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

Extended adjuvant endocrine therapy for women with hormone receptor-positive early breast cancer: A meta-analysis with trial sequential analysis of randomized controlled trials

OBJECTIVES

The aim of the current study is to explore the association between extended adjuvant endocrine treatment and prognosis of women with hormone receptor-positive (HR+) early breast cancer.

METHODS

Databases including PubMed, Web of Science, Embase and the Cochrane Library databases were electronically searched to identify randomized controlled trials (RCTs) that reported extended endocrine therapy for women with HR+ early breast cancer. The retrieval time was limited from inception to September 2022. Two reviewers independently screened literature, extracted data, and assessed risk bias of included studies. Meta-analysis was performed by using R software Version 4.1.2 and STATA Version 12.0.

RESULTS

A total of 15 RCTs involving 29497 cases were included. The overall analysis showed that compared with the control, extended adjuvant endocrine therapy increased disease-free survival (DFS) (HR=0.814, 95% CI: 0.720-0.922, 95% PI: 0.556-1.194), overall survival (OS) (HR=0.885, 95% CI: 0.822-0.953, 95% PI: 0.771-1.035), relapse-free survival (RFS) (HR=0.833, 95% CI: 0.747-0.927, 95% PI: 0.575-1.159), distant metastatic-free survival (DMFS) (HR=0.824, 95% CI: 0.694-0.979, 95% PI: 0.300-2.089) and reduced new breast cancer cumulative incidence (NBCCI) (HR=0.484, 95% CI: 0.403-0.583, 95% PI: 0.359-0.654). For adverse events, extended adjuvant endocrine treatment was associated with a significantly higher risk of bone fracture (RR=1.446, 95% CI: 1.208-1.730, 95% PI: 1.154-1.854) and osteoporosis (RR=1.377, 95% CI: 1.018-1.862, 95% PI: 0.347-5.456).

CONCLUSION

Our study showed that extended adjuvant endocrine therapy increased DFS, OS, RFS, DMFS, the incidence of bone fracture and osteoporosis, and reduced NBCCI.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero, identifier (CRD42022351295).

Competing Nomogram for Late-Period Breast Cancer-Specific Death in Patients with Early-Stage Hormone Receptor-Positive Breast Cancer

BACKGROUND

More than half of early breast cancer recurrences occur after 5 years from the initial diagnosis. An individualized estimate of the risk of late-period breast cancer-specific death (LP-BCSD) after 5 years of endocrine therapy (ET) can improve decision-making for extended endocrine therapy (EET).

MATERIALS AND METHODS

A total of 147,059 eligible patients with breast cancer who survived 5+ years after diagnosis between 1990 and 2007 were identified from the Surveillance, Epidemiology, and End Results (SEER) database. Univariate and multivariate analyses based on the competing risk regression model were used to evaluate predictive factors for high risk of LP-BCSD or late-period non-breast cancer-specific death (LP-non-BCSD). Significant factors were used to build a nomogram to individualize estimates of LP-BCSD or LP-non-BCSD.

RESULTS

The 5- and 10-year LP-BCSD rates were 5.7% and 10.1%, respectively, and the 5- and 10-year LP-non-BCSD rates were 6.7% and 15.5%, respectively. Young age, black race, single marital status, poor differentiation, large tumor size, lymph node metastasis, and estrogen receptor-positive/progesterone receptor-negative (ER+/PR-) status were independent predictive factors for high risk of LP-BCSD. Age was the most important factor for predicting high risk of LP-non-BCSD. The nomograms, which were based on significant factors identified by the competing risk regression model. A risk score system based on the competing risk nomogram was established to describe the relative risk of LP-BCSD and LP-non-BCSD.

CONCLUSION

This study explored the novel endpoint of LP-BCSD for further clinical trials. The risk score system might be highly useful for patient counseling, especially in discussing EET options with elderly or comorbid patients.

A follow-up study of a randomized controlled study evaluating safety and efficacy of leuprorelin acetate every-3-month depot for 2 versus 3 or more years with tamoxifen for 5 years as adjuvant treatment in premenopausal patients with endocrine-responsive breast cancer

Background

Previously, we conducted the 5-year open-label, randomized controlled trial (RCT) of leuprorelin adjuvant therapy in post-operative premenopausal patients with endocrine-responsive breast cancer, which was a pilot study to investigate the optimal duration of leuprorelin treatment. Since, however, long-term outcomes became required for the adjuvant endocrine therapy, we performed this follow-up observation study.

Methods

Follow-up observation study was performed up to 10th year after randomization, continuing RCT to evaluate the efficacy and safety of leuprorelin every 3 months for ≥ 3 versus 2 years, with daily tamoxifen for 5 years. Primary endpoints were disease-free survival (DFS) and 2-year landmark DFS.

Results

Eligible patients (N = 222) were randomly assigned to receive leuprorelin for either 2 years (N = 112) or ≥ 3 years (N = 110) with tamoxifen. Leuprorelin treatment for ≥ 3 years versus 2 years provided no significant difference in DFS (HR 0.944, 95% CI 0.486–1.8392) or 2-year landmark DFS (N = 99 and 102 in 2-year and ≥ 3-year groups, HR 0.834, 0.397–1.753). In small, higher-risk subgroup (n = 17); however, 2-year landmark DFS in ≥ 3-year group was significantly longer (HR 0.095, 0.011–0.850) than that in 2-year group. The incidence of bone-related adverse events was around 5% in both groups.

Conclusions

Adjuvant leuprorelin treatment for ≥ 3 years with tamoxifen only showed similar efficacy and safety profiles to those for 2 years in analyses among all patients but suggested greater benefit in higher-risk patients. No new safety signal was identified for long-term leuprorelin treatment.

Trial registration number

Not applicable. This was an observational study.

