Bladder only Versus Standard Whole Pelvis Chemo-Irradiation In Clinically Node Negative Muscle Invasive Bladder Cancer
DOI:
https://doi.org/10.64149/J.Carcinog.24.2s.1167-1182Keywords:
Muscle-invasive bladder cancer, bladder-only radiotherapy, chemo-radiation, pelvic lymph nodes, toxicity, survival.Abstract
Background: Bladder-preserving chemo-radiation has become a viable substitute for radical cystectomy for individuals suffering from muscle-invasive bladder cancer (MIBC). But in clinically node-negative (cN0) patients, the necessity of elective pelvic nodal irradiation remains controversial. The incidental dose delivered to pelvic lymphatics during bladder-only radiotherapy (BORT) may be sufficient for microscopic nodal disease control, potentially reducing unnecessary toxicity. So, we aimed to determine the dose of radiotherapy received by pelvic lymph nodes in bladder only radiotherapy technique and to compare toxicity, pelvic nodal relapse, systemic relapse of BORT vs standard technique.
Methods: This prospective comparative study enrolled patients with cT2-T3N0M0 MIBC who were randomized into two arms: Arm A (WPRT) receiving standard whole-pelvis fields followed by bladder boost and Arm B (BORT) receiving bladder-only chemo-radiation. Both groups received concurrent cisplatin-based chemotherapy. Acute and late toxicities were graded according to CTCAE version 5. Nodal and systemic relapse rates were analyzed alongside overall survival (OS), and dosimetric parameters for pelvic lymph node regions.
Results: Both treatment arms achieved comparable complete response (CR) rates, with no statistically significant difference in regional control or OS. The mean dose received incidentally by external, internal, obturator, and presacral lymph nodes during BORT reached therapeutic thresholds (>30 Gy) in most patients. Acute gastrointestinal and hematologic toxicities were significantly lower in the BORT group. No increase in nodal relapse was observed with bladder-only irradiation.
Conclusion: Bladder-only chemo-radiation provides equivalent tumor control and survival outcomes compared to whole-pelvis fields in cN0 MIBC while significantly reducing toxicity. Incidental nodal dose coverage during bladder-only irradiation may be sufficient to eradicate microscopic nodal disease, supporting its role as a safe and effective bladder-preserving strategy.
