Ovarian ablation in breast cancer, 1896 to 1998: milestones along hierarchy of evidence from case report to Cochrane review

The quest for improving the management of breast cancer by functional imaging: The discovery and development of 16α-[18F]fluoroestradiol (FES), a PET radiotracer for the estrogen receptor, a historical review

INTRODUCTION

16α-[18F]Fluoroestradiol (FES), a PET radiotracer for the estrogen receptor (ER) in breast cancer, was the first receptor-targeted PET radiotracer for oncology and is continuing to prove its value in clinical research, antiestrogen development, and breast cancer care. The story of its conception, design, evaluation and use in clinical studies parallels the evolution of the whole field of receptor-targeted radiotracers, one greatly influenced by the research and intellectual contributions of William C. Eckelman.

METHODS AND RESULTS

The development of methods for efficient production of fluorine-18, for conversion of [18F]fluoride ion into chemically reactive form, and for its rapid and efficient incorporation into suitable estrogen precursor molecules at high molar activity, were all methodological underpinnings required for the preparation of FES. FES binds to ER with very high affinity, and its in vivo uptake by ER-dependent target tissues in animal models was efficient and selective, findings that preceded its use for PET imaging in patients with breast cancer.

ADVANCES IN KNOWLEDGE AND IMPLICATIONS FOR PATIENT CARE

Comparisons between ER levels measured by FES-PET imaging of breast tumors with tissue-specimen ER quantification by IHC and other methods show that imaging provided improved prediction of benefit from endocrine therapies. Serial imaging of ER by FES-PET, before and after dosing patients with antiestrogens, is used to determine the efficacious dose for established antiestrogens and to facilitate clinical development of new ER antagonists. Beyond FES imaging, PET-based hormone challenge tests, which evaluate the functional status of ER by monitoring rapid changes in tumor metabolic or transcriptional activity after a brief estrogen challenge, provide highly sensitive and selective predictions of whether or not there will be a favorable response to endocrine therapies. There is sufficient interest in the clinical applications of FES that FDA approval is being sought for its wider use in breast cancer.

CONCLUSIONS

FES was the first PET probe for a receptor in cancer, and its development and clinical applications in breast cancer parallel the conceptual evolution of the whole field of receptor-binding radiotracers.

PET Imaging Agents (FES, FFNP, and FDHT) for Estrogen, Androgen, and Progesterone Receptors to Improve Management of Breast and Prostate Cancers by Functional Imaging

Many breast and prostate cancers are driven by the action of steroid hormones on their cognate receptors in primary tumors and in metastases, and endocrine therapies that inhibit hormone production or block the action of these receptors provide clinical benefit to many but not all of these cancer patients. Because it is difficult to predict which individuals will be helped by endocrine therapies and which will not, positron emission tomography (PET) imaging of estrogen receptor (ER) and progesterone receptor (PgR) in breast cancer, and androgen receptor (AR) in prostate cancer can provide useful, often functional, information on the likelihood of endocrine therapy response in individual patients. This review covers our development of three PET imaging agents, 16α-[18F]fluoroestradiol (FES) for ER, 21-[18F]fluoro-furanyl-nor-progesterone (FFNP) for PgR, and 16β-[18F]fluoro-5α-dihydrotestosterone (FDHT) for AR, and the evolution of their clinical use. For these agents, the pathway from concept through development tracks with an emerging understanding of critical performance criteria that is needed for successful PET imaging of these low-abundance receptor targets. Progress in the ongoing evaluation of what they can add to the clinical management of breast and prostate cancers reflects our increased understanding of these diseases and of optimal strategies for predicting the success of clinical endocrine therapies.

Ovarian suppression for adjuvant treatment of hormone receptor-positive early breast cancer

BACKGROUND

Approximately 80% of breast cancers amongst premenopausal women are hormone receptor-positive. Adjuvant endocrine therapy is an integral component of care for hormone receptor-positive breast cancer and in premenopausal women includes oestrogen receptor blockade with tamoxifen, temporary suppression of ovarian oestrogen synthesis by luteinising hormone releasing hormone (LHRH) agonists, and permanent interruption of ovarian oestrogen synthesis with oophorectomy or radiotherapy. Recent international consensus statements recommend single-agent tamoxifen or aromatase inhibitors with ovarian function suppression (OFS) as the current standard adjuvant endocrine therapy for premenopausal women (often preceded by chemotherapy). This review examined the role of adding OFS to another treatment (i.e. chemotherapy, endocrine therapy, or both) or comparing OFS to no further adjuvant treatment.

