Concurrent chemo-endocrine treatment for early hormone-positive breast cancer: a no-go???

PURPOSE

Endocrine therapy is one of the cornerstones of early breast cancer treatment. While this medication could be initiated on the day of diagnosis, it is often postponed until after completion of surgery, radiotherapy, and chemotherapy. This practice is based on preclinical data suggesting an antagonistic effect between endocrine therapy and cytostatic agents, and on the interpretation of clinical trials comparing concurrent versus sequential use of tamoxifen and chemotherapy. These clinical trials, however, have never shown a statistically significant difference in overall survival or disease-free survival and focused on tamoxifen rather than aromatase inhibitors. Nevertheless, sequentially administered endocrine and chemotherapy have become standard of care worldwide.

RESULTS

We performed a literature review and conclude that concurrent endocrine chemotherapy is at least as effective as sequential treatment. In fact, higher response rates have been observed in trials with aromatase inhibitors rather than tamoxifen in a neoadjuvant setting.

CONCLUSION

We encourage breast cancer oncologists to re-consider concurrent endocrine chemotherapy as a possible treatment strategy enabling early start of potentially curative endocrine treatment.

Concurrent and sequential initiation of ovarian function suppression with chemotherapy in premenopausal women with endocrine-responsive early breast cancer: an exploratory analysis of TEXT and SOFT

BACKGROUND

Recent breast cancer treatment guidelines recommend that higher-risk premenopausal patients should receive ovarian function suppression (OFS) as part of adjuvant endocrine therapy. If chemotherapy is also given, it is uncertain whether to select concurrent or sequential OFS initiation.

DESIGN AND METHODS

We analyzed 1872 patients enrolled in the randomized phase III TEXT and SOFT trials who received adjuvant chemotherapy for hormone receptor-positive, HER2-negative breast cancer and upon randomization to an OFS-containing adjuvant endocrine therapy, initiated gonadotropin-releasing-hormone-agonist triptorelin. Breast cancer-free interval (BCFI) was compared between patients who received OFS concurrently with chemotherapy in TEXT (n = 1242) versus sequentially post-chemotherapy in SOFT (n = 630). Because timing of trial enrollment relative to adjuvant chemotherapy differed, we implemented landmark analysis re-defining BCFI beginning 1 year after final dose of chemotherapy (median, 15.5 and 8.1 months from enrollment to landmark in TEXT and SOFT, respectively). As a non-randomized treatment comparison, we implemented comparative-effectiveness propensity score methodology with weighted Cox modeling.

RESULTS

Distributions of several clinico-pathologic characteristics differed between groups. Patients who were premenopausal post-chemotherapy in SOFT were younger on average. The median duration of adjuvant chemotherapy was 18 weeks in both groups. There were 231 (12%) BC events after post-landmark median follow-up of about 5 years. Concurrent use of triptorelin with chemotherapy was not associated with a significant difference in post-landmark BCFI compared with sequential triptorelin post-chemotherapy, either in the overall population (HR = 1.11, 95% CI 0.72-1.72; P = 0.72; 4-year BCFI 89% in both groups), or in the subgroup of 692 women <40 years at diagnosis (HR = 1.13, 95% CI 0.69-1.84) who are less likely to develop chemotherapy-induced amenorrhea.

CONCLUSION

Based on comparative-effectiveness modeling of TEXT and SOFT after about 5 years median follow-up, with limited statistical power especially for the subgroup <40 years, neither detrimental nor beneficial effect of concurrent administration of OFS with chemotherapy on the efficacy of adjuvant therapy that includes chemotherapy was detected.

CLINICALTRIALS.GOV

NCT00066690 and NCT00066703.

Concurrent versus sequential adjuvant chemo-endocrine therapy in hormone-receptor positive early stage breast cancer patients: a systematic review and meta-analysis

BACKGROUND

Although in clinical practice adjuvant chemotherapy (CT) and endocrine therapy (ET) are administered sequentially in patients with hormone-receptor positive breast cancer, the optimal timing, i.e. concurrent or sequential administration, of these treatments has been scarcely investigated. To better clarify this issue we conducted a systematic review and meta-analysis of randomized studies comparing these two modalities of administrations in terms of disease-free survival (DFS) and overall survival (OS).

