Comparative Effectiveness of Adjuvant Chemotherapy in Early-Stage Breast Cancer: A Network Meta-analysis

BACKGROUND

There are several regimens recommended by the National Comprehensive Cancer Network (NCCN) for HER2-negative operable breast cancer. To our knowledge, no trials have yet been performed comparing these regimens head to head. We performed a network meta-analysis comparing the efficacy of NCCN-recommended chemotherapy regimens.

METHODS

We searched Medline, Embase, Web of Science, the Cochrane Central Register of Controlled Trials, and World Health Organization (WHO) International Clinical Trials Registry Platform from inception to February 2020. We included randomized clinical trials comparing adjuvant regimens in predominantly node-positive operable breast cancer patients. We compared (1) DDACT, (2) TCx4 cycles, (3) TAC, and (4) ACWKT. Common comparators were (5) AC, (6) ACT, and (7) ACD. Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines were followed. The Cochrane risk of bias tool assessed quality of the studies. Odds ratios (ORs) were calculated as measures of treatment effects with AC as reference. We used Bayesian hierarchical random-effects models with noninformative priors for mixed multiple treatment comparisons. Effectiveness was estimated by disease-free and overall survival using ORs. Sensitivity analyses were performed. Safety outcomes included febrile neutropenia.

RESULTS

We identified 7 randomized controlled trials with 16,332 patients. TC (odds ratio [95% confidence interval], 0.71 [0.36-1.40]), TAC (0.77 [0.37-1.57]), ACWKT (0.68 [0.34-1.38]), and DDACT (0.72 [0.35-1.42]) were similar for overall survival. TC (0.64 [0.36-1.14]), TAC (0.67 [0.39-1.15]), ACWKT (0.63 [0.37-1.07]), and DDACT (0.59 [0.35-1.01]) had similar disease-free survival benefit. With regard to toxicity, TAC (2.67 [0.30-21.04]) had the highest odds of febrile neutropenia.

CONCLUSION

The current generation of regimens are similar in efficacy. Given the lower toxicity of TCx4 comparatively, it is an acceptable alternative for lower-risk early-stage HER2-negative breast cancers.

Taxane & cyclophosphamide vs anthracycline & taxane-based chemotherapy as adjuvant treatment for breast cancer: a pooled analysis of randomized controlled trials by the Hellenic Academy of Oncology

Background

Adjuvant chemotherapy has an indisputable value for early breast cancer patients. Anthracycline and taxane-based regimens (TaxAC) have not been proven superior to taxane & cyclophosphamide (TC), a less toxic combination. Our objective was to estimate the cumulative evidence for non-inferiority of TC against TaxAC, in the adjuvant setting of patients with HER2-negative, breast cancer.

Results

Overall, 7,341 patients were included in this analysis. Superiority of TaxAC or non-inferiority of TC was not established either for the overall population (DFS HR, 1.11; 95% CI, 0.95-1.30; p = 0.18), or for the node-negative patients (HR, 1.05; 95% CI, 0.82-1.34; p = 0.71). A difference in DFS of 1.28% (TC DFS, 89.04%; 95% CI, 88%-90% & TaxAC DFS, 90.32%; 95% CI, 89%-91%) was found in favor of TaxAC. Lower risk of death was not established for either treatment regimen (OS-HR, 1.02; 95% CI, 0.82-1.25; p = 0.88). Overall, the toxicity profile favored TC.

Conclusion

Although non-inferiority of TC was not proven, superiority of TaxAC is still questioned. The present analysis narrows the risk of recurrence between the treatment groups. Considering TC has a more favorable safety profile, the question as to which treatment regimen should be preferred under what circumstances, needs to be individualized according to patients' characteristics and desires.

Methods

Treatment efficacy data from The ABC trials, the Plan B trial and a trial by the Hellenic Oncology Research group (HORG) were pooled. Disease free survival (DFS) and overall survival (OS) were scrutinized. A HR of 1.18 for TC versus TaxAC was chosen to demonstrate inferiority.

