Che-Kai Tsao

Effectiveness of Adjuvant Chemotherapy for Locally Advanced Bladder Cancer

PURPOSE Given that randomized trials exploring adjuvant chemotherapy for bladder cancer have been underpowered and/or terminated prematurely, yielding inconsistent results and creating an evidence gap, we sought to compare the effectiveness of cystectomy versus cystectomy plus adjuvant chemotherapy in real-world patients. PATIENTS AND METHODS We conducted an observational study to compare the effectiveness of adjuvant chemotherapy versus observation postcystectomy in patients with pathologic T3-4 and/or pathologic node-positive bladder cancer using the National Cancer Data Base. We compared overall survival using propensity score (-adjusted, -stratified, -weighted, and -matched) analyses based on patient-, facility-, and tumor-level characteristics. A sensitivity analysis was performed to examine the impact of performance status. RESULTS A total of 5,653 patients met study inclusion criteria; 23% received adjuvant chemotherapy postcystectomy. Chemotherapy-treated patients were younger and more likely to have private insurance, live in areas with a higher median income and higher percentage of high school-educated residents, and have lymph node involvement and positive surgical margins (P < .05 for all comparisons). Stratified analyses adjusted for propensity score demonstrated an improvement in overall survival with adjuvant chemotherapy (hazard ratio, 0.70; 95% CI, 0.64 to 0.76), and similar results were achieved with propensity score matching and weighting. The association between adjuvant chemotherapy and improved survival was consistent in subset analyses and was robust to the effects of poor performance status. CONCLUSION In this observational study, adjuvant chemotherapy was associated with improved survival in patients with locally advanced bladder cancer. Although neoadjuvant chemotherapy remains the preferred approach based on level I evidence, these data lend further support for the use of adjuvant chemotherapy in patients with locally advanced bladder cancer postcystectomy who did not receive chemotherapy preoperatively.

Targeting the androgen receptor signalling axis in castration‐resistant prostate cancer (CRPC)

Whats known on the subject? and What does the study add?

Patients with Biopsy Gleason 9 and 10 Prostate Cancer Have Significantly Worse Outcomes Compared to Patients with Gleason 8 Disease

PURPOSE We examined differences in outcome in patients with biopsy Gleason score 8 vs 9-10 who received definitive local therapy. MATERIALS AND METHODS Using an institutional database we identified a cohort of 847 patients with biopsy Gleason 8-10 disease who received definitive local therapy with radiation therapy or radical prostatectomy between January 2001 and December 2011. Multivariable Cox modeling was used to assess the association of Gleason score 8 vs 9-10 with time to biochemical recurrence, metastasis and overall survival, and evaluate treatment by Gleason score interaction. Median followup in the cohort was 5.3 years. RESULTS Baseline patient characteristics were similar for biopsy Gleason 8 vs 9-10. Gleason 9-10 disease was associated with higher prostate specific antigen at diagnosis. As local treatment such patients were also more likely to have received radiation therapy (58% vs 46%, p = 0.001) and neoadjuvant/adjuvant androgen deprivation therapy (64% vs 49%, p <0.001). Those with higher grade disease were at increased risk for metastasis (HR 1.41, 95% CI 1.11-1.79). There was a trend toward an increased risk of death in Gleason 9-10 vs 8 cases (HR 1.28, 95% CI 0.98-1.66). The increased risk of death for Gleason 9-10 was mainly observed in patients treated with radical prostatectomy with or without additional radiation therapy (HR 1.74, 95% CI 1.15-2.65). CONCLUSIONS Patients with localized biopsy Gleason 9-10 disease treated with definitive local therapy had worse outcomes than those diagnosed with biopsy Gleason 8 disease. Clinical trials are urgently needed that incorporate newer approaches to Gleason 9-10 cancer.

Clinical development of novel therapeutics for castration-resistant prostate cancer: historic challenges and recent successes.

There have been more drugs approved by the US Food and Drug Administration for the treatment of castration‐resistant prostate cancer in the past 3 years than in the prior 3 decades, with additional drugs on the verge of approval based on the results of recently reported randomized trials. While an improvement in the understanding of the pathogenesis of castration‐resistant prostate cancer has undeniably accelerated the transition of novel approaches from “bench to bedside,” the recent successes in the treatment of prostate cancer are also a result of the efforts of clinical investigators to redefine the framework in which drugs for castration‐resistant disease are evaluated. This review will explore the shifting paradigm in drug development for castration‐resistant prostate cancer over the past several decades, and highlight how new definitions, trial designs, and endpoints have facilitated the emergence of new therapies for this challenging disease. CA Cancer J Clin 2012;.

