important for more accurate staging and prediction of patient outcomes. Current standards for the use of systemic therapy recommend multidrug chemotherapy for all but the most favorable disease (T1a/b, NO). The detection of micrometastases by SLNB in this low-risk group may change treatment recommendations to include systemic therapy. Because of the significant frequency of false-negative results in SLNB, which will depend upon the surgeon's experience, caution is urged in determining when ALND can be safely eliminated in patients with a negative SLNB.

Locoregional failure rates in patients with involved axillary nodes after mastectomy and systemic therapy

Published series vary substantially in describing the incidence of locoregional failure after mastectomy among patients with involved axillary lymph nodes who receive systemic therapy. There are few data on such risks with regards to particular patient subsets (such as those defined by combinations of tumor size and nodal status). This article reviews the available data on these subjects as well as problems in their interpretation and clinical use.

Locoregional failure 10 years after mastectomy and adjuvant chemotherapy with or without tamoxifen without irradiation: experience of the Eastern Cooperative Oncology Group

PURPOSE

To assess patterns of failure and how selected prognostic and treatment factors affect the risks of locoregional failure (LRF) after mastectomy in breast cancer patients with histologically involved axillary nodes treated with chemotherapy with or without tamoxifen without irradiation.

PATIENTS AND METHODS

The study population consisted of 2,016 patients entered onto four randomized trials conducted by the Eastern Cooperative Oncology Group. The median follow-up time for patients without recurrence was 12.1 years (range, 0.07 to 19.1 years).

RESULTS

A total of 1,099 patients (55%) experienced disease recurrence. The first sites of failure were as follows: isolated LRF, 254 (13%); LRF with simultaneous distant failure (DF), 166 (8%); and distant only, 679 (34%). The risk of LRF with or without simultaneous DF at 10 years was 12.9% in patients with one to three positive nodes and 28.7% for patients with four or more positive nodes. Multivariate analysis showed that increasing tumor size, increasing numbers of involved nodes, negative estrogen receptor protein status, and decreasing number of nodes examined were significant for increasing the rate of LRF with or without simultaneous DF.

CONCLUSION

LRF after mastectomy is a substantial clinical problem, despite the use of chemotherapy with or without tamoxifen. Prospective randomized trials will be necessary to estimate accurately the potential disease-free and overall survival benefits of postmastectomy radiotherapy for patients in particular prognostic subgroups treated with presently used and future systemic therapy regimens.

The role of radionuclide angiocardiography in the treatment of patients receiving doxorubicin-based chemotherapy: a reassessment

We attempted to evaluate the role of radionuclide angiography in the routine treatment of patients receiving doxorubicin-based therapy in a university hospital setting. We identified 222 cancer patients treated with doxorubicin or who underwent radionuclide angiography with the intent to receive doxorubicin at the University of Iowa in 1989. We examined the cumulative doses of doxorubicin, results of radionuclide angiograms, cardiac risk factors, and clinical outcomes and survival of patients. Of 222 patients, 168 (76%) underwent at least one radionuclide angiogram and received doxorubicin. Only a baseline study was performed in 136 (81%) of these 168 patients. Only 32 underwent follow-up study during therapy; six patients discontinued therapy for an 11-21% decrease in left ventricular function. The mean dose of doxorubicin received was 211 mg/m2, and 193 patients (96%) received a cumulative dose <450 mg/m2. Only two patients (1%) had heart failure. A questionnaire sent to medical oncologists in Iowa showed that use of radionuclide angiography in our institution reflected practice throughout the state. The majority of patients in our population who underwent radionuclide angiography had a single baseline study, which provides little clinically useful information. The majority of patients receiving doxorubicin as currently employed can be safely treated without radionuclide angiography.