METHODS

Relevant studies were identified by searching PubMed, Web of Knowledge and the proceedings of the major conferences with no date restriction up to March 2016. The summary risk estimates (pooled hazard ratio [HR] and 95% confidence intervals [CI]) for DFS and OS were calculated using random effect models (DerSimonian and Laird method).

RESULTS

A total of three randomized studies were eligible including 2021 breast cancer patients. Overall, 755 DFS events were observed, 365 in the sequential arm and 390 in the concomitant arm, with a pooled HR of 0.95 (95% CI = 0.76 to 1.18, P = 0.643). No association between timing of treatment and OS was observed (HR = 0.95; 95% CI = 0.80 to 1.12, P = 0.529).

CONCLUSION

Our pooled analysis showed no association between the timing of administration of adjuvant CT and ET and DFS and OS in breast cancer patients candidates for both adjuvant treatments. Because of the small number of published trials, the lack of data on the timing with modern adjuvant treatments, i.e. taxane-containing CT and aromatase inhibitors, this topic remain still controversial and requires further studies to be clarified.

Breast cancer

Breast cancer is one of the three most common cancers worldwide. Early breast cancer is considered potentially curable. Therapy has progressed substantially over the past years with a reduction in therapy intensity, both for locoregional and systemic therapy; avoiding overtreatment but also undertreatment has become a major focus. Therapy concepts follow a curative intent and need to be decided in a multidisciplinary setting, taking molecular subtype and locoregional tumour load into account. Primary conventional surgery is not the optimal choice for all patients any more. In triple-negative and HER2-positive early breast cancer, neoadjuvant therapy has become a commonly used option. Depending on clinical tumour subtype, therapeutic backbones include endocrine therapy, anti-HER2 targeting, and chemotherapy. In metastatic breast cancer, therapy goals are prolongation of survival and maintaining quality of life. Advances in endocrine therapies and combinations, as well as targeting of HER2, and the promise of newer targeted therapies make the prospect of long-term disease control in metastatic breast cancer an increasing reality.

Tamoxifen enhances the cytotoxicity of conventional chemotherapy in esophageal adenocarcinoma cells

INTRODUCTION

Esophageal adenocarcinoma is a lethal malignancy which is increasing in incidence, and many patients receive chemotherapy as part of their treatment. We have previously demonstrated that esophageal adenocarcinoma-derived cell lines respond to treatment with estrogen receptor modulators, such as tamoxifen. Reports from breast cancer suggest that tamoxifen may attenuate the efficacy of other chemotherapeutic agents. We have therefore assessed the response of esophageal adenocarcinoma cell lines to tamoxifen therapy when given in combination with conventional agents.

METHODS

Two estrogen receptor (ER)-positive esophageal adenocarcinoma cell lines (OE-19 and OE-33) were treated with combinations of tamoxifen, cisplatin and 5-fluorouracil (5-FU). Effects on cell viability were measured using an MTS assay, and cell death was detected with annexin V/propidium iodide flow cytometry. To assess whether the efficacy of tamoxifen in these cell lines might be relevant to the clinical setting, we analyzed ER status in 10 esophageal adenocarcinoma tissue specimens by immunohistochemistry.

RESULTS

IC50 values (μM) for OE-19 and OE-33 were 11.2 and 7.1 for tamoxifen, 19.6 and 4.7 for cisplatin, and 1.7 and 5.9 for 5-FU, respectively. Cell death was detected in 11.9% and 15.8% of cells treated with tamoxifen, 7.9% and 8.7% cells treated with cisplatin, and 3.6% and 8.6% cells treated with 5-FU at their IC50s. The addition of tamoxifen to cisplatin increased cell death by 11.4% in OE-19 (p < 0.0001) and 16.3% in OE-33 (p < 0.0001). Similarly, the addition of tamoxifen to 5-FU increased cell death by 11.6% in OE-19 (p < 0.0001) and 15.9% in OE-33 (p < 0.0001). Eight of 10 tissue specimens showed positive staining for ERα and 7 of 10 for ERβ.

CONCLUSIONS

In a cell culture model the addition of tamoxifen to conventional chemotherapy appears to be both feasible and beneficial. Expression of ERα and ERβ was also confirmed in esophageal adenocarcinoma tissues.

