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Incidence of peritoneal carcinomatosis in recurrent plasmacytoid urothelial carcinomas (PUC) of the bladder: A retrospective analysis of patient outcomes at M. D. Anderson Cancer Center (MDACC).

297 Background: PUC are a rare subset of urothelial cancers with a paucity of available literature regarding their clinical behavior.


METHODS
Retrospective analysis of outcomes among all patients (pts) with predominant PUC (pPUC) seen at MDACC from 1999-2010.


RESULTS
31 pts with pPUC histology were identified (median age:63.5yrs; 83.3% male; TNM stage:cT1N0,n=4;cT2N0,n=8;cT3b-4aN0,n=6; cT4b, N+ or M+ n = 13). Median survival for all pts was 17.7mo (Stage I-III vs IV: 38.1 vs 13.3mo). Of 18 pts with potentially surgically resectable PUC (<=pT4aN0M0) 7 received neoadjuvant chemotherapy,10 had initial surgery, and one was treated with TURBT alone. Despite pathologic downstaging in 67% of pts treated with neoadjuvant chemotherapy relapses were common and there was no difference in survival between pts treated with neoadjuvant chemotherapy compared to initial surgery, even though adjuvant chemotherapy was given in 7 patients. Only 1 pt in pCR remains in remission >18 mo after surgery. The most common site of recurrence was in the peritoneum (13/18pts), with relapses occurring even in those with pCR at surgery. At least 4 pts developed CNS involvement with lepto-meningeal disease. In pts presenting with metastatic disease who were treated with chemotherapy, the median survival was 12.6 months.


CONCLUSIONS
Plasmacytoid bladder tumors are a very aggressive subset with overall poor outcomes. Though chemotherapy sensitive with downstaging seen with neoadjuvant chemotherapy, there are few long-term survivors. There is a strong predilection for recurrences along the peritoneal lining, and peritoneal carcinomatosis should remain high on a clinician's differential when patients develop obstructive bowel symptoms.