OBJECTIVES

To assess effects of OFS for treatment of premenopausal women with hormone receptor-positive early breast cancer.

SEARCH METHODS

For this review update, we searched the Specialised Register of the Cochrane Breast Cancer Group, MEDLINE, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL; 2019, Issue 8), the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP), and ClinicalTrials.gov on 26 September 2019. We screened the reference lists of related articles, contacted trial authors, and applied no language restrictions.

SELECTION CRITERIA

We included all randomised trials assessing any method of OFS, that is, oophorectomy, radiation-induced ovarian ablation, or LHRH agonists, as adjuvant treatment for premenopausal women with early-stage breast cancer. We included studies that compared (1) OFS versus observation, (2) OFS + chemotherapy versus chemotherapy, (3) OFS + tamoxifen versus tamoxifen, and (4) OFS + chemotherapy + tamoxifen versus chemotherapy + tamoxifen.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed risk of bias and certainty of evidence using the GRADE approach. Hazard ratios (HRs) were derived for time-to-event outcomes, and meta-analysis was performed using a fixed-effect model. The primary outcome measures were overall survival (OS) and disease-free survival (DFS). Toxicity, contralateral breast cancer, and second malignancy were represented as risk ratios (RRs), and quality of life data were extracted when provided.

MAIN RESULTS

This review update included 15 studies involving 11,538 premenopausal women with hormone receptor-positive early breast cancer; these studies were conducted from 1978 to 2014. Some of these treatments are not current standard of care, and early studies did not assess HER2 receptor status. Studies tested OFS versus observation (one study), OFS plus chemotherapy versus chemotherapy (six studies), OFS plus tamoxifen versus tamoxifen (six studies), and OFS plus chemotherapy and tamoxifen versus chemotherapy and tamoxifen (two studies). Of those studies that reported the chemotherapy regimen, an estimated 72% of women received an anthracycline. The results described below relate to the overall comparison of OFS versus no OFS. High-certainty evidence shows that adding OFS to treatment resulted in a reduction in mortality (hazard ratio (HR) 0.86, 95% confidence interval (CI) 0.78 to 0.94; 11 studies; 10,374 women; 1933 reported events). This treatment effect was seen when OFS was added to observation, to tamoxifen, or to chemotherapy and tamoxifen. The effect on mortality was not observed when OFS was added to chemotherapy without tamoxifen therapy (HR 0.95, 95% CI 0.82 to 1.09; 5 studies; 3087 women; median follow-up: range 7.7 to 12.1 years). The addition of OFS resulted in improved DFS (HR 0.83, 95% CI 0.77 to 0.90; 10 studies; 8899 women; 2757 reported events; high-certainty evidence). The DFS treatment effect persisted when OFS was added to observation, to tamoxifen, and to chemotherapy and tamoxifen. The effect on DFS was reduced when OFS was added to chemotherapy without tamoxifen therapy (HR 0.90, 95% CI 0.79 to 1.01; 5 studies; 2450 women). Heterogeneity was low to moderate across studies for DFS and OS (respectively). Evidence suggests that adding OFS slightly increases the incidence of hot flushes (grade 3/4 or any grade; risk ratio (RR) 1.60, 95% CI 1.41 to 1.82; 6 studies; 5581 women; low-certainty evidence, as this may have been under-reported in these studies). Two other studies that could not be included in the meta-analysis reported a higher number of hot flushes in the OFS group than in the no-OFS group. Seven studies involving 5354 women collected information related to mood; however this information was reported as grade 3 or 4 depression, anxiety, or neuropsychiatric symptoms, or symptoms were reported without the grade. Two studies reported an increase in depression, anxiety, and neuropsychiatric symptoms in the OFS group compared to the no-OFS group, and five studies indicated an increase in anxiety in both treatment groups (but no difference between groups) or no difference overall in symptoms over time or between treatment groups. A single study reported bone health as osteoporosis (defined as T score < -2.5); this limited evidence suggests that OFS increases the risk of osteoporosis compared to no-OFS at median follow-up of 5.6 years (RR 1.16, 95% CI 1.10 to 28.82; 2011 women; low-certainty evidence). Adding OFS to treatment likely reduces the risk of contralateral breast cancer (HR 0.75, 95% CI 0.57 to 0.97; 9 studies; 9138 women; moderate-certainty evidence). Quality of life was assessed in five studies; four studies used validated tools, and the fifth study provided no information on how data were collected. Two studies reported worse quality of life indicators (i.e. vaginal dryness, day and night sweats) for women receiving OFS compared to those in the no-OFS group. The other two studies indicated worsening of symptoms (e.g. vasomotor, gynaecological, vaginal dryness, decline in sexual interest, bone and joint pain, weight gain); however these side effects were reported in both OFS and no-OFS groups. The study that did not use a validated quality of life tool described no considerable differences between groups.

