Intravesical bacille Calmette-Guérin in the treatment of carcinoma in situ or high-grade superficial bladder carcinoma after radiotherapy for bladder carcinoma

BCG Administration after Prior Radiation Treatment for Prostate Cancer

INTRODUCTION

Prostate radiotherapy is associated with worse oncologic outcomes in patients with bladder cancer. The underlying mechanism is incompletely understood but is thought to be related to an altered microenvironment promoting tumorigenesis. However, there is a gap in the literature regarding how the effect of BCG varies according to prior radiotherapy in patients with non-muscle invasive bladder cancer (NMIBC). In this context, we sought to evaluate oncologic outcomes in NMIBC patients who have previously undergone prostate radiotherapy compared to patients with no prior history of pelvic radiotherapy.

METHODS

This is a retrospective cohort study that includes all patients who received intravesical for NMIBC at our institution from 2001 to 2019. Patients were stratified into 3 cohorts: prior radiotherapy (RT), radical prostatectomy (RP), and no prostate cancer (No PCa). The outcomes of interest were recurrence at 1-year, progression to muscle-invasive bladder cancer (MIBC), and progression to metastatic disease. Comparisons were also made between cohorts with respect to elapsed time from radiation therapy. Wilcoxon rank-sum test was used for comparing continuous variables, while χ² and Fischer's exact tests were used to examine categorical variables.

RESULTS

In 199 total patients who underwent BCG for NMIBC, 23 had a prior history of prostate radiotherapy treatment, while 17 underwent prior radical prostatectomy. Overall, 41.2% of patients had recurrence at 1 year. There was no difference in the number of induction or maintenance BCG administrations received between the cohorts within the first year. There was no significant difference in recurrence at 1 year between the 3 cohorts (P = .56). There was also no difference in progression to MIBC or progression to metastatic disease with P = .50 and 0.89, respectively.

CONCLUSION

The risk of recurrence after induction BCG treatment for high-grade NMIBC does not vary according to prior radiation treatment for prostate cancer.

Current management of muscle-invasive bladder cancer

Management of muscle-invasive bladder cancer (MIBC) has changed little in the last twenty years. The gold standard treatment is still cystectomy, but it has a significant negative impact on quality of life. Bladder-preservation strategies can be used in some cases but patient selection for this approach remains unclear. New chemotherapy and biologic agents in combination with surgery or radiotherapy could improve results and these possibilities are currently under investigation.

Intravesical bacillus Calmette-Guerin immunotherapy after previous prostate radiotherapy for high-grade non-muscle-invasive bladder cancer

OBJECTIVES

Intravesical bacillus Calmette-Guerin (BCG) immunotherapy is a standard treatment for high-grade non-muscle-invasive bladder cancer (NMIBC). We evaluated outcomes of BCG therapy for NMIBC in patients with a previous history of prostate cancer (CaP) radiotherapy (RT).

MATERIALS AND METHODS

A retrospective review of patients with a history of CaP RT who subsequently underwent treatment with intravesical BCG for high-grade NMIBC was performed. Patients were categorized as "BCG success" or "BCG failure" (defined as stage progression or recurrent/persistent disease). We evaluated factors related to the radiotherapy (type, interval to BCG), bladder cancer (clinical stage, immunotherapy type, and course), and patient comorbidities, to identify factors associated with BCG failure.

RESULTS

From 1996 to 2008, 26 patients with high-grade NMIBC received intravesical BCG immunotherapy after CaP RT. At a mean follow-up of nearly 5 years, 13 patients (50%) were successfully managed with one or more induction courses of BCG with or without the addition of interferon alpha. Twelve (46%) eventually required cystectomy for disease recurrence or progression, of which half had pathologically advanced disease (≥pT3). Clinical stage was similar between BCG success and failure patients (P = 0.40). Those who failed immunotherapy were more likely to have had a longer interval between RT and BCG induction (5.8 vs. 2.4 years, P = 0.02).

CONCLUSION

Approximately 50% of patients with NMIBC who were previously exposed to prostate radiation had a durable response to intravesical BCG. For non-responders, extravesical progression was common.

