Hypofractionated stereotactic body radiotherapy in low- and intermediate-risk prostate carcinoma.
OBJECTIVE
Stereotactic body radiotherapy (SBRT) takes advantage of low α/β ratio of prostate cancer to deliver a large dose in few fractions. We examined clinical outcomes of SBRT using CyberKnife for the treatment of low- and intermediate-risk prostate cancer.


METHODS
This study was based on a retrospective analysis of the 33 patients treated with SBRT using CyberKnife for localized prostate cancer (27.3% in low-risk and 72.7% in intermediate-risk). Total dose of 36.25 Gy in 5 fractions of 7.25 Gy were administered. The acute and late toxicities were recorded using the Radiation Therapy Oncology Group scale. Prostate-specific antigen (PSA) response was monitored.


RESULTS
Thirty-three patients with a median 51 months (range, 6 to 71 months) follow-up were analyzed. There was no biochemical failure. Median PSA nadir was 0.27 ng/mL at median 33 months and PSA bounce occurred in 30.3% (n = 10) of patients at median at median 10.5 months after SBRT. No grade 3 acute toxicity was noted. The 18.2% of the patients had acute grade 2 genitourinary (GU) toxicities and 21.2% had acute grade 2 gastrointestinal (GI) toxicities. After follow-up of 2 months, most complications had returned to baseline. There was no grade 3 late GU and GI toxicity.


CONCLUSIONS
Our experience with SBRT using CyberKnife in low- and intermediate-risk prostate cancer demonstrates favorable efficacy and toxicity. Further studies with more patients and longer follow-up duration are required.
Department of Radiation Oncology, Inha University Hospital, Inha University School of Medicine, Incheon, Korea.
Hun Jung
HJ
Kim
Department of Radiation Oncology, Inha University Hospital, Inha University School of Medicine, Incheon, Korea.
Jeong Hoon
JH
Phak
Department of Radiation Oncology, Inha University Hospital, Inha University School of Medicine, Incheon, Korea.
Woo Chul
WC
Kim
CyberKnife; Hypofractionation; Prostate cancer; Prostate-specific antigen; Radiotherapy; Stereotactic body radiotherapy