Adjuvant six cycles of high-dose adriamycin, cyclophosphamide, methotrexate, 5-fluorouracil (ACMF) vs. 12 cycles of low-dose ACMF with tamoxifen for premenopausal, node-positive breast cancer patients: results of a prospective randomized study

A prospective randomized study was conducted to compare the adjuvant efficacy of six cycles of high-dose ACMF (Adriamycin, ADM; cyclophosphamide, CPA; methotrexate, MTX; 5-fluorouracil, 5-FU) with that of 12 cycles of low-dose ACMF in premenopausal, node-positive breast cancer patients. The six-cycle ACMF group (93 patients) received, intravenously (i.v.), 130 mg/m2 CPA, 26 mg/m2 MTX, and 600 mg/m2 5FU on days 1 and 8, and 26 mg/m2 ADM on day 1 of each cycle. The 12-cycle ACMF group (97 patients) received i.v. 65 mg/m2 CPA, 13 mg/m2 MTX, and 300 mg/m2 5-FU on days 1 and 8, and 13 mg/m2 ADM on day 1 of each cycle. These treatments were repeated every 4 weeks, and all the patients took tamoxifen (30 mg/day) for 2 years. The background factors of the two groups were comparable. There were non-significant trends toward better disease-free and overall survival rates in the high-dose, six-cycle ACMF group. Both treatments were well tolerated, but more patients in the low-dose, 12 cycle group refused to continue to receive chemotherapy. These data suggest that escalating doses of ACMF over a shorter period, even with doses within the conventional range, are superior to low-dose prolonged therapy.

Third annual William L. McGuire Memorial Lecture. "Studies on the estrogen receptor in breast cancer"--20 years as a target for the treatment and prevention of cancer

In 1973, McGuire and Chamness (In: O'Malley BW and Means AR (ed) Receptors for Reproductive Hormones, Plenum Press) summarized their work on the estrogen receptor in animal and human breast tumors, and in so doing described a target for therapeutic intervention. At that time there were no clinically useful antiestrogens, but the subsequent development of tamoxifen for breast cancer therapy has revolutionized the approach to treatment. Long-term adjuvant tamoxifen adjuvant therapy (i.e., greater than one year) has proven efficacy to enhance the survival of breast cancer patients. In addition, because there is an associated 40% decrease in contralateral breast cancer during adjuvant tamoxifen therapy and tamoxifen maintains bone density and reduces fatal myocardial infarction, clinical trials to test the worth of tamoxifen as a preventive for breast cancer in high risk women have started in the United States, United Kingdom, and Italy. Initial concerns that long-term tamoxifen causes endometrial cancer have been placed in perspective and analyzed by a review of the literature. Tamoxifen only doubles the normal risk of detecting endometrial cancer (i.e., to 2 per 1,000 tamoxifen-treated women per year), and 80% of these cases are early stage, good prognosis disease. Annual gynecological examinations and education are essential to provide reassurance for patients. The success of tamoxifen has encouraged the development of new antiestrogens to exploit the estrogen receptor as a therapeutic target. Droloxifene and TAT-59 mimic the metabolite 4-hydroxytamoxifen in having a high affinity for the estrogen receptor (Jordan et al, J Endocrinol 75:305, 1977). These drugs appear to have a pharmacological profile similar to tamoxifen. In contrast, the new pure antiestrogens have a distinct mechanism of action and will be valuable either as a first line therapy for advanced breast cancer or as a second line endocrine therapy after the failure of long-term adjuvant tamoxifen therapy. Finally, a new strategy is being developed to exploit the target site specific action of antiestrogens. Raloxifene, an antiestrogen with high affinity for the estrogen receptor but only weak estrogenicity for the uterus, prevents rat mammary tumorigenesis and maintains bone density. The drug is to be evaluated as a treatment for osteoporosis, but may also prevent the development of breast and endometrial cancer in a broad group of treated subjects. The identification of the estrogen receptor as a target for therapeutic opportunities has proved to be extremely beneficial for the control of breast cancer and has the added potential to control osteoporosis and coronary heart disease in women.