AUTHORS' CONCLUSIONS

This review found evidence that supports adding OFS for premenopausal women with early, hormone receptor-positive breast cancers. The benefit of OFS persisted when compared to observation, and when added to endocrine therapy (tamoxifen) or chemotherapy and endocrine therapy (tamoxifen). The decision to use OFS may depend on the overall risk assessment based on tumour and patient characteristics, and may follow consideration of all side effects that occur with the addition of OFS.

History of Estrogen: Its Purification, Structure, Synthesis, Biologic Actions, and Clinical Implications

This mini-review summarizes key points from the Clark Sawin Memorial Lecture on the History of Estrogen delivered at Endo 2018 and focuses on the rationales and motivation leading to various discoveries and their clinical applications. During the classical period of antiquity, incisive clinical observations uncovered important findings; however, extensive anatomical dissections to solidify proof were generally lacking. Initiation of the experimental approach followed later, influenced by Claude Bernard's treatise "An Introduction to the Study of Experimental Medicine." With this approach, investigators began to explore the function of the ovaries and their "internal secretions" and, after intensive investigations for several years, purified various estrogens. Clinical therapies for hot flashes, osteoporosis, and dysmenorrhea were quickly developed and, later, methods of hormonal contraception. Sophisticated biochemical methods revealed the mechanisms of estrogen synthesis through the enzyme aromatase and, after discovery of the estrogen receptors, their specific biologic actions. Molecular techniques facilitated understanding of the specific transcriptional and translational events requiring estrogen. This body of knowledge led to methods to prevent and treat hormone-dependent neoplasms as well as a variety of other estrogen-related conditions. More recently, the role of estrogen in men was uncovered by prismatic examples of estrogen deficiency in male patients and by knockout of the estrogen receptor and aromatase in animals. As studies became more extensive, the effects of estrogen on nearly every organ were described. We conclude that the history of estrogen illustrates the role of intellectual reasoning, motivation, and serendipity in advancing knowledge about this important sex steroid.

Change in risk of breast cancer after receiving hormone replacement therapy by considering effect-modifiers: a systematic review and dose-response meta-analysis of prospective studies

We synthesize the current literatures and use the power of meta-analysis to examine trends on association between hormone replacement therapy (HRT) and the risk of breast cancer (BC). We performed a comprehensive literature search using PubMed, EMBASE, and Web of Science from their inception until Jan 2017. Prospective studies that provided adjusted risk estimates of HRT and BC risk were eligible. Categorical and dose-response meta-analyses followed the PRISMA were conducted using random effects model and restricted cubic spline model, respectively. Forty-seven publications from thirty-five unique studies were included, involving 3,898,376 of participants and 87,845 of BC cases. Compared with non-users, RR for current estrogen-only therapy (ET) users was 1.14 (95% confidence interval (CI) = 1.05–1.22), and for per year increases was 1.02 (95% CI = 1.02–1.02). Moreover, RR for current estrogen plus progestin therapy (EPT) users was 1.76, (95% CI = 1.56–1.96), and for per year increases was 1.08 (95% CI = 1.08–1.08). Dose-response analyses revealed 8–10 years’ onset peaks, and indicated residual increased BC risk remained after stopping use of ET regimen rather than for EPT. Effect-modifiers like BMI, duration of use, race/ethnicity, routes of administration were recognized. In Conclusions, current use of EP or EPT and ever use of tibolone are associated with an elevated risk of BC. Compared with slim HRT users and non-users, lower BC risks were found among overweight/obese HRT users and former EPT users, respectively. Both ET and EPT users are associated with higher risk of lobular BC than ductal BC, and more ER-positive than negative BC cases were detected among EPT users.

