title: A pilot study of intensity modulated radiation therapy with hypofractionated stereotactic body radiation therapy (SBRT) boost in the treatment of intermediate- to high-risk prostate cancer.
abstract: Clinical data suggest that large radiation fractions are biologically superior to smaller fraction sizes in prostate cancer radiotherapy. The CyberKnife is an appealing delivery system for hypofractionated radiosurgery due to its ability to deliver highly conformal radiation and to track and adjust for prostate motion in real-time. We report our early experience using the CyberKnife to deliver a hypofractionated stereotactic body radiation therapy (SBRT) boost to patients with intermediate- to high-risk prostate cancer. Twenty-four patients were treated with hypofractionated SBRT and supplemental external radiation therapy plus or minus androgen deprivation therapy (ADT). Patients were treated with SBRT to a dose of 19.5 Gy in 3 fractions followed by intensity modulated radiation therapy (IMRT) to a dose of 50.4 Gy in 28 fractions. Quality of life data were collected with American Urological Association (AUA) symptom score and Expanded Prostate Cancer Index Composite (EPIC) questionnaires before and after treatment. PSA responses were monitored; acute urinary and rectal toxicities were assessed using Common Toxicity Criteria (CTC) v3. All 24 patients completed the planned treatment with an average follow-up of 9.3 months. For patients who did not receive ADT, the median pre-treatment PSA was 10.6 ng/ml and decreased in all patients to a median of 1.5 ng/ml by 6 months post-treatment. Acute effects associated with treatment included Grade 2 urinary and gastrointestinal toxicity but no patient experienced acute Grade 3 or greater toxicity. AUA and EPIC scores returned to baseline by six months post-treatment. Hypofractionated SBRT combined with IMRT offers radiobiological benefits of a large fraction boost for dose escalation and is a well tolerated treatment option for men with intermediate- to high-risk prostate cancer. Early results are encouraging with biochemical response and acceptable toxicity. These data provide a basis for the design of a phase II clinical trial.
authors.affiliation: Department of Radiation Medicine, Georgetown University Hospital, Washington, DC, USA.
authors.forename: Eric K
authors.initials: EK
authors.lastname: Oermann
authors.forename: Rebecca S
authors.initials: RS
authors.lastname: Slack
authors.forename: Heather N
authors.initials: HN
authors.lastname: Hanscom
authors.forename: Sue
authors.initials: S
authors.lastname: Lei
authors.forename: Simeng
authors.initials: S
authors.lastname: Suy
authors.forename: Hyeon U
authors.initials: HU
authors.lastname: Park
authors.forename: Joy S
authors.initials: JS
authors.lastname: Kim
authors.forename: Benjamin A
authors.initials: BA
authors.lastname: Sherer
authors.forename: Brian T
authors.initials: BT
authors.lastname: Collins
authors.forename: Andrew N
authors.initials: AN
authors.lastname: Satinsky
authors.forename: K William
authors.initials: KW
authors.lastname: Harter
authors.forename: Gerald P
authors.initials: GP
authors.lastname: Batipps
authors.forename: Nicholas L
authors.initials: NL
authors.lastname: Constantinople
authors.forename: Stephen W
authors.initials: SW
authors.lastname: Dejter
authors.forename: William C
authors.initials: WC
authors.lastname: Maxted
authors.forename: James B
authors.initials: JB
authors.lastname: Regan
authors.forename: John J
authors.initials: JJ
authors.lastname: Pahira
authors.forename: Kevin G
authors.initials: KG
authors.lastname: McGeagh
authors.forename: Reena C
authors.initials: RC
authors.lastname: Jha
authors.forename: Nancy A
authors.initials: NA
authors.lastname: Dawson
authors.forename: Anatoly
authors.initials: A
authors.lastname: Dritschilo
authors.forename: John H
authors.initials: JH
authors.lastname: Lynch
authors.forename: Sean P
authors.initials: SP
authors.lastname: Collins
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003131:Combined Modality Therapy; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011471:Prostatic Neoplasms / Q000628:therapy*; D016634:Radiosurgery / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*