Theories behind Bacillus Calmette-Guérin failure in high-risk non-muscle-invasive bladder cancer and update on current management

Bladder cancer encapsulates a wide spectrum of disease severities, with non-muscle invasive bladder cancer (NMIBC) representing an entirely different entity from muscle-invasive disease. Bacillus Calmette-Guérin (BCG) is one of the most successful intravesical treatment methods for patients diagnosed. However, a considerable proportion of patients fail to respond to BCG treatment. Given the propensity for recurrence in patients with high-risk bladder cancer, these patients present with surgical dilemmas. There is currently no gold standard for salvage treatment post-BCG failure or unified definition as to what that means. In this review, we discuss the mechanisms of action and pathophysiology of BCG, potential theories behind BCG failure, and the scope of novel treatments for this surgical conundrum.

Second-Line Conservative Device-Assisted Intravesical Treatment in Selected Patients With Recurrent High-Risk Non-Muscle-Invasive Bladder Cancer

INTRODUCTION

In cases of recurrent high-risk non-muscle-invasive bladder cancer, radical cystectomy (RC) is recommended. We compared oncologic and treatment-related outcomes of second-line conservative device-assisted therapy to RC.

PATIENTS AND METHODS

In a retrospective cohort study, we analyzed 209 consecutive patients with recurrent bacillus Calmette-Guérin-unresponsive high-risk non-muscle-invasive bladder cancer; 107 subjects refused RC and were offered electromotive drug administration (n = 44) or chemohyperthermia (n = 63) (group A), and 102 patients underwent RC (group B). In group A, patients who did not benefit from device-assisted treatment underwent RC. The endpoints were high-grade disease-free survival, progression-free survival, cancer-specific survival, overall survival, and treatment-related complications. Follow-up was based on international guideline recommendations. Analyses were performed with log-rank and Fisher exact tests.

RESULTS

The median follow-up was 59 months (SD ± 5.3). When comparing group A to B, overall survival rates were 91.6% and 90.2%, respectively (P > .05); cancer-specific survival was 94.4% and 96.1%, respectively (P > .05); high-grade disease-free survival was 43% and 74.5%, respectively (P < .05); and progression-free survival was 59.8% and 75.5%, respectively (P < .05). Patients with carcinoma-in-situ had worse oncologic outcomes compared to patients with papillary disease. In the multivariate analysis, multifocality, disease recurrence, and progression risk group were independently associated with device treatment failure. The 90-day RC-related overall complications rates were 63.9% in group A and 66.6% in group B (P = .63); grade 3 to 5 complications were 9.8% in group A and 9.8% in group B(P = .99). Complications within group A were comparable (P > .05).

CONCLUSION

Device-assisted treatment may a represent a valid second-line conservative tool in selected patients with recurrent high-risk non-muscle-invasive bladder cancer.

ElectroMotive drug administration (EMDA) of Mitomycin C as first-line salvage therapy in high risk "BCG failure" non muscle invasive bladder cancer: 3 years follow-up outcomes

BACKGROUND

In case of high grade non-muscle invasive bladder cancer (HG-NMIBC), intravesical BCG represents the first-line treatment; despite the "gold" standard therapy, up to 50% of patients relapse, needing radical cystectomy. Hence, alternative therapeutic strategies have been developed. The aim of the study was to evaluate a first-line salvage treatment with EMDA®-MMC in patients with HGNMIBC unresponsive to BCG.

METHODS

We carried out a prospective, single-center, single-arm Phase II study in order to evaluate the efficacy (in terms of recurrence and progression) and the safety of the EMDA®-MMC treatment in 26 (21 male, 5 female) consecutive patients with "BCG refractory" HGNMIBC on a 3 years follow-up. EMDA®-MMC treatment consisted of 40 mg of MMC diluted in 100 ml of sterile water retained in the bladder for 30 min with 20 mA pulsed electric current. EMDA®-MMC regimen consisted of an induction course of 6 weekly instillations followed by a maintenance course of 6 monthly instillations. Follow-up was performed with systematic mapping biopsies of the bladder (with sampling in the prostatic urethra for men), voiding and washing urinary cytology, radiological study of the upper urinary tract. We performed Survival Kaplan-Meier curves and Log-rank test in order to analyze high grade disease-free survival.

RESULTS

At the end of follow-up, 16 patients (61.5%) preserved their native bladder; 10 patients (38.4%) underwent radical cystectomy, in 6 patients (23.1%) for recurrent HGNMIBC and in 4 patients (15.4%) for progression to muscle-invasive disease. At the end of follow-up, stratifying patients based on TNM classification (TaG3, T1G3, Cis, TaT1G3 + Cis), disease-free rates were 75, 71.4, 50 and 25%, respectively; survival curves showed statistically significant differences (p value < 0.05). Regarding toxicity, we reported severe adverse systemic event of hypersensitivity to the MMC in 3 patients (11.5%), and local side effects in 6 patients (26.1%).

CONCLUSIONS

In the field of alternative strategies to radical cystectomy, the EMDA®-MMC could be considered safe and effective in high-risk NMIBC unresponsive to BCG, as a "bladder sparing" therapy in selected patients. Multicenter studies with a larger number of patients and a longer follow-up might confirm our preliminary results.

TRIAL REGISTRATION

EudraCT2017-002585-43. 17 June 2017 (retrospectively registered).