Evaluating the Survival Benefit Following Ovarian Function Suppression in Premenopausal Patients with Hormone Receptor Positive Early Breast Cancer

There are divergent opinions regarding the use of ovarian function suppression or ablation (hereafter, OFS) in hormone receptor positive early breast cancer patients. In order to clarify the survival benefit of OFS, a meta-analysis was performed. The result is that use of OFS was more effective than no OFS on DFS (the pooled relative risk (pRR) = 0.86; 95% CI: 0.75–0.96) and on OS (pRR = 0.79; 95% CI: 0.70–0.89). In subgroup analysis, we found that increased DFS was positively associated with patients who had received chemotherapy (pRR = 0.85; 95% CI: 0.74–0.96), who were lymph node negative (pRR = 0.74; 95% CI: 0.61–0.91) and were less than 40 years old (pRR = 0.71; 95% CI: 0.59–0.83). There was a significant difference in OS between the groups receiving chemotherapy (pRR = 0.73; 95% CI: 0.58–0.89) or for patients less than 40 years old (pRR = 0.52; 95% CI: 0.18–0.87). The use of OFS also produces statistical differences in the occurrence of the side-effects; severe hot flashes (pRR = 2.32; 95% CI: 1.36–3.97), and hypertension (pRR = 1.54; 95% CI: 1.12–2.12). In general, OFS should be considered as one treatment for hormone receptor positive premenopausal early breast cancer patients who have received chemotherapy and are less than 40 years old. We also should pay attention to the side-effects and weigh the advantages and disadvantages before deciding on using OFS.

Incidence, time trends, laterality, indications, and pathological findings of unilateral oophorectomy before menopause

OBJECTIVE

Unilateral oophorectomy (UO) is a common surgical practice, yet it remains understudied. We investigated trends in incidence rates, indications, and pathological differences in the right and left ovaries in women younger than 50 years.

METHODS

The Rochester Epidemiology Project medical records linkage system was used to identify all women in Olmsted County, MN, who underwent UO between 1950 and 2007 (n = 1,838). We studied the incidence rates, indications, and pathologies of UO by laterality, and investigated trends across time.

RESULTS

Pooling all oophorectomies across a 58-year period, we found that the incidence of UO was higher than the incidence of bilateral oophorectomy through the age of 39 years; however, bilateral oophorectomy surpassed UO thereafter. The incidence of UO increased from 1950 to 1974 but decreased thereafter and was surpassed by the rate of bilateral oophorectomy after 1979. Before 1985, left ovaries were removed more frequently than right ovaries with or without a medical indication for UO. Ovaries removed with a medical indication showed pathological differences between the right ovary and the left ovary, with endometriosis being more common in the left ovary. Ovaries removed without a medical indication did not differ in pathology by side.

CONCLUSIONS

There have been major changes in incidence rates of UO across six decades. Medically indicated UO has been more common on the left side due, in part, to the higher prevalence of endometriosis. However, UO without a medical indication has also been more common on the left side because of surgical preferences and traditions. The long-term consequences of right or left UO on timing of menopause, morbidity, and mortality need further study.

LH-RH analogues in the treatment of young women with early breast cancer: long-term follow-up of a phase II study