Fertility in female cancer survivors: a systematic review and meta-analysis

Data on the effects of cancer treatments on fertility are conflicting. The aim of the present systematic review and meta-analysis was to determine the chances of childbirth in women survivors of different types of cancer. PubMed, MEDLINE, Embase and Scopus were searched from database inception to 17 July 2019 for published cohort, case-control and cross-sectional studies that investigated the reproductive chances in women survivors of different cancer types. Random-effects models were used to pool childbirth hazard ratios, relative risks, rate ratios and odds ratios, and 95% confidence intervals were estimated; 18 eligible studies were identified. Childbirth chances were significantly reduced in women with a history of bone cancer (HR 0.86, 95% CI 0.77 to 0.97; I² = 0%; P = 0.02 (two studies); RaR 0.76, 95% CI 0.61 to 0.95; I² = 69%; P = 0.01 (two studies); breast cancer (HR 0.74, 95% CI 0.61 to 0.90 (one study); RaR 0.51, 95% CI 0.47 to 0.57; I² = 0%; P < 0.00001 (two studies); brain cancer (HR 0.61, 95% CI 0.51 to 0.72; I² = 14%; P < 0.00001 (three studies); RR 0.62, 95% CI 0.42 to 0.91 (one study); RaR 0.44, 95% CI 0.33 to 0.60; I² = 95%; P < 0.00001 (four studies); OR 0.49, 95% CI 0.40 to 0.60 (one study); and kidney cancer (RR 0.66, 95% CI 0.43 to 0.98 (one study); RaR 0.69, 95% CI 0.61 to 0.78 (one study). Reproductive chances in women survivors of non-Hodgkin's lymphoma, melanoma and thyroid cancer were unaffected. Women with a history of bone, breast, brain or kidney cancer have reduced chances of childbirth. Thyroid cancer, melanoma and non-Hodgkin's lymphoma survivors can be reassured.

TGF-β Family Signaling Pathways in Cellular Dormancy

Individual cancer cells can switch, reversibly, to a non-proliferative dormant state, a process characterized by two principal stages: (i) establishment and maintenance, and (ii) the breaking of dormancy. This phenomenon is of clinical importance because dormant cells resist chemotherapy, and this can result in cancer relapse following years, if not decades, of clinical remission. Although the molecular mechanisms governing tumor cell dormancy have not been clearly delineated, accumulating evidence suggests that members of the transforming growth factor-β (TGF-β) family are integral. We summarize here recent findings which support the view that TGF-β family signaling pathways play a pivotal role in cellular dormancy, and discuss how affected cells could be therapeutically targeted to prevent cancer relapse.

Adjuvant endocrine monotherapy for postmenopausal early breast cancer patients with hormone-receptor positive: a systemic review and network meta-analysis

BACKGROUND

In patients with hormone receptor-positive postmenopausal of early stage breast cancer, adjuvant endocrine monotherapies include letrozole, anastrozole, exemestane, toremifene and tamoxifen. But the optimum regimen remains controversial.

METHODS

PubMed, Cochrane Database and ClinicalTrials.gov were systematically reviewed of abstract for randomized-controlled trials (RCTs) to assess the efficacy of tamoxifen, letrozole, exemestane, anastrozle and toremifene for postmenopausal patients with hormone-receptor positive (HR+), who have not received prior therapy for early stage breast cancer. The outcomes were measured by disease-free survival (DFS) and overall survival (OS). We evaluated relative hazard ratios (HRs) for death of different therapies by combination hazard ratios for death of included trials. The SUCRA values were used to evaluate the rankings of efficacy for these monotherapies.

RESULTS

A total of fourteen studies including 19,517 patients in our research were absorbed and estimated. The superiority of efficacy for DFS were 5-year letrozole and 10-year tamoxifen (SUCRA values 0.743/0.657) in all comparisons. A more efficient SUCRA values for OS were 5-year Exemestane, 5-year letrozole and 10-year tamoxifen (0.756/0.677/0.669).

CONCLUSIONS

Clinically important differences exist between commonly prescribed different adjuvant endocrine monotherapy regimens for both efficacy and acceptability in favor of exemestane and letrozole. 10-year tamoxifen for early breast cancer patients is noninferior to 5-year anastrozle, and might be the best choice where aromatase inhibitors (AIs) are not easy to acquire.

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.

A randomized controlled study evaluating safety and efficacy of leuprorelin acetate every-3-months depot for 2 versus 3 or more years with tamoxifen for 5 years as adjuvant treatment in premenopausal patients with endocrine-responsive breast cancer

BACKGROUND

Luteinizing hormone-releasing hormone (LH-RH) agonists provide effective adjuvant treatment for premenopausal women with endocrine-responsive breast cancer. Here, we investigated appropriate treatment durations of an LH-RH agonist, leuprorelin.

METHODS

We conducted an open-label, randomized controlled pilot study to evaluate the safety and efficacy of leuprorelin subcutaneously administered every-3-months for 2 versus 3 or more, up to 5 years, together with daily tamoxifen for 5 years in premenopausal endocrine-responsive breast cancer patients. Primary endpoints were disease-free survival (DFS) and safety.

RESULTS

Eligible patients (N = 222) were randomly assigned to receive leuprorelin for either 2 years (N = 112) or 3 or more years (N = 110) with tamoxifen for 5 years after surgery. Leuprorelin treatment for 3 or more years provided no significant difference in DFS rate over 2 years: 94.1 versus 91.8 % at 144 weeks (3 years) after the second year (week 96) and 90.8 versus 90.4 % at the fifth year (week 240). The overall survival rate was 100 % for both groups during the third through fifth year study period. There were no significant differences in the incidence of adverse events (AEs) between the 2 groups: most AEs were rated grade 1 or 2.

CONCLUSIONS

Adjuvant leuprorelin treatment for 3 or more years with tamoxifen showed a survival benefit and safety profile similar to that for 2 years in premenopausal endocrine-responsive breast cancer patients. No new safety signal was identified for long-term leuprorelin treatment. Longer follow-up observation is needed to determine the optimal duration of leuprorelin treatment.

Risk of Recurrence or Contralateral Breast Cancer More than 5 Years After Diagnosis of Hormone Receptor-Positive Early-Stage Breast Cancer

BACKGROUND

Three large studies have shown a survival benefit from 10 years of adjuvant hormone therapy (AHT). We evaluated the risk of an event 5 years after the initial breast cancer (BC) diagnosis and identified the prognostic factors to assist clinicians considering extended AHT.

PATIENTS AND METHODS

Patients newly referred to the BC Cancer Agency with stage I to III estrogen receptor-positive BC diagnosed from 1989 to 2004 who had undergone AHT were identified by the BC Cancer Agency's Breast Cancer Outcomes Unit. Cases with recurrence, death, or contralateral BC occurring within the first 5 years were excluded. The 10-year event-free survival (EFS) and 95% confidence intervals (CIs) were calculated using the Kaplan-Meier method. This provided estimates of recurrence risk after the fifth year following the diagnosis. The histopathologic and age variables were examined for prognostic value by univariate analysis.

RESULTS

Within our cohort, 6615 women were postmenopausal and 1886 were premenopausal at the BC diagnosis. The median follow-up period was 11 years. The 10-year EFS for women aged < 50 years with stage I, II, and III disease was 94.8% (95% CI, 92.8%-96.3%), 88.3% (95% CI, 86.0%-90.2%), and 80.4% (95% CI, 73.6%-85.6%), respectively. Among women aged ≥ 50 years, the corresponding EFS rates were 94.8% (95% CI, 93.8%-95.6%), 86.3% (95% CI, 85.0%-87.5%), and 73.8% (95% CI, 69.1%-77.8%). EFS varied significantly by grade. The 10-year recurrence risk was < 10% with stage I cancer (any grade) and for stage II (node-negative and node-positive), grade I cancer.

