The challenge of matching assays to biology in DNA damage response biomarkers for response to radiotherapy in bladder cancer

For the last 40 years of investigations into radiation (RT) for bladder preservation in muscle invasive bladder cancer (MIBC), the best predictor of response has remained early response. Specifically, the ability to achieve complete transurethral resection of bladder tumor (TURBT) prior to treatment (1) and complete or near-complete (Ta/Tis) response following a 4–5 week induction phase each are strongly associated with improved outcome (2).