To prevent premature ovarian failure (POF), high-risk, premenopausal women with early breast cancer were given a luteinizing-hormone releasing hormone (LH-RH) analogue during adjuvant chemotherapy. After an adriamycin-based regimen, patients received radiation therapy concomitant with cyclophosphamide, methotrexate and 5-fluorouracil. An aromatase inhibitor was given to patients positive for the estrogen receptor (ER+). The median age was 43 years (range, 26-45). Among 200 consecutive patients, 46% had no axillary node, and 54% had a mean of 5.4 positive nodes (range, 1-25); 56% were ER+, 44% were estrogen receptor negative (ER-), 13% were triple negative, and 20 had tumors positive for the oncogene, c-erb-B2 (identified with fluorescent in situ hybridization). After a median follow-up of 105 months (range, 65-180), no patient under 40 years old exhibited POF, while 44% of patients over 40 years old exhibited POF. Eight pregnancies were recorded: 7 at term and 1 voluntary interruption. The 10-year disease-free survival and overall survival rates were 85 and 91%, respectively. These data showed that, in premenopausal patients with early breast cancer, the addition of an LH-RH analogue to adjuvant chemotherapy was well tolerated, prevented POF, and was associated with excellent disease-free survival and overall survival rates.

Ovarian Ablation Using Goserelin Improves Survival of Premenopausal Patients with Stage II/III Hormone Receptor-Positive Breast Cancer without Chemotherapy-Induced Amenorrhea

Purpose

The purpose of this study was to assess the value of ovarian ablation using goserelin in premenopausal patients with stage II/III hormone receptor-positive breast cancer without chemotherapy-induced amenorrhea (CIA).

Materials and Methods

We retrospectively reviewed the data of breast patients treated between October 1999 and November 2007 without CIA. The Kaplan-Meier method was used for calculation of the survival rate. Log rank method and Cox regression analysis were used for univariate and multivariate prognostic analysis.

Results

The median follow-up period was 61 months. Initially, 353 patients remained without CIA after chemotherapy and 98 among those who received goserelin and tamoxifen (TAM). In univariate analysis, goserelin improved locoregional recurrence-free survival (LRFS) (98.9% vs. 94.1%, p=0.041), distant metastasis-free survival (DMFS) (85.4% vs. 71.9%, p=0.006), disease-free survival (DFS) (85.4% vs. 71.6%, p=0.005), and overall survival (OS) (93.5% vs. 83.5%, p=0.010). In multivariate analysis, goserelin treatment was an independent factor influencing DMFS (hazard ratio [HR], 1.603; 95% confidence interval [CI], 1.228 to 2.092; p=0.001), DFS (HR, 1.606; 95% CI, 1.231 to 2.096; p=0.001), and OS (HR, 3.311; 95% CI, 1.416 to 7.742; p=0.006). In addition, treatment with goserelin resulted in significantly improved LRFS (p=0.039), DMFS (p=0.043), DFS (p=0.036), and OS (p=0.010) in patients aged < 40 years. In patients aged ≥ 40 years, goserelin only improved DMFS (p=0.028) and DFS (p=0.027).

Conclusion

Ovarian ablation with goserelin plus TAM resulted in significantly improved therapeutic efficacy in premenopausal patients with stage II/III hormone receptor-positive breast cancer without CIA.

Adjuvant endocrine therapy for premenopausal women with breast cancer

AIMS

Endocrine therapy is a pivotal treatment for women with hormone-receptor positive breast cancer. In premenopausal women, endocrine therapy primarily consists of tamoxifen and ovarian suppressive strategies. Younger women experience improvements in the risks of relapse or death from breast cancer with the use of chemotherapy as well, with part of this benefit explained by resultant premature amenorrhea. Unfortunately despite a centuries worth of clinical trials, the most efficacious combination of hormonal therapies and chemotherapy has yet to be determined. This paper serves as a comprehensive review of the substantial data in the adjuvant treatment of premenopausal, hormone receptor-positive women with breast cancer.

METHODS AND RESULTS

PubMed and American Society of Clinical Oncology (ASCO) Proceedings searches from 1896 to present were performed. All of the trials examining the role of ovarian suppression and tamoxifen with and without chemotherapy in premenopausal women were included. The current data suggests that endocrine therapy can be an important alternative to chemotherapy in select patient populations, and improvements in outcome are also seen with the combination of hormonal and chemotherapy strategies in other populations. A majority of the trials examined did not use what is considered to be current standards of care regarding chemotherapy regimens and durations of adjuvant hormonal therapy. Many unanswered questions remain particularly regarding the combined use of ovarian suppression and tamoxifen in women who are also receiving chemotherapy.

CONCLUSION

There is a persistent need to define optimal endocrine therapy in premenopasusal women with hormone-receptor positive breast cancer. Contemporaneous trials, such as the SOFT trial will provide direction, and additional biomarker and pharmacogenomic data will further supplement individualized patient decision making.

