Phase 1 Trial of Atezolizumab Plus Trimodal Therapy in Patients With Localized Muscle-Invasive Bladder Cancer

Pembrolizumab with Chemoradiation as Treatment for Muscle-invasive Bladder Cancer: Analysis of Safety and Efficacy of the PCR-MIB Phase 2 Clinical Trial (ANZUP 1502)

BACKGROUND

Radiation may improve the efficacy of immune checkpoint inhibition. This study investigates the combination of pembrolizumab and chemoradiation (CRT) for muscle-invasive bladder cancer (MIBC).

OBJECTIVE

To assess the feasibility and safety of pembrolizumab combined with CRT for MIBC.

DESIGN, SETTING, AND PARTICIPANTS

A single-arm phase 2 trial was performed with 28 participants having cT2-T4aN0M0 MIBC (Eastern Cooperative Oncology Group performance status 0-1; estimated glomerular filtration rate ≥40 ml/min; no contraindications to pembrolizumab) suitable for CRT.

INTERVENTION

Whole bladder radiation therapy (RT; 64 Gy in 32 daily fractions, over 6.5 wk, combined with cisplatin (35 mg/m2 intravenously [IV] weekly, six doses) and pembrolizumab (200 mg IV q3 weeks, seven doses), both starting with RT. Surveillance cystoscopy/biopsy and computerised tomography scans performed 12 and 24 wk after CRT.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary endpoint was feasibility, determined by a prespecified satisfactory low rate of grade 3 or worse nonurinary toxicity or completion of planned CRT according to defined parameters. Secondary endpoints were complete cystoscopic response, locoregional progression-free survival (LRPFS), distant metastasis-free survival (DMFS), and overall survival (OS).

RESULTS AND LIMITATIONS

Twenty-eight patients were enrolled with a 31-mo median follow-up. Six had Grade >3 nonurinary adverse events during/within 12 wk after treatment; three had more than one cisplatin dose reduction. The 24-wk post-CRT complete response (CR) rate was 88%. Eight patients developed metastatic disease, and three had nonmetastatic progression. The DMFS at 2 yr is 78% (95% confidence interval [CI] 54-90%), with LRPFS at 2 yr of 87% (95% CI 64-96%) and median OS of 39 mo (95% CI 17.1-not evaluable). Limitations are the single-arm design and sample size.

CONCLUSIONS

Combining pembrolizumab with CRT for MIBC was feasible, with manageable toxicity and promising CR rates.

PATIENT SUMMARY

Immunotherapy treats nonmetastatic/metastatic bladder cancer effectively. We combined pembrolizumab with chemotherapy and radiation to assess its safety and impact on treatment delivery. The combination was feasible with encouraging early activity. Further larger trials are warranted.

Beyond surgery: bladder preservation and the role of systemic treatment in localised muscle-invasive bladder cancer

Over the last two to three decades the non-surgical curative management of bladder cancer has significantly progressed. Increasing evidence supports the use of bladder preservation as an alternative to radical cystectomy (RC) for localised muscle-invasive bladder cancer (MIBC). Radiosensitisation with chemotherapy or hypoxia modification improves the efficacy of radiotherapy. Systemic treatments play an important role in the management of localised MIBC with the benefit of neoadjuvant chemotherapy prior to radical treatment well established. The use of immune checkpoint inhibitors (ICIs) in the radical treatment of bladder cancer, their safe combination with radical radiotherapy regimens and whether the addition of ICIs improve rates of cure are outstanding questions beginning to be answered by ongoing clinical trials. In this narrative review, we discuss the current evidence for bladder preservation and the role of systemic treatments for localised MIBC.