Molecular alterations associated with bladder cancer initiation and progression

Bladder cancer is the fifth most commonly diagnosed non-cutaneous solid malignancy, and the second most commonly diagnosed genitourinary malignancy amongst people living in the United States, where it is estimated that more than 61,000 new cases of bladder cancer will be diagnosed in the year 2008. Approximately 90% of malignant tumors arising in the urinary bladder are of epithelial origin, the majority being transitional cell carcinomas. Early stage bladder tumors have been classified into two groups with distinct behavior and unique molecular profiles: low grade tumors (always papillary and usually superficial), and high-grade tumors (either papillary or non-papillary, and often invasive). Clinically, superficial bladder tumors (stages Ta and Tis) account for 75% to 85% of neoplasms, while the remaining 15% to 25% are invasive (T1, T2-T4) or metastatic lesions at the time of initial presentation. Studies from the author's group and others have revealed that distinct genotypic and phenotypic patterns are associated with early versus late stages of bladder cancer. Most importantly, early superficial diseases appear to segregate into two main pathways. Superficial papillary bladder tumors are characterized by gain-of-function mutations, mainly affecting classical oncogenes such as RAS and FGFR3. Deletions of chromosome 9, mainly allelic losses on the long arm (9q) are also frequent events in these tumors. Such genetic alterations are observed in most if not all superficial papillary non-invasive tumors (Ta), but only in a small subset of invasive bladder neoplasms. Flat carcinoma in situ (Tis) and invasive tumors are characterized by loss-of-function mutations, affecting the prototype tumor suppressor genes, including p53, RB and PTEN. These alterations are absent or very rare in the Ta tumors analyzed, but have been frequently identified in invasive bladder carcinomas. Based on these data, a novel model for bladder tumor progression has been proposed in which two separate genetic pathways characterize the evolution of superficial bladder neoplasms. Numerous individual molecular markers have been identified in the tissue specimens that correlate to some extent with tumor stage, and possibly with prognosis in bladder cancer. However, these molecular prognosticators do not play a role in the clinical routine management of patients with bladder tumors, mainly due to lack of large prospective validation studies. Thus, the need for development of specific tissue and serum tumor markers for prognostic stratification remains. The advent of high-throughput microarrays technologies allows comprehensive discovery of targets relevant in bladder cancer progression, which could be translated into new approaches for drug and biomarker development. Further investigation is warranted to define novel biomarkers specific for bladder cancer patients based on the molecular alterations of tumor progression, and multiplexed strategies for clinical management.

Molecular alterations associated with bladder cancer progression

Clinically, superficial tumors (stages Ta, Tis, and T1) account for 75% to 85% of bladder neoplasms, while the remaining 15% to 25% are invasive (T2, T3, T4) or metastatic lesions at the time of initial presentation. More than 70% of patients with superficial tumors will have one or more recurrences after initial treatment, and about one third of those patients will progress and eventually die of the disease. New methods are needed to identify and monitor patients presenting with "high-risk" superficial tumors likely to develop into invasive carcinoma. Once invasive into muscle, the natural history is quite variable but highly lethal. Despite aggressive surgical resection, radiotherapy, and/or chemotherapy, the overall cure rate remains in the range of 20% to 50%. New biological determinants are needed both for proper selection of therapy and monitoring. In this review, we describe and update molecular alterations reportedly associated with bladder tumorigenesis and cancer progression. We also review novel genes and "signaling networks" identified by the use of high-throughput technologies. The concept of alterations affecting "genetic pathways" is becoming more than just a molecular biology exercise. The challenge is to evaluate such targets for therapeutic development, as well as to translate progression and outcome biomarkers into improved clinical management. Integration of data generated from in-depth clinical evaluation, histologic tumor characteristics, and validated biomarkers could provide highly accurate, predictive tools for management of the bladder cancer patient.

Radiotherapy for Bladder Cancer

The radiotherapy panel met to develop international consensus about the optimal use of radiotherapy, alone or in combination with surgery and chemotherapy, in the radical treatment of patients with bladder cancer. A consensus meeting of experts in the treatment of bladder cancer was convened by the Société Internationale d'Urologie (SIU). The radiotherapy committee, which had international representation from 6 countries, performed a critical review of the English-language literature and developed evidence-based guidelines for the use of radiotherapy in the treatment of patients with bladder cancer. The strength of the evidence supporting each recommendation was ranked according to a 4-point scale. Consensus statements were developed that address (1) the effectiveness of radiotherapy in the treatment of bladder cancer, (2) the most appropriate patients for curative treatment with radiotherapy, (3) the optimal method of delivery of radiotherapy, (4) the best radiation prescription for treating bladder cancer, and (5) optimal management of the patient's condition after radiotherapy has been provided. Radiotherapy is effective treatment for selected patients with bladder cancer; it produces long-term disease control with preservation of normal bladder function. Modern radiotherapy treatment techniques offer the potential to improve cure rates and reduce adverse effects. All patients in whom the condition is newly diagnosed should be assessed in a multidisciplinary setting, where the relative merits of surgery, radiotherapy, and chemotherapy can be considered on an individual basis with the aim of optimizing overall outcomes.