What is the current status of ovarian suppression/ablation in women with premenopausal early-stage breast cancer?

The role of ovarian suppression/ablation (OS/OA) in premenopausal women with hormone receptor-positive breast cancer has been evolving for more than a century. It is clear that OS/OA is an effective adjuvant therapy for these women, but despite numerous studies enrolling thousands of women, many unanswered questions remain. In particular, a major question is whether additional benefit is gained with combination treatment comprising luteinizing hormone-releasing hormone (LH-RH) agonists and tamoxifen over tamoxifen alone. Ongoing trials also are assessing the coupling of aromatase inhibitors (traditionally contraindicated in these patients because of paradoxic stimulation of estrogen production) and LH-RH agonists. Any potential disease-free or overall survival advantage of combination treatment must be balanced against a possible increase in adverse effects and impairment of quality of life. This review focuses on new data on how to incorporate OS/OA into the rational treatment of this challenging patient population.

Adjuvant endocrine therapy for premenopausal women with early breast cancer

Adjuvant endocrine therapy is a pivotal component of treatment for premenopausal women with early-stage hormone receptor-positive breast cancer. Currently, the standard endocrine therapy for premenopausal women is tamoxifen; a role for ovarian suppression or ablation has also been identified. Uncertainty remains about the optimal use of endocrine therapy in this setting. The role of ovarian suppression with tamoxifen or aromatase inhibitor, the optimal duration of adjuvant endocrine therapy and the utility of biomarkers and pharmacogenetic studies to select therapy are questions worthy of further investigation.

Current controversies in the management of early breast cancer

Medical professionals in general, and medical oncologists in particular, have highly stressful practices because they are under constant pressure to have the highest-quality, up-to-date evidence available in order to make the right decision for each individual patient. From a practical point of view, being updated on oncological and other medical specialties may seem an insurmountable task because the number of scientific publications has increased dramatically. The use of systematic reviews of randomised controlled trials or the application of results obtained from high-quality randomised controlled trials are some of the most common ways to address this need. Unfortunately, they do not cover all complex clinical situations that the majority of medical oncologists face in their outpatient consultations. In this review, we report the conclusions achieved in a multiexpert meeting where five important controversies in the treatment of breast cancer were analysed. Five highly experienced medical oncologists were required to defend an affirmative answer and another five were required to defend a negative answer for each of the clinical questions. After that, a one-day meeting was organised to debate each clinical question and to reach a consensus. We report here the content of this multi-expert meeting along with the conclusions drawn.

Controversies in the therapy of early stage breast cancer

Breast cancer is the most common malignancy among U.S. women, with more than 200,000 new cases diagnosed annually. In the U.S., mortality from breast cancer has declined in recent years as a result of more widespread screening, leading to earlier detection, as well as advances in the adjuvant treatment of early-stage disease. It is widely accepted that the appropriate use of adjuvant chemotherapy and endocrine therapy improves the disease-free and overall survival of patients with early-stage breast cancer. It is, therefore, standard clinical practice to administer adjuvant systemic therapy to patients with node-positive and high-risk, node-negative breast cancer. There remain, however, many controversies in the primary systemic therapy of breast cancer, which are discussed in this review.

Chemoendocrine therapy for premenopausal women with axillary lymph node-positive, steroid hormone receptor-positive breast cancer: results from INT 0101 (E5188)

PURPOSE

Chemotherapy, tamoxifen, and ovarian ablation/suppression (OA/OS) are effective adjuvant approaches for premenopausal, steroid hormone receptor-positive breast cancer. The value of combined therapy has not been clearly established.

PATIENTS AND METHODS

Premenopausal women with axillary lymph node-positive, steroid hormone receptor-positive breast cancer (1,503 eligible patients) were randomly assigned to six cycles of cyclophosphamide, doxorubicin, and fluorouracil (CAF), CAF followed by 5 years of monthly goserelin (CAF-Z), or CAF followed by 5 years of monthly goserelin and daily tamoxifen (CAF-ZT). The primary end points were time to recurrence (TTR), disease-free survival (DFS), and overall survival (OS) for CAF-Z versus CAF, and CAF-ZT versus CAF-Z.