CONCLUSION

Our data have identified BCs associated with a very low recurrence risk 5 to 10 years after diagnosis, providing women with such cancers confidence about a decision to discontinue AHT after 5 years.

The Modern Landscape of Endocrine Therapy for Premenopausal Women with Breast Cancer

The optimal endocrine therapy for premenopausal women with early and advanced breast cancer still remains an important and controversial issue. For over 30 years, tamoxifen has been the gold standard in the adjuvant setting. New therapeutic options, such as the addition of ovarian function suppression to oral endocrine therapy (either tamoxifen or aromatase inhibitors), can improve outcomes over tamoxifen alone in well-selected patients. Treatment duration has also been revisited, and extended therapy is becoming a new standard of care, especially in high-risk patients. Endocrine therapy for advanced disease still represents a challenge and a research priority. New drugs and combinations able to overcome endocrine resistance are at the horizon, and their role in premenopausal women should be better elucidated. Side effects and quality of life (including family planning considerations) play an important role in treatment selection and in the patients' treatment adherence and should always be discussed before start of treatment. The paper will specifically focus on how to integrate all new treatment options in the current armamentarium of endocrine therapy of premenopausal women, with the aim of best fine-tuning treatment selections according to the individual risk/benefit evaluation.

Clinical utility of genetic signatures in selecting adjuvant treatment: Risk stratification for early vs. late recurrences

Adjuvant endocrine therapy (ET) reduces the odds of distant recurrence and mortality by nearly one-half in women with hormone receptor (HR) positive early stage breast cancer. While the risk of recurrence is lower for HR positive than negative patients during the first 5-7 years, HR positive patients suffer ongoing recurrences between 0.5 and 2% year over subsequent years. Extended adjuvant ET further reduces recurrence during this late phase of follow-up. ET is associated with post-menopausal side effects (hot flashes, sexual dysfunction, mood changes, and weight gain), and occasional major toxicities (thrombosis and endometrial cancer with tamoxifen; bone mineral loss and possibly heart disease with AIs) persist throughout therapy. Accurate and reliable estimates of the risk of recurrence after five years of ET for women with prior HR positive breast cancer would permit appropriate extended ET decisions. The risk of long-term relapse is related to lymph node status and size of tumor, but these are relatively crude. Several groups have investigated whether multi-parameter tumor biomarker tests might identify those patients whose risk of recurrence is so low that extended ET is not justified. These assays include IHC4, the 21-gene "OncotypeDX", the 12-gene "Endopredict," the PAM50, and the 2-gene "Breast Cancer Index (BCI)" assays. The clinical validity of all these tests for this use context have been established, with at least one paper for each that shows a statistically significant difference in risk of distant recurrence during the 5-10 years after the initial five years of adjuvant endocrine therapy. However, the stakes are high, and although each of these represents a "prospective retrospective" study, they require further validation in subsequent datasets before they should be considered to have "clinical utility" and are used to withhold potentially life-saving treatment. Perhaps more importantly, the clinical breast cancer community, and especially the patient, need to determine how low the risk of late recurrence needs to be to forego the toxicities and side effects of extended adjuvant ET.

New insights into endocrine therapy for young women with breast cancer

Managing estrogen receptor-positive breast cancer in young women (<40 years) requires a multidisciplinary/personalized approach, covering both clinical and psychosocial aspects. Five years of tamoxifen has been the standard adjuvant endocrine therapy for many years. Recent data from the adjuvant randomized trials TEXT-SOFT show that the aromatase inhibitor exemestane plus ovarian suppression significantly reduces recurrences as compared with tamoxifen plus ovarian suppression. The ATLAS and aTToM trials represent the first evidence of a beneficial effect of extended endocrine therapy with tamoxifen in premenopausal women. Outside of a clinical trial, no data support neoadjuvant endocrine therapy in young women. In the metastatic setting, tamoxifen or aromatase inhibitors, both with ovarian suppression/ablation, should be the preferred choice, unless rapid tumor shrinkage is needed. No data are available with fulvestrant in young patients.

Identification of patients with hormone receptor-positive breast cancer who need adjuvant tamoxifen therapy for more than 5 years

BACKGROUND/PURPOSE

Extended hormonal therapy with tamoxifen for > 5 years has improved disease-free survival (DFS) and overall survival (OS) in hormone receptor (HR)-positive breast cancer patients. The aim of this study was to identify the HR-positive breast cancer women who need adjuvant tamoxifen for > 5 years.

METHODS

Between 1990 and 2004, 1104 HR-positive breast cancer patients who had received tamoxifen treatment at our institution and had been disease free for at least 6 years were included in this analysis. Univariate and multivariate analyses of prognostic factors for late recurrence were performed using the binary logistic regression model.

RESULTS

During a median follow-up period of 10.9 years after surgery, 70 patients died and 99 showed recurrence. In multivariate analysis, age < 40 years (p < 0.001) and lymph node metastasis (p < 0.001) were associated with higher rates of recurrence. We stratified patients into high-risk (age < 40 years or positive lymph node status, 536 patients) and low-risk (age > 40 years and negative lymph node status, 566 patients) groups. The recurrence rates were 14.6% and 3.5% in the high-risk and low-risk groups, respectively. Patients in the high-risk group had poorer disease-free survival (p < 0.001) and overall survival (p = 0.010) than those in the low-risk group.

CONCLUSION

Our findings suggest that HR-positive breast cancer women either aged < 40 years or with positive lymph node status were justified in continuing with tamoxifen therapy for > 5 years.

Status of adjuvant endocrine therapy for breast cancer

Adjuvant endocrine therapy reduces the risk of recurrence and death from breast cancer in women with hormone receptor-positive early breast cancer. Tamoxifen has been the standard therapy for decades, and this is still the case for pre-menopausal women. Ovarian suppression is of similar efficacy but currently there is no strong evidence for adding this to tamoxifen and the additional morbidity can be considerable. Results from two important trials addressing this issue are imminent. In post-menopausal women, aromatase inhibitors (AIs) (letrozole, anastrozole, or exemestane) are superior to tamoxifen in preventing recurrence but only letrozole has been shown to improve survival. The main gain is against high-risk cancers, and tamoxifen gives very similar benefit for low-risk disease. Traditionally, treatment has been given for around 5 years, but many women remain at risk of relapse for 10 years or more. The AIs, and more recently tamoxifen, have been shown to reduce further the risk of late recurrence in women still in remission after 5 years of tamoxifen if given for a further 5 years. The comparative benefits of these two options and the selection of patients most likely to benefit from long-term adjuvant endocrine therapy are important topics for further research, as is the optimum duration of AI therapy started upfront.

