A Phase 1/2 Trial of Brief Androgen Suppression and Stereotactic Radiation Therapy (FASTR) for High-Risk Prostate Cancer.
OBJECTIVE
To initiate a phase 1/2 trial to examine the tolerability of a condensed combined-modality protocol for high-risk prostate cancer.


METHODS
Men scoring ≥3 on the Vulnerable Elderly Scale (VES) or refusing conventionally fractionated treatment for high-risk prostate cancer were eligible to participate. Androgen suppression was delivered for 12 months, and radiation therapy was delivered using 25 Gy to pelvic nodes delivered synchronously with 40 Gy to the prostate given as 1 fraction per week over 5 weeks. The phase 1 component included predetermined stopping rules based on 6-month treatment-related toxicity, with trial suspension specified if there were ≥6 of 15 patients (40%) or ≥3 of 15 (20%) who experienced grade ≥2 or ≥3 gastrointestinal (GI) or genitourinary (GU) toxicity, respectively.


RESULTS
Sixteen men were enrolled, with 7 men meeting the criteria of VES ≥3 and 9 men having a VES <3 but choosing the condensed treatment. One man was not treated owing to discovery of a synchronous primary rectal cancer. Four patients (26%) experienced grade ≥2 toxicity at 6 weeks after treatment. There were 9 of 15 (60%) who experienced grade ≥2 GI or GU toxicity and 4 of 15 (26%) grade ≥3 GI or GU toxicity at 6 months, and 5 of 15 (30%) grade ≥2 GI and GU toxicity at 6 months. A review of the 15 cases did not identify any remedial changes, thus the phase 1 criteria were not met.


CONCLUSIONS
This novel condensed treatment had higher than anticipated late toxicities and was terminated before phase 2 accrual. Treatment factors, such as inclusion of pelvic lymph node radiation therapy, planning constraints, and treatment margins, or patient factors related to the specific frail elderly population may be contributing.
Division of Radiation Oncology, Department of Oncology, Western University and London Regional Cancer Program, London, Ontario, Canada. Electronic address: Glenn.bauman@lhsc.on.ca.
Glenn
G
Bauman
Department of Radiation Oncology, Allan Blair Cancer Centre, Regina, Saskatchewan, Canada.
Michelle
M
Ferguson
Division of Radiation Oncology, Department of Oncology, Western University and London Regional Cancer Program, London, Ontario, Canada.
Michael
M
Lock
Division of Radiation Oncology, Department of Oncology, Western University and London Regional Cancer Program, London, Ontario, Canada.
Jeff
J
Chen
Division of Radiation Oncology, Department of Oncology, Western University and London Regional Cancer Program, London, Ontario, Canada.
Belal
B
Ahmad
Division of Radiation Oncology, Department of Oncology, Western University and London Regional Cancer Program, London, Ontario, Canada.
V M
VM
Venkatesan
Division of Radiation Oncology, Department of Oncology, Western University and London Regional Cancer Program, London, Ontario, Canada.
Tracy
T
Sexton
Division of Radiation Oncology, Department of Oncology, Western University and London Regional Cancer Program, London, Ontario, Canada.
David
D
D'Souza
Department of Radiation Medicine, University of Toronto and Odette Cancer Center, Toronto, Ontario, Canada.
Andrew
A
Loblaw
Division of Radiation Oncology, Department of Oncology, Western University and London Regional Cancer Program, London, Ontario, Canada.
Andrew
A
Warner
Division of Radiation Oncology, Department of Oncology, Western University and London Regional Cancer Program, London, Ontario, Canada.
George
G
Rodrigues
D000368:Aged; D000369:Aged, 80 and over; D000726:Androgen Antagonists / Q000627:therapeutic use*; D003131:Combined Modality Therapy / Q000379:methods; D019583:Dose Fractionation, Radiation; D007987:Gonadotropin-Releasing Hormone / Q000819:agonists*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000188:drug therapy* / Q000601:surgery*; D016634:Radiosurgery
D000726:Androgen Antagonists; D007987:Gonadotropin-Releasing Hormone