Hypofractionated boost with high-dose-rate brachytherapy and open magnetic resonance imaging-guided implants for locally aggressive prostate cancer: a sequential dose-escalation pilot study.
OBJECTIVE
To evaluate the feasibility, tolerance, and preliminary outcome of an open MRI-guided prostate partial-volume high-dose-rate brachytherapy (HDR-BT) schedule in a group of selected patients with nonmetastatic, locally aggressive prostatic tumors.


METHODS
After conventional fractionated three-dimensional conformal external radiotherapy to 64-64.4 Gy, 77 patients with nonmetastatic, locally aggressive (e.g., perineural invasion and/or Gleason score 8-10) prostate cancer were treated from June 2000 to August 2004, with HDR-BT using temporary open MRI-guided (192)Ir implants, to escalate the dose in the boost region. Nineteen, 21, and 37 patients were sequentially treated with 2 fractions of 6 Gy, 7 Gy, and 8 Gy each, respectively. Neoadjuvant androgen deprivation was given to 62 patients for 6-24 months. Acute and late toxicity were scored according to the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer scoring system.


RESULTS
All 77 patients completed treatment as planned. Only 2 patients presented with Grade > or =3 acute urinary toxicity. The 3-year probability of Grade > or =2 late urinary and low gastrointestinal toxicity-free survival was 91.4% +/- 3.4% and 94.4% +/- 2.7%, respectively. Rates of 3-year biochemical disease-free survival (bDFS) and disease-specific survival were 87.1% +/- 4.1% and 100%, respectively.


CONCLUSIONS
Boosting a partial volume of the prostate with hypofractionated HDR-BT for aggressive prostate cancer was feasible and showed limited long-term toxicity, which compared favorably with other dose-escalation methods in the literature. Preliminary bDFS was encouraging if one considers the negatively selected population of high-risk patients in this study.
Ares
Carmen
C
Department of Radiation Oncology, University Hospital of Geneva, Geneva, Switzerland.
Popowski
Youri
Y
Pampallona
Sandro
S
Nouet
Philippe
P
Dipasquale
Giovanna
G
Bieri
Sabine
S
Ozsoy
Orhan
O
Rouzaud
Michel
M
Khan
Haleem
H
Miralbell
Raymond
R
D000368:Aged; D000726:Androgen Antagonists / Q000627:therapeutic use; D001918:Brachytherapy / Q000009:adverse effects / Q000379:methods*; D018572:Disease-Free Survival; D019583:Dose Fractionation, Radiation; D005240:Feasibility Studies; D006801:Humans; D007496:Iridium Radioisotopes / Q000627:therapeutic use; D053783:Magnetic Resonance Imaging, Interventional; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy / Q000379:methods; D009361:Neoplasm Invasiveness; D010865:Pilot Projects; D011467:Prostate / Q000473:pathology; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy*; D020266:Radiotherapy, Conformal; D014555:Urination Disorders / Q000209:etiology
D000726:Androgen Antagonists; D007496:Iridium Radioisotopes; D017430:Prostate-Specific Antigen