Neoadjuvant gemcitabine-cisplatin (GC) for muscle-invasive bladder cancer (MIBC): Does midway CT staging predict for pathologic complete response (pCR)?

Abstract

306 Background: Neoadjuvant cisplatin-based chemotherapy (NC) improves overall survival in MIBC, with pCR post radical cystectomy (RC) linked to better outcomes. NC is underutilized in part due to concerns over disease progression during NC. Midway radiological CT (post 2 NC cycles) may identify patients (pts) progressing on NC who should proceed to definitive therapy (DT). Methods: We reviewed 39 MIBC pts planned to receive 4 cycles of NC (GC) between Jan2005-April2013. Most pts (70%) had midway CT staging. A radiological response was defined as clear improvement in tumour +/- nodal status on CT compared to baseline, taking into account prior trans-urethral resection of bladder tumour; any other result was considered no response. DT consisted of RC, concurrent chemoradiation (CCR), or radiation alone (R). Descriptive statistics and Fisher’s exact test examined associations between disease characteristics and outcomes. Results: Overall, 28 pts (72%) completed planned NC; 7 pts (18%) stopped early due to no response on midway CT; 4 (10%) discontinued due to death (1), sepsis (2), and fatigue (1). Twenty-six pts (67%) had RC, 3 (8%) had CCR, 6 (15 %) had R and 4 (10%) did not receive DT. Of the 26 RC pts – 6 (23%) had a pCR. There were no pCRs among pts who had no radiological response at midway CT. At time of last follow up, 8 pts (21%) had died, 13 (33%) had recurrence/ metastases, and the remainder are being actively followed. Of pts with pCR, there were no recurrences (median follow up 12.2 mo (range 6.3-20.9 mos). The rate of venothromboembolism (VTE) was 26%, and nearly half occurred during NC, but did not affect treatment. Conclusions: Lack of response on midway CT was associated with a lack of pCR at RC, suggesting midway staging may be of value in MIBC receiving NC. The rates of pCR were consistent with reported literature, but rates of VTE appear higher than expected and requires further investigation. [Table: see text]