Integrating novel immunotherapeutic approaches in organ-preserving therapies for bladder cancer

Bladder cancer (BC) is a prevalent malignancy with significant morbidity and mortality. Over the years, the landscape of bladder cancer treatment has witnessed notable advancements, particularly in the realm of immunotherapy. Immunotherapy has emerged as a promising adjunct to organ-preserving approaches, harnessing the immune system's potential to target and eliminate cancer cells. Organ preservation strategies offer viable alternatives to radical cystectomy to avoid the morbidities associated with radical surgery, as well as to respond to the needs of patients unfit for or who have refused surgery. However, the challenge lies in achieving durable disease control while minimizing treatment-related toxicities. This review highlights the significance of immune checkpoint inhibitors, such as anti-programmed cell death 1 (PD-1)/programmed cell death 1 ligand 1 (PD-L1) antibodies, in the treatment of localized bladder cancer. The clinical efficacy of immune checkpoint inhibitors, as both neoadjuvant and adjuvant therapies in combination with radiation or chemotherapy, is discussed. Moreover, the potential of immunotherapies beyond immune checkpoint inhibition, including combinations with bacillus Calmette-Guérin (BCG) instillations and/or investigational gene therapies, is explored. Furthermore, the predictive value of the tumour immune microenvironment for the success of these strategies is examined. Understanding the complex interplay between tumour immunity and therapeutic interventions can aid in identifying predictive biomarkers and tailoring personalized treatment strategies. Further research and clinical trials are warranted to optimize the use of immunotherapy in conjunction with organ-preserving therapies, potentially leading to enhanced patient outcomes and quality of life.

Bladder-sparing treatment for muscle-invasive bladder carcinoma using immune checkpoint inhibitors

Multimodal bladder preservation therapy is already an alternative for patients with muscle-invasive bladder cancer (MIBC) who are unable or unwilling to undergo radical cystectomy. Various bladder-preserving strategies that employ immune checkpoint inhibitors (ICIs) for MIBC have been investigated. There are three common modes of ICI-based bladder preservation therapy, of which the most studied is ICIs combined with chemoradiotherapy. The bladder-preserving strategy of ICIs combined with radiation has been investigated in patients who poorly tolerate chemotherapy. ICIs combined with chemotherapy have also been explored in patients who responded to neoadjuvant therapy with a clinical complete response. All the above-described strategies have shown promising efficacy and manageable safety profiles. However, the value of programmed death-ligand 1 (PD-L1) expression, tumor mutation burden and gene alterations for predicting the efficacy of immune-based bladder preservation therapy is still controversial. There remain some challenges for immune-based bladder preservation therapy, and large-sample randomized trials are needed.

Efficacy and Safety of Bladder Preservation Therapy in Combination with Atezolizumab and Radiation Therapy (BPT-ART) for Invasive Bladder Cancer: Interim Analysis from a Multicenter, Open-label, Prospective Phase 2 Trial

PURPOSE

To evaluate the safety and pathologic complete response (pCR) rate of radiation therapy with atezolizumab as bladder-preserving therapy for invasive bladder cancer.

METHODS AND MATERIALS

A multicenter, phase 2 study was conducted with patients with clinically T2-3 or very-high-risk T1 bladder cancer who were poor candidates for or refused radical cystectomy. The interim analysis of pCR is reported as a key secondary endpoint ahead of the progression-free survival rate primary endpoint. Radiation therapy (41.4 Gy to the small pelvic field and 16.2 Gy to the whole bladder) was given in addition to 1200 mg intravenous atezolizumab every 3 weeks. After 24 treatment weeks, response was assessed after transurethral resection, and tumor programmed cell death ligand-1 (PD-L1) expression was assessed using tumor-infiltrating immune cell scores.

RESULTS

Forty-five patients enrolled from January 2019 to May 2021 were analyzed. The most common clinical T stage was T2 (73.3%), followed by T1 (15.6%) and T3 (11.1%). Most tumors were solitary (77.8%), small (<3 cm) (57.8%), and without concurrent carcinoma in situ (88.9%). Thirty-eight patients (84.4%) achieved pCR. High pCR rates were achieved in older patients (90.9%) and in patients with high PD-L1-expressing tumors (95.8% vs 71.4%). Adverse events (AEs) occurred in 93.3% of patients, with diarrhea being the most common (55.6%), followed by frequent urination (42.2%) and dysuria (20.0%). The frequency of grade 3 AEs was 13.3%, whereas no grade 4 AEs were observed.

CONCLUSIONS

Combination therapy with radiation therapy and atezolizumab provided high pCR rates and acceptable toxicity, indicating it could be a promising option for bladder preservation therapy.