Dose intensity and high dose therapy. Two different concepts

"Dose response" refers to a direct relationship between the amount of chemotherapy administered and observed degree of antitumor effect. What is often implied by the term is the administration of pulsed, high dose therapy, resulting in very high peak concentrations. Clinically, this has been translated as multiple alkylating agent-based regimens requiring intensive supportive care and associated with substantial morbidity and an appreciable mortality risk. Such regimens typically are given as consolidation after an initial period of standard outpatient therapy and may require autologous hematopoietic stem cell support. "Dose intensity" is defined as the amount of drug administered per unit of time, typically reported in mg/m2/week. This is a more precise term than "dose response." A dose-intensive regimen may or may not be one associated with high peak concentrations. For example, prolonged or continuous administration of an agent like cyclophosphamide may be quite dose-intensive, but will be associated with lower peak concentrations and less acute toxicity than a similarly dose-intensive, pulsed high dose regimen of the same drug. Retrospective analyses and prospective, randomized trials suggest the importance of dose intensity in the treatment of breast cancer. The evidence that high dose therapy (associated with high peak plasma levels) is beneficial in breast cancer rests on a number of Phase II trials. In the setting of poor prognosis Stage IV disease, these trials suggest little improvement in median survival, but better long term survival (at or beyond 2 years) in 15-25% of such patients. This benefiting cohort appears to be in unmaintained disease free remission, whereas standard therapy in the past has almost never produced such remissions in the poor prognosis subgroup of Stage IV disease. In the setting of high risk Stage II disease, Phase II trials of similar high dose therapy indicate a higher proportion of patients who are free of recurrence at 2-3 years than expected from available historic controls. Randomized trials are now underway in Stage IV poor prognosis patients and in Stage II high risk patients to see whether the apparent improvements in outcome associated with pulsed high dose chemotherapy can be validated prospectively. The regimens under study in these randomized trials include agents that require autologous support with harvested bone marrow and/or peripheral blood progenitor cells. Such obligate stem cell support carries with it the risk of tumor cell contamination in the collection and subsequent iatrogenic dissemination of disease.(ABSTRACT TRUNCATED AT 400 WORDS)

Studies of tamoxifen as a promoter of hepatocarcinogenesis in female Fischer F344 rats

Tamoxifen, an antiestrogen used in the treatment of breast cancer, was assessed for carcinogenic potential in the two-stage model of experimental hepatocarcinogenesis. Groups of female Fisher F344 rats were initiated with a non-necrogenic, subcarcinogenic dose of diethylnitrosamine (DEN; 10 mg/kg, po) and fed tamoxifen at a concentration of 250 mg per kg of AIN-76A diet for 6 or 15 months. The livers of these animals exhibited an increase in size and number of altered hepatic foci compared with those animals which were initiated with DEN but not exposed to tamoxifen. This finding indicates that tamoxifen may have a carcinogenic potential in the rat liver. After 6 months of treatment, neoplastic nodules were observed in 3/8 rats in the DEN-initiated, tamoxifen-treated group. In the initiated group provided with tamoxifen for 15 months, neoplastic nodules were observed in 7/8 rats and hepatocellular carcinomas in 3/8 rats. The serum level of tamoxifen in these rats was 200-300 ng/ml. The ratio of tamoxifen, 4-hydroxy tamoxifen, and N-desmethyl tamoxifen was 1:0.1:0.5-1 in the serum. When adjusted for age-related weight increases, the serum and liver levels of tamoxifen and its N-desmethyl metabolite did not change over the 15 months. In the rat liver, the level of tamoxifen and its N-desmethyl metabolite was 10-29 micrograms/g liver after 6 or 15 months of chronic dietary administration. The ratio of tamoxifen:4-hydroxy tamoxifen:N-desmethyl tamoxifen was 1:0.1.3-3.3 in the liver. Therefore, the liver had 20- to 30-fold more tamoxifen and 4-hydroxy tamoxifen and at least 100-fold more N-desmethyl tamoxifen than the serum (assuming 1 gram of tissue is equivalent to 1 ml of serum). These results indicate that tamoxifen is a promoting agent for the rat liver at serum levels found in patients given the usual therapeutic course of tamoxifen. The high concentrations of tamoxifen attained in the rat liver indicate that actions other than its known estrogenicity for liver could contribute to its promoting action. In addition, these results indicate that the pharmacodynamic differences in tamoxifen metabolism in rats and humans and at low versus high doses should be determined. Thus, the therapeutic indications for tamoxifen should be balanced by the potential risk it may present as a promoting agent in mammalian liver.