Comparative Effectiveness of Treatment Strategies for Bladder Cancer With Clinical Evidence of Regional Lymph Node Involvement

PURPOSE Patients with bladder cancer with clinical lymph node involvement (cN+) are at high risk for distant metastases, but are potentially curable. Such patients are excluded from neoadjuvant chemotherapy trials and pooled with patients with distant metastases in first-line chemotherapy trials not suited to define the role of combined-modality therapy. To address this evidence void, we performed a comparative effectiveness analysis. METHODS We included cTanyN1-3M0 bladder cancer patients from the National Cancer Data Base (2003-2012) treated with chemotherapy and/or cystectomy. We used multistate survival analysis, allowing for delayed entry, to assess overall survival (OS) according to various treatment strategies. Effectiveness was estimated with multivariable adjustment for tumor-, patient-, and facility-level characteristics. RESULTS Among 1,739 patients (cN1, 48%; cN2, 45%; cN3, 7%), 1,104 underwent cystectomy and 635 were treated with chemotherapy alone. Of the cystectomy patients, 363 received preoperative and 328 received adjuvant chemotherapy. The crude 5-year OS for chemotherapy alone, cystectomy alone, preoperative chemotherapy followed by cystectomy, and cystectomy followed by adjuvant chemotherapy was 14% (95% CI, 11% to 17%), 19% (95% CI, 15% to 24%), 31% (95% CI, 25% to 38%), and 26% (95% CI, 21% to 34%), respectively. Compared with cystectomy alone, preoperative chemotherapy was associated with a significant improvement in OS (hazard ratio, 0.80; 95% CI, 0.66 to 0.97). Adjuvant chemotherapy was also associated with a significant improvement in survival compared with cystectomy alone. The survival of patients treated with chemotherapy alone was worse than those treated with cystectomy alone. CONCLUSION A subset of patients with cN+ bladder cancer achieves long-term survival. Combined-modality therapy, with chemotherapy and cystectomy, is associated with the best outcomes.

Overcoming castration resistance in prostate cancer.

Purpose of review Recent advances in our understanding of the androgen axis signaling pathway have led to the development of therapeutic strategies to overcome the state of ‘castration resistance’ in prostate cancer. In this review, we examine the mechanisms of castration resistance, as well as recently reported and ongoing clinical studies, which will further identify therapeutic opportunities for novel therapeutics targeting the androgen-signaling axis in advanced prostate cancer. Recent findings As evidenced by recently reported positive phase III clinical trials, secondary hormonal agents such as abiraterone and MDV3100 may still be very effective in the treatment of castration-resistant prostate cancer, even after the use of docetaxel chemotherapy. Summary Novel agents targeting this pathway have demonstrated a proof of principle that overcoming castration resistance is possible, leading to significant changes in the landscape of treatment in this disease. The optimal combination, sequence, and pattern of use in these novel therapies will be the focus of clinical research in the near future.

The role of cabazitaxel in the treatment of metastatic castration-resistant prostate cancer

For decades, cytotoxic therapy was considered ineffective for the treatment of metastatic castration-resistant prostate cancer (mCRPC). Earlier therapies such as estramustine and mitoxantrone received regulatory approval based upon improvement in palliative endpoints. In 2004, docetaxel became the first treatment to demonstrate a significant survival benefit in patients with mCRPC based on two randomized phase III studies, TAX327 and SWOG 99-16. Cabazitaxel, a third-generation taxane, was chosen for clinical development based on its decreased affinity for the drug efflux pump, p-glycoprotein, which is a frequent cause of drug resistance in docetaxel-resistant preclinical models. In 2010, cabazitaxel was approved by the US Food and Drug Administration as the first therapy to show a survival benefit for the treatment of patients with docetaxel-refractory mCRPC. This review summarizes the existing literature on the use of cabazitaxel, focusing on its efficacy and safety in combination with prednisone in the treatment of mCRPC, as well as its role in an era of new therapeutic options.