3D laparoscopic treatment of bladder cancer with pelvic multi-organ invasion: a case report and literature review

Introduction

Radical cystectomy with dissection of pelvic lymph nodes and urethral diversion is the standard surgical treatment for muscle-invasive non-metastatic bladder cancer. In rare cases where patients with bladder cancer without distant metastasis have pelvic multi-organ invasion, the cancer compresses or invades the ureter and, in severe cases, leads to bilateral upper urinary tract obstruction and renal damage. The treatment recommended by guidelines often cannot improve the patients' clinical symptoms immediately, and patients cannot complete the treatment owing to severe side effects, resulting in poor survival benefits.

Case presentation

A 69-year-old woman with facial edema was treated at the First Affiliated Hospital of Jinan University. The serum creatinine and potassium values were 1244 umol/L and 5.86 mmol/L, respectively. Pelvic magnetic resonance and abdominal computed tomography revealed that the bladder tumor had infiltrated the uterus, anterior vaginal wall, rectum, right ureter, right fallopian tube, and right ovary and metastasized to multiple pelvic lymph nodes. Tumor invasion of the right ureter resulted in severe hydronephrosis of the right kidney and loss of function and obstructive symptoms in the left kidney. Four days later, the patient's creatinine level decreased to 98 u mol/L, the general condition significantly improved, and the patient and family members strongly desired surgical treatment of the tumor. Through a comprehensive preoperative discussion, possible intraoperative and postoperative complications were evaluated. Right nephrectomy, right ureterectomy, total pelvic organ resection, extended pelvic lymph node dissection, and bowel and urinary diversion were conducted under 3D laparoscopy-assisted treatment. The patient was followed-up for 1.5 years and showed good tumor control, self-care, and mental status.

Conclusion

Minimally invasive surgery is a curative option for patients with bladder cancer with pelvic multi-organ invasion without distant metastasis. Surgeons should strictly control the indications for surgery and warn patients about the occurrence of related post-surgical complications.

Clinical outcomes of adapted hypofractionated radiotherapy for bladder cancer in elderly patients

OBJECTIVE

To investigate the feasibility, efficacy, and safety of trimodal therapy (TMT) using a bifractionated split-course hypofractionated radiotherapy (RT) for non-metastatic muscle-invasive bladder cancer (MIBC) in elderly patients.

PATIENTS AND METHODS

We retrospectively reviewed the characteristics and outcomes of patients aged >75 years with non-metastatic MIBC suitable or not for radical cystectomy (RC) and treated with transurethral resection of bladder tumour followed by concomitant radio-chemotherapy (platinum salt and 5-fluorouracil) at two institutions (Saint Louis Hospital, Paris, France and European Georges Pompidou Hospital, Paris, France) between 1990 and 2021. RT consisted of an adapted bifractionated split-course hypofractionated RT. Acute toxicities were reported according to Common Terminology Criteria for Adverse Events version 5.0 and late toxicities were reported according to the Radiation Therapy Oncology Group/European Organisation for Research and Treatment of Cancer late radiation morbidity scoring schema. The primary end-point was overall survival (OS). Secondary end-points included other survivals outcomes and safety.

RESULTS

A total of 122 patients were identified, with a median (range) follow-up of 51.1 (0.5-210.8) months. In all, 83.5% of patients completed radio-chemotherapy. The OS rate was 61.7% at 3 years and 51.2% at 5 years. In multivariate analysis, the completion of RT and concomitant chemotherapy were significantly associated with better OS and cancer-specific survival. For patients fit for RC, a complete histological response was achieved for 77 patients (91.7%) with radio-chemotherapy and the bladder conservation rate was 90.5%. Acute and late Grade ≥3 toxicities were <5%.

CONCLUSION

Bifractionated split-course hypofractionated RT with concomitant chemotherapy regimen appears to be well-tolerated and effective. Trimodal treatment seems to be a curative option for elderly patients unfit for radical surgery compared with palliative care and may contribute to improved survival in these patients.

