#ASCO14 - Comparative effectiveness of gemcitabine plus cisplatin (GC) versus methotrexate, vinblastine, doxorubicin, plus cisplatin (MVAC) as neoadjuvant therapy for muscle-invasive bladder cancer (MIBC) - Session Highlights

CHICAGO, IL USA (UroToday.com) - This poster is part of a session presenting in projects focusing on determining molecular markers of prognosis, targets for therapy, and clinical care of patients with urothelial cancers.

Data demonstrating an overall survival benefit from neoadjuvant methotrexate, vinblastine, doxorubicin, plus cisplatin (MVAC) chemotherapy for muscle-invasive bladder cancer has been available for several years. However, in clinical practice, many practitioners use gemcitabine, cisplatin (GC) chemotherapy based on extrapolated data from treatment of metastatic urothelial cancer that suggests a similar benefit to MVAC chemotherapy with less toxicity.

asco xThis study attempts to compare the effectiveness of GC with MVAC chemotherapy to determine whether patient outcomes are truly similar when these regimens are used neoadjuvantly. The study approach was via retrospective review of data collected from 25 international centers evaluating outcomes in bladder cancer patients. Patients included in the study had cT2-4aN0M0 urothelial bladder cancer and had received neoadjuvant chemotherapy with GC or MVAC. All patients included in the study received chemotherapy prior to cystectomy. The investigators attempted to standardize the comparison of subjects, with varied clinical characteristics, by creating propensity scores that included age, calculated creatinine clearance, number of chemotherapy cycles, histology, Eastern Cooperative Oncology Group performance status, year of diagnosis, cT-stage, and gender. This advanced statistical technique allowed them to incorporate that extensive list of clinical factors into their analysis. They then performed a log binomial model that estimated the adjusted relative risk of patients experiencing a complete pathologic response (pCR). This intermediate endpoint has been accepted in urothelial literature as it correlates with overall survival in this population. In total, 244 patients (GC 175, MVAC 69) were included in the analysis. The majority of patients were men, and the median creatinine clearance of the group was 72. The median number of neoadjuvant chemotherapy cycles completed was 3. The investigators found that the rates of pCR for the two chemotherapy regimens were 27% and 28% for GC and MVAC, respectively. The relative risk of pCR was not significantly different between the groups. Overall survival was not significantly different between the two groups.

The investigators concluded that relevant outcomes did not significantly differ between the two chemotherapy regimens, making current clinical practice reasonable despite the lack of clear prospective data to support it. Importantly, 77% of the subjects receiving MVAC were treated with dose dense MVAC, the MVAC regimen that is currently considered the most efficacious. This study provides clinicians with some data to support the common clinical practice of using GC despite the lack of primary data. The take-home message of this well-designed analysis is that there does not appear to be a significant difference between GC and MVAC in pCR and overall survival outcomes, allowing clinicians the ability to choose the regimen with which they are most comfortable.

Presented by Matt D. Galsky, MD at the American Society of Clinical Oncology (ASCO) 50th Annual Meeting - May 30 - June 3, 2014 - Chicago, Illinois USA

Assistant Professor, Urology, Mt. Sinai Hospital, New York, NY USA

Written by Alicia K. Morgans, MD, assistant professor of medicine and medical oncologist at Vanderbilt-Ingram Cancer Center, and medical writer for UroToday.com