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7-yr SBRT results for low/intermediate risk from Dr. Katz

hopeful and opt...
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Joined: Apr 2009
Old Salt
Posts: 803
Joined: Aug 2014

for the (low to medium risk) patients who have undergone the 'standard' (five sessions) Cyberknife procedure (around 35 Gy total).

I hope that the results for high-risk patients will be equally encouraging.

hopeful and opt...
Posts: 2327
Joined: Apr 2009



Stereotactic body radiotherapy for localized prostate cancer: disease control and quality of life at 6 years

Alan J Katz, Michael Santoro, Fred Diblasio and Richard Ashley

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Radiation Oncology 2013, 8:118 doi:10.1186/1748-717X-8-118

Published: 13 May 2013

Abstract (provisional)


Stereotactic body radiotherapy (SBRT) may yield disease control for prostate cancer in a brief, hypofractionated treatment regimen without increasing treatment toxicity. Our report presents a 6-year update from 304 low- (n = 211), intermediate- (n = 81), and high-risk (n = 12) prostate cancer patients who received CyberKnife SBRT.


The median PSA at presentation was 5.8 ng/ml. Fifty-seven patients received neoadjuvant hormonal therapy for up to one year. The first 50 patients received a total dose of 35 Gy in 5 fractions of 7 Gy. The subsequent 254 patients received a total dose of 36.25 Gy in 5 fractions of 7.25 Gy. Toxicity was assessed with the Expanded Prostate Cancer Index Composite questionnaire and the Radiation Therapy Oncology Group urinary and rectal toxicity scale. Biochemical failure was assessed using the nadir + 2 definition.


No patients experienced Grade III or IV acute complications. Fewer than 5% of patients experienced any acute Grade II urinary or rectal toxicities. Late urinary Grade II complications were observed in 4% of patients treated to 35 Gy and 9% of patients treated to 36.25 Gy. Five (2%) late Grade III urinary toxicities occurred in patients who were treated with 36.25 Gy. Late Grade II rectal complications were observed in 2% of patients treated to 35 Gy and 5% of patients treated to 36.25 Gy. Bowel and urinary quality of life (QOL) scores initially decreased, but later returned to baseline values. An overall decrease of 20% in the sexual QOL score was observed. QOL in each domain was not differentially affected by dose. For patients that were potent prior to treatment, 75% stated that they remained sexually potent. Actuarial 5-year biochemical recurrence-free survival was 97% for low-risk, 90.7% for intermediate-risk, and 74.1% for high-risk patients. PSA fell to a median of 0.12 ng/ml at 5 years; dose did not influence median PSA levels.


In this large series with long-term follow-up, we found excellent biochemical control rates and low and acceptable toxicity, outcomes consistent with those reported for from high dose rate brachytherapy (HDR BT). Provided that measures are taken to account for prostate motion, SBRT's distinct advantages over HDR BT include its noninvasiveness and delivery to patients without anesthesia or hospitalization.

Posts: 261
Joined: Sep 2010

Thanks for posting the abstract. It is good to see some numbers. I did not read the paper, and the following question may be answered in it, but why did the author spend 2/3 of the conclusion paragraph comparing SBRT to HDR BT? The methods and results sections did not address this comparison, but a comparison is made in the conclusion.

Old Salt
Posts: 803
Joined: Aug 2014

It's noteworthy, I think, that even the high-risk patients were given about 35 Gy in five fractions. No other external or internal radiation.

The Georgetown U Hosp group (Washington DC) treats high-risk patients with 3 CK fractions followed by 25 IMRT sessions.

I wonder which regimen will turn out to be better in the long run. To my knowledge, there hasn't been a longer (5 year or so) follow-up paper for the high-risk patients cared for by the Georgetown radiation oncology group (Dr Collins et al)

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