The Legacy of RTOG/NRG Protocols in Shaping Current Bladder Preservation Therapy in North America

For muscle-invasive bladder cancer, the historical, gold standard treatment was radical cystectomy. However, the notion of organ preservation using trimodality therapy (TMT, consisting of maximal transurethral resection of bladder tumor followed by chemoradiation) has been established as a viable treatment alternative to complete removal of the bladder. Despite the lack of direct head-to-head randomized comparisons of TMT to radical cystectomy, the Radiation Therapy Oncology Group (RTOG)/NRG has spearheaded the use of radiation therapy as part of bladder preservation for years, with prospective data demonstrating similar long-term clinical outcomes to cystectomy series, particularly with contemporary treatment. We summarize these trials and discuss the evolution of bladder preservation throughout the decades, culminating in our current TMT protocols. We further discuss the future of organ-preservation therapy in MIBC, with continued improvement in radiation techniques, incorporation of novel therapies, and personalization of treatment to optimize benefit for bladder cancer patients.

Combination of radiation and immunotherapy in the treatment of genitourinary malignancies: A systematic review and meta-analysis

BACKGROUND

Due to possible synergistic effects, the combination of radiation therapy (RT) and immune checkpoint inhibitors (ICI) represents an interesting therapeutic option. An increasing number of clinical trials are ongoing to investigate this combination in genitourinary malignancies and the first results are available.

OBJECTIVES

To review and summarize available data on the combination of RT and ICI in genitourinary malignancies and update the evidence for this potential therapeutic approach.

EVIDENCE ACQUISITION

A study protocol was registered in the PROSPERO-Database. Terms of search were prostate cancer, bladder cancer, renal cell carcinoma, penile cancer, testicular cancer, radiotherapy, and immunotherapy in multiple literature databases and study registers. Clinical studies reporting on the combination treatment of RT and ICI were included. A systematic review of ongoing trials according to the PRISMA statement and a meta-analysis of available trials were performed.

EVIDENCE SYNTHESIS

Overall, 43 studies met the inclusion criteria examining the therapeutic effect of combined RT and ICI. For bladder cancer, renal cell carcinoma, prostate cancer, and penile cancer 28, 9, 5, and 1 trial could be identified, respectively. No study was found for testicular cancer. Three phases III trials were identified, all other trials were phase I or II. Twelve studies have been completed so far. The meta-analysis of available data indicates comparable toxicity of RT plus ICI vs. ICI alone for grade 3/4 AEs. Mature efficacy data is limited with interesting early results.

CONCLUSION

This article reviews the clinical trial landscape investigating RT and ICI in genitourinary malignancies. It provides an overview of ongoing trials and discusses available results. Actual data regarding efficacy is limited, while toxicities seem comparable to ICI alone. Especially in bladder and kidney cancer, further trial results might impact on the clinical use of the combination therapy.

Mapping Local Failure Following Bladder Radiotherapy According to Dose

AIMS

To determine the relationship between local relapse following radical radiotherapy for muscle-invasive bladder cancer (MIBC) and radiation dose.

MATERIALS AND METHODS

Patients with T2-4N0-3M0 MIBC were recruited to a phase II study assessing the feasibility of intensity-modulated radiotherapy to the bladder and pelvic lymph nodes. Patients were planned to receive 64 Gy/32 fractions to the bladder tumour, 60 Gy/32 fractions to the involved pelvic nodes and 52 Gy/32 fractions to the uninvolved bladder and pelvic nodes. Pre-treatment set-up was informed by cone-beam CT. For patients who experienced local relapse, cystoscopy and imaging (CT/MRI) was used to reconstruct the relapse gross tumour volume (GTVrelapse) on the original planning CT . GTVrelapse D98% and D95% was determined by co-registering the relapse image to the planning CT utilising deformable image registration (DIR) and rigid image registration (RIR). Failure was classified into five types based on spatial and dosimetric criteria as follows: A (central high-dose failure), B (peripheral high-dose failure), C (central elective dose failure), D (peripheral elective dose failure) and E (extraneous dose failure).

