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Robotic Stereotactic Body Radiation Therapy for Prostate Adenocarcinoma
Poster Viewing Abstracts S429
Volume 90 Number 1S Supplement 2014 Scientific Abstract 2547; Table
Set-up error > > > > >
0.6 0.6 0.8 1.0 1.2 1.5
cm cm; cm; cm; cm; cm
0.8 1.0 1.2 1.5
Set-up errors
S-P AP (%) cm cm cm cm
9604 1152 558 254 105 53
(81.90) (9.82) (4.76) (2.17) (0.90) (0.45)
S-P LL (%)
S-P CC (%) 9923 918 545 195 97 48
(84.62) (7.83) (4.65) (1.66) (0.83) (0.41)
9222 1161 669 326 238 110
random errors (s) were determined. The CTV-PTV margin was calculated using van Herk equation to ensure a minimum of 95% prescription dose to cover the CTV for 90% of the population (2,5 + 0,7 s). The correlations between CTV-PTV margins and various patients’ characteristics (average rectal area, volume of bladder, volume of CTV, age, BMI, hormonal therapy) and prostate locations were further investigated. Results: A total of 307 patients were included in this study, which represented 11,726 localizations resulting in 35,178 skin-prostate (S-P) shifts and 35,178 bone-prostate (B-P) shifts. The mean skin-prostate set-up inaccuracy was 0.8 5.4 mm (AP), 1.3 4.8 mm (CC), and 0.1 5.6 mm (LL). The mean B-P set-up inaccuracy was 0.4 3.3 mm (AP), 0.1 2.5 mm (CC), and 0.1 1.4 mm (LL). According to van Herk equation, the CTV-PTV margins of 11.4, 10.6, and 11.8 mm (AP, CC, and LL) would be required for set-up using skin markers and margins of 7.0, 4.7, and 2.1 mm for set-up using bone structures. The average rectal area 300 cm3 were associated with smaller CTV-PTV margins for set-up using bones structures. Unfortunately, this difference did not translate into the set-up margins using skin markers. Conversely, margins for patiens with voluminous bladder were larger. The largest margins (15.8 mm in LL direction) were needed in patients with BMI > 35 using skin markers. This difference disapeared in set-up using bone structures. Age and extent of clinical target volume had no influence on set-up margins. Conclusions: Our results comfirm that commonly used CTV-PTV margins (especially for AP direction) are inadequate. The margin of 9 mm for AP direction ensures only 80% minimum dose for 80% of the patients without using IGRT. The margin of 7 mm for identical direction is adequate only for daily online set-up using bone structures. While the set-up using bone structures was associated with reduced safely margins in LR and CC directions, it has only limited impact on CTV-PTV margin in AP direction. Author Disclosure: M. Dolezel: None. K. Odrazka: None. J. Vanasek: None. A. Hlavka: None. V. Ulrych: None. J. Stuk: None. M. Vitkova: None.