Adjuvant endocrine therapy for women with hormone receptor-positive breast cancer: american society of clinical oncology clinical practice guideline focused update

PURPOSE

To update the ASCO clinical practice guideline on adjuvant endocrine therapy on the basis of emerging data on the optimal duration of treatment, particularly adjuvant tamoxifen.

METHODS

ASCO convened the Update Committee and conducted a systematic review of randomized clinical trials from January 2009 to June 2013 and analyzed three historical trials. Guideline recommendations were based on the Update Committee's review of the evidence. Outcomes of interest included survival, disease recurrence, and adverse events.

RESULTS

This guideline update reflects emerging data on duration of tamoxifen treatment. There have been five studies of tamoxifen treatment beyond 5 years of therapy. The two largest studies with longest reported follow-up show a breast cancer survival advantage with 10-year durations of tamoxifen use. In addition to modest gains in survival, extended therapy with tamoxifen for 10 years compared with 5 years was associated with lower risks of breast cancer recurrence and contralateral breast cancer.

RECOMMENDATIONS

Previous ASCO guidelines recommended treatment of women who have hormone receptor-positive breast cancer and are premenopausal with 5 years of tamoxifen, and those who are postmenopausal a minimum of 5 years of adjuvant therapy with an aromatase inhibitor or tamoxifen followed by an aromatase inhibitor (in sequence). If women are pre- or perimenopausal and have received 5 years of adjuvant tamoxifen, they should be offered 10 years total duration of tamoxifen. If women are postmenopausal and have received 5 years of adjuvant tamoxifen, they should be offered the choice of continuing tamoxifen or switching to an aromatase inhibitor for 10 years total adjuvant endocrine therapy.

The optimal duration and selection of adjuvant endocrine therapy for breast cancer: how long is enough?

Women with estrogen receptor (ER)+ early breast cancer (BC) are at continuing risk of relapse up to at least 15 years after diagnosis, despite being on adjuvant endocrine therapy for approximately 5 years. Extended adjuvant endocrine therapy with an aromatase inhibitor (AI) after 5 years of tamoxifen further reduces the risk of recurrence in postmenopausal women. More recently, continuing tamoxifen for 10 years has also been shown to further reduce the risk of recurrence compared with 5 years. There are no direct comparative data on the relative merits of extended tamoxifen compared with an AI; indirect evidence suggests that an AI may have increased efficacy but a greater adverse effect on quality of life. Results are awaited on the need for continuing front-line adjuvant AIs for more than 5 years. The next challenge is to determine which patients will benefit from this long-term treatment. Currently, tumor size, nodal involvement, and gene expression profile as measured by the PAM50 Risk of Recurrence (ROR) score have all been shown to have prognostic significance for late recurrence beyond 5 years.

Luminal breast cancer: from biology to treatment

Oestrogen receptor (ER)-positive--or luminal--tumours represent around two-thirds of all breast cancers. Luminal breast cancer is a highly heterogeneous disease comprising different histologies, gene-expression profiles and mutational patterns, with very varied clinical courses and responses to systemic treatment. Despite adjuvant endocrine therapy and chemotherapy treatment for patients at high risk of relapse, both early and late relapses still occur, a fact that highlights the unmet medical needs of these patients. Ongoing research aims to identify those patients who can be spared adjuvant chemotherapy and who will benefit from extended adjuvant hormone therapy. This research also aims to explore the role of adjuvant bisphosphonates, to interrogate new agents for targeting minimal residual disease, and to address endocrine resistance. Data from next-generation sequencing studies have given us new insight into the biology of luminal breast cancer and, together with advances in preclinical models and the availability of newer targeted agents, have led to the testing of rationally chosen combination treatments in clinical trials. However, a major challenge will be to make sense of the large amount of patient genomic data that is becoming increasingly available. This analysis will be critical to our understanding how intertumour and intratumour heterogeneity can influence treatment response and resistance.

Hormonal therapies in young breast cancer patients: when, what and for how long?

Breast cancer in young women (<40 years) is a rare and complex clinical and psychosocial condition, which deserves multidisciplinary and personalized approaches. In young women with hormone-receptor positive disease, 5 years of adjuvant tamoxifen, with or without ovarian suppression/ablation, is considered the standard endocrine therapy. The definitive role of adjuvant aromatase inhibitors has still to be elucidated: the upcoming results of the Tamoxifen and EXemestane Trial (TEXT) and Suppression of Ovarian Function Trial (SOFT) trials will help understanding if we can widen our current endocrine therapeutic options. The optimal duration of adjuvant endocrine therapy in young women also remains an unresolved issue. The recently reported results of the ATLAS and aTToM trials represent the first evidence of a beneficial effect of extended endocrine therapy in premenopausal women and provide an important opportunity in high-risk young patients. In the metastatic setting, endocrine therapy should be the preferred choice for endocrine responsive disease, unless there is evidence of endocrine resistance or need for rapid disease and/or symptom control. Tamoxifen in combination with ovarian suppression/ablation remains the 1st-line endocrine therapy of choice. Aromatase inhibitors in combination with ovarian suppression/ablation can be considered after progression on tamoxifen and ovarian suppression/ablation. Fulvestrant has not yet been studied in pre-menopausal women. Specific age-related treatment side effects (i.e., menopausal symptoms, change in body image and weight gain, cognitive function impairment, fertility damage/preservation, long-term organ dysfunction, sexuality) and the social impact of diagnosis and treatment (i.e., job discrimination, family management) should be carefully addressed when planning long-lasting endocrine therapies in young women with hormone-receptor positive early and advanced breast cancer.

Long-term effects of continuing adjuvant tamoxifen to 10 years versus stopping at 5 years after diagnosis of oestrogen receptor-positive breast cancer: ATLAS, a randomised trial

BACKGROUND

For women with oestrogen receptor (ER)-positive early breast cancer, treatment with tamoxifen for 5 years substantially reduces the breast cancer mortality rate throughout the first 15 years after diagnosis. We aimed to assess the further effects of continuing tamoxifen to 10 years instead of stopping at 5 years.

METHODS

In the worldwide Adjuvant Tamoxifen: Longer Against Shorter (ATLAS) trial, 12,894 women with early breast cancer who had completed 5 years of treatment with tamoxifen were randomly allocated to continue tamoxifen to 10 years or stop at 5 years (open control). Allocation (1:1) was by central computer, using minimisation. After entry (between 1996 and 2005), yearly follow-up forms recorded any recurrence, second cancer, hospital admission, or death. We report effects on breast cancer outcomes among the 6846 women with ER-positive disease, and side-effects among all women (with positive, negative, or unknown ER status). Long-term follow-up still continues. This study is registered, number ISRCTN19652633.