RESULTS

Between June 2009 and November 2012, 38 patients were recruited. Following treatment, 18/38 (47%) patients experienced local relapse within the bladder. The median time to local relapse was 9.0 months (95% confidence interval 6.3-11.7). Seventeen of 18 patients were evaluable based on the availability of cross-sectional relapse imaging. A significant difference between DIR and RIR methods was seen. With the DIR approach, the median GTVrelapse D98% and D95% was 97% and 98% of prescribed dose, respectively. Eleven of 17 (65%) patients experienced type A failure and 6/17 (35%) patients type B failure. No patients had type C, D or E failure. MIBC failure occurred in 10/17 (59%) relapsed patients; of those, 7/11 (64%) had type A failure and 3/6 (50%) had type B failure. Non-MIBC failure occurred in 7/17 (41%) patients; 4/11 (36%) with type A failure and 3/6 (50%) with type B failure.

CONCLUSION

Relapse following radiotherapy occurred within close proximity to the original bladder tumour volume and within the planned high-dose region, suggesting possible biological causes for failure. We advise caution when considering margin reduction for future reduced high-dose radiation volume or partial bladder radiotherapy protocols.

Impact of sarcopenia in bladder preservation therapy for muscle-invasive bladder cancer patients: a narrative review

BACKGROUND AND OBJECTIVE

Muscle-invasive bladder cancer (MIBC) is a biologically aggressive disease and its prognosis is poor. Radical cystectomy (RC) with urinary diversion and lymph node dissection is the gold standard treatment for MIBC patients. Accumulating evidence indicates that sarcopenia, the degenerative and systemic loss of skeletal muscle mass, is a significant predictor of higher rates of mortality and perioperative complications following RC. Recently, bladder preservation therapy has been offered as an alternative in appropriately selected MIBC patients who desire to preserve their bladders and those unfit or unwilling for RC. Here, we performed a narrative review on the impact of sarcopenia on oncological outcomes and complication rates in MIBC patients treated with bladder preservation therapy.

METHODS

A literature review was performed using the PubMed and Scopus databases.

KEY CONTENT AND FINDINGS

We identified two studies reported the impact of sarcopenia on responses to trimodal therapy and survival outcomes in MIBC patients. Consolidative partial cystectomy was performed in patients who achieved clinical complete response (CR) to trimodal therapy in one of the two studies. In both studies, CR rates to trimodal therapy are comparable between sarcopenic and non-sarcopenic patients. Sarcopenia was not significantly associated with shorter survival after completing bladder preservation therapy in either study. For complication rates of bladder preservation therapy, one study showed equivalent complication rates of consolidative partial cystectomy between sarcopenic and non-sarcopenic patients. In addition, in another small series of trimodal therapy, sarcopenic patients showed a higher rate of complications of trimodal therapy compared with non-sarcopenic patients.

CONCLUSIONS

According to the result of our literature review, sarcopenia would not affect responses to trimodal therapy and prognosis in MIBC patients treated with bladder preservation therapy. Although the effect of sarcopenia on complication rates of bladder preservation therapy is inconclusive due to limited evidence, bladder preservation therapy could be a viable alternative option in carefully selected MIBC patients regardless of the presence of sarcopenia.

Phase 1 Study of Chemoradiotherapy Combined with Nivolumab ± Ipilimumab for the Curative Treatment of Muscle-invasive Bladder Cancer

BACKGROUND

Muscle-invasive bladder cancer (MIBC) has a poor prognosis. Chemoradiotherapy (CRT) in selected patients has comparable results to radical cystectomy. Results of neoadjuvant immune checkpoint inhibitors (ICIs) before radical cystectomy are promising. We hypothesize that ICI concurrent to CRT (iCRT) is safe and may improve treatment outcomes.

OBJECTIVE

To determine the safety of iCRT for MIBC.

DESIGN, SETTING, AND PARTICIPANTS

This multicenter, phase 1b, open-label, dose-escalation study determined the safety of CRT with three ICI regimens in patients with nonmetastatic (T2-4aN0-1) MIBC. Twenty-six patients received mitomycin C/capecitabine and 20 × 2.75 Gy to the bladder. Tolerability was evaluated in a cohort of up to ten patients. If two or fewer out of the first six patients or three or fewer of ten patients experienced dose-limiting toxicity (DLT), accrual continued in the next cohort.

INTERVENTION

Patients received nivolumab 480 mg (NIVO480), nivolumab 3 mg/kg and ipilimumab 1 mg/kg (NIVO3 + IPI1), or nivolumab 1 mg/kg and ipilimumab 3 mg/kg (IPI3 + NIVO1).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary endpoint was safety. Secondary objectives were response rate, disease-free survival, metastatic-free survival (MFS), and overall survival (OS).

