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Dosimetric and Radiobiological Comparison of Volumetric Modulated Arc Therapy, High Dose Rate Brachytherapy and Low Dose Rate Permanent Seeds Implant for Localized Prostate Cancer
Poster Viewing Session E629
Volume 93 Number 3S Supplement 2015 whole image and the Hausdorff distance with the land markers of lipiodol. The comparison of GTV between 4D-CT and PCT show that significant volume reduction can be achieved with spatiotemporal 4D-CT registration. Conclusion: The proposed method can achieve efficient tumor positioning by spatiotemporal registration of 4D-CT images for liver cancer patients. Author Disclosure: D. Li: None. X. Liu: None. J. Chen: None. H. Li: None.
3575 Dosimetric and Radiobiological Comparison of Volumetric Modulated Arc Therapy, High Dose Rate Brachytherapy and Low Dose Rate Permanent Seeds Implant for Localized Prostate Cancer R. Yang and J. Wang; Peking University Third Hospital, Beijing, China Purpose/Objective(s): To investigate the dosimetric and radiobiological differences among volumetric modulated arc therapy (VMAT), high-doserate (HDR) brachytherapy, and low-dose-rate (LDR) permanent seeds implant for localized prostate cancer. Materials/Methods: Ten patients with localized prostate cancer were selected for this study. VMAT, HDR brachytherapy and LDR permanent seeds implant plans were created for each patient. For VMAT, planning target volume (PTV) was defined as the clinical target volume plus a margin of 5 mm. Rectum, bladder, urethra and femoral heads were considered as organs at risk. 78 Gy in 39 fractions were prescribed for PTV. For HDR and LDR plans, the dose prescription was D90 of 34 Gy in 8.5 Gy per fraction, and 145 Gy to clinical target volume, respectively. The dose and dose volume parameters were evaluated for target, organs at risk and normal tissue. Physical dose were converted to dose based on 2-Gy fractions (equivalent dose in 2 Gy per fraction, EQD2) for comparison of three techniques. Results: HDR and LDR significantly reduced the dose to rectum and bladder compared with VMAT. The Dmean (EQD2) of rectum decreased 22.36 Gy in HDR and 17.01 Gy in LDR from 30.24 Gy in VMAT, respectively. The Dmean (EQD2) of bladder decreased 6.91 Gy in HDR and 2.53 Gy in LDR from 13.46 Gy in VMAT. For the femoral heads and normal tissue, the mean doses were also significantly reduced in both HDR and LDR compared with VMAT. For the urethra, the mean dose was 80.26 Gy, 70.23 Gy and 104.91 Gy in VMAT, HDR and LDR brachytherapy, respectively. Conclusion: For localized prostate cancer, both HDR and LDR brachytherapy were clearly superior in the sparing of rectum, bladder, femoral heads and normal tissue compared with VMAT. HDR provided the advantage in sparing of urethra compared with VMAT and LDR. Author Disclosure: R. Yang: None. J. Wang: None.
3576 Roles of Adjuvant and Salvage Radiation Therapy for Desmoplastic Melanoma D.E. Oliver,1 K. Patel,2 J. Switchenko,3 D.C. Parker,1 D.H. Lawson,1 K.A. Delman,1 R.R. Kudchadkar,1 and M.K. Khan1; 1Emory University, Atlanta, GA, 2Winship Cancer Institute, Emory University, Atlanta, GA, 3 Winship Cancer Institute of Emory University, Atlanta, GA Purpose/Objective(s): Current guidelines are unclear as to the precise role of radiation therapy (RT) in patients with desmoplastic melanoma (DM). The purpose of this study was to evaluate our institutional outcomes in patients with DM, and to explore the roles of both adjuvant and salvage RT in these patients. Materials/Methods: We reviewed records of 2200 melanoma patients to identify 100 patients with a histopathologic diagnosis of DM who received treatment at our institution from 2000 to 2014. Local control, distant metastasis-free survival (DMFS), and overall survival (OS) were evaluated in the 95 patients managed surgically with or without adjuvant and/or salvage radiation therapy. Results: The overall rate of local recurrence was 10%. There was no local recurrence in either adjuvant or salvage RT arm. Adjuvant RT did not significantly improve local recurrence-free survival at 5 years (100% vs.