FINDINGS

Among women with ER-positive disease, allocation to continue tamoxifen reduced the risk of breast cancer recurrence (617 recurrences in 3428 women allocated to continue vs 711 in 3418 controls, p=0·002), reduced breast cancer mortality (331 deaths vs 397 deaths, p=0·01), and reduced overall mortality (639 deaths vs 722 deaths, p=0·01). The reductions in adverse breast cancer outcomes appeared to be less extreme before than after year 10 (recurrence rate ratio [RR] 0·90 [95% CI 0·79–1·02] during years 5–9 and 0·75 [0·62–0·90] in later years; breast cancer mortality RR 0·97 [0·79–1·18] during years 5–9 and 0·71 [0·58–0·88] in later years). The cumulative risk of recurrence during years 5–14 was 21·4% for women allocated to continue versus 25·1% for controls; breast cancer mortality during years 5–14 was 12·2% for women allocated to continue versus 15·0% for controls (absolute mortality reduction 2·8%). Treatment allocation seemed to have no effect on breast cancer outcome among 1248 women with ER-negative disease, and an intermediate effect among 4800 women with unknown ER status. Among all 12,894 women, mortality without recurrence from causes other than breast cancer was little affected (691 deaths without recurrence in 6454 women allocated to continue versus 679 deaths in 6440 controls; RR 0·99 [0·89–1·10]; p=0·84). For the incidence (hospitalisation or death) rates of specific diseases, RRs were as follows: pulmonary embolus 1·87 (95% CI 1·13–3·07, p=0·01 [including 0·2% mortality in both treatment groups]), stroke 1·06 (0·83–1·36), ischaemic heart disease 0·76 (0·60–0·95, p=0·02), and endometrial cancer 1·74 (1·30–2·34, p=0·0002). The cumulative risk of endometrial cancer during years 5–14 was 3·1% (mortality 0·4%) for women allocated to continue versus 1·6% (mortality 0·2%) for controls (absolute mortality increase 0·2%).

INTERPRETATION

For women with ER-positive disease, continuing tamoxifen to 10 years rather than stopping at 5 years produces a further reduction in recurrence and mortality, particularly after year 10. These results, taken together with results from previous trials of 5 years of tamoxifen treatment versus none, suggest that 10 years of tamoxifen treatment can approximately halve breast cancer mortality during the second decade after diagnosis.

FUNDING

Cancer Research UK, UK Medical Research Council, AstraZeneca UK, US Army, EU-Biomed.

Impact of premenopausal status at breast cancer diagnosis in women entered on the placebo-controlled NCIC CTG MA17 trial of extended adjuvant letrozole

BACKGROUND

MA17 showed improved outcomes in postmenopausal women given extended letrozole (LET) after completing 5 years of adjuvant tamoxifen.

PATIENTS AND METHODS

Exploratory subgroup analyses of disease-free survival (DFS), distant DFS (DDFS), overall survival (OS), toxic effects and quality of life (QOL) in MA17 were performed based on menopausal status at breast cancer diagnosis.

RESULTS

At diagnosis, 877 women were premenopausal and 4289 were postmenopausal. Extended LET was significantly better than placebo (PLAC) in DFS for premenopausal [hazard ratio (HR) = 0.26, 95% confidence interval (CI) 0.13-0.55; P = 0.0003] and postmenopausal women (HR = 0.67; 95% CI 0.51-0.89; P = 0.006), with greater DFS benefit in those premenopausal (interaction P = 0.03). In adjusted post-unblinding analysis, those who switched from PLAC to LET improved DDFS in premenopausal (HR = 0.15; 95% CI 0.03-0.79; P = 0.02) and postmenopausal women (HR = 0.45; 95% CI 0.22-0.94; P = 0.03).

CONCLUSIONS

Extended LET after 5 years of tamoxifen was effective in pre- and postmenopausal women at diagnosis, and significantly better in those premenopausal. Women premenopausal at diagnosis should be considered for extended adjuvant therapy with LET if menopausal after completing tamoxifen.

Making Sense of Clinical Trial Data: Is Inverse Probability of Censoring Weighted Analysis the Answer to Crossover Bias?

Ideally, therapeutic interventions are evaluated through randomized clinical trials. These trials are commonly analyzed with an intent-to-treat (ITT) approach, whereby patients are analyzed in their assigned treatment group regardless of actual treatment received. If an interim analysis of such trials demonstrates compelling evidence of a difference in benefit, ethical considerations often dictate that the trial be unblinded and participants be provided access to the more efficacious agent. Because interim analysis may not address longer-term outcomes of interest, important clinical questions such as overall survival benefit—the ultimate test of efficacy to many—may remain unanswered. The ensuing crossover disturbs randomization and may lead to biased longer-term analysis, compromising the utility of clinical data. This has been especially apparent in recent adjuvant and prevention breast cancer trials. We consider four such trials: HERA (Herceptin Adjuvant), NSABP P-1 (National Surgical Adjuvant Breast and Bowel Project Breast Cancer Prevention P-1), MA.17, and BIG 1-98 (Breast International Group 1-98), the long-term outcomes of which were complicated by unblinding and selective crossover. We also discuss the biases associated with ITT analysis and, alternatively, censoring of follow-up data (ie, dropping out) after selective crossover. Moreover, we discuss how the statistical procedure of inverse probability of censoring weighted (IPCW) analysis may be used to account for selective crossover as an alternative to ITT or censoring analysis, as was recently done for the BIG 1-98 trial. Notably, IPCW analysis may be particularly suited for detecting overall survival benefits that otherwise would not be detected with an ITT approach, as reported for the BIG 1-98 trial.

Individualization of treatment strategies

This section focuses on different aspects of the individualization of hormone treatment in breast cancer. This includes tumor-related biological factors such as expression of hormone receptors, HER-2, and Ki-67; host-related factors such as CYP2D6 or body mass index, and risk and/or development of specific toxicities and treatment adherence. The best predictor of response to hormonal interventions is the expression of hormone receptors, in particular, estrogen receptors. Treatment adherence and compliance are key factors and strategies aiming to identify and intervene when patients are at risk of abandoning treatment. Currently, routine assessment of CYP2D6 is not recommended to guide tamoxifen treatment. Likewise, there are no criteria regarding bone mass density, lipid profile, or arthralgias to recommend one class of agent versus another. Aromatase inhibitors should not be administered to patients who are pre- or perimenopausal.

