Efficacy of BCG for non-muscle invasive bladder cancer following nephroureterectomy for upper tract urothelial carcinoma.

PURPOSE

To evaluate the efficacy of intravesical (IVe) Bacillus Calmette-Guerin (BCG) to treat non-muscle invasive bladder cancer (NMIBC) recurrences in patients who have previously undergone nephroureterectomy for upper tract urothelial carcinoma (UTUC).

METHODS

We performed a single institution retrospective review of patients who underwent nephroureterectomy for UTUC from 2009 to 2021. Patients who subsequently developed NMIBC treated with transurethral resection followed by IVe BCG were included in the study group. A control cohort was formed by retrospective review of patents with primary NMIBC treated with BCG during the same period. Patients in the control cohort were matched by stage of bladder cancer at a 2:1 ratio of control to study subjects. Demographic data, pathology of bladder tumors prior to and following BCG, use of maintenance BCG (mBCG), time to recurrence, time to progression, progression to cystectomy, and progression to metastatic disease were collected on all patients. Descriptive statistics were utilized to compare the 2 groups. The primary outcome was progression to muscle invasive disease. Secondary outcomes included intravesical recurrence free survival, disease free survival, and progression to metastatic disease. Univariable and multivariable logistic regression analysis was performed to elucidate independent variables associated with bladder tumor recurrence. Multivariable Cox regression analysis was used to assess the impact of prior UTUC on time to bladder tumor recurrence.

RESULTS

One-hundred and ninety-one patients underwent nephroureterectomy at our institution from 2009 to 2021 for UTUC. Twenty-five patients were identified to have subsequently developed NMIBC recurrences treated with inductions BCG. The control group was comprised of 50 patients with primary NMIBC matched by stage of bladder cancer for which BCG was indicated in the study group. Median (interquartile range [IQR]) follow-up was significantly longer in the control group relative to the study group (64.8 [50.1-85.6] vs 25 months [17-35]; P = 0.001). There were no significant differences in demographics between the study and control groups. The rate of progression to muscle invasive disease was 17% vs 0% in the study group and control group respectively (P = 0.0521). History of UTUC was associated with increased risk of intravesical bladder tumor recurrence post BCG on multivariable analysis (HR 2.5; P = 0.017) and Kaplan Meier survival analysis (P = 0.039). The mean time to bladder tumor recurrence after treatment with BCG was significantly worse in the study group at (7.9 vs. 23.9 months; P = 0.0322). Similarly, the rate of progression to metastatic disease was worse in the study group (24% vs 2%; P = 0.0047). Overall disease-free survival was also noted to be significantly worse on Kaplan Meier survival analysis in the study group (P = 0.0074). No statistically significant differences in the stage grade of bladder tumor recurrence, grade of bladder tumor recurrence, or rate of progression to cystectomy were identified.

CONCLUSIONS

Our study suggests reduced efficacy of BCG for NMIBC in patients with a history of UTUC. Patients in this population should be counseled accordingly. Research into alternative treatments for bladder tumor recurrence and more aggressive prophylactic regimens after nephroureterectomy for prevention of bladder tumor recurrence in this population is encouraged.