RESULTS

With a median follow-up of 9.6 years, the addition of tamoxifen to CAF-Z improved TTR and DFS but not OS. There was no overall advantage for addition of goserelin to CAF.

CONCLUSION

Addition of tamoxifen to CAF-Z improves outcome for premenopausal node-positive, receptor-positive breast cancer. The role of OA/OS alone or with other endocrine agents should be studied more intensely.

What Is the Role of Ovarian Ablation in the Management of Primary and Metastatic Breast Cancer Today?

Ovarian ablation has been used for more than a century in the treatment of breast cancer. Methods of irreversible ovarian ablation include surgical oophorectomy and ovarian irradiation. Potentially reversible castration can be accomplished medically using luteinizing hormone releasing hormone (LHRH) analogues. In addition, cytotoxic chemotherapy unpredictably produces amenorrhea and primary ovarian failure in 10%-95% of premenopausal women as a function of patient age, cumulative dose, and the specific agents used. In the metastatic setting, ovarian ablation and tamoxifen monotherapies produce comparable outcomes and may be more effective when used together. While many early adjuvant trials of ovarian ablation were methodologically flawed, a more recent meta-analysis by the Early Breast Cancer Trialists' Collaborative Group of 12 properly designed randomized trials found significantly greater disease-free and overall survival rates for women under the age of 50, regardless of nodal status, receiving ovarian ablation as a single adjuvant therapy. Several important issues regarding the role of ovarian ablation in the treatment of breast cancer remain unresolved. Data suggest that ovarian ablation followed by some years of tamoxifen produces similar results to those seen with adjuvant chemotherapy in women with hormone-receptor positive breast cancer; however, the value of combining these modalities is still unclear. Other areas of ongoing investigation include the appropriate duration of therapy with LHRH analogues in the adjuvant setting, the long-term sequelae of ovarian suppression among young breast cancer survivors, and refinement of the population most likely to benefit from ovarian ablation or suppression.

Methods of ovarian suppression used in the UK

Ovarian suppression in the management of breast cancer has had a resurgence in the 1990s. In view of the development of luteinizing hormone-releasing hormone (LHRH) analogues and advances in laparoscopic surgery, we wished to determine whether more consultants are considering these methods for achieving ovarian suppression than radiotherapy. A questionnaire was designed to determine the current practice of consultants in the UK and to discover who is involved in making this decision. It was distributed via the Adjuvant Breast Cancer (ABC) trials office to consultants who enter patients into the ABC premenopausal trial. Seventy-four (72%) questionnaires were analysed. The preferred method of treatment was radiotherapy in 60%, surgery in 30% and LHRH analogues in 9%. Seventy-three per cent of consultants were using more than one technique but did not always involve the patient in the decision-making process to determine which treatment modality to use. Radiotherapy techniques used included using bony landmarks for field borders (46%), using a standard field size (20%) or using ultrasound localization (15%).

Drug interactions of the newer oral antifungal agents

The newer oral antifungal agents, such as fluconazole, itraconazole and terbinafine, are generally both effective and well tolerated in the management of widespread or resistant dermatomycoses such as onychomycosis. However, these agents differ markedly in their potential to cause clinically significant drug interactions. Triazoles such as fluconazole and itraconazole have been responsible for a greater number of clinically significant drug interactions than terbinafine. For example, itraconazole, and to a lesser extent fluconazole (in high doses) are inhibitors of CYP3A4. Therefore certain agents that are substrates of this enzyme, such as some of the new generation of H1-antihistamines, several HMG-CoA reductase inhibitors and certain benzodiazepines, are contraindicated. Other drugs like cyclosporine and quinidine need careful monitoring if administered concurrently with these triazoles. In contrast, there are no drug-drug contraindications with terbinafine. Indeed, in a postmarketing surveillance study, in which 42.8% of the 25,884 participating patients were taking a variety of concomitant therapies, no new drug-drug interactions were revealed. Physicians should be aware of the potential for interaction of the medications that they prescribe, in order to prevent or reduce the burden of adverse events. Terbinafine may be the most rational choice of oral antifungal agent in patients receiving concomitant medications that may adversely affect or be affected by either fluconazole or itraconazole.