Breast cancer (non-metastatic)

INTRODUCTION

Breast cancer affects at least 1 in 10 women in the UK, but most present with primary operable disease, which has an 80% 5-year survival rate overall.

METHODS AND OUTCOMES

We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of interventions after breast-conserving surgery for ductal carcinoma in situ? What are the effects of treatments for primary operable breast cancer? What are the effects of interventions in locally advanced breast cancer (stage 3B)? We searched: Medline, Embase, The Cochrane Library, and other important databases up to April 2009 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).

RESULTS

We found 83 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.

CONCLUSIONS

In this systematic review we present information relating to the effectiveness and safety of the following interventions: adding chemotherapy (cyclophosphamide/methotrexate/fluorouracil and/or anthracycline and/or taxane-based regimens), or hormonal treatment to radiotherapy; adjuvant treatments (aromatase inhibitors, adjuvant anthracycline regimens, tamoxifen); axillary clearance; axillary dissection plus sentinel node dissection; axillary radiotherapy; axillary sampling; combined chemotherapy plus tamoxifen; chemotherapy plus monoclonal antibody (trastuzumab); extensive surgery; high-dose chemotherapy; hormonal treatment; less extensive mastectomy; less than whole-breast radiotherapy plus breast-conserving surgery; multimodal treatment; ovarian ablation; primary chemotherapy; prolonged adjuvant combination chemotherapy; radiotherapy (after breast-conserving surgery, after mastectomy, plus tamoxifen after breast-conserving surgery, to the internal mammary chain, and to the ipsilateral supraclavicular fossa, and total nodal radiotherapy); sentinel node biopsy; and standard chemotherapy regimens.

Does tumour dormancy offer a therapeutic target?

The increasing number of cancer survivors is cause for celebration, but this expanding population has highlighted the problem of tumour dormancy, which can lead to relapse. As we start to understand more about the biology of dormant cancer cells, we can begin to address how best to treat this form of disease. Preclinical models and initial clinical trials, as exemplified in patients with breast cancer, are paving the way to address how best to treat long-term cancer survivors to minimize the risk of cancer recurrence.

Changes to adjuvant systemic therapy in breast cancer: a decade in review

Breast cancer is the second most common cause of cancer death in women among the United States. Fortunately, it continues to be an active area of research. Today, it is well recognized that breast cancer can often be a systemic disease, with micrometastatic involvement at diagnosis in many patients. Over the past decade, adjuvant systemic therapy has been used to eradicate micrometastatic disease, and it has been shown to decrease the rates of recurrence and improve the survival of patients with early-stage, resected breast cancer. Some of the success of modern adjuvant systemic therapy has come from the advent of new chemotherapy and endocrine agents but also from the development of targeted therapies, which have improved the efficacy of conventional, cytotoxic therapy. There has also been increasing awareness that the dosing and schedule of administration of systemic therapies are equally important factors in achieving better outcomes in patients with early-stage breast cancer. Growing research into the biology and genomics of breast cancer has fueled the development of more accurate risk stratification tools and helped individualize the decision to recommend adjuvant systemic therapy. Herein, we present a review of salient developments over the past decade that have helped shape the adjuvant systemic therapy of today.

NCCN Task Force Report: Bone Health in Cancer Care

Bone health and maintenance of bone integrity are important components of comprehensive cancer care in both early and late stages of disease. Risk factors for osteoporosis are increased in patients with cancer, including women with chemotherapy-induced ovarian failure, those treated with aromatase inhibitors for breast cancer, men receiving androgen-deprivation therapy for prostate cancer, and patients undergoing glucocorticoid therapy. The skeleton is a common site of metastatic cancer recurrence, and skeletal-related events are the cause of significant morbidity. The National Comprehensive Cancer Network (NCCN) convened a multidisciplinary task force on Bone Health in Cancer Care to discuss the progress made in identifying effective screening and therapeutic options for management of treatment-related bone loss; understanding the factors that result in bone metastases; managing skeletal metastases; and evolving strategies to reduce bone recurrences. This report summarizes presentations made at the meeting.

Endocrine therapy for the treatment of postmenopausal women with breast cancer

The treatment of women with estrogen receptor-positive breast cancer has advanced significantly in the past decade. Tamoxifen was the gold standard hormonal therapy for breast cancer until the introduction of aromatase inhibitors and fulvestrant. Many of these new treatments are useful only for patients who are postmenopausal. There are data to support the use of these new agents both in the metastatic and adjuvant settings. Here, we briefly review the recent clinical trials supporting the use of these agents in both the adjuvant and metastatic settings. We will discuss possible mechanisms of resistance to endocrine agents that could be exploited therapeutically to improve the outcome for patients with hormone receptor-positive breast cancers.

Cohort study examining tamoxifen adherence and its relationship to mortality in women with breast cancer

Increasing duration of tamoxifen therapy improves survival in women with breast cancer but the impact of adherence to tamoxifen on mortality is unclear. This study investigated whether women prescribed tamoxifen after surgery for breast cancer adhered to their prescription and whether adherence influenced survival. A retrospective cohort study of all women with incident breast cancer in the Tayside region of Scotland between 1993 and 2002 was linked to encashed prescription records to calculate adherence to tamoxifen. Survival analysis was used to determine the effect of adherence on all-cause mortality. In all 2080 patients formed the study cohort with 1633 (79%) prescribed tamoxifen. The median duration of use was 2.42 years (IQR=1.04–4.89 years). Longer duration was associated with better survival but this varied over time. The hazard ratio for mortality in relation to duration at 2.4 years was 0.85, 95% CI=0.83–0.87. Median adherence to tamoxifen was 93% (interquartile range=84–100%). Adherence <80% was associated with poorer survival, hazard ratio 1.10, 95% CI=1.001–1.21. Persistence with tamoxifen was modest with only 49% continuing therapy for 5 years of those followed up for 5 years or more. Increased duration of tamoxifen reduces the risk of death, although one in two women do not complete the recommended 5-year course of treatment. A significant proportion of women have low adherence to tamoxifen and are at increased risk of death.

WITHDRAWN: Tamoxifen for early breast cancer

BACKGROUND

There have been many randomised trials of adjuvant tamoxifen among women with early breast cancer, and an updated overview of their results is presented.

OBJECTIVES

In this report, the Early Breast Cancer Trialists' Collaborative Group present their third 5-yearly systematic overview (meta-analysis) of treatment with tamoxifen.

SEARCH STRATEGY

Trial identification procedures for the EBCTCG overviews have been described elsewhere. See under "EBCTCG" in the Breast Cancer Collaborative Review Group module.

SELECTION CRITERIA

All randomised trials that began before 1990 and compared adjuvant tamoxifen for any duration versus no such treatment for women with early breast cancer.