81%, PZ0.59), despite the RT patients having worse pathological features than the surgery-alone cohort. 4 of 7 (57%) salvage patients developed distant metastases, despite 100% local control. Adjuvant RT did not significantly impact 5-year overall OS (86% vs. 82%, PZ0.43). Absence of ulceration was significantly associated with increased OS on univariate and multivariate analyses. Conclusion: RT appears to provide superior local control in both the adjuvant and salvage settings for patients with DM, and likely overcomes adverse risk factors after surgery in appropriately selected patients. In light of poor survival and metastatic disease outcomes for the salvage cohort, upfront adjuvant RT as opposed to RT in the salvage setting may be of particular benefit for those patients with high-risk features. Future prospective studies are needed to better address the optimal management for these patients. Author Disclosure: D.E. Oliver: None. K. Patel: None. J. Switchenko: None. D.C. Parker: None. D.H. Lawson: None. K.A. Delman: None. R.R. Kudchadkar: None. M.K. Khan: None.
3577 Early Local Recurrence Presents Adverse Effect on Outcomes of Primary Breast Sarcoma: A Retrospective Study From SingleInstitute Q.C. Hu, X. Mei, Y. Feng, J. Ma, Z. Yang, Z. Shao, X. Yu, and X. Guo; Fudan University Shanghai Cancer Center, Shanghai, China Purpose/Objective(s): Primary breast sarcomas (PBSs) are spectrum heterogeneous sarcomas in breast and the optimal treatment for it is still under discussion. Our study was to investigate clinical characteristics and identify potential prognostic factors for this rare malignancy. Materials/Methods: We retrospectively reviewed 38 patients confirmed with PBSs between 2000 and 2014. Local control rate and overall survival (OS) were determined by Kaplan-Meier actuarial method. Univariate analysis and Cox proportional hazards model was applied to identify potential prognostic factors. Results: With median follow-up of 40.19 months, fourteen patients (14/38) were found local recurrence. Wider resection like mastectomy was not superior to local resection (P Z 0.167). Three-year recurrence free survival and OS rate were 61.9% and 89%,respectively. Larger tumor size and local recurrence were indicated as unfavorable prognostic factors in univariate analysis. Cox model identified time to recurrence as an independent predictor (P Z 0.048). Conclusion: Surgery remains crucial treatment for PBSs. However, mastectomy is not routinely necessary if clear margin could be achieved by local excision. Time to recurrence was only factor significantly associating with OS. Author Disclosure: Q. Hu: None. X. Mei: None. Y. Feng: None. J. Ma: None. Z. Yang: None. Z. Shao: None. X. Yu: Research Grant; National Natural Science Foundation of China. X. Guo: Research Grant; National Natural Science Foundation of China.
3578 A Comparison of Stereotactic Body Radiation Therapy (SBRT) Versus Conventional/Hypofractionated Radiation Therapy (CHRT) for Metastatic Malignant Melanoma (MM) R.S. Youland, M.J. Blanchard, S.N. Markovic, K. Olivier, and S.S. Park; Mayo Clinic, Rochester, MN Purpose/Objective(s): MM is considered to be radioresistant. However, substantial data from stereotactic radiosurgery for intracranial MM metastases suggest that local control (LC) rates are similar to those of other histologies. Therefore, SBRT for extracranial MM metastases may offer improved LC. Materials/Methods: This is a single-institution retrospective study of metastatic MM patients treated between 1999 and 2014. Each metastatic lesion was assessed independently. Only patients with 1 post-radiation therapy imaging study were assessed for LC, progression-free survival (PFS), and overall survival (OS). The Likelihood Ratio was used for
Volume 93 Number 3S Supplement 2015 whole image and the Hausdorff distance with the land markers of lipiodol. The comparison of GTV between 4D-CT and PCT show that significant volume reduction can be achieved with spatiotemporal 4D-CT registration. Conclusion: The proposed method can achieve efficient tumor positioning by spatiotemporal registration of 4D-CT images for liver cancer patients. Author Disclosure: D. Li: None. X. Liu: None. J. Chen: None. H. Li: None.
