Login to Access Video or Poster Abstract: MP34-05
Sources of Funding: none

Introduction

Classification of response to neoadjuvant chemotherapy (NAC) in muscle-invasive bladder cancer (MIBC) is based primarily on TNM stage at cystectomy. We recently described post-NAC tumor regression grades (TRG) as an alternative method of risk stratification. Here we aim to validate our findings in an independent cohort and to integrate TRG with TNM staging.

Methods

Fifty-five patients with MIBC received at least 3 cycles of cisplatin-based NAC and underwent cystectomy. As previously described (Fleischmann et al. Am J Surg Pathol 2014) TRG was assessed in cystectomy specimens by two independent investigators blinded to patient outcomes. TRG 1 represents absence of residual cancer, TRG 2 is characterized by predominant fibrosis containing scattered residual cancer cells, and TRG 3 shows residual cancer with minor component of fibrosis or absence of regressive changes. Major response to NAC was defined as absence of muscle invasive disease and lymph node involvement (

Results

The 22/55 (40%) patients with major response to NAC had a significantly longer OS compared to the remaining patients (90% vs. 50% 5yr OS, p=0.005). TRG was successfully determined in all cases and concordance between both observers was high (91%). Of the 33/55 (60%) patients without major response, 13/55 (24%) and 20/55 (36%) were partial- and non-responders after combining TRG with the TNM stages. Kaplan-Meier estimates yielded an additional stratification of the cohort in 3 separated prognostic categories. Five-year OS of major-, partial- and non-responders was 90%, 65% and 40%, respectively. Multivariate survival analysis showed that the prognostic stratification of the cohort could be improved by integrating the TRG with the TNM stages (p<0.001).

Conclusions

Measurement of TRG after NAC is simple and reproducible. We successfully validated our prior discovery in an independent cohort. Moreover, integrating TRG with the current TNM classification significantly improved prognostic stratification.

Funding

none