Definitive radiotherapy in bladder cancer

Abstract

Bladder cancer is the most common cancer among urinary tract cancers; urothelial carcinoma accounts for 90% of the cases. The presence of muscle invasion in the specimen is a significant factor that worsens the prognosis and leads to radical changes in treatment. The management of non-metastatic disease is divided into two main groups: non-muscle invasive bladder cancer (NMIBC) and musle invazive baldder cancer (MIBC). The aim of this review is to provide information about the role, technique, dose-fractionation regimens, and toxicity of definitive radiotherapy in non-metastatic localized bladder cancer. Evaluating studies related to definitive radiotherapy in NMIBC suggests that there are potential benefits; however, the literature does not provide clear information regarding the role of radiotherapy. In MIBC patients, the radiotherapy regimen administered simultaneously with radiosensitizing chemotherapy following maximal transurethral resection is referred to as trimodal therapy (TMT). The role of definitive radiotherapy in the MIBC group is clearer. Although there is no randomized study directly comparing TMT with radical cystectomy, TMT applied after careful patient selection has emerged as an effective treatment method that provides treatment success comparable to radical cystectomy. Adding concurrent chemotherapy to curative radiotherapy increases disease control rates. The most commonly used and currently recommended first-line agent in concurrent therapy is cisplatin. Conventional fractionation, hypofractionation, or accelerated hyperfractionation treatments may be preferred. The most commonly used conventional fractionation regimen is 45-46 Gy to the pelvis at 1.8-2 Gy daily, followed by 63-66 Gy to the bladder with a concomitant boost. The inclusion of pelvic lymph nodes in curative radiotherapy remains a controversial topic. The use of intensity-modulated radiotherapy provides dosimetric advantages over three-dimensional conformal radiotherapy and leads to a decrease in side effects. Follow-up after TMT is crucial for the early detection of local and distant recurrences and for monitoring treatment-related toxicity.