Radiotherapy Intensified by Increase of Fraction Size Using Three-Dimensional Conformal Radiotherapy in Bladder Preservation Therapy

Abstract

Purpose: The impact of radiotherapy on bladder cancers heightened by increase of fraction size using three-dimensional conformal radiotherapy (3DCRT) was verified with biologically effective dose (BED, Gy10). Method: Twenty-five patients who were considered unsuitable for total cystectomy underwent 3DCRT between 2009 and 2014. When a gross tumor volume (GTV) did not neighbor guts and the patient was cooperative to radiotherapy (radical), the GTV was treated with a fraction size of ≥3.0 Gy, while a clinical target volume (CTV) of a whole bladder and lymph nodes at small pelvis were treated with a conventional fraction size of 2.0 Gy. When a GTV neighbored guts (palliative), only a CTV was treated with an increased fraction size of 2.5 Gy. Results: Compared to conventional two-dimensional radiotherapy, BED increased to 62.3 - 77.0 Gy10 (radical) or to 56.1 - 68.0 Gy10 (palliative) but the treatment period shortened to 4 - 5 weeks. Acute adverse events (≤3 months), determined by common terminology criteria for adverse events, were Grade 2 at most, but late adverse events were not observed. Only one patient (6%) lost the bladder. Conclusions: Patients who receive bladder preservation therapy appear good candidates to intensify impact of radiotherapy with 3DCRT.