RESULTS AND LIMITATIONS

In the NIVO480 cohort, no patients experienced DLT. The NIVO3 + IPI1 2 patients experienced DLT, thrombocytopenia (grade 4), and asystole (grade 5). IPI3 + NIVO1 was discontinued after three out of six patients experienced DLT. Clinically significant adverse events (AEs) of grade ≥3 occurred in zero, three, and five patients in the NIVO480, NIVO3 + IPI1, and IPI3 + NIVO1 groups, respectively. The most common AEs were immune related and gastrointestinal. MFS and OS were 90% at 2 yr for NIVO480 and 90% at 1 yr for NIVO3 + IPI1. Limitations include the absence of a centralized pathology and radiology review, and a lack of biomarker analysis.

CONCLUSIONS

In this dose-finding study of iCRT, the regimens of nivolumab monotherapy and nivolumab 3 mg/kg with ipilimumab 1 mg/kg have acceptable toxicity.

PATIENT SUMMARY

We tested the safety of a new bladder-sparing treatment modality for muscle-invasive bladder cancer patients, combining immune checkpoint inhibitors simultaneously with chemoradiotherapy. We report that two regimens, nivolumab monotherapy and nivolumab 3 mg/kg with ipilimumab 1 mg/kg, are safe and can be used in phase 3 trials.

Comprehensive analysis of autophagy related long non-coding RNAs in prognosis, immunity, and treatment of muscular invasive bladder cancer

To predict disease outcome in muscle-invasive bladder cancer (MIBC), we constructed a prognostic autophagy-related (PAR) lncRNA signature. Comprehensive bioinformatics analyses were performed using data from TCGA and GTEx databases. Univariate Cox, and least absolute shrinkage and selection operator regression analyses were also performed, based on differentially expressed genes, to identify PAR-related lncRNAs to establish the signature. Furthermore, the Kaplan–Meier OS curve and receiver operating characteristic curve analyses were performed and a nomogram was constructed, all of which together confirmed the strong predictive ability of the constructed signature. Patients with MIBC were then divided into high- and low-risk groups. Gene enrichment and immune infiltration analyses revealed the potential mechanisms in MIBC. We also further evaluated the signature of molecules related to immune checkpoints and the sensitivity toward chemotherapeutic agents and antitumor-targeted drugs to find better treatment prescriptions. We identified a number of PAR-related lncRNA signatures, including HCP5, AC024060.1, NEAT1, AC105942.1, XIST, MAFG-DT, and NR2F1-AS1, which could be valuable prognostic tools to develop more efficient, individualized drug therapies for MIBC patients.

Advances in Diagnosis and Therapy for Bladder Cancer

Bladder cancer (BCa) is one of the most common and expensive urinary system malignancies for its high recurrence and progression rate. In recent years, immense amounts of studies have been carried out to bring a more comprehensive cognition and numerous promising clinic approaches for BCa therapy. The development of innovative enhanced cystoscopy techniques (optical techniques, imaging systems) and tumor biomarkers-based non-invasive urine screening (DNA methylation-based urine test) would dramatically improve the accuracy of tumor detection, reducing the risk of recurrence and progression of BCa. Moreover, intravesical instillation and systemic therapeutic strategies (cocktail therapy, immunotherapy, vaccine therapy, targeted therapy) also provide plentiful measures to break the predicament of BCa. Several exploratory clinical studies, including novel surgical approaches, pharmaceutical compositions, and bladder preservation techniques, emerged continually, which are supposed to be promising candidates for BCa clinical treatment. Here, recent advances and prospects of diagnosis, intravesical or systemic treatment, and novel drug delivery systems for BCa therapy are reviewed in this paper.

