Radiotherapy for muscle-invasive carcinoma of the bladder: results of a randomized trial comparing conventional whole bladder with dose-escalated partial bladder radiotherapy.
OBJECTIVE
To investigate whether delivering an increased radiation dose to the tumor-bearing region of the bladder alone would improve local disease control without increasing treatment toxicity.


METHODS
A total of 149 patients with unifocal T2-T3N0M0 bladder carcinoma were randomized between whole bladder conformal radiotherapy (WBRT, 52.5 Gy in 20 fractions, n = 60) and partial bladder conformal RT (PBRT) to tumor alone with 1.5-cm margins within either 4 weeks (PBRT4, 57.5 Gy in 20 fractions, n = 44) or 3 weeks (PBRT3, 55 Gy in 16 fractions, n = 45). The response was assessed cystoscopically after 4 months.


RESULTS
The 5-year overall and CFS rate was 58% and 47%, respectively, for the whole population. The CR rate was 75% for WBRT, 80% for PBRT4, and 71% for PBRT3 (p = 0.6), with a 5-year local control rate of 58%, 59%, and 34%, respectively (p = 0.18). Solitary new tumors arose within the bladder, outside the irradiated volume, in 6 (7%) of 89 patients who underwent PBRT. The 5-year overall survival and cystectomy-free survival rate was 61% and 49% for WBRT, 60% and 50% for PBRT4, and 51% and 41% for PBRT3 (p = 0.81 and p = 0.59). The treatment toxicity was mild and equivalent across the three trial arms.


CONCLUSIONS
The reduction in treatment volume allowed delivery of an increased radiation dose without a reduction in local tumor control or the development of excess toxicity. However, this dose-escalated partial bladder approach did not result in significantly improved overall survival.
Cowan
Richard A
RA
Department of Clinical Oncology, Christie Hospital NHS Trust, Manchester, United Kingdom. richard.cowan@christie-tr.nwest.nhs.uk
McBain
Catherine A
CA
Ryder
W David J
WD
Wylie
James P
JP
Logue
John P
JP
Turner
Sandra L
SL
Van der Voet
Johannes
J
Collins
Conor D
CD
Khoo
Vincent S
VS
Read
Graham R
GR
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D002295:Carcinoma, Transitional Cell / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D003558:Cystoscopy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000401:mortality / Q000601:surgery; D009367:Neoplasm Staging; D011446:Prospective Studies; D011832:Radiation Injuries / Q000145:classification; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000379:methods*; D012074:Remission Induction; D016879:Salvage Therapy; D001749:Urinary Bladder Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*