2548 Robotic Stereotactic Body Radiation Therapy for Prostate Adenocarcinoma S. Lloyd,1 C.D. Corso,1 F.S. Cardinale,1 C. McLaughlin,2 and J.G. Cardinale1; 1Yale University School of Medicine, New Haven, Connecticut, CT, 2Tufts University School of Medicine, Boston, Massachusetts, MA Purpose/Objective(s): Recent publications have reported favorable rates of biochemical progression free survival (bPFS), overall survival (OS), and toxicity with stereotactic body radiation therapy (SBRT) for organconfined prostate adenocarcinoma. We investigate the results of hypofractionated SBRT for prostate cancer over a four year period in a single institution. Materials/Methods: We retrospectively reviewed 68 patients with low to intermediate-risk prostate cancer treated with image-guided, robotic SBRT between 2008 and 2012. Patients were treated daily or every other day with a total dose of 36.25 Gy in five fractions of 7.25 Gy. A follow up physical examination and PSA were conducted at months one, three, six and every six months thereafter. Kaplan-Meier analysis was used to measure the bPFS and OS; the toxicity profile was measured using the Common
B-P AP (%)
(78.65) (9.90) (5.71) (2.78) (2.03) (0.94)
11,106 (94.71) 405 (3.45) 152 (1.30) 45 (0.38) 18 (0.15) 0
B-P CC (%) 11,369 238 71 36 11 1
(96.96) (2.03) (0.61) (0.31) (0.09) (0.01)
B-P LL (%) 11,657 (99.41) 23 (0.20) 21 (0.18) 16 (0.14) 9 (0.08) 0
Terminology Criteria for Adverse Events (CTCAE) version 4.03. Biochemical progression was defined using the Phoenix criteria of a rise of 2 ng/mL above nadir. Results: Median follow-up was 23 months with a range of 2 to 65 months. Thirty-four patients (50%) had a Gleason score of 3+3 Z 6, twenty-six (38%) had a Gleason score of 3+4 Z 7, and eight (12%) had a Gleason score of 4+3 Z 7. The median pretreatment PSA was 6.25. The median pretreatment American Urological Association (AUA) Symptom Score was 3. One case of biochemical progression occurred in a patient with Gleason 4+3 Z 7 disease at 22 months who is being managed with androgen suppression. One patient died of unrelated causes. Three-year bPFS was 94.3% and the three-year OS was 97.7%. Of 31 patients with follow-up of 24 months or greater, 25 patients (81%) recorded their lowest PSA at last follow-up. Twelve patients (18%) had grade 1 genitourinary toxicity, one patient (1%) had temporary grade 2 urinary retention, one patient (1%) had grade 3 urinary retention, and one patient (1%) had grade 3 hematuria. Pretreatment AUA Symptom Score was not predictive of genitourinary toxicity on logistic regression. Also, thirteen patients (19%) reported grade 1 gastrointestinal toxicity. Four patients (6%) reported erectile dysfunction. Conclusions: With limited follow-up, robotic SBRT provided a high rate of bPFS with acceptable toxicity for patients with low to intermediate-risk prostate cancer. PSA levels commonly continue to decline beyond two years post-treatment. Author Disclosure: S. Lloyd: None. C.D. Corso: None. F.S. Cardinale: O. Partnership; Accelitech LLC. C. McLaughlin: None. J.G. Cardinale: O. Partnership; Accelitech LLC.
