Potential therapeutic effects of adjuvant chemotherapy after neoadjuvant chemotherapy for locally advanced muscle-invasive bladder cancer

Background Although the administration of neoadjuvant chemotherapy has been associated with improved prognosis in patients with muscle-invasive bladder cancer, the therapeutic effects of adjuvant chemotherapy remain unknown in real-world settings. Therefore, we herein evaluated the clinical outcomes of adjuvant chemotherapy in pT3/4 muscle-invasive bladder cancer patients. Materials and Methods Among 587 bladder cancer patients who underwent radical cystectomy, 200 with a pathological T3 or higher muscle-invasive bladder cancer were included in the present analysis. Recurrence-free survival and cancer-specific survival were assessed by multivariate Cox regression analysis. Results Median age was 73 years, and the median follow-up duration was 17 months. The 5-year cancer-specific survival rate was 53.6% in 66 patients treated with adjuvant chemotherapy, which was significantly higher than that in those without adjuvant chemotherapy (34.0%, P = 0.025). The absence of adjuvant chemotherapy (hazard ratio = 2.114, P = 0.004) and lymphovascular invasion (hazard ratio = 2.203, P = 0.011) was identified as independent prognostic indicators for cancer-specific death. In patients treated without neoadjuvant chemotherapy (n = 143), the absence of adjuvant chemotherapy (hazard ratio:1.887, P = 0.030) remained an independent indicator for cancer-specific death. For those treated with adjuvant chemotherapy without neoadjuvant chemotherapy, three or more adjuvant chemotherapy cycles were independently associated with favourable outcome (hazard ratio = 0.240, P = 0.009). In contrast, for neoadjuvant chemotherapy-treated patients (N = 57), adjuvant chemotherapy was not independently associated with disease recurrence or cancer-specific death. Conclusion Adjuvant chemotherapy was associated with improvements in the prognosis of patients, even in those with pT3 or higher muscle-invasive bladder cancer. Although three or more cycles of adjuvant chemotherapy were effective for muscle-invasive bladder cancer patients treated without neoadjuvant chemotherapy, no therapeutic advantages were observed with additional adjuvant chemotherapy in patients treated with neoadjuvant chemotherapy. Our retrospective real-world database analysis on locally advanced muscle-invasive bladder cancer patients displayed improved prognosis with adjuvant chemotherapy delivery only in chemo-naive settings.