Effect of tamoxifen on serum cholesterol and lipoproteins during chemohormonal therapy

The effect of tamoxifen on serum cholesterol, high density lipoprotein cholesterol (HDL-cholesterol), low density lipoprotein cholesterol (LDL-cholesterol) and the ratio of LDL-cholesterol to HDL-cholesterol (LDL-C/HDL-C) was investigated in breast cancer patients undergoing therapy for advanced disease. Longitudinal studies in 24 patients treated with tamoxifen (10 mg, twice daily) indicated average decreases in total serum cholesterol (17%) and LDL-cholesterol (27%), whereas the effect of tamoxifen on HDL-cholesterol varied with the individual patient. There was a significant decrease in the LDL-C/HDL-C ratio (33%) consistent with a decreased risk for coronary artery disease. This beneficial influence of tamoxifen on risk factors associated with cardiovascular disease was evident in both premenopausal and postmenopausal patients whether tamoxifen was administered alone or in combination with cytotoxic chemotherapy.

Fourteenth Gaddum Memorial Lecture. A current view of tamoxifen for the treatment and prevention of breast cancer

Tamoxifen has been found to be a safe and effective treatment for all stages of breast cancer. Long term tamoxifen therapy is associated with some rare, but potentially serious, side effects so patients should be carefully monitored. However, long term tamoxifen therapy is also associated with a number of physiological benefits over and above its tumouristatic action. These benefits include a decrease in the development of contralateral breast cancer, the maintenance of bone density in postmenopausal women and a decrease in cardiovascular disease. The successful application of tamoxifen to treat breast cancer has increased enthusiasm to test its worth to prevent breast cancer. Although there are individual requests by patients for tamoxifen to prevent breast cancer, individual treatment is inappropriate. Tamoxifen can only be adequately evaluated as a preventive in randomized, double-blind clinical trials. These trials are in place and physicians should encourage women to participate and establish a new therapeutic option as rapidly as possible.

The effects of intermittent progesterone upon tamoxifen inhibition of tumor growth in the 7,12-dimethylbenzanthracene rat mammary tumor model

The development of endometrial cancer is a potential risk during long-term tamoxifen therapy for breast cancer. In order to protect the uterus, progestin treatment has been proposed for these patients. However, within the 7,12-dimethylbenzanthracene-induced rat mammary model, progesterone is known to reverse the antitumor effects of tamoxifen. This study shows that progesterone administered intermittently still reverses the antitumor effects of tamoxifen in this model. This effect of progesterone is not due to a decrease in the tissue levels of tamoxifen, and may be direct, via the progesterone receptor.

Hormonal chemoprevention of cancer in women

The use of oral contraceptives in the United States during the past three decades has led to a dramatic decline in the incidence of cancers of the ovary and endometrium. The magnitude of these declines was predictable both from epidemiologic data and from the biologic effects of oral contraceptives on these tissues. Although the incidence of breast cancer has not been substantially affected by current oral contraceptives, it may be possible to develop alternative forms of contraception that provide protection against all three cancers. The major goal of hormonal chemoprevention of cancer is to reduce cell proliferation in the relevant epithelial tissue. New chemopreventive agents such as tamoxifen exemplify the application of this principle.

