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

Evidence-based clinical recommendations for hypofractionated radiotherapy: exploring efficacy and safety - Part 3. Genitourinary and gynecological cancers

Hypofractionated radiotherapy (RT) has become a trend in the modern era, as advances in RT techniques, including intensity-modulated RT and image-guided RT, enable the precise and safe delivery of high-dose radiation. Hypofractionated RT offers convenience and can reduce the financial burden on patients by decreasing the number of fractions. Furthermore, hypofractionated RT is potentially more beneficial for tumors with a low α/β ratio compared with conventional fractionation RT. Therefore, hypofractionated RT has been investigated for various primary cancers and has gained status as a standard treatment recommended in the guidelines. In genitourinary (GU) cancer, especially prostate cancer, the efficacy, and safety of various hypofractionated dose schemes have been evaluated in numerous prospective clinical studies, establishing the standard hypofractionated RT regimen. Hypofractionated RT has also been explored for gynecological (GY) cancer, yielding relevant evidence in recent years. In this review, we aimed to summarize the representative evidence and current trends in clinical studies on hypofractionated RT for GU and GY cancers addressing several key questions. In addition, the objective is to offer suggestions for the available dose regimens for hypofractionated RT by reviewing protocols from previous clinical studies.

Long-term Outcomes of Chemoradiation for Muscle-invasive Bladder Cancer in Noncystectomy Candidates. Final Results of NRG Oncology RTOG 0524-A Phase 1/2 Trial of Paclitaxel + Trastuzumab with Daily Radiation or Paclitaxel Alone with Daily Irradiation

BACKGROUND

Chemo-radiation is a well-established alternative to radical cystectomy in patients with muscle-invasive bladder cancer. Many patients due to age or medical comorbidity are unfit for either radical cystectomy, or standard cisplatin- or 5-fluorouracil-based chemoradiation, and do not receive appropriate treatment with curative intent. We treated patients with a less aggressive protocol employing seven weekly doses of paclitaxel and daily irradiation. In those whose tumors showed overexpression of her2/neu, seven weekly doses of trastuzumab were also administered.

OBJECTIVE

To report the long-term survival outcomes and toxicity results of the of NRG Oncology RTOG 0524 study.

DESIGN, SETTING, AND PARTICIPANTS

Seventy patients were enrolled and 65 (median age: 76 yr) were deemed eligible. Patients were assigned to daily radiation and weekly paclitaxel + trastuzumab (group 1, 20 patients) or to daily radiation plus weekly paclitaxel (group 2, 45 patients) based on tumor her2/neu overexpression. Radiation was delivered in 1.8 Gy fractions to a total dose of 64.8 Gy.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary endpoint was unresolved treatment-related toxicity. The secondary endpoints were complete response rate, protocol completion rate, and disease-free and overall survival.

RESULTS AND LIMITATIONS

Protocol therapy was completed by 60% (group 1) and 76% (group 2); complete response rates at 12 wk were 62% in each group. Acute treatment-related adverse events (AEs) of grade ≥3 were observed in 80% in group 1 and 58% in group 2. There was one treatment-related grade 5 AE in group 1. Unresolved acute treatment-related toxicity was 35% in group 1 and 31% in group 2. The median follow-up was 2.3 yr in all patients and 7.2 yr in surviving patients. Overall survival at 5 yr was 25.0% in group 1 and 37.8% in group 2 (33.8% overall). At 5 yr, disease-free survival was 15.0% in group 1 and 31.1% in group 2.

CONCLUSIONS

In a cohort of patients with muscle-invasive bladder cancer who are not candidates for cystectomy or cisplatin chemotherapy, chemoradiation therapy offers a treatment with a significant response rate and 34% 5-yr overall survival. While there were many AEs in this medically fragile group, there were few grade 4 events and one grade 5 event attributable to therapy.

PATIENT SUMMARY

Patients with invasive bladder cancer who cannot tolerate surgery were treated with radiation and systemic therapy without surgically removing their bladders. Most patients tolerated the treatment, were able to keep their bladders, and showed a significant treatment response rate.

[Bladder preservation treatments for bladder cancer: Trimodality therapy, an overview of clinical practices in 2023]

Bladder cancer is the most frequent tumor of the urinary tract. Patients diagnosed at a stage when the tumor has spread into or through the muscle layer of the bladder wall are usually treated with cystectomy. The evolution of cancer treatments, related to the development of alternative treatment options to the historical surgical standard and to the implication of the patient as an actor in decision-making, trends towards organ and function preservation without sacrificing efficacy. Trimodality therapy, which is a maximal transurethral resection of the tumor followed by concurrent chemoradiation, is an interesting therapeutic alternative for patients unfit for surgery and for those wishing to benefit from organ preservation. Radiotherapy offers excellent treatment possibilities for muscle-invasive bladder cancer. In selected T2-stage patients fit for trimodality therapy, it has an equivalent oncological outcome compared to cystectomy while having less severe complications and offering organ preservation. It remains feasible in inoperable patients while offering significant perspectives of relapse-free survival. Finally, it also is an efficient palliative treatment in patients where mid-term local control and hemostasis are sought after.