DATA COLLECTION AND ANALYSIS

In 1995, information was sought on each woman in any randomised trial that began before 1990 of adjuvant tamoxifen versus no tamoxifen before recurrence. Information was obtained and analysed centrally on each of 37,000 women in 55 such trials, comprising about 87% of the worldwide evidence. Compared with the previous such overview, this approximately doubles the amount of evidence from trials of about 5 years of tamoxifen and, taking all trials together, on events occurring more than 5 years after randomisation.

MAIN RESULTS

Nearly 8000 of the women had a low, or zero, level of the oestrogen-receptor protein (ER) measured in their primary tumour. Among them, the overall effects of tamoxifen appeared to be small, and subsequent analyses of recurrence and total mortality are restricted to the remaining women (18,000 with ER-positive tumours, plus nearly 12,000 more with untested tumours, of which an estimated 8000 would have been ER-positive). For trials of 1 year, 2 years, and about 5 years of adjuvant tamoxifen, the proportional recurrence reductions produced among these 30,000 women during about 10 years of follow-up were 21% (SD 3), 29% (SD 2), and 47% (SD 3), respectively, with a highly significant trend towards greater effect with longer treatment (2p<0.00001). The corresponding proportional mortality reductions were 12% (SD 3), 17% (SD 3), and 26% (SD 4), respectively, and again the test for trend was significant (2p=0.003). The absolute improvement in recurrence was greater during the first 5 years, whereas the improvement in survival grew steadily larger throughout the first 10 years. The proportional mortality reductions were similar for women with node-positive and node-negative disease, but the absolute mortality reductions were greater in node-positive women. In the trials of about 5 years of adjuvant tamoxifen the absolute improvements in 10-year survival were 10.9% (SD 2.5) for node-positive (61.4% vs 50.5% survival, 2p<0.00001) and 5.6% (SD 1.3) for node-negative (78.9% vs 73.3% survival, 2p<0.00001). These benefits appeared to be largely irrespective of age, menopausal status, daily tamoxifen dose (which was generally 20 mg), and of whether chemotherapy had been given to both groups. In terms of other outcomes among all women studied (ie, including those with "ER-poor" tumours), the proportional reductions in contralateral breast cancer were 13% (SD 13), 26% (SD 9), and 47% (SD 9) in the trials of 1, 2, or about 5 years of adjuvant tamoxifen. The incidence of endometrial cancer was approximately doubled in trials of 1 or 2 years of tamoxifen and approximately quadrupled in trials of 5 years of tamoxifen (although the number of cases was small and these ratios were not significantly different from each other). The absolute decrease in contralateral breast cancer was about twice as large as the absolute increase in the incidence of endometrial cancer. Tamoxifen had no apparent effect on the incidence of colorectal cancer or, after exclusion of deaths from breast or endometrial cancer, on any of the other main categories of cause of death (total nearly 2000 such deaths; overall relative risk 0.99 [SD 0.05]).

AUTHORS' CONCLUSIONS

For women with tumours that have been reliably shown to be ER-negative, adjuvant tamoxifen remains a matter for research. However, some years of adjuvant tamoxifen treatment substantially improves the 10-year survival of women with ER-positive tumours and of women whose tumours are of unknown ER status, with the proportional reductions in breast cancer recurrence and in mortality appearing to be largely unaffected by other patient characteristics or treatments.

Late extended adjuvant treatment with letrozole improves outcome in women with early-stage breast cancer who complete 5 years of tamoxifen

PURPOSE

The National Cancer Institute of Canada Clinical Trials Group MA.17 trial examined the efficacy of letrozole (LET) started within 3 months of 5 years of adjuvant tamoxifen in postmenopausal hormone receptor-positive early-stage breast cancer. When the trial was unblinded, patients who received placebo (PLAC) were offered LET.

PATIENTS AND METHODS

This cohort analysis describes the outcomes of women assigned PLAC at the initial random assignment after unblinding. Efficacy outcomes of women who chose LET (PLAC-LET group) were compared with those who did not (PLAC-PLAC group) by the hazard ratios and by P values calculated from Cox models that adjusted for imbalances between the groups. Toxicity analyses included only events that occurred after unblinding.

RESULTS

There were 1,579 women in the PLAC-LET group (median time from tamoxifen, 2.8 years) and 804 in the PLAC-PLAC group. Patients in the PLAC-LET group were younger; had a better performance status; and were more likely to have had node-positive disease, axillary dissection, and adjuvant chemotherapy than those in the PLAC-PLAC group. At a median follow-up of 5.3 years, disease-free survival (DFS; adjusted hazard ratio [HR], 0.37; 95% CI, 0.23 to 0.61; P < .0001) and distant DFS (HR, 0.39; 95% CI, 0.20 to 0.74; P = .004) were superior in the PLAC-LET group. More self-reported new diagnoses of osteoporosis and significantly more clinical fractures occurred in the women who took LET (5.2% v 3.1%, P = .02).

CONCLUSION

Interpretation of this cohort analysis suggests that LET improves DFS and distant DFS even when there has been a substantial period of time since the discontinuation of prior adjuvant tamoxifen.

Estrogen receptor modulators and down regulators: optimal use in postmenopausal women with breast cancer

Endocrine treatments have been used in breast cancer since 1896, when Beatson reported on the results of oophorectomy for advanced breast cancer. In the second half of the last century, different endocrine-based compounds were developed and, in this review, the role of the selective estrogen receptor modulators (SERMs) and selective estrogen receptor down regulators (SERDs) in the postmenopausal setting are discussed. Tamoxifen is the most investigated and most widely used representative of these agents, and has been introduced in the advanced disease, in the neoadjuvant and adjuvant setting, and for the prevention of the disease. Its role has been challenged in recent years by the introduction of third-generation aromatase inhibitors that have proven higher activities than tamoxifen with different toxicity patterns. Several other SERMs have been investigated, but none have been clearly superior to tamoxifen. SERDs act as pure estrogen antagonists and should compare favourably to tamoxifen. For the time being, they have been used in the treatment of advanced breast cancers and their role in other settings still needs investigation. The increased use of aromatase inhibitors as first-line endocrine therapy has resulted in new discussions regarding the role that tamoxifen and other SERMs or SERDs may play in breast cancer. The sequencing of endocrine therapies in hormone-sensitive breast cancer remains a very important research issue.