Randomized prospective trial of 5 versus 10 cycles of cyclophosphamide, doxorubicin, and cisplatin in advanced ovarian carcinoma

Five versus ten cycles of cyclophosphamide, doxorubicin, and cisplatin (CAP) were compared in advanced ovarian carcinoma by a prospective randomized study of 78 patients, 41 receiving 5 cycles (CAP5) and 37 receiving 10 cycles (CAP10) of chemotherapy. Patients were stratified by histologic grade and size of residual disease. Cyclophosphamide, 600 mg/m2, doxorubicin, 40 mg/m2, and cisplatin, 100 mg/m2, were administered every 4 weeks for 5 or 10 cycles. Second-look laparotomy was performed to evaluate response and plan further therapy. CAP5 patients found a second-look laparotomy to have partially responded to chemotherapy were treated with 5 additional cycles of CAP. CAP10 was more toxic than CAP5 with respect to myelosuppression, hospital admissions for nadir fever, median elevation of creatinine, and degree of peripheral neuropathy. Median follow-up is 64 months. CAP5 and CAP10 were equivalent in surgically documented complete responses (34 versus 35%) and survival (P = 0.41). Twelve partial responders to CAP5 received additional CAP chemotherapy; one complete response resulted. We conclude that CAP5 is preferable to CAP10 in treatment of advanced ovarian cancer as it is equally effective and less toxic.

The role of tamoxifen in the treatment and prevention of breast cancer

Tamoxifen is a nonsteroidal antiestrogen that has found successful applications for each stage of breast cancer in the treatment of selected patients. Tamoxifen was originally introduced for the treatment of advanced disease in postmenopausal women; however, the drug is now also available for the palliative treatment of premenopausal women with estrogen receptor (ER) positive disease. The proven efficacy of tamoxifen and the low incidence of side effects made the drug an ideal agent to test as an adjuvant therapy for women with node-positive breast cancer. Laboratory studies indicate that long-term treatment schedules may provide maximal benefit in preventing recurrence, and recent analysis of clinical trials demonstrates that between 2 and 5 years of adjuvant tamoxifen therapy provides a survival advantage for postmenopausal women with node-positive disease. Similarly, adjuvant studies in node-negative breast cancer have demonstrated an increase in the disease-free survival of both pre- and postmenopausal patients with ER-positive tumors. However, the extended use of tamoxifen has raised questions about the long-term safety of antiestrogen therapy. Of special concern is the impact of tamoxifen on ovarian function in premenopausal women and the potential risks to the fetus if pregnancy occurs. Fortunately, there are no reports about the teratogenicity of tamoxifen in the human, but it is important that physicians counsel women about the risk of pregnancy. Tamoxifen should not be used if a patient is pregnant. Initial concerns that the long-term administration of an antiestrogen would increase bone loss and increase the risks of coronary heart disease appear to be unwarranted. Tamoxifen has some estrogen-like activities in postmenopausal women and causes a preservation of bone in the lumbar spine and a decrease in circulating cholesterol. Indeed, a reduction in fatal myocardial infarction (MI) has been noted during 5 years of tamoxifen therapy, possibly the direct result of a prolonged reduction in circulating cholesterol. However, the estrogen-like qualities of tamoxifen that could be valuable as a hormone replacement therapy for all postmenopausal women following a diagnosis of breast cancer may also increase the risk for developing endometrial carcinoma. To date, there are only a few reports of endometrial carcinoma being diagnosed during adjuvant therapy with tamoxifen; however, any instances of uterine bleeding or spotting should be followed up with an endometrial biopsy. There are some concerns about large doses of tamoxifen promoting liver cancer in rats. These results are of particular concern if tamoxifen is to be used as a preventive in normal women.(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of tamoxifen on bone mineral density in postmenopausal women with breast cancer

BACKGROUND AND METHODS

Tamoxifen, a synthetic antiestrogen, increases disease-free and overall survival when used as adjuvant therapy for primary breast cancer. Because it is given for long periods, it is important to know whether tamoxifen affects the skeleton, particularly since it is used extensively in postmenopausal women who are at risk for osteoporosis. Using photon absorptiometry, we studied the effects of tamoxifen on the bone mineral density of the lumbar spine and radius and on biochemical measures of bone metabolism in 140 postmenopausal women with axillary-node-negative breast cancer, in a two-year randomized, double-blind, placebo-controlled trial.

