Neoadjuvant chemotherapy in the management of muscle-invasive bladder cancer: bridging the gap between evidence and practice

The Role and Importance of Timely Radical Cystectomy for High-Risk Non-muscle-Invasive Bladder Cancer

Non-muscle-invasive bladder cancer accounts for the majority of incident bladder cancers but is a heterogeneous disease with variation in clinical presentation, course, and outcomes. Risk stratification techniques have attempted to identify those at highest risk of cancer recurrence and progression to help personalize and individualize treatment options. Radical cystectomy during the optimal window of curability could improve cancer outcomes; however, identifying the disease and patient characteristics as well as the correct timing to intervene remains difficult. We review the natural history of non-muscle-invasive bladder cancer, discuss different risk-stratification techniques and how they can help identify those most likely to benefit from radical treatment, and examine the evidence supporting the benefit of timely cystectomy.

Impact of preoperative diagnostic TURBT on progression-free survival in patients with pathological high-grade, stage T3/T4 bladder urothelial carcinoma

Transurethral bladder tumor resection (TURBT) reportedly increases the circulating tumor cell count in patients with urothelial carcinoma of the bladder (UCB). To determine whether diagnostic TURBT leads to poorer progression-free survival (PFS) than diagnostic cystoscopic biopsy, we retrospectively reviewed the records of 96 consecutive primary pathological high-grade, stage T3/T4 UCB patients treated with radical cystectomy (RC) between January 2009 to December 2013. Clinicopathological features were collected from the medical records. PFS was determined from Kaplan-Meier curves, and potential independent prognostic factors for PFS were identified based on multivariable Cox analysis. During the follow-up period (median, 29 months), 43 patients experienced tumor progression (40 received diagnostic TURBT, 56 received cystoscopic biopsy). Patients who received cystoscopic biopsy had better PFS than those who received diagnostic TURBT (p = 0.008). Additionally, diagnostic TURBT was a significant risk factor for tumor metastasis in both univariable (HR: 2.219; 95% CI: 1.207–4.079; p = 0.010) and multivariable (HR: 2.455; 95% CI: 1.278–4.714; p = 0.007) Cox analyses. The present study provides the first evidence that diagnostic TURBT before RC negatively affects PFS in patients with pathological high-grade, stage T3/T4 UCB.

Platinum Concentration and Pathologic Response to Cisplatin-Based Neoadjuvant Chemotherapy in Muscle-Invasive Bladder Cancer

Background

Platinum (Pt)-based chemotherapy is the standard of care for muscle-invasive bladder cancer (MIBC). However, resistance is a major limitation. Reduced intratumoral drug accumulation is an important mechanism of platinum resistance. Our group previously demonstrated a significant correlation between tissue Pt concentration and tumor response to Pt-based neoadjuvant chemotherapy (NAC) in lung cancer. We hypothesized that increased Pt concentration in radical cystectomy (RC) specimens would correlate with improved pathologic response to Pt-based NAC in MIBC.

Methods

A cohort of 19 clinically annotated, archived, fresh frozen RC specimens from patients with MIBC treated with Pt-based NAC was identified [ypT0 (pathologic complete response, pCR), N = 4; ≤ypT1N0M0 (pathologic partial response, pPR), N = 6; ≥ypT2 (minimal pathologic response/progression), N = 9)]. RC specimens from 2 patients with MIBC who did not receive NAC and 1 treated with a non-Pt containing NAC regimen were used as negative controls. Total Pt concentration in normal adjacent urothelial tissue and bladder tumors from RC specimens was measured by flameless atomic absorption spectrophotometry.

Results

Total Pt concentration in normal urothelium differed by tumor pathologic response (P = 0.011). Specimens with pCR had the highest Pt concentrations compared to those with pPR (P = 0.0095) or no response/progression (P = 0.020). There was no significant difference in Pt levels in normal urothelium and tumor between pPR and no response/progression groups (P = 0.37; P = 0.25, respectively). Conclusions: Our finding of increased intracellular Pt in RC specimens with pCR following NAC for MIBC compared to those with residual disease suggests that enhanced Pt accumulation may be an important determinant of Pt sensitivity. Factors that modulate intracellular Pt concentration, such as expression of Pt transporters, warrant further investigation as predictive biomarkers of response to Pt-based NAC in MIBC.

Pharmacogenomics: Biomarker-Directed Therapy for Bladder Cancer

The clinical management of bladder cancer has seen little change over the last three decades and there is pressing need to identify more effective treatments for advanced disease. Low clinical use of neoadjuvant therapies stems from historical limitations in the ability to predict patients most likely to respond to combination chemotherapies. This article focuses on recent molecular and genetic studies, highlighting promising clinical trials and retrospective studies, and discusses emerging trials that use predictive biomarkers to match patients with therapies to which they are most likely to respond. The implementation of predictive genomic and molecular biomarkers will revolutionize urologic oncology and the clinical management of bladder cancer.