2549 Seminal Vesicle Interfraction Displacement and Dose Variations Throughout the CBCT-Guided Radiation Therapy for Prostate Cancer D.C. Oksuz,1 F.O. Dincbas,1 S.A. Ergen,1 B. Iktueren,1 A. Bakır,2 and S. Koca3; 1Istanbul University Cerrahpasa Medical Faculty Department of Radiation Oncology, Istanbul, Turkey, 2Istanbul University Cerrahpasa Medical Faculty Department of Biostatistics and Medical Informatics, Istanbul, Turkey, 3Bahcesehir University Department of Radiation Oncology, Istanbul, Turkey Purpose/Objective(s): Prostate and the seminal vesicle (SV) may be subject to inter-and intrafractional motions because of changes in rectal and bladder filling. Movement of the prostate is well documented in the literature where as SV motion has been relatively less well described. In this study, the interfraction motion and the variation in the actual doses delivered to SV in prostate patients, using kV-CBCT datasets acquired during IGRT were analyzed. Materials/Methods: Ten consecutive patients treated with IMRT or IMAT to the prostate and the SV were retrospectively evaluated. PTV was generated from the prostate and SV using expansion margins of 8 mm in all directions except posterior, where it was 5 mm. All of the treatments were planned and optimized using the Eclipse version 8.6 treatment planning system. Target localization was performed on the basis of prostate matching using kV-CBCT scans before each treatment. Sixteen kV-CBCTs which were taken at the first 5 days of treatment and then 2 times per week for each patient were used for assessments. SV were re-contoured in 3 different parts as proximal, distal and the whole SV on each offline CBCT
Volume 90 Number 1S Supplement 2014 Scientific Abstract 2547; Table
Set-up error > > > > >
0.6 0.6 0.8 1.0 1.2 1.5
cm cm; cm; cm; cm; cm
0.8 1.0 1.2 1.5
Set-up errors
S-P AP (%) cm cm cm cm
9604 1152 558 254 105 53
(81.90) (9.82) (4.76) (2.17) (0.90) (0.45)
S-P LL (%)
S-P CC (%) 9923 918 545 195 97 48
(84.62) (7.83) (4.65) (1.66) (0.83) (0.41)
9222 1161 669 326 238 110
random errors (s) were determined. The CTV-PTV margin was calculated using van Herk equation to ensure a minimum of 95% prescription dose to cover the CTV for 90% of the population (2,5 + 0,7 s). The correlations between CTV-PTV margins and various patients’ characteristics (average rectal area, volume of bladder, volume of CTV, age, BMI, hormonal therapy) and prostate locations were further investigated. Results: A total of 307 patients were included in this study, which represented 11,726 localizations resulting in 35,178 skin-prostate (S-P) shifts and 35,178 bone-prostate (B-P) shifts. The mean skin-prostate set-up inaccuracy was 0.8 5.4 mm (AP), 1.3 4.8 mm (CC), and 0.1 5.6 mm (LL). The mean B-P set-up inaccuracy was 0.4 3.3 mm (AP), 0.1 2.5 mm (CC), and 0.1 1.4 mm (LL). According to van Herk equation, the CTV-PTV margins of 11.4, 10.6, and 11.8 mm (AP, CC, and LL) would be required for set-up using skin markers and margins of 7.0, 4.7, and 2.1 mm for set-up using bone structures. The average rectal area 300 cm3 were associated with smaller CTV-PTV margins for set-up using bones structures. Unfortunately, this difference did not translate into the set-up margins using skin markers. Conversely, margins for patiens with voluminous bladder were larger. The largest margins (15.8 mm in LL direction) were needed in patients with BMI > 35 using skin markers. This difference disapeared in set-up using bone structures. Age and extent of clinical target volume had no influence on set-up margins. Conclusions: Our results comfirm that commonly used CTV-PTV margins (especially for AP direction) are inadequate. The margin of 9 mm for AP direction ensures only 80% minimum dose for 80% of the patients without using IGRT. The margin of 7 mm for identical direction is adequate only for daily online set-up using bone structures. While the set-up using bone structures was associated with reduced safely margins in LR and CC directions, it has only limited impact on CTV-PTV margin in AP direction. Author Disclosure: M. Dolezel: None. K. Odrazka: None. J. Vanasek: None. A. Hlavka: None. V. Ulrych: None. J. Stuk: None. M. Vitkova: None.
