Toxicity and early treatment outcomes in low- and intermediate-risk prostate cancer managed by high-dose-rate brachytherapy as a monotherapy.
OBJECTIVE
To determine the acute and late genitourinary (GU) and gastrointestinal (GI) toxicity and present short-term biochemical no evidence of disease (bNED) rates after high-dose-rate brachytherapy (HDR-B) monotherapy.


METHODS
Between October 2003 and June 2006, 36 patients with low (28) and intermediate (8) risk prostate cancer (PCA) were treated by HDR-B monotherapy. All patients received one implant and four fractions of 9.5Gy within 48h for a total prescribed dose (PD) of 38Gy. Five patients received hormonal therapy (HT). Median age was 63.5 years and median followup was 3 years (range, 0.4-4 years). Toxicity was scored according to the CTCAE version 3.0. Biochemical failure was defined according to the Phoenix criteria.


RESULTS
Acute and late Grade 3 GU toxicity was observed in 1 (3%) and 4 (11%) patients, respectively. Grade 3 GI toxicity was absent. The three- year bNED survival rate was 100%. The sexual preservation rate in patients without HT was 75%. Late Grade 3 GU toxicity was associated with the planning target volume (PTV) V(100) (% PTV receiving > or =100% of the PD; p=0.036), D(90) (dose delivered to 90% of the PTV; p=0.02), and the urethral V(120) (urethral volume receiving > or =120% of the PD; p=0.043). The urethral V(120) was associated with increased PTV V(100) (p<0.001) and D(90) (p=0.003).


CONCLUSIONS
After HDR-B monotherapy, late Grade 3 GU toxicity is associated with the urethral V(120) and the V(100) and D(90) of the PTV. Decrease of the irradiated urethral volume may reduce the GU toxicity and potentially improve the therapeutic ratio of this treatment.
Ghadjar
Pirus
P
Department of Radiation Oncology, University of Bern, Inselspital, Bern, Switzerland.
Keller
Tamara
T
Rentsch
Cyrill A
CA
Isaak
Bernhard
B
Behrensmeier
Frank
F
Stroux
Andrea
A
Thalmann
George N
GN
Aebersold
Daniel M
DM
D000230:Adenocarcinoma / Q000532:radiotherapy*; D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000009:adverse effects* / Q000379:methods; D018572:Disease-Free Survival; D004307:Dose-Response Relationship, Radiation; D005500:Follow-Up Studies; D006801:Humans; D007496:Iridium Radioisotopes / Q000008:administration & dosage / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D014521:Urethra / Q000528:radiation effects*
D007496:Iridium Radioisotopes