Superficial (pT2a) and deep (pT2b) muscle invasion in pathological staging of bladder cancer following radical cystectomy

Abstract

Purpose: We compared and evaluated clinical outcomes in patients with pathological superficial (pT2a) and deep (pT2b) invasion of bladder muscle with transitional cell carcinoma following radical cystectomy and urinary diversion.

Materials and methods: From 1971 to 2001, 311 of 1,359 patients (23%), including 244 males (78%) and 67 females, were found to have pathological muscle invasive (pT2) bladder cancer following radical cystectomy. Of this group 147 patients (47%) had pT2a (superficial) and 164 (53%) had pT2b (deep) muscle invasive tumors. Overall 242 patients had no evidence of lymph node metastasis, including 127 with pT2a (86%) and 115 with pT2b (70%). A total of 69 patients (22%) had lymph node involvement, including 20 with pT2a (14%) and 49 with pT2b (30%). At a median followup of 14.3 years (range 0 to 30.1) clinical outcomes were determined, including recurrence-free and overall survival, and local vs distant recurrence.

Results: In the 311 patients with pT2 tumors 10-year recurrence-free and overall survival rates were 72% and 47%, respectively. There was a significantly higher risk of node positive disease with pT2b vs pT2a tumors (30% vs 14%, p <0.001). No significant difference was observed in 10-year recurrence-free survival in patients with pT2a node negative vs pT2b node negative tumors (84% vs 72%, p = 0.091). When comparing pT2a node positive vs pT2b node positive tumors, no significant difference was observed in 10-year recurrence-free survival (50% vs 48%, p = 0.84). Recurrence-free survival was significantly higher in patients with pT2 lymph node negative tumors than in those with pT2 lymph node positive tumors (79% vs 49%, p <0.001). Furthermore, these differences remained significant when stratified by pT2a and pT2b node negative vs positive disease. Local pelvic recurrence developed in 10 of 311 patients (3%) with pT2 disease, while 69 (22%) had distant metastatic disease. In patients with recurrence the local or distant recurrence site was not associated with tumor stage (pT2a vs pT2b p = 0.24) or lymph node status (node negative vs positive p = 0.37).

Conclusions: In muscle invasive (pT2) bladder cancer treated with radical cystectomy there is a higher risk of lymph node positive disease in deep muscle (pT2b) vs superficial (pT2a) invasion. However, no apparent difference was observed in recurrence-free survival between pT2a (superficial) vs pT2b (deep) muscle invasive tumors when controlling for lymph node status. Recurrence-free survival is significantly improved in patients with pT2 lymph node negative tumors compared to survival in those with pT2 lymph node positive tumors. Patients with muscle invasive (pT2), lymph node negative tumors have excellent clinical outcomes following cystectomy, while those with muscle invasive (pT2), lymph node positive tumors have higher recurrence rates and should be considered for adjuvant treatment protocols.