Toxicity assessment of pelvic intensity-modulated radiotherapy with hypofractionated simultaneous integrated boost to prostate for intermediate- and high-risk prostate cancer.
OBJECTIVE
To evaluate the toxicity of pelvic intensity-modulated radiotherapy (IMRT) with hypofractionated simultaneous integrated boost (SIB) to the prostate for patients with intermediate- to high-risk prostate cancer.


METHODS
A retrospective toxicity analysis was performed in 30 consecutive patients treated definitively with pelvic SIB-IMRT, all of whom also received androgen suppression. The IMRT plans were designed to deliver 70 Gy in 28 fractions (2.5 Gy/fraction) to the prostate while simultaneously delivering 50.4 Gy in 28 fractions (1.8 Gy/fraction) to the pelvic lymph nodes. The National Cancer Institute Common Terminology Criteria for Adverse Events, version 3.0, was used to score toxicity.


RESULTS
The most common acute Grade 2 events were cystitis (36.7%) and urinary frequency/urgency (26.7%). At a median follow-up of 24 months, late toxicity exceeding Grade 2 in severity was uncommon, with two Grade 3 events and one Grade 4 event. Grade 2 or greater acute bowel toxicity was associated with signficantly greater bowel volume receiving > or =25 Gy (p = .04); Grade 2 or greater late bowel toxicity was associated with a higher bowel maximal dose (p = .04) and volume receiving > or =50 Gy (p = .02). Acute or late bladder and rectal toxicity did not correlate with any of the dosimetric parameters examined.


CONCLUSIONS
Pelvic IMRT with SIB to the prostate was well tolerated in this series, with low rates of Grade 3 or greater acute and late toxicity. SIB-IMRT combines pelvic radiotherapy and hypofractionation to the primary site and offers an accelerated approach to treating intermediate- to high-risk disease. Additional follow-up is necessary to fully define the long-term toxicity after hypofractionated, whole pelvic treatment combined with androgen suppression.
Department of Radiation Oncology, University of Colorado Denver, Aurora, CO 80045-0508, USA.
Robert
R
McCammon
Kyle E
KE
Rusthoven
Brian
B
Kavanagh
Sherri
S
Newell
Francis
F
Newman
David
D
Raben
D000368:Aged; D000726:Androgen Antagonists / Q000627:therapeutic use; D003556:Cystitis / Q000209:etiology; D019583:Dose Fractionation, Radiation; D006801:Humans; D007422:Intestines / Q000528:radiation effects*; D015182:Lymphatic Irradiation / Q000009:adverse effects / Q000379:methods; D008297:Male; D008875:Middle Aged; D010388:Pelvis; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000150:complications*; D011859:Radiography; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects* / Q000379:methods; D012189:Retrospective Studies; D001743:Urinary Bladder / Q000528:radiation effects*; D014555:Urination Disorders / Q000209:etiology
D000726:Androgen Antagonists; D017430:Prostate-Specific Antigen