The Impact of an Enrolment in Clinical Trial on Tolerance and Pathological Response for Patients Treated by Neoadjuvant MVAC Against an Invasive Bladder Cancer. A Retrospective Comparative Study

Introduction: MVAC (Methotrexate, Vinblastine, Adriamycin, and Cisplatin) neoadjuvant chemotherapy a standard treatment for invasive bladder cancer is associated with mainly haematological toxicities. Randomized clinical trials remain a gold standard for treatment outcomes and efficacy assessment. Patients enrolled in clinical trials are selected and tend to benefit from a stricter follow-up unlike everyday clinical practice patients. Conversely, real-life observational studies better define the effectiveness of treatments in clinical routine practice. The aim of this study is to analyse the impact of clinical trial monitoring on MVAC-related toxicities.

Material and methods: Patients with an infiltrative localized bladder cancer treated by MVAC neoadjuvant chemotherapy between 2013 and 2019 were enrolled, and divided into 2 groups: patients included in a clinical trial namely "VESPER study" during their treatment and patients treated in clinical routine practice.

Results: Out of 59 patients were enrolled in this retrospective study, 13 patients were included in a clinical trial. Clinical characteristics were similar between the 2 groups. Comorbidities were more frequent in the nonclinical trial group (NCTG). Completed 6 cures treatment proportion was higher in the clinical trial group (CTG) (69.2% vs. 50%). Yet, in this group, patients had more doses reduction (38.5% vs. 19.6%). The proportion of complete pathologic response was higher in patients enrolled in clinical trial (53.8% vs. 39.1%). Statistically, the expected stricter monitoring due to clinical trial enrolment had no impact on the complete pathologic response and clinically relevant toxicities.

Discussion: When compared to conventional clinical practice, clinical trial enrolment induced no significant difference on the pathologic complete response or toxicity rate. Further large prospective studies are needed to confirm these data.