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The Application of Volumetric Modulated Arc Therapy (VMAT) in Esophageal Carcinoma
S344
International Journal of Radiation Oncology Biology Physics
2320
received by PTV and OARs, MUs, treatment delivery times of the two plans were compared. Results: (1) Both the plans of VMAT and IMRT could satisfy the clinical dosimetry requirements. VMAT plan had better conformal index (CI) of PTV and lower maximum dose of spinal cord, but V30, V40 and mean dose of heart in VMAT plans were higher than those of IMRT (P<0.05). (2) For cervical cases, the V5, V10, V15 and mean doses of lungs were significantly higher in VMAT plans (P<0.05). (3) For upper-thoracic cases, the V30 and mean doses of heart were significantly higher in VMAT plans (P<0.05). However, the maximum dose of spinal cord in VMAT plans was lower than IMRT (P<0.05). (4) For middle-thoracic cases, the V10, V15, V20 of the lungs were lower in plans of VMAT (P<0.05). (5) There were no significant differences between the comparison of VMAT and IMRT plans for lower-thoracic esophageal cancers. (6) The 3mm/3% Gamma pass rates for VMAT and IMRT plans were 92.75% and 92.98%, respectively. (8) The average MUs of VMAT and IMRT plans were 460.66 and 522.55, respectively, the former was significantly smaller than the latter, t Z -3.870, P Z 0.001. The treatment delivery times of VMAT and IMRT plans were 139.6s and 298.73s, respectively, t Z -16.943, P Z 0.000. Conclusions: VMAT plans of esophageal carcinoma could afford similar dose distribution as IMRT plans and even could afford better CI. The implementation of Synergy is stable and reliable. Compared with IMRT, the execution of VMAT plans need fewer MUs, shorten treatment delivery time, and therefore had potential advantage of biological effects enhancement. Author Disclosure: C. Han: None. L. Liu: None. L. Wang: None. J. Zhang: None. H. Tian: None.
Risk Factors of Lymph Node Micrometastasis in Negative Node of Esophageal Squamous Cell Carcinoma Detected by Conventional Pathological Technique, and Its Relationship With Primary Tumor FDG PET/CT Uptake D. Han, Y. Yuan, Z. Fu, D. Mu, and J. Yu; Shandong Cancer Hospital and Institute, Jinan, China Purpose/Objective(s): To evaluate risk factors of micro-metastasis in negative lymph node in esophageal squamous cell carcinoma detected by conventional pathological technique, further investigate its relationship with primary tumor FDG PET/CT uptake, for a successful prediction could be helpful in screening appropriate candidates for definite radiation therapy or surgery. Materials/Methods: We have prospectively enrolled 49 patients who diagnosed as esophageal squamous cell carcinoma and detected by (18)FFDG PET/CT from January 2008 to July 2013. All patients underwent radical surgery and systematic lymph node dissection and preoperative (18)F-FDG PET/CT scanning. For the objective of this study, several additional sections (4 mm in thickness and contiguous) of all resected nodes as negative detected by conventional pathological technique, were obtained from archived paraffin embedded lymph node tissue. For the immunohistochemical analysis, a previously validated technique (anticytokeratin AE1/AE3) was used. This immunoperoxidase staining works by exposing the lymph node tissue to a monoclonal antibody directed against a spectrum of cytokeratins, allowing for identification of epithelial cells. The prevalence of lymph node micro-metastasis was analyzed according to clinicopathologic factors such as tumor site, grade of differentiation, longitudinal length, invasion depth and primary tumor maximum standard uptake value (SUVmax). Results: Lymph node micro-metastasis was detected in 26.53% (13/49) of the patients. SUV(max) of the primary tumor and T stage were independent predictors of occult nodal metastasis for patients with negative node by both conventional pathological detected and FDG PET/CT. Accordingly we divided all patients into three teams: team 1 (low-risk) without metastasis or micro-metastasis; team 2 (moderate-risk) with micrometastasis but no metastasis; team 3 (high-risk) macro-metastasis with or without micro-metastasis. The mean value of SUVmax were 8.242.25, 13.23.28, and 13.1711.18, respectively, there are significant differences among those teams (P less than 0.05). Conclusions: The patients underwent PET/CT scanning showed higher SUV(max) and deeper invasion depth constitutes a high-risk group for occult nodal metastasis. The combined information of primary tumor SUV (max) and invasion depth have potential values in the clinic. These findings would be helpful in selection for benefit from definite radiation therapy or surgery candidates. Author Disclosure: D. Han: None. Y. Yuan: None. Z. Fu: None. D. Mu: None. J. Yu: None.
