Genomic Tumor Correlates of Clinical Outcomes Following Organ-Sparing Chemoradiation Therapy for Bladder Cancer

Bladder preservation with trimodality therapy (TMT), consisting of transurethral tumor resection followed by chemoradiation, is an alternative to radical cystectomy for muscle-invasive bladder cancer (MIBC), but molecular determinants of response are poorly understood. Patients with cT2-T4aN0M0 MIBC treated with definitive-intent chemoradiation as part of TMT were retrospectively identified from a single institution between 1986-2015. Pre-treatment Formalin Fixed Paraffin Embedded (FFPE) tumors from 76 MIBC patients were subjected to whole exome sequencing (WES). Our integrated analysis yielded insights into molecular features associated with favorable long-term response to TMT, including alterations in DNA damage response genes. Of these, mutations in ERCC2, a DNA helicase in the nucleotide excision repair pathway, were significantly associated with improved long-term outcomes after TMT, particularly in patients who received concurrent cisplatin-based chemotherapy. ]]>
Samples were collected from patients in IRB-approved studies. For inclusion, patients with confirmed cT2-T4aN0M0 muscle-invasive bladder cancer had to have received a complete course of definitive-intent chemoradiation as part of trimodality therapy, as per standard clinical practice. ]]>