The use of third-generation aromatase inhibitors and tamoxifen in the adjuvant treatment of postmenopausal patients with hormone-dependent breast cancer: evidence based review

(1) Worldwide, breast cancer is the most common type of cancer in women, and the second most frequently diagnosed cancer overall.(2) Since its approval approximately 20 years ago, a 5-year course of tamoxifen has been the standard adjuvant therapy for patients with hormone-dependent breast cancer.(3) Recently, data from large randomised clinical trials have indicated that the third-generation aromatase inhibitors (letrozole, anastrozole and exemestane) are more effective than tamoxifen as adjuvant therapy in postmenopausal women with operable breast cancer when given either initially, or sequentially following initial tamoxifen therapy, within the first five years post-operatively.(4) One large randomised trial demonstrated that administration of letrozole to high-risk (node-positive) postmenopausal patients who have completed 5 years' adjuvant tamoxifen further prevents late recurrences and contralateral breast cancer, contrary to the lack of obvious benefit of extending tamoxifen treatment to 10 years found in another large randomised study.(5) Aromatase inhibitors and tamoxifen should not be administered concomitantly as this does not provide additional benefit, and a large, randomised study demonstrated reduced disease-free survival with the combination of anastrozole plus tamoxifen compared with anastrozole alone.(6) Further studies are required to establish whether the third-generation aromatase inhibitors prolong overall survival compared with tamoxifen, to evaluate their long-term efficacy and tolerability profiles, and to determine the optimal treatment duration with these agents.

Breast cancer (non-metastatic)

INTRODUCTION

Breast cancer affects at least 1 in 10 women in the UK, but most present with primary operable disease, which has an 80% 5-year survival rate overall.

METHODS AND OUTCOMES

We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of interventions after breast-conserving surgery for ductal carcinoma in situ? What are the effects of treatments for primary operable breast cancer? What are the effects of interventions in locally advanced breast cancer (stage IIIB)? We searched: Medline, Embase, The Cochrane Library and other important databases up to February 2006 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).

RESULTS

We found 79 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.

CONCLUSIONS

In this systematic review we present information relating to the effectiveness and safety of the following interventions: adding chemotherapy (cyclophosphamide/methotrexate/ fluorouracil and/or anthracycline and/or taxane-based regimens), or hormonal treatment to radiotherapy; adjuvant treatments (aromatase inhibitors, adjuvant anthracycline regimens, tamoxifen); axillary clearance; axillary dissection plus sentinel node dissection; axillary radiotherapy; axillary sampling; combined chemotherapy plus tamoxifen; chemotherapy plus monoclonal antibody (trastuzumab); extensive surgery; high-dose chemotherapy; hormonal treatment; less extensive mastectomy; less than whole breast radiotherapy plus breast conserving surgery; multimodal treatment; ovarian ablation; primary chemotherapy; prolonged adjuvant combination chemotherapy; radiotherapy (after breast-conserving surgery, after mastectomy, plus tamoxifen after breast-conserving surgery, to the internal mammary chain, and to the ipsilateral supraclavicular fossa, and total nodal radiotherapy); sentinel node biopsy; and standard chemotherapy regimens.

Controversies of adjuvant endocrine treatment for breast cancer and recommendations of the 2007 St Gallen conference

Endocrine treatment for breast cancer was introduced more than a century ago. The discovery of hormone receptors has allowed targeting of endocrine treatment to patients whose primary tumours express these receptors. In the adjuvant setting, different approaches are used in premenopausal or postmenopausal women. In premenopausal patients, suppression of ovarian function and the use of tamoxifen are the most important therapeutic options, even though questions on timing, duration, and combination of these compounds remain unanswered. The use of aromatase inhibitors in combination with ovarian-function suppression is currently under investigation in the premenopausal setting. In postmenopausal patients, aromatase inhibitors given after 2-3 years or 5 years of tamoxifen have shown a significant benefit over tamoxifen alone. However, questions on this treatment also remain unanswered. For example, whether all patients should receive an aromatase inhibitor or whether some subgroups of patients might be optimally treated by tamoxifen alone is yet to be established. In this paper we review the published work on adjuvant endocrine treatment in breast cancer and provide recommendations from the 2007 St Gallen International Conference on Primary Therapy of Early Breast Cancer.

Breast Cancer Adjuvant Endocrine Therapy

Adjuvant endocrine therapy with the selective estrogen receptor modulator, tamoxifen, has significantly improved mortality from early-stage breast cancer for both pre- and postmenopausal women with hormone receptor-positive breast cancer. Recent large clinical trials have demonstrated a clear and consistent benefit for the incorporation of aromatase inhibitor (AI) therapy within adjuvant endocrine regimens for postmenopausal women. The AIs, which are associated with myalgias, arthralgias, and a reduction in bone mineral density, are generally well tolerated and have lower risks of endometrial carcinoma and thromboembolic events than tamoxifen. Data are awaited from ongoing trials to better define the optimal sequencing strategy, duration, and AI agent. Attempts to further optimize adjuvant endocrine therapy by identifying predictive biomarkers of response, as well as by developing strategies to overcome endocrine resistance are underway. In premenopausal women AI monotherapy is currently contraindicated and tamoxifen remains the standard of care. The role of ovarian function suppression in addition to tamoxifen or combined with AI therapy is being explored. The hope is that continued advances in endocrine therapy will translate into improved survival among both pre- and postmenopausal women with receptor-positive breast cancer.

Late risk of relapse and mortality among postmenopausal women with estrogen responsive early breast cancer after 5 years of tamoxifen

BACKGROUND

Letrozole after 5 years of adjuvant tamoxifen results in a significant reduction in risk of recurrence from estrogen receptor (ER) positive breast cancer. An individualized estimate of the risk of relapse and death after 5 years of tamoxifen could improve decisions regarding extended hormonal therapy.

METHODS

The British Columbia Breast Cancer Outcomes database was used to identify women aged 45 years or older at the time of diagnosis with early-stage (I-IIIA) breast cancer who received tamoxifen and were disease free 5 years after diagnosis. Ten-year breast cancer event rates and mortality were calculated as well as annualized hazard rates of recurrence.

RESULTS

A total of 1086 women were identified with a median age of 64 years and follow-up of 10.5 years. The relative risk (RR) of death was 3.1 (P=0.003) and for recurrence was 1.7 (P=0.037) for N1 (one to three positive nodes) versus N0 (zero nodes positive) disease. N2 (four to nine nodes positive) had a RR of 5.8 (P<0.001) for death and 3.0 (P=0.002) for recurrence. Low tumor grade and high ER level subgroups had a more favorable prognosis. Annual breast cancer risk between years 6 and 10 was, respectively, 2.2%, 3.5% and 7.6% for N0, N1 and N2 disease and 2.6% and 4.5% for T1 and T2 breast cancer.

CONCLUSION

T and N stages predicted late relapse and death from breast cancer in a population-based cohort of postmenopausal women. Risk estimates reported herein may be used to optimize decision making regarding adjuvant therapy after 5 years of tamoxifen.