Bladder-Sparing Chemoradiotherapy Combined with Immune Checkpoint Inhibition for Locally Advanced Urothelial Bladder Cancer-A Review

Simple Summary

Immunotherapy with immune checkpoint inhibition (ICI) has provided durable treatment responses in advanced, metastatic, bladder cancer patients. The first trials using checkpoint inhibitors before surgery, when the cancer is still confined to the pelvis, without signs of metastasis, have reported promising results. We reviewed the literature to identify clinical trials combining ICI with bladder-sparing chemoradiotherapy (CRT). Radiotherapy stimulates the immune system, thereby possibly inducing an additive effect in combination with checkpoint inhibition. Currently, twelve trials are treating patients with this immunochemoradiotherapy (iCRT) combination treatment. Several combinations with different chemotherapeutics and ICI added to CRT appear safe and feasible. Further research and comparative trials are needed to prove whether iCRT has additional clinical value for bladder cancer patients.

Abstract

Despite current treatment strategies, the 5-year overall survival of muscle-invasive bladder cancer (MIBC) is approximately 50%. Historically, radical cystectomy (RC) with neoadjuvant chemotherapy has been the first-choice treatment for this patient group. Recently, several studies have reported encouraging results of using immune checkpoint inhibitors (ICI) prior to RC. However, in recent years, bladder-sparing alternatives such as CRT have gained popularity. The effect of radiotherapy on the tumor microenvironment is an important rationale for combining CRT with ICI therapy. Worldwide, twelve immunochemoradiotherapy (iCRT) trials are ongoing. Each study employs a different chemotherapy and radiotherapy regimen and varies the timing of ICI administration concurrent to radiotherapy, adjuvant, or both. Five studies have presented (preliminary) results showing promising safety and short-term survival data. The first peer-reviewed publications are expected in the near future. The preclinical evidence and preliminary patient data demonstrate the potential of iCRT bladder-sparing treatment for bladder cancer.

Bladder-sparing combination treatments for muscle-invasive bladder cancer: A plea for standardized assessment and definition of clinical trials endpoints

Radical cystectomy is the standard of care for muscle invasive bladder cancer, although it represents a surgical procedure with high complication and mortality burden. Thus, more and more emphasis has been placed in favor of alternative treatments especially for patients who are unfit for or aim to avoid radical cystectomy. In this context, preclinical studies highlighted that chemoradiation therapy (CRT) may have immunomodulatory properties on tumor microenvironment with a consequent increase in immune biomarkers. Thus, following the encouraging results reached by immune checkpoint inhibitors (ICIs) in both metastatic and localized disease, CRT and ICIs combination treatment gained momentum as bladder-sparing option and several clinical trials were recently launched both as concurrent and sequential treatments. A narrative review of the literature was performed to summarize the rationale and clinical outcomes of trials testing CRT and ICIs combination. Promising results were recently released mainly from phase II trials reporting clinal complete response rates from 48% to 83%. Moreover, combination treatment, both as concurrent and sequential schedules, appeared to be quite tolerable. However, interpretation of preliminary findings is made difficult due to the heterogeneity of clinical endpoints among trials, patient population included and different measurement of response to treatment. Novel bladder-sparing strategies are finally gaining momentum in bladder cancer treatment. Despite preliminary findings are encouraging, harmonization of terminology and definition of clinical endpoints among trials will be mandatory to correctly assess the potential role of CRT and immunotherapy combination as bladder-sparing solution in routine clinical practice.

A practical approach to bladder preservation with hypofractionated radiotherapy for localised muscle-invasive bladder cancer

Bladder preservation with trimodality treatment (TMT) is an alternative strategy to radical cystectomy (RC) for the management of localised muscle invasive bladder cancer (MIBC). TMT comprises of transurethral resection of the bladder tumour (TURBT) followed by radiotherapy with concurrent radiosensitisation. TMT studies have shown neo-adjuvant chemotherapy with cisplatin-based regimens is often given to further improve survival outcomes. A hypofractionated radiotherapy regimen is preferable due to its non-inferiority in local control and late toxicities. Radiosensitisation can comprise concurrent chemotherapy (with gemcitabine, cisplatin or combination fluorouracil and mitomycin), CON (carbogen and nicotinomide) or hyperthermic treatment. Radiotherapy techniques are continuously improving and becoming more personalised. As the bladder is a mobile structure subject to volumetric changes from filling, an adaptive approach can optimise bladder coverage and reduce dose to normal tissue. Adaptive radiotherapy (ART) is an evolving field that aims to overcome this. Improved knowledge of tumour biology and advances in imaging techniques aims to further optimise and personalise treatment.

