Genomic Analysis and Treatment Response of a Bladder Urothelial Carcinoma With Sarcomatoid Variant Histology

Sarcomatoid Urothelial Carcinoma Is Associated With Limited Response to Neoadjuvant Chemotherapy and Poor Oncologic Outcomes After Radical Cystectomy

INTRODUCTION

To examine oncologic outcomes and response to neoadjuvant chemotherapy (NAC) in patients with sarcomatoid urothelial carcinoma (SUC) treated with radical cystectomy (RC).

MATERIALS AND METHODS

We retrospectively queried our institutional database (2003-18) and Surveillance, Epidemiology, and End Results (SEER)-Medicare (2004-2015) for patients with cT2-4, N0-2, M0 SUC and conventional UC (CUC) treated with RC. Clinicopathologic characteristics were described using descriptive statistics (t test, χ2-test and log-rank-test for group comparison). Overall (OS) and recurrence-free-survival (RFS) after RC were estimated with the Kaplan Meier method and associations with OS were evaluated with Cox proportional hazards models.

RESULTS

We identified 38 patients with SUC and 287 patients with CUC in our database, and 190 patients with SUC in SEER-Medicare. In the institutional cohort, patients with SUC versus CUC had higher rates of pT3/4 stage (66% vs. 35%, P < 0.001), lower rates of ypT0N0 (6% vs. 35%, P = .02), and worse median OS (17.5 vs. 120 months, P < .001). Further, patients with SUC in the institutional versus SEER-Medicare cohort had similar median OS (17.5 vs. 21 months). In both cohorts, OS was comparable between patients with SUC undergoing NAC+RC vs. RC alone (17.5 vs. 18.4 months, P = .98, institutional cohort; 24 vs. 20 months, P = .56, SEER cohort). In Cox proportional hazards models for the institutional RC cohort, SUC was independently associated with worse OS (HR 2.3, CI 1.4-3.8, P = .001).

CONCLUSION

SUC demonstrates poor pathologic response to NAC and worse OS compared with CUC, with no OS benefit associated with NAC. A unique pattern of rapid abdominopelvic cystic recurrence was identified.

Efficacy of pembrolizumab in a rare type of bladder cancer arising 25 years after augmentation cystoplasty

We report using the checkpoint inhibitor, pembrolizumab, as part of a multimodal treatment plan in a 36-year-old man with a rare bladder cancer arising 25 years after augmentation cystoplasty (sigmoid colonic cystectomy for neuropathic bladder was performed at 9 years old). On a regular clinic visit for clean intermittent catheterisation, the patient presented with gross haematuria and was diagnosed with urothelial carcinoma with sarcomatoid change. Gemcitabine and cisplatin-based neoadjuvant chemotherapy was unsuccessful, and pembrolizumab infusions (200 mg every 3 weeks) were initiated. A partial response was confirmed after six courses of pembrolizumab, with significant tumour shrinkage. A radical cystoprostatectomy and ileal conduit construction was performed, and pathology revealed no evidence of malignancy (ypT0, N0). The patient was successfully treated with the anti-programmed death-1 inhibitor, pembrolizumab, which was curative after total cystectomy. Further research is required to elucidate the potential role of checkpoint inhibitors in bladder cancers arising after augmentation cystoplasty.

Gene Expression Profiling of Muscle-Invasive Bladder Cancer With Secondary Variant Histology

OBJECTIVES

To determine the potential impact of the presence of secondary variant histology on the gene expression profiles of muscle-invasive bladder cancer (MIBC) tumors.

METHODS

For six tumors, revised samples were collected from urothelial and secondary variant components (cohort A). The commercial cohort (cohort B) consisted of the anonymized gene expression profiles of 173 patients with MIBC. Samples were obtained from the clinical use of the Decipher Bladder test that were available as part of the Decipher GRID prospective registry (NCT02609269). Secondary variant presence in cohort B was abstracted from institutional pathology reports. For the commercial cohort, only the urothelial carcinoma component was profiled.

RESULTS

Molecular subtyping of both urothelial and variant components found micropapillary and nested cases were classified as a luminal subtype. Conversely, the sarcomatoid and small cell cases were classified as basal/squamous or neuroendocrine-like, respectively. For cohort B, 50 (29%) of 173 cases had reported secondary variant histology. Cases with squamous variant had basal profiles, small cell cases expressed neuronal markers, and micropapillary cases were classified as luminal. Sarcomatoid tumors had robust epithelial-mesenchymal transition marker expression.

CONCLUSIONS

Our data suggest that in MIBC with secondary variant, the urothelial component can demonstrate an expression profile that closely resembles the variant component.

Genomic Subtyping in Bladder Cancer

PURPOSE OF REVIEW

Molecular characterization of cancer allows us to understand oncogenesis and clinical prognosis as well as facilitates development of biomarkers and treatment. Our aim was to review the current literature on genomic characterization of bladder cancer, and how far we are in implementing genomics into clinical practice.

RECENT FINDINGS

Bladder cancers are molecularly diverse tumors with a high mutational rate. On molecular level, bladder cancer can be categorized into at least six subtypes called luminal-papillary, luminal-unstable, luminal non-specified, basal-squamous, neuroendocrine-like, and stroma-rich. These subtypes have characteristic genomic and transcriptomic profiles and appear to have different prognoses. Several molecular subtypes have been identified in bladder cancer. Prospective trials are underway to validate the applicability of genomic subtypes for clinical decision making. Further integrative analyses of genomic alterations, gene expression, epigenetics, and proteomics need to be performed before genomic subtyping can be attained in clinical practice.