Approaches to Clinical Complete Response after Neoadjuvant Chemotherapy in Muscle-Invasive Bladder Cancer: Possibilities and Limitations

In the surgical oncology field, the change from a past radical surgery to an organ preserving surgery is a big trend. In muscle-invasive bladder cancer treatment, neoadjuvant chemotherapy (NAC) followed by radical cystectomy (RC) is the standard of care for muscle-invasive bladder cancer (MIBC) patients eligible for cisplatin. There is a growing interest in bladder preserving strategies after NAC because good oncologic outcome has been reported for pathologic complete response (pCR) patients after NAC, and many studies have continued to discuss whether bladder preservation treatment is possible for these patients. However, in actual clinical practice, decision-making should be determined according to clinical staging and there is a gap that cannot be ignored between clinical complete response (cCR) and pCR. Currently, there is a lack in a uniform approach to post-NAC restaging of MIBC and a standardized cCR definition. In this review, we clarify the gap between cCR and pCR at the current situation and focus on emerging strategies in bladder preservation in selected patients with MIBC who achieve cCR following NAC.

French AFU Cancer Committee Guidelines - Update 2022-2024: Muscle-Invasive Bladder Cancer (MIBC)

OBJECTIVE

To update the CCAFU recommendations for the management of muscle invasive bladder carcinoma (MIBC).

METHODS

A systematic review (Medline) of the literature from 2020 to 2022 was performed taking account of the diagnosis, treatment options and surveillance of NMIBC and MIBC, while evaluating the references with their levels of evidence.

RESULTS

MIBC is diagnosed after the most complete tumour resection possible. MIBC grading is based on CTU along with chest CT. Multiparametric pelvic MRI could be an alternative. Cystectomy with extensive lymphadenectomy is the gold standard treatment for non-metastatic MIBC. It should be preceded by platinum-based neoadjuvant chemotherapy in patients in good general health with satisfactory renal function. Enterocystoplasty is proposed in men and women in the absence of contraindications and when the urethral resection is negative on extemporaneous examination. Otherwise, transileal cutaneous ureterostomy is the recommended method of urinary diversion. Inclusion of all patients in an ERAS (Enhanced Recovery After Surgery) protocol is recommended. For metastatic MIBC, first line treatment with platinum-based chemotherapy (GC or MVAC) is recommended, if general health (PS>1) and renal function (clearance>60mL/min) so allow (only 50% of the cases). Pembrolizumab immunotherapy has demonstrated an overall survival benefit in second-line treatment.

CONCLUSION

Updating the ccAFU recommendations should contribute to improving patient management, as well as the diagnosis and decision-making concerning MIBC treatment.

Optimized Adaptive Radiotherapy with Individualized Plan Library for Muscle-Invasive Bladder Cancer Using Internal Target Volume Generation

Simple Summary

The bladder is a mobile target and is subject to filling variation. This poses a considerable challenge for effective radiotherapy (RT) delivery. We applied an internal target volume to the plan library to resolve intra-fractional errors caused by bladder filling during treatment. Adaptive radiotherapy using ITV is easy to perform and a feasible treatment approach. In this study, image-guided RT-based adaptive RT showed good survival outcomes with a high local control rate.

Abstract

The bladder is subject to filling variation, which poses a challenge to radiotherapy (RT) delivery. We aimed to assess feasibility and clinical outcomes in patients with bladder cancer treated with adaptive RT (ART) using individualized plan libraries. We retrospectively analyzed 19 patients who underwent RT for muscle-invasive bladder cancer (MIBC) in 2015–2021. Four planning computed tomography (CT) scans were acquired at 15-min intervals, and a library of three intensity-modulated RT plans were generated using internal target volumes (ITVs). A post-treatment cone-beam CT (CBCT) scan was acquired daily to assess intra-fraction filling and coverage. All patients completed the treatment, with 408 post-treatment CBCT scans. The bladder was out of the planning target volume (PTV) range in 12 scans. The volumes of the evaluated PTV plans were significantly smaller than those of conventional PTV. The 1-year and 2-year overall survival rates were 88.2% and 63.7%, respectively. Of eight cases that experienced recurrence, only two developed MIBC. There were no grade 3 or higher RT-related adverse events. ART using plan libraries and ITVs demonstrated good survival outcomes with a high local control rate. Irradiated normal tissue volume and treatment margins may be reduced through this approach, potentially resulting in lower toxicity rates.

[Bladder-sparing trimodal therapy for muscle invasive bladder cancer]

Organ-sparing strategies in the management of local or locally advanced cancers meet a dual objective: tumor control and preservation of the function of the involved organ. Given the morbidity and mortality of cystectomy and its impact on quality of life and bladder function, bladder-sparing strategies have emerged for the management of urothelial muscle invasive bladder cancer, mostly through trimodal treatment, which consists in maximal trans-urethral resection of bladder tumor, followed by chemo-radiotherapy. This review presents the modalities of trimodal treatment, before exposing the advantages and limitations of this strategy compared to cystectomy among operable patients. Despite the absence of comparative data from randomized trials, the two approaches seem to provide similar oncological results among appropriately selected patients. In modern series, the rate of salvage cystectomy is approximately 15% at 5 years; this delayed cystectomy does not seem to be associated with greater morbidity and mortality as compared to upfront cystectomy. Emphasis is placed in the review on quality of life data of these two approaches. In order to optimize the selection of patients eligible to trimodal therapy, the classical predictive factors of response to radio(chemo)therapy are critically analyzed, with the perspective of innovative molecular biomarkers. Finally, a close multidisciplinary collaboration is needed for the choice and the execution of the therapeutic strategy, and the patient should be fully involved in the decision-making process.