RESULTS

In the women given tamoxifen, the mean bone mineral density of the lumbar spine increased by 0.61 percent per year, whereas in those given placebo it decreased by 1.00 percent per year (P less than 0.001). Radial bone mineral density decreased to the same extent in both groups. In a subgroup randomly selected from each group, serum osteocalcin and alkaline phosphatase concentrations decreased significantly in women given tamoxifen (P less than 0.001 for each variable), whereas serum parathyroid hormone and 1,25-dihydroxyvitamin D concentrations did not change significantly in either group.

CONCLUSIONS

In postmenopausal women, treatment with tamoxifen is associated with preservation of the bone mineral density of the lumbar spine. Whether this favorable effect on bone mineral density is accompanied by a decrease in the risk of fractures remains to be determined.

Tamoxifen in axillary node--negative breast cancer: multisystem benefits and risks

Adjuvant tamoxifen therapy is associated with modest improvement in disease-free and overall survival in women with invasive axillary node-negative breast cancer. The preponderance of data supporting these general conclusions are from trials in postmenopausal women; in premenopausal women data appear convincing regarding disease-free, but not overall, survival. Firm conclusions regarding magnitude of benefit related to presence of different prognostic factors cannot be drawn at present. In postmenopausal women tamoxifen appears to alter favorably some risk factors for cardiovascular diseases and osteoporosis, which are the most common causes of mortality or morbidity in older American women. Adjuvant tamoxifen is associated with a significantly reduced risk of second primary breast cancer. Major serious risks of tamoxifen therapy include depression, and possibly thrombophlebitis and uterine endometrial cancer. Symptomatic vasomotor and gynecological side effects are frequent. Decision making with women should include assessment of these multisystem benefits and risks.

Overprolonged adjuvant tamoxifen therapy in breast cancer

While adjuvant tamoxifen therapy given continuously for 2-3 years can lead to a modest improvement in survival rates in early breast cancer, there is no evidence that prolonging tamoxifen administration beyond that time is likely to improve survival rates any further in unselected cases. In the case of advanced disease, an alternating tamoxifen/progestagen regimen has been shown to increase the response rate and also its duration, beyond that to be expected from either agent alone. The next generation of adjuvant trials in breast cancer needs to explore the potential of an alternating tamoxifen/megestrol regimen.

Recent advances in the treatment of breast cancer

Multidisciplinary efforts have defined a number of prognostic factors and newer strategies to improve the outcome of patients with breast cancer. Conservative surgery has led to improved functional and cosmetic results. The development of a number of effective adjuvant regimens has led to improved survival. In patients with stage I disease, several biological characteristics of tumor have been identified that are associated with increased risk of relapse. A multimodality approach to patients with locally advanced disease and inflammatory cancer has resulted in improved survival. A number of hormonal and cytotoxic drug contaminations can palliate metastatic disease, with a small fraction of patients remaining in extended remission. Dose-intensive programs may lead to further improvements in survival of selected patients with this disease.

Tamoxifen-stimulated growth of human endometrial carcinoma

An estrogen receptor and progesterone receptor positive endometrial carcinoma (EnCa101) will grow in response to either estradiol or tamoxifen when transplanted into athymic mice. We have tested several antiestrogens with different properties to determine their ability to support endometrial tumor growth. Trioxifene, enclomiphene and nafoxidine are all as active as tamoxifen whereas the antiestrogen keoxifene, that has reduced estrogen-like properties, will partially inhibit tamoxifen-stimulated growth. Furthermore, the pure antiestrogen ICI 164,384 will block tamoxifen-stimulated growth without having any effect itself on tumor growth rate. Overall, the ability of antiestrogens to stimulate the growth of human endometrial carcinoma EnCa101 appears to be related to their intrinsic estrogenic activity.