BCG-Unresponsive Non-Muscle-Invasive Bladder Cancer: Current Treatment Landscape and Novel Emerging Molecular Targets

Urothelial carcinoma (UC), the sixth most common cancer in Western countries, includes upper tract urothelial carcinoma (UTUC) and bladder carcinoma (BC) as the most common cancers among UCs (90-95%). BC is the most common cancer and can be a highly heterogeneous disease, including both non-muscle-invasive (NMIBC) and muscle-invasive (MIBC) forms with different oncologic outcomes. Approximately 80% of new BC diagnoses are classified as NMIBC after the initial transurethral resection of the bladder tumor (TURBt). In this setting, intravesical instillation of Bacillus Calmette-Guerin (BCG) is the current standard treatment for intermediate- and high-risk patients. Unfortunately, recurrence occurs in 30% to 40% of patients despite adequate BCG treatment. Radical cystectomy (RC) is currently considered the standard treatment for NMIBC that does not respond to BCG. However, RC is a complex surgical procedure with a recognized high perioperative morbidity that is dependent on the patient, disease behaviors, and surgical factors and is associated with a significant impact on quality of life. Therefore, there is an unmet clinical need for alternative bladder-preserving treatments for patients who desire a bladder-sparing approach or are too frail for major surgery. In this review, we aim to present the strategies in BCG-unresponsive NMIBC, focusing on novel molecular therapeutic targets.

Impact of systemic inflammatory markers on the response to Hyperthermic IntraVEsical Chemotherapy (HIVEC) in patients with non-muscle-invasive bladder cancer after bacillus Calmette-Guérin failure

Objectives: To evaluate the impact of pre- and post-treatment systemic inflammatory markers on the response to Hyperthermic IntraVEsical Chemotherapy (HIVEC) treatment in a cohort of patients with high-grade non-muscle-invasive bladder cancer with bacillus Calmette–Guérin (BCG) failure or intolerance who were unsuitable or unwilling to undergo early radical cystectomy. As a secondary endpoint, we assessed the influence of some demographic, clinical and pathological factors on the response to chemo-hyperthermia.

Patients and methods: Between March 2017 and December 2019, 72 consecutive patients were retrospectively analysed. Patients with diseases or conditions that could interfere with systemic inflammatory status or full blood count were excluded. The HIVEC protocol consisted of six weekly intravesical treatments with 40 mg Mitomycin-C diluted in 50 mL distilled water. The drug was heated to a temperature of 43°C. Association of categorical variables with response to HIVEC was evaluated using Yates’ chi-squared test and differences in continuous variable were analysed using the Mann–Whitney test. Logistic regression analysis was performed to define independent predictors of response to HIVEC.

Results: Patients who failed HIVEC were more likely to have multiple tumours (P = 0.039) at transurethral resection of bladder and a recurrence rate of >1/year (P = 0.046). Lower post-HIVEC inflammatory indices [C-reactive protein (P = 0.021), erythrocyte sedimentation rate (P = 0.027)] and lower pre- (P = 0.014) and post-treatment (P = 0.004) neutrophil-to-lymphocyte ratio (NLR) values were significantly associated with the response to the HIVEC regimen (no bladder cancer recurrence or progression). In the multivariate analysis, patients with a recurrence rate of >1/year were eight-times more likely to experience failure of HIVEC (P = 0.007). Higher pre- (P = 0.023) and post-treatment NLR values (P = 0.046) were associated with a worse response to the HIVEC regimen.

Conclusions: The recurrence rate and systemic inflammatory response markers could be useful tools to predict the likelihood of obtaining a response with the HIVEC regimen. These markers might help to guide patients about the behaviour of the tumour after BCG failure, predicting failure or success of a conservative treatment.

Abbreviations: CHT: chemo-hyperthermia; CIS: carcinoma in situ; CRP: C-reactive protein; EAU: European Association of Urology; ESR: erythrocyte sedimentation rate; HG: high grade; HIVEC: Hyperthermic IntraVEsical Chemotherapy; ICD: immunogenic cell death; IL: interleukin; MMC: Mitomycin-C; NK: natural killer; NLR: neutrophil-to-lymphocyte ratio; NMIBC: non-muscle-invasive bladder cancer; PLR: platelet-to-lymphocyte ratio; RC: radical cystectomy; SIR: systemic inflammatory response; TURB: transurethral resection of bladder

Hyperthermic Intravesical Chemotherapy for BCG Unresponsive Non-Muscle Invasive Bladder Cancer Patients

Background:

Adjuvant intravesical instillations with bacillus Calmette-Guérin (BCG) is the recommended treatment option for patients with intermediate-and high-risk non-muscle invasive bladder cancer (NMIBC). Despite adequate BCG treatment, a large proportion of patients experience a recurrence. Although radical cystectomy is the gold standard for BCG unresponsive NMIBC, some patients are unfit or unwilling to consider this option.

Objective:

To assess the effectiveness of Hyperthermic IntraVEsical Chemotherapy (HIVEC^®) in BCG unresponsive NMIBC patients.

Methods:

A post-hoc analysis was conducted of prospectively included intermediate-and high-risk NMIBC patients who were planned to receive HIVEC^® treatment between October 2014 and November 2017. For the present analysis, only patients who met the BCG unresponsive definition were included. Patients were followed by cystoscopy and cytology every 3 months and a CT-urography scan yearly. The primary outcome was the disease-free survival (DFS). The Common Terminology Criteria for Adverse Events (CTCAE) was used to assess side-effects.

Results:

The study population consisted of 55 BCG unresponsive NMIBC patients of whom 52 underwent≥5 HIVEC^® treatments. The median age and follow-up were 73 years and 14.0 months (IQR 7.6 – 24.6). The median DFS was 17.7 months (SE 6.72) and progression occurred in four patients. The 1-year cumulative incidence rate of disease recurrence/progression was 53%. Two patients experienced severe side-effects (CTCAE≥3).

Conclusions:

HIVEC^® seems a valid treatment option for BCG unresponsive NMIBC patients. We report a median DFS of 17.7 months (SE 6.72), potentially avoiding or postponing the need for radical surgery in a proportion of these patients.

The role of hyperthermia as a treatment for non-muscle invasive bladder cancer

Non-muscle invasive bladder cancer (NMIBC) has a high tendency for recurrence and progression. Currently, all known intravesical agents are associated with adverse effects (AEs) and limited efficacy. The combination of hyperthermia (HT) with intravesical Mitomycin C (MMC) chemotherapy has been shown to improve outcomes. The added efficacy of HT to MMC was first shown in preclinical studies. The reports on patients with NMIBC have indicated that the treatment is safe and well tolerated. Several clinical studies reported the efficacy of radiofrequency-induced chemotherapy effect (RITE) in the treatment of patients with NMIBC. This modality was shown to be superior to MMC alone. RITE was effective also in patients with high-risk NMIBC, including those who failed Bacillus Calmette-Guérin (BCG). This study provides an updated review of literature regarding the use of RITE in patients with NMIBC.