The goal of this clinical trial is to improve the quality of life and prolong survival in bladder cancer patients unfit for curative treatment. The trial will compare the survival and symptoms of patients randomized to either local radiotherapy in addition to standard of care or standard of care alone.

Using modern radiotherapy techniques, including hypofractionation and image-guided treatment adaptation, the aim is to deliver a well-tolerated, time-efficient, and effective treatment strategy for these patients.

The trial collaborates with two ongoing exploratory biomarker studies collecting and analyzing potential biomarkers in urothelial bladder cancer. The hope is to provide biomarkers for prognosis and treatment response which is essential to ensure bladder cancer patients individualized treatment in the future, like those with breast and prostate cancer.

Around 700 individuals in Sweden are diagnosed each year with muscle-invasive bladder cancer (MIBC), and a similar number die annually from the disease (SVF RCC 2023). With a median age at diagnosis approaching 76 years (Swedish National Quality Registry for Urothelial Carcinoma), the incidence is expected to rise as the population ages.

Due to advanced age and comorbidity, many patients are not eligible for the demanding multimodal treatments used with curative intent. Recently introduced systemic therapies for palliation, such as antibody-drug conjugates and immunotherapy, also require a WHO performance status <2 and regular hospital-based administration. Consequently, up to 30% of patients receive no tumor-directed therapy at diagnosis (Swedish National Quality Registry for Urothelial Carcinoma).

Without treatment, MIBC often progresses rapidly, with a median overall survival of approximately 12 months in this cohort. Symptom burden is substantial, commonly involving pain, bleeding, and urinary tract obstruction, which frequently require repeated hospital admissions late in the disease trajectory.

Radiation therapy (RT) is an established curative modality in bladder cancer and is well documented for symptom palliation. In other malignancies, such as prostate cancer, limited radiation doses have been shown to prolong survival and reduce the development of distressing symptoms. Although some studies indicate similar benefits in bladder cancer, a clear survival effect has not been demonstrated, representing an important knowledge gap in the management of a common cancer type.

The LORUP project builds on existing translational research infrastructures to address this gap. Its aim is to develop a treatment strategy for MIBC patients unfit for curative therapy, focused on improving quality of life by reducing symptom burden and potentially prolonging survival, while maintaining a low treatment burden and minimal side effects.

Inclusion Criteria:

1. Oral and written consent
2. Histologically confirmed MIBC with urothelial component
3. Male or female participants ≥ 18 years old
4. Deemed not to benefit from curative treatment at a multidisciplinary tumour conference (MDT) or having declined curative treatment of their own accord.

Exclusion Criteria:

1. Clinical Fragility Scale score ≥8
2. Previous pelvic RT with significant overlap
3. Visceral or bone metastases on CT scan
4. Multiple (>3) lymph node metastases with a measurement of >2 cm on CT scan
5. Planed for systemic treatment at the time of inclusion.
6. Local RT to the bladder indicated for the palliation of symptoms at the time of inclusion.

Individual participant data (IPD) will not be shared because the study collects sensitive health information and no compliant, consented mechanism for sharing individual-level data has been established for this randomized controlled trial.