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Long-term intra-fractional motion of the prostate using hydrogel spacer during Cyberknife® treatment for prostate cancer--a case report.

Sumila M, Mack A, Schneider U, Storelli F, Curschmann J, Gruber G - Radiat Oncol (2014)

Bottom Line: After each beam the corresponding data reporting on the intra-fractional movement were pre-processed, the generated log-files extracted and the data analysed according to different directions: left -right (LR); anterior - posterior (AP); inferior -superior (IS).On 1-, 6- and 12-months follow-up the patient was free of any symptoms with only slight decrease of erectile function (grade 1).There was a continuous PSA decline.

View Article: PubMed Central - PubMed

Affiliation: Institute of Radiotherapy, Klinik Hirslanden, Witellikerstrasse 40, Zürich CH-8032, Switzerland. guenther.gruber@hirslanden.ch.

ABSTRACT

Background: There is a trend towards hypofractionated stereotactic radiotherapy (RT) in prostate cancer to apply high single doses in a few fractions. Using the Cyberknife® robotic system multiple non-coplanar fields are usually given with a treatment time of one hour or more. We planned to evaluate organ motion in this setting injecting a hydrogel spacer to protect the anterior rectal wall during treatment.

Methods: A 66 years old man with low risk prostate cancer was planned for robotic hypofractionated stereotactic RT. After implantation of fiducial markers and a hydrogel spacer a total dose of 36.25 Gy in 5 fractions was given to the planning target volume (clinical target volume + 3 mm). After each beam the corresponding data reporting on the intra-fractional movement were pre-processed, the generated log-files extracted and the data analysed according to different directions: left -right (LR); anterior - posterior (AP); inferior -superior (IS). Clinical assessments were prospectively done before RT start, one week after the end of treatment as well as 1, 6 and 12 months afterwards. Symptoms were documented using Common Toxicity and Adverse Events Criteria 4.0.

Results: Tolerability of marker and hydrogel implantation was excellent. A total of 284 non-coplanar fields were used per fraction. The total treatment time for all fields per fraction lasted more than 60 minutes. The detected and corrected movements over all 5 fractions were in a range of +/- 4 mm in all directions (LR: mean 0,238 - SD 0,798; AP: mean 0,450 - SD 1,690; and IS: mean 0,908 - SD 1,518). V36Gy for the rectum was 0.062 ccm. After RT, grade 1-2 intestinal toxicity and grade 1 genitourinarytoxicity occurred, but resolved completely after 10 days. On 1-, 6- and 12-months follow-up the patient was free of any symptoms with only slight decrease of erectile function (grade 1). There was a continuous PSA decline.

Conclusions: Prostate movement was relatively low (+/- 4 mm) even during fraction times of more than 60 minutes. The hydrogel spacer might serve as a kind of stabilisator for the prostate, but this should be analysed in a larger cohort of patients.

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Related in: MedlinePlus

Dose-volume histogram (DVH) for PTV, rectum, bladder and urethra.
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Fig1: Dose-volume histogram (DVH) for PTV, rectum, bladder and urethra.

Mentions: The planning was done according to the so-called Seattle protocol. For the planning target volume (PTV) the CTV was expended with a 3 mm margin in all directions and a total dose of 36.25 Gray was delivered to the PTV in 5 fractions given every second day. The dose-constraint for the rectum proposed in the protocol is V36Gy <1 ccm.A total of 284 non-coplanar fields were used per fraction. The treatment time for all fields per fraction lasted from 59 to 68 minutes.The dose-volume histogram is shown in Figure 1.Figure 1


Long-term intra-fractional motion of the prostate using hydrogel spacer during Cyberknife® treatment for prostate cancer--a case report.

Sumila M, Mack A, Schneider U, Storelli F, Curschmann J, Gruber G - Radiat Oncol (2014)

Dose-volume histogram (DVH) for PTV, rectum, bladder and urethra.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4150956&req=5

Fig1: Dose-volume histogram (DVH) for PTV, rectum, bladder and urethra.
Mentions: The planning was done according to the so-called Seattle protocol. For the planning target volume (PTV) the CTV was expended with a 3 mm margin in all directions and a total dose of 36.25 Gray was delivered to the PTV in 5 fractions given every second day. The dose-constraint for the rectum proposed in the protocol is V36Gy <1 ccm.A total of 284 non-coplanar fields were used per fraction. The treatment time for all fields per fraction lasted from 59 to 68 minutes.The dose-volume histogram is shown in Figure 1.Figure 1

Bottom Line: After each beam the corresponding data reporting on the intra-fractional movement were pre-processed, the generated log-files extracted and the data analysed according to different directions: left -right (LR); anterior - posterior (AP); inferior -superior (IS).On 1-, 6- and 12-months follow-up the patient was free of any symptoms with only slight decrease of erectile function (grade 1).There was a continuous PSA decline.

View Article: PubMed Central - PubMed

Affiliation: Institute of Radiotherapy, Klinik Hirslanden, Witellikerstrasse 40, Zürich CH-8032, Switzerland. guenther.gruber@hirslanden.ch.

ABSTRACT

Background: There is a trend towards hypofractionated stereotactic radiotherapy (RT) in prostate cancer to apply high single doses in a few fractions. Using the Cyberknife® robotic system multiple non-coplanar fields are usually given with a treatment time of one hour or more. We planned to evaluate organ motion in this setting injecting a hydrogel spacer to protect the anterior rectal wall during treatment.

Methods: A 66 years old man with low risk prostate cancer was planned for robotic hypofractionated stereotactic RT. After implantation of fiducial markers and a hydrogel spacer a total dose of 36.25 Gy in 5 fractions was given to the planning target volume (clinical target volume + 3 mm). After each beam the corresponding data reporting on the intra-fractional movement were pre-processed, the generated log-files extracted and the data analysed according to different directions: left -right (LR); anterior - posterior (AP); inferior -superior (IS). Clinical assessments were prospectively done before RT start, one week after the end of treatment as well as 1, 6 and 12 months afterwards. Symptoms were documented using Common Toxicity and Adverse Events Criteria 4.0.

Results: Tolerability of marker and hydrogel implantation was excellent. A total of 284 non-coplanar fields were used per fraction. The total treatment time for all fields per fraction lasted more than 60 minutes. The detected and corrected movements over all 5 fractions were in a range of +/- 4 mm in all directions (LR: mean 0,238 - SD 0,798; AP: mean 0,450 - SD 1,690; and IS: mean 0,908 - SD 1,518). V36Gy for the rectum was 0.062 ccm. After RT, grade 1-2 intestinal toxicity and grade 1 genitourinarytoxicity occurred, but resolved completely after 10 days. On 1-, 6- and 12-months follow-up the patient was free of any symptoms with only slight decrease of erectile function (grade 1). There was a continuous PSA decline.

Conclusions: Prostate movement was relatively low (+/- 4 mm) even during fraction times of more than 60 minutes. The hydrogel spacer might serve as a kind of stabilisator for the prostate, but this should be analysed in a larger cohort of patients.

Show MeSH
Related in: MedlinePlus