2548 Robotic Stereotactic Body Radiation Therapy for Prostate Adenocarcinoma S. Lloyd,1 C.D. Corso,1 F.S. Cardinale,1 C. McLaughlin,2 and J.G. Cardinale1; 1Yale University School of Medicine, New Haven, Connecticut, CT, 2Tufts University School of Medicine, Boston, Massachusetts, MA Purpose/Objective(s): Recent publications have reported favorable rates of biochemical progression free survival (bPFS), overall survival (OS), and toxicity with stereotactic body radiation therapy (SBRT) for organconfined prostate adenocarcinoma. We investigate the results of hypofractionated SBRT for prostate cancer over a four year period in a single institution. Materials/Methods: We retrospectively reviewed 68 patients with low to intermediate-risk prostate cancer treated with image-guided, robotic SBRT between 2008 and 2012. Patients were treated daily or every other day with a total dose of 36.25 Gy in five fractions of 7.25 Gy. A follow up physical examination and PSA were conducted at months one, three, six and every six months thereafter. Kaplan-Meier analysis was used to measure the bPFS and OS; the toxicity profile was measured using the Common
B-P AP (%)
(78.65) (9.90) (5.71) (2.78) (2.03) (0.94)
11,106 (94.71) 405 (3.45) 152 (1.30) 45 (0.38) 18 (0.15) 0
B-P CC (%) 11,369 238 71 36 11 1
(96.96) (2.03) (0.61) (0.31) (0.09) (0.01)
B-P LL (%) 11,657 (99.41) 23 (0.20) 21 (0.18) 16 (0.14) 9 (0.08) 0
Terminology Criteria for Adverse Events (CTCAE) version 4.03. Biochemical progression was defined using the Phoenix criteria of a rise of 2 ng/mL above nadir. Results: Median follow-up was 23 months with a range of 2 to 65 months. Thirty-four patients (50%) had a Gleason score of 3+3 Z 6, twenty-six (38%) had a Gleason score of 3+4 Z 7, and eight (12%) had a Gleason score of 4+3 Z 7. The median pretreatment PSA was 6.25. The median pretreatment American Urological Association (AUA) Symptom Score was 3. One case of biochemical progression occurred in a patient with Gleason 4+3 Z 7 disease at 22 months who is being managed with androgen suppression. One patient died of unrelated causes. Three-year bPFS was 94.3% and the three-year OS was 97.7%. Of 31 patients with follow-up of 24 months or greater, 25 patients (81%) recorded their lowest PSA at last follow-up. Twelve patients (18%) had grade 1 genitourinary toxicity, one patient (1%) had temporary grade 2 urinary retention, one patient (1%) had grade 3 urinary retention, and one patient (1%) had grade 3 hematuria. Pretreatment AUA Symptom Score was not predictive of genitourinary toxicity on logistic regression. Also, thirteen patients (19%) reported grade 1 gastrointestinal toxicity. Four patients (6%) reported erectile dysfunction. Conclusions: With limited follow-up, robotic SBRT provided a high rate of bPFS with acceptable toxicity for patients with low to intermediate-risk prostate cancer. PSA levels commonly continue to decline beyond two years post-treatment. Author Disclosure: S. Lloyd: None. C.D. Corso: None. F.S. Cardinale: O. Partnership; Accelitech LLC. C. McLaughlin: None. J.G. Cardinale: O. Partnership; Accelitech LLC.
2549 Seminal Vesicle Interfraction Displacement and Dose Variations Throughout the CBCT-Guided Radiation Therapy for Prostate Cancer D.C. Oksuz,1 F.O. Dincbas,1 S.A. Ergen,1 B. Iktueren,1 A. Bakır,2 and S. Koca3; 1Istanbul University Cerrahpasa Medical Faculty Department of Radiation Oncology, Istanbul, Turkey, 2Istanbul University Cerrahpasa Medical Faculty Department of Biostatistics and Medical Informatics, Istanbul, Turkey, 3Bahcesehir University Department of Radiation Oncology, Istanbul, Turkey Purpose/Objective(s): Prostate and the seminal vesicle (SV) may be subject to inter-and intrafractional motions because of changes in rectal and bladder filling. Movement of the prostate is well documented in the literature where as SV motion has been relatively less well described. In this study, the interfraction motion and the variation in the actual doses delivered to SV in prostate patients, using kV-CBCT datasets acquired during IGRT were analyzed. Materials/Methods: Ten consecutive patients treated with IMRT or IMAT to the prostate and the SV were retrospectively evaluated. PTV was generated from the prostate and SV using expansion margins of 8 mm in all directions except posterior, where it was 5 mm. All of the treatments were planned and optimized using the Eclipse version 8.6 treatment planning system. Target localization was performed on the basis of prostate matching using kV-CBCT scans before each treatment. Sixteen kV-CBCTs which were taken at the first 5 days of treatment and then 2 times per week for each patient were used for assessments. SV were re-contoured in 3 different parts as proximal, distal and the whole SV on each offline CBCT