Presentation Authors: Justin Matulay*, Houston, TX, Solomon Woldu, Dallas, TX, Vikram Narayan, Amy Lim, Andrew McIntosh, Ashish Kamat, Houston, TX, Christopher Anderson, New York, NY
Introduction: Bladder cancer is the 4th most common malignancy in the US but only 2-5% have squamous cell carcinoma (SCC). Neoadjuvant chemotherapy (NAC) is well established for muscle invasive urothelial carcinoma (MI-UC). Its role in SCC has not been directly studied but is an important question given the tendency of SCC for muscle-invasion at diagnosis. We used the National Cancer Database (NCDB) to explore survival in patients undergoing radical cystectomy (RC) +/- NAC for MI-SCC.
Methods: We queried the NCDB for diagnoses of either UC or SCC using ICD-0-3 morphologic codes from cases reported between 2004 and 2015. Outcomes of interest were overall survival (OS) and pathologic complete response (pT0) in cT2-4N0M0 muscle invasive bladder cancer (MIBC) who underwent radical cystectomy (RC). NAC was defined as chemotherapy start date < 120 days prior to RC. For all statistical measures, p < 0.05 considered statistically significant.
Results: There were 394,979 bladder cancer patients identified, of which histology was SCC in 1.4% (n=4,783). MIBC at presentation was more likely in SCC than UC (70% v. 19%, p < 0.01). A total of 21,233 patients had RC for cT2-4N0M0. NAC was more common for UC than SCC (19% v. 7%, p < 0.01). The proportion of patients with pT0 was higher with NAC compared to RC alone in both groups: SCC (7.5% v. 1%; p < 0.01) and UC (14.0% v. 4.0%; p < 0.01). Predictors of pT0 status included SCC (OR 0.42, 95% CI 0.24-0.74, p < 0.01) and use of NAC (OR 3.72, 95% CI 3.29-4.22, p < 0.01, Table). NAC significantly improved survival (HR 0.81, 95% CI 0.77-0.86, p < 0.01) over RC alone for UC but not SCC (HR 0.93, 95% CI 0.67-1.30, p=0.69).
Conclusions: Patients with SCC are far more likely to present with MIBC, though utilization of NAC is lower than UC. NAC improved the pT0 status for both SCC and UC but did not impart a survival benefit in the former. Though NAC is the current standard treatment for cT2-4N0M0 bladder cancer, SCC will require a different approach to improve outcomes.