Pathological T0 following radical cystectomy with or without neoadjuvant chemotherapy: a useful surrogate

Several large, randomized, controlled trials provide evidence that neoadjuvant chemotherapy improves the outcome of radical cystectomy for muscle invasive urothelial bladder cancer. We analyzed the designs, methods and observations of these trials to identify patient subgroups that appeared most likely to benefit. We also identified distinguishing features compared to groups that did not achieve improved outcomes.

We analyzed initial and updated methods and results of the 4 main prospective trials of neoadjuvant chemotherapy (SWOG, Medical Research Council, and Nordic I and II) and subsequent meta-analyses. These series are the basis for advocating neoadjuvant chemotherapy in all patients with muscle invasive urothelial bladder cancer who undergo radical cystectomy.

The greatest apparent benefit was seen in patients free of cancer at radical cystectomy (pT0). They had markedly improved overall and disease specific survival compared to patients with residual disease. However, improvements occurred regardless of whether there was down-staging from muscle invasive urothelial bladder cancer to pT0 after transurethral resection alone (controls) or after resection plus neoadjuvant chemotherapy. Thus, the major benefit of chemotherapy appeared to be that more patients achieved pT0. We also explored the study limitations that may have influenced outcomes and considered the potential for overtreatment in patients not likely to benefit from chemotherapy. Finally, we used risk stratification to create a decision tree model for selecting patients for neoadjuvant chemotherapy that could conceivably maximize oncologic outcome and minimize overtreatment.

Patients with pT0 in the 4 main neoadjuvant chemotherapy trials and their subsequent meta-analyses experienced similar survival, far exceeding that in groups that did not achieve pT0. The benefit of neoadjuvant chemotherapy appears to be the larger number of cases than in the transurethral resection only group that were down-staged to pT0, suggesting that variables other than chemotherapy may have influenced outcomes. Therefore, strategies to selectively administer neoadjuvant chemotherapy to certain patients at risk have the potential to maintain improved bladder cancer outcomes while reducing overtreatment and its associated toxicity.