2321 The Application of Volumetric Modulated Arc Therapy (VMAT) in Esophageal Carcinoma C. Han, L. Liu, L. Wang, J. Zhang, and H. Tian; Department of radiation oncology, the fourth hospital of Hebei Medical University, Shijiazhuang, China Purpose/Objective(s): To compare the dosimetric difference between the technology of volumetric modulated arc therapy (VMAT) and static intensity modulated radiation therapy(IMRT) for Esophageal Carcinoma, and to investigate the feasibility and potential advantage of VMAT. Materials/Methods: Thirty patients were selected for this study which including 5 cases of cervical esophageal cancers, 10 cases of upperthoracic esophageal cancers, 10 of middle-thoracic esophageal cancers and 5 of lower-thoracic esophageal cancers. VMAT plans with single arc and IMRT plans with five fields were designed for each patients and a treatment planning system was used. The prescription dose was 60Gy (2Gy per fraction). Delta4 was used for dosimetric verification, radiation doses
2322 Feasibility of Endoscopic Guided Placement of Markers in Patients With Esophageal Tumors M. Machiels, J. van Hooft, T. Alderliesten, P. Jin, and M.C.C. Hulshof; AMC Amsterdam, Amsterdam, Netherlands Purpose/Objective(s): Fiducial markers have been successfully used in the management of various tumor sites to improve radiation accuracy. Fiducials placed at the margins of esophageal tumors are potentially useful to facilitate both radiation therapy (RT) target delineation and image-guided RT (IGRT). In this pilot study we investigated the feasibility, safety, visibility and stability of endoscopic guided placement of two different types of fiducial markers in patients with esophageal tumors referred for RT. Materials/Methods: Sixteen esophageal cancer patients underwent endoscopic ultrasound (EUS) guided implantation. The first 7 patients received Cook gold markers and consecutive 9 patients Visicoil markers. The length of the Cook markers was 5 mm (pre-loaded system), but length of Visicoils varied from 3 to 10 mm (back loaded). Pain and toxicity were scored after implantation. Visibility and stability were evaluated on simulation CT scan and on weekly cone-beam CT (CBCT) images during the course of radiation. Results: A total of 41 fiducials were placed (18 Cooks and 23 Visicoils). Technical success was achieved in 15 out of 16 patients. In one patient the implantation failed because of a non-preloaded needle system (Cook) and was left out of analyses. Two grade 1 complications were noticed. Visibility on CT scan of both types of implanted markers was adequate for tumor delineation. Of the Cook markers, 50% remained visible during the whole course of radiation compared to 65% of the Visicoil markers. However, when selecting only Visicoils with a length of >5 mm, all (15/ 15) remained stable and visible on CBCT scan between implantation and end of radiation. Conclusions: EUS-guided placement of gold fiducials is both safe and feasible for esophageal tumors and adequate for tumor delineation and positional verification. The results imply an advantage of Visicoil markers over Cook markers in terms of stability over time, but the effects of a learning curve should be ruled out. Visicoil markers have to be at least 5 mm in length for visibility on CBCT scan. Author Disclosure: M. Machiels: None. J. van Hooft: None. T. Alderliesten: None. P. Jin: None. M.C.C. Hulshof: None.
International Journal of Radiation Oncology Biology Physics
2320
received by PTV and OARs, MUs, treatment delivery times of the two plans were compared. Results: (1) Both the plans of VMAT and IMRT could satisfy the clinical dosimetry requirements. VMAT plan had better conformal index (CI) of PTV and lower maximum dose of spinal cord, but V30, V40 and mean dose of heart