Anthracycline and taxane-based chemotherapy versus docetaxel and cyclophosphamide in the adjuvant treatment of HER2-negative breast cancer patients: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

Standard adjuvant chemotherapy for HER2-negative breast cancer consists generally in an anthracycline and taxane-based regimen (A+T). The TC (docetaxel and cyclophosphamide) regimen arises as a potential alternative, although individual randomized controlled trials (RCTs) could not demonstrate the non-inferiority of TC over A+T. This is a systematic review and meta-analysis of RCTs comparing 6 cycles of TC versus sequential A+T in the adjuvant treatment of HER2-negative breast cancer.

METHODS

A systematic literature search was performed to identify RCTs comparing TC versus A+T. Disease-free survival (DFS) and overall survival (OS) were assessed. Subgroup analyses of DFS according to hormone receptor status, lymph node involvement, and menopausal status were performed. Hazard ratios (HRs) and 95% confidence intervals (CI) for DFS and OS were extracted from each trial, and a pooled analysis was conducted using the random-effect model. The Higgins' I-Squared Test was used to quantify heterogeneity.

RESULTS

Seven RCTs were included (12,741 patients). Overall, no difference was observed between TC and A+T in DFS (HR 1.08, 95% CI 0.96-1.20) and OS (HR 1.05; 95% CI 0.90-1.22). A trend favoring A+T was observed in hormone receptor-negative (HR 1.12, 95% CI 0.93-1.34) and N2 patients (HR 1.25; 95% CI 0.82-1.90). Emesis/vomiting, mucositis, thrombocytopenia and sensory neuropathy were significantly more frequent with A+T.

CONCLUSION

As adjuvant treatment of HER2-negative breast cancer, sequential A+T regimen was associated with increased risk of toxicities and no clear survival benefit as compared to 6 cycles of TC. Higher-risk patients may benefit the most from A+T, whilst TC may be an efficacious and less toxic alternative for lower-risk patients.

Adjuvant Anthracyclines in Breast Cancer: What Is Their Role?

Anthracyclines have been a mainstay of breast cancer therapy for decades, with strong evidence demonstrating their impact on breast cancer survival. However, concerns regarding rare but serious long-term toxicities including cardiotoxicity and hematologic malignancies have driven interest in alternative adjuvant therapy options with more favorable toxicity profiles. This article provides an update of data that help inform clinicians of the role anthracyclines should play in adjuvant breast cancer therapy. Two recently reported large randomized trials-the Anthracycline in Early Breast Cancer and Western German Study Plan B studies-compared a taxane and cyclophosphamide regimen with an anthracycline, taxane, and cyclophosphamide regimen. Although the studies had conflicting results, together these studies suggest that the benefit of adjuvant anthracycline therapy over a nonanthracycline taxane-containing regimen is modest at best and may be primarily seen in patients with especially high-risk disease (i.e., triple-negative breast cancer, involvement of multiple lymph nodes). A third study-the MINDACT study-compared an anthracycline-based regimen to a nonanthracycline regimen, with similar outcomes in both groups. Despite the toxicities, no adjuvant breast cancer regimen has been shown to be superior to an anthracycline-taxane regimen in high-risk patients. These data can directly inform clinical decision-making in determining which patients warrant use of adjuvant anthracycline therapy. Future research may focus on confirming subgroups for whom it is reasonable to forgo adjuvant anthracyclines and validating predictive biomarkers or scores for anthracycline benefit.

IMPLICATIONS FOR PRACTICE

In patients with early breast cancer, the choice of adjuvant chemotherapy should be based on its effectiveness in reducing breast cancer recurrences and its short- and long-term toxicities. Although adjuvant anthracycline and taxane chemotherapy has the most data supporting its effectiveness, anthracyclines carry a small but important increased risk for cardiotoxicity and leukemia. Two recent clinical trials help describe the degree of benefit with adjuvant anthracycline therapy compared with taxane therapy alone. They suggest that in patients with hormone receptor-positive breast cancer and limited lymph node involvement, nonanthracycline taxane-based adjuvant therapy may be adequate.