MP16-02: Prognosis of Variant Histology in Non-Muscle Invasive Bladder Cancer with Low Tumor Burden: A Propensity Score-Matched Analysis with Pure Urothelial Carcinoma
Friday, May 3, 2024 1:00 PM to 3:00 PM · 2 hr. (US/Central)
221B
Abstract
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Full Abstract and Figures
Author Block
Chan Ho Lee, Sung Jun Sou*, Won IK Seo, Jae Il Chung, Busan, Korea, Republic of
Introduction
Urothelial carcinoma (UC) with variant histology (VH) in muscle invasive bladder cancer is reported as poor prognostic factor for RFS and OS. There is limited evidence and recommendations for VH in NMIBC with low tumor burden. We evaluated the prognostic value of VH in NMIBC compared to conventional UC with similar tumor burden.
Methods
Patients diagnosed with NMIBC byTUR-BT at a single center between Jan 2012 and Dec 2020 were retrospectively reviewed. Propensity scores for VH status were calculated, and patients with VH were matched with patients with pure UC at a 1:3 ratio. The VH of NMIBC was further stratified into two groups according to its pathological aggressiveness nature: aggressive variants (glandular, squamous, microcystic, giant cell, nested), highly aggressive variants (micropapillary, plasmacytoid, sarcomatoid). The oncological outcome was compared according to the three groups.
Results
Of the 494 patients with NMIBC, 60 (12.1%) had VH. Of the 60 patients with VH, 22 (36.7%) patients expressed highly aggressive variants. Patients with VH presented with older age at TUR-BT, higher tumor stage and grade, more multiple tumors, and a higher risk group in the AUA risk stratification for NMIBC (all p<0.05). After matching, most of the patients had lower tumor burden; more than 80% of patients had tumor size less than 3cm and more than 65% of patients had solitary tumor. Among 240 propensity score-matched patients, 85 (35.1%) patients experienced disease recurrence and 13 (5.4%) patients were progressed to MIBC during a median follow-up period of 42.5 months. Distant metastasis occurred in 2 of 180 conventional UC patients (1.1%) and 1 of 60 VH patients (1.7%), all of whom developed pathologic progression followed by distant metastasis. Patients with VH did not have a worse prognosis compared to patients with pure UC, including 5-year RFS (log-rank, p=0.510) and pathologic PFS (log-rank, p=0.257). Univariate analysis showed that intravesical BCG treatment was the only factors associated with reduced recurrence.
Conclusions
We have validated that VH is not a significant prognostic factor in low tumor burden NMIBC. Low tumor burden NMIBC with VH could be controlled with bladder sparing methods currently used in high-risk conventional NMIBC.
Source Of Funding
None
Author Block
Chan Ho Lee, Sung Jun Sou*, Won IK Seo, Jae Il Chung, Busan, Korea, Republic of
Introduction
Urothelial carcinoma (UC) with variant histology (VH) in muscle invasive bladder cancer is reported as poor prognostic factor for RFS and OS. There is limited evidence and recommendations for VH in NMIBC with low tumor burden. We evaluated the prognostic value of VH in NMIBC compared to conventional UC with similar tumor burden.
Methods
Patients diagnosed with NMIBC byTUR-BT at a single center between Jan 2012 and Dec 2020 were retrospectively reviewed. Propensity scores for VH status were calculated, and patients with VH were matched with patients with pure UC at a 1:3 ratio. The VH of NMIBC was further stratified into two groups according to its pathological aggressiveness nature: aggressive variants (glandular, squamous, microcystic, giant cell, nested), highly aggressive variants (micropapillary, plasmacytoid, sarcomatoid). The oncological outcome was compared according to the three groups.
Results
Of the 494 patients with NMIBC, 60 (12.1%) had VH. Of the 60 patients with VH, 22 (36.7%) patients expressed highly aggressive variants. Patients with VH presented with older age at TUR-BT, higher tumor stage and grade, more multiple tumors, and a higher risk group in the AUA risk stratification for NMIBC (all p<0.05). After matching, most of the patients had lower tumor burden; more than 80% of patients had tumor size less than 3cm and more than 65% of patients had solitary tumor. Among 240 propensity score-matched patients, 85 (35.1%) patients experienced disease recurrence and 13 (5.4%) patients were progressed to MIBC during a median follow-up period of 42.5 months. Distant metastasis occurred in 2 of 180 conventional UC patients (1.1%) and 1 of 60 VH patients (1.7%), all of whom developed pathologic progression followed by distant metastasis. Patients with VH did not have a worse prognosis compared to patients with pure UC, including 5-year RFS (log-rank, p=0.510) and pathologic PFS (log-rank, p=0.257). Univariate analysis showed that intravesical BCG treatment was the only factors associated with reduced recurrence.
Conclusions
We have validated that VH is not a significant prognostic factor in low tumor burden NMIBC. Low tumor burden NMIBC with VH could be controlled with bladder sparing methods currently used in high-risk conventional NMIBC.
Source Of Funding
None