Is prostate cancer changing?: Evolving patterns of metastatic castration-resistant prostate cancer

Metastatic castration‐resistant prostate cancer (mCRPC) most commonly metastasizes to the bone, and less commonly to nonosseous sites (eg, lymph nodes, liver, lung). With new therapies extending survival in mCRPC, it was hypothesized that the pattern of metastases is changing over time. The pattern of metastatic disease was evaluated in men with mCRPC, as reported in baseline characteristics of prospective clinical trials over 2 decades.

Randomized, noncomparative, phase II trial of early switch from docetaxel to cabazitaxel or vice versa, with integrated biomarker analysis, in men with chemotherapy-naïve, metastatic, castration-resistant prostate cancer

Purpose The TAXYNERGY trial ( ClinicalTrials.gov identifier: NCT01718353) evaluated clinical benefit from early taxane switch and circulating tumor cell (CTC) biomarkers to interrogate mechanisms of sensitivity or resistance to taxanes in men with chemotherapy-naïve, metastatic, castration-resistant prostate cancer. Patients and Methods Patients were randomly assigned 2:1 to docetaxel or cabazitaxel. Men who did not achieve ≥ 30% prostate-specific antigen (PSA) decline by cycle 4 (C4) switched taxane. The primary clinical endpoint was confirmed ≥ 50% PSA decline versus historical control (TAX327). The primary biomarker endpoint was analysis of post-treatment CTCs to confirm the hypothesis that clinical response was associated with taxane drug-target engagement, evidenced by decreased percent androgen receptor nuclear localization (%ARNL) and increased microtubule bundling. Results Sixty-three patients were randomly assigned to docetaxel (n = 41) or cabazitaxel (n = 22); 44.4% received prior potent androgen receptor-targeted therapy. Overall, 35 patients (55.6%) had confirmed ≥ 50% PSA responses, exceeding the historical control rate of 45.4% (TAX327). Of 61 treated patients, 33 (54.1%) had ≥ 30% PSA declines by C4 and did not switch taxane, 15 patients (24.6%) who did not achieve ≥ 30% PSA declines by C4 switched taxane, and 13 patients (21.3%) discontinued therapy before or at C4. Of patients switching taxane, 46.7% subsequently achieved ≥ 50% PSA decrease. In 26 CTC-evaluable patients, taxane-induced decrease in %ARNL (cycle 1 day 1 v cycle 1 day 8) was associated with a higher rate of ≥ 50% PSA decrease at C4 ( P = .009). Median composite progression-free survival was 9.1 months (95% CI, 4.9 to 11.7 months); median overall survival was not reached at 14 months. Common grade 3 or 4 adverse events included fatigue (13.1%) and febrile neutropenia (11.5%). Conclusion The early taxane switch strategy was associated with improved PSA response rates versus TAX327. Taxane-induced shifts in %ARNL may serve as an early biomarker of clinical benefit in patients treated with taxanes.

A robust blood gene expression-based prognostic model for castration-resistant prostate cancer

BackgroundCastration-resistant prostate cancer (CRPC) is associated with wide variations in survival. Recent studies of whole blood mRNA expression-based biomarkers strongly predicted survival but the genes used in these biomarker models were non-overlapping and their relationship was unknown. We developed a biomarker model for CRPC that is robust, but also captures underlying biological processes that drive prostate cancer lethality.MethodsUsing three independent cohorts of CRPC patients, we developed an integrative genomic approach for understanding the biological processes underlying genes associated with cancer progression, constructed a novel four-gene model that captured these changes, and compared the performance of the new model with existing gene models and other clinical parameters.ResultsOur analysis revealed striking patterns of myeloid- and lymphoid-specific distribution of genes that were differentially expressed in whole blood mRNA profiles: up-regulated genes in patients with worse survival were overexpressed in myeloid cells, whereas down-regulated genes were noted in lymphocytes. A resulting novel four-gene model showed significant prognostic power independent of known clinical predictors in two independent datasets totaling 90 patients with CRPC, and was superior to the two existing gene models.ConclusionsWhole blood mRNA profiling provides clinically relevant information in patients with CRPC. Integrative genomic analysis revealed patterns of differential mRNA expression with changes in gene expression in immune cell components which robustly predicted the survival of CRPC patients. The next step would be validation in a cohort of suitable size to quantify the prognostic improvement by the gene score upon the standard set of clinical parameters.