Efficacy of taxanes as adjuvant treatment of breast cancer: a review and meta-analysis of randomised clinical trials

OBJECTIVES

To evaluate the magnitude of benefit obtained by taxanes as adjuvant treatment of breast cancer and to assess the best method for their administration.

MATERIAL AND METHODS

We performed a systematic search of phase III randomised clinical trials that included patients with non-metastatic breast cancer in whom comparisons were chemotherapy (CT) containing a taxane (docetaxel or paclitaxel) vs. CT without taxanes (first-generation trials), or CT with taxane in both treatment arms (second-generation trials), administered after surgery. The parameters of efficacy evaluated were disease-free survival (DFS) and overall survival (OS). The data obtained in the first-generation trials (number of relapses and deaths) were submitted to a meta-analysis. The odds ratio (OR) combined with DerSimonian and Laird (OR DL) and 95% confidence interval (95% CI) were calculated. Further, an analysis was performed of those trials that included only patients with nodal involvement (N+). In both cases, the results were also analysed as a function of the taxane used, and with indirect comparisons between the two. The second-generation trials were analysed to assess the optimum method of administration.

RESULTS

A total of 17 trials were selected for the meta-analysis (30,672 patients). The OR DL was 0.82 (95%CI: 0.76-0.88) for DFS and 0.83 (95% CI: 0.75-0.91) for OS. In N+ patients the results were 0.80 (95% CI: 0.74-0.86) and 0.79 (95% CI: 0.69-0.89), respectively. Docetaxel and paclitaxel significantly increased the DFS and OS. In our indirect comparison, the benefit of docetaxel on OS was significantly superior to that obtained with paclitaxel in N+ patients (OR: 0.79; 95% CI: 0.63-0.98).

CONCLUSIONS

The administration of adjuvant CT-based taxanes reduces the risk of relapse and death. This reduction is superior in clinical trials that included only N+ patients. With the available evidence, it would appear that the best method of administering paclitaxel is weekly and for docetaxel tri-weekly.

Concurrent vs sequential adjuvant chemotherapy and hormone therapy in breast cancer: a multicenter randomized phase III trial

BACKGROUND

The most appropriate timing of chemotherapy and hormone therapy administration is a critical issue in early breast cancer patients. The purpose of our study was to compare the efficacy of concurrent vs sequential administration of adjuvant chemotherapy and tamoxifen.

METHODS

Women with node-positive primary breast cancer were randomly assigned to receive tamoxifen (20 mg/d for 5 years) during (concurrent arm) or after (sequential arm) adjuvant chemotherapy. Chemotherapy consisted of alternating regimens of cyclophosphamide, epidoxorubicin, and 5-fluorouracil and cyclophosphamide, methotrexate, and 5-fluorouracil every 21 days for a total of 12 cycles. The primary endpoint was overall survival (OS), and secondary endpoints were toxic effects and disease-free survival (DFS). No provision for interim analyses was made in the original study protocol. Survival curves were estimated by the Kaplan-Meier method. Multivariable Cox regression models, adjusted for age, menopausal status, tumor stage, and lymph node and hormone receptor status, were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). All statistical tests were two-sided.

RESULTS

From 1985 to 1992, 431 patients were randomly assigned and studied according to the intention-to-treat principle. After a maximum of 15.4 years of follow-up (median 12.3 years), the estimated actuarial 10-year OS was equivalent for the two study arms (concurrent arm: 111 patients, 66%, 95% CI = 59% to 72%; sequential arm: 114 patients, 65%, 95% CI = 59% to 72%, P = .86). No differences in DFS and toxic effects were evident. Four interim analyses were performed, but no alpha error adjustment was necessary because of the largely negative results of this final analysis (sequential vs concurrent arm: HR of death = 1.06, 95% CI = 0.78 to 1.44, P = .76; HR of relapse = 1.16, 95% CI = 0.88 to 1.52, P = .36).

CONCLUSIONS

No statistically significant differences in OS, DFS, and toxic effects between concurrent and sequential adjuvant chemo- and hormone therapies were observed. Our study does not support the superiority of one schedule of chemo- and hormone-therapy administration over the other. However, because of the limited statistical power of the study, these results must be considered with caution.