Image-guided Adaptive Radiotherapy for Bladder Cancer

Technological advancement has facilitated patient-specific radiotherapy in bladder cancer. This has been made possible by developments in image-guided radiotherapy (IGRT). Particularly transformative has been the integration of volumetric imaging into the workflow. The ability to visualise the bladder target using cone beam computed tomography and magnetic resonance imaging initially assisted with determining the magnitude of inter- and intra-fraction target change. It has led to greater confidence in ascertaining true anatomy at each fraction. The increased certainty of dose delivered to the bladder has permitted the safe reduction of planning target volume margins. IGRT has therefore improved target coverage with a reduction in integral dose to the surrounding tissue. Use of IGRT to feed back into plan and dose delivery optimisation according to the anatomy of the day has enabled adaptive radiotherapy bladder solutions. Here we undertake a review of the stepwise developments underpinning IGRT and adaptive radiotherapy strategies for external beam bladder cancer radiotherapy. We present the evidence in accordance with the framework for systematic clinical evaluation of technical innovations in radiation oncology (R-IDEAL).

Current State of Personalized Genitourinary Cancer Radiotherapy in the Era of Precision Medicine

Radiation therapy plays a crucial role for the management of genitourinary malignancies, with technological advancements that have led to improvements in outcomes and decrease in treatment toxicities. However, better risk-stratification and identification of patients for appropriate treatments is necessary. Recent advancements in imaging and novel genomic techniques can provide additional individualized tumor and patient information to further inform and guide treatment decisions for genitourinary cancer patients. In addition, the development and use of targeted molecular therapies based on tumor biology can result in individualized treatment recommendations. In this review, we discuss the advances in precision oncology techniques along with current applications for personalized genitourinary cancer management. We also highlight the opportunities and challenges when applying precision medicine principles to the field of radiation oncology. The identification, development and validation of biomarkers has the potential to personalize radiation therapy for genitourinary malignancies so that we may improve treatment outcomes, decrease radiation-specific toxicities, and lead to better long-term quality of life for GU cancer survivors.

Radiotherapy in the Era of Immunotherapy With a Focus on Non-Small-Cell Lung Cancer: Time to Revisit Ancient Dogmas?

Radiation-induced immune effects have been extensively deciphered over the last few years, leading to the concept of the dual immune effect of radiotherapy with both immunostimulatory and immunosuppressive effects. This explains why radiotherapy alone is not able to drive a strong anti-tumor immune response in most cases, hence underlining the rationale for combining both radiotherapy and immunotherapy. This association has generated considerable interest and hundreds of trials are currently ongoing to assess such an association in oncology. However, while some trials have provided unprecedented results or shown much promise, many hopes have been dashed. Questions remain, therefore, as to how to optimize the combination of these treatment modalities. This narrative review aims at revisiting the old, well-established concepts of radiotherapy relating to dose, fractionation, target volumes and organs at risk in the era of immunotherapy. We then propose potential innovative approaches to be further assessed when considering a radio-immunotherapy association, especially in the field of non-small-cell lung cancer (NSCLC). We finally propose a framework to optimize the association, with pragmatic approaches depending on the stage of the disease.

Is There a Benefit of Combining Immunotherapy and Radiotherapy in Bladder Cancer?

Immune checkpoint inhibitors have transformed the management of patients with metastatic urothelial cancer, by leading to long-term response and prolongation of survival in a subset of patients. Unfortunately, only one in five patients with metastatic urothelial cancer responds to anti-programmed death ligand-1 ([AQ1]anti-PD-1) monotherapy. Preclinical and early clinical evidence indicates that radiotherapy not only acts locally, but also exerts systemic anti-tumour effects by modulating the immune system. It is hypothesised that combining checkpoint inhibitors with radiotherapy might enhance an anti-tumour immune response and increase response rates. So far, a handful of early phase clinical trials have been performed seeking to answer this question in urothelial cancer patients. The current review summarises the available preclinical and clinical evidence on radiotherapy/immunotherapy combinations in locally advanced and metastatic bladder cancer and suggests future avenues worthy of exploration.