3575 Dosimetric and Radiobiological Comparison of Volumetric Modulated Arc Therapy, High Dose Rate Brachytherapy and Low Dose Rate Permanent Seeds Implant for Localized Prostate Cancer R. Yang and J. Wang; Peking University Third Hospital, Beijing, China Purpose/Objective(s): To investigate the dosimetric and radiobiological differences among volumetric modulated arc therapy (VMAT), high-doserate (HDR) brachytherapy, and low-dose-rate (LDR) permanent seeds implant for localized prostate cancer. Materials/Methods: Ten patients with localized prostate cancer were selected for this study. VMAT, HDR brachytherapy and LDR permanent seeds implant plans were created for each patient. For VMAT, planning target volume (PTV) was defined as the clinical target volume plus a margin of 5 mm. Rectum, bladder, urethra and femoral heads were considered as organs at risk. 78 Gy in 39 fractions were prescribed for PTV. For HDR and LDR plans, the dose prescription was D90 of 34 Gy in 8.5 Gy per fraction, and 145 Gy to clinical target volume, respectively. The dose and dose volume parameters were evaluated for target, organs at risk and normal tissue. Physical dose were converted to dose based on 2-Gy fractions (equivalent dose in 2 Gy per fraction, EQD2) for comparison of three techniques. Results: HDR and LDR significantly reduced the dose to rectum and bladder compared with VMAT. The Dmean (EQD2) of rectum decreased 22.36 Gy in HDR and 17.01 Gy in LDR from 30.24 Gy in VMAT, respectively. The Dmean (EQD2) of bladder decreased 6.91 Gy in HDR and 2.53 Gy in LDR from 13.46 Gy in VMAT. For the femoral heads and normal tissue, the mean doses were also significantly reduced in both HDR and LDR compared with VMAT. For the urethra, the mean dose was 80.26 Gy, 70.23 Gy and 104.91 Gy in VMAT, HDR and LDR brachytherapy, respectively. Conclusion: For localized prostate cancer, both HDR and LDR brachytherapy were clearly superior in the sparing of rectum, bladder, femoral heads and normal tissue compared with VMAT. HDR provided the advantage in sparing of urethra compared with VMAT and LDR. Author Disclosure: R. Yang: None. J. Wang: None.
3576 Roles of Adjuvant and Salvage Radiation Therapy for Desmoplastic Melanoma D.E. Oliver,1 K. Patel,2 J. Switchenko,3 D.C. Parker,1 D.H. Lawson,1 K.A. Delman,1 R.R. Kudchadkar,1 and M.K. Khan1; 1Emory University, Atlanta, GA, 2Winship Cancer Institute, Emory University, Atlanta, GA, 3 Winship Cancer Institute of Emory University, Atlanta, GA Purpose/Objective(s): Current guidelines are unclear as to the precise role of radiation therapy (RT) in patients with desmoplastic melanoma (DM). The purpose of this study was to evaluate our institutional outcomes in patients with DM, and to explore the roles of both adjuvant and salvage RT in these patients. Materials/Methods: We reviewed records of 2200 melanoma patients to identify 100 patients with a histopathologic diagnosis of DM who received treatment at our institution from 2000 to 2014. Local control, distant metastasis-free survival (DMFS), and overall survival (OS) were evaluated in the 95 patients managed surgically with or without adjuvant and/or salvage radiation therapy. Results: The overall rate of local recurrence was 10%. There was no local recurrence in either adjuvant or salvage RT arm. Adjuvant RT did not significantly improve local recurrence-free survival at 5 years (100% vs.
81%, PZ0.59), despite the RT patients having worse pathological features than the surgery-alone cohort. 4 of 7 (57%) salvage patients developed distant metastases, despite 100% local control. Adjuvant RT did not significantly impact 5-year overall OS (86% vs. 82%, PZ0.43). Absence of ulceration was significantly associated with increased OS on univariate and multivariate analyses. Conclusion: RT appears to provide superior local control in both the adjuvant and salvage settings for patients with DM, and likely overcomes adverse risk factors after surgery in appropriately selected patients. In light of poor survival and metastatic disease outcomes for the salvage cohort, upfront adjuvant RT as opposed to RT in the salvage setting may be of particular benefit for those patients with high-risk features. Future prospective studies are needed to better address the optimal management for these patients. Author Disclosure: D.E. Oliver: None. K. Patel: None. J. Switchenko: None. D.C. Parker: None. D.H. Lawson: None. K.A. Delman: None. R.R. Kudchadkar: None. M.K. Khan: None.
3577 Early Local Recurrence Presents Adverse Effect on Outcomes of Primary Breast Sarcoma: A Retrospective Study From SingleInstitute Q.C. Hu, X. Mei, Y. Feng, J. Ma, Z. Yang, Z. Shao, X. Yu, and X. Guo; Fudan University Shanghai Cancer Center, Shanghai, China Purpose/Objective(s): Primary breast sarcomas (PBSs) are spectrum heterogeneous sarcomas in breast and the optimal treatment for it is still under discussion. Our study was to investigate clinical characteristics and identify potential prognostic factors for this rare malignancy. Materials/Methods: We retrospectively reviewed 38 patients confirmed with PBSs between 2000 and 2014. Local control rate and overall survival (OS) were determined by Kaplan-Meier actuarial method. Univariate analysis and Cox proportional hazards model was applied to identify potential prognostic factors. Results: With median follow-up of 40.19 months, fourteen patients (14/38) were found local recurrence. Wider resection like mastectomy was not superior to local resection (P Z 0.167). Three-year recurrence free survival and OS rate were 61.9% and 89%,respectively. Larger tumor size and local recurrence were indicated as unfavorable prognostic factors in univariate analysis. Cox model identified time to recurrence as an independent predictor (P Z 0.048). Conclusion: Surgery remains crucial treatment for PBSs. However, mastectomy is not routinely necessary if clear margin could be achieved by local excision. Time to recurrence was only factor significantly associating with OS. Author Disclosure: Q. Hu: None. X. Mei: None. Y. Feng: None. J. Ma: None. Z. Yang: None. Z. Shao: None. X. Yu: Research Grant; National Natural Science Foundation of China. X. Guo: Research Grant; National Natural Science Foundation of China.
3578 A Comparison of Stereotactic Body Radiation Therapy (SBRT) Versus Conventional/Hypofractionated Radiation Therapy (CHRT) for Metastatic Malignant Melanoma (MM) R.S. Youland, M.J. Blanchard, S.N. Markovic, K. Olivier, and S.S. Park; Mayo Clinic, Rochester, MN Purpose/Objective(s): MM is considered to be radioresistant. However, substantial data from stereotactic radiosurgery for intracranial MM metastases suggest that local control (LC) rates are similar to those of other histologies. Therefore, SBRT for extracranial MM metastases may offer improved LC. Materials/Methods: This is a single-institution retrospective study of metastatic MM patients treated between 1999 and 2014. Each metastatic lesion was assessed independently. Only patients with 1 post-radiation therapy imaging study were assessed for LC, progression-free survival (PFS), and overall survival (OS). The Likelihood Ratio was used for