Purpose: The Southwest Oncology Group conducted a randomized trial of induction bacillus Calmette-Guérin (BCG) with or without maintenance BCG. In these additional retrospective analyses, our goal was to evaluate the association of a complete response (CR) or remaining with no evidence of disease (NED) vs. no CR during induction therapy with subsequent survival after adjusting for other potential confounders. Among all patients randomized to maintenance treatment, we also wanted to identify combinations of baseline covariates in order to define prognostic groups for subsequent worsening-free survival.
Methods: Outcome measures of worsening-free and overall survival were assessed using Kaplan Meier estimates and proportional hazards regression models. For the classification and regression tree (CART) analysis, 434 patients randomized to maintenance vs. no therapy with complete covariate information were included.
Results: Of the 593 evaluable patients, 341 were not randomized to maintenance BCG. Patients who achieved a prior complete response during induction BCG had a 5-year survival probability of 77% compared with 62% for patients who did not [hazard ratio (HR) 0.60; 95% confidence interval (CI) 0.44, 0.81; P = 0.0008]. Prior CR retained significance when adjusted for age, gender, prior intravesical chemotherapy, and papillary disease versus CIS (HR = 0.63; 95% CI: 0.46, 0.86; P = 0.003). CART analysis identified 4 prognostic groups. Older patients (> or =62 years old) previously treated with intravesical chemotherapy who failed to achieve a CR had a 5-fold higher risk of a worsening event relative to those who are younger (<67 years old) and achieve a CR (HR = 5.09; 95% CI: 3.37, 7.68; P < 0.0001).
Conclusion: Failure to achieve a complete response after induction BCG is associated with a significant risk of a worsening event and death for patients with CIS or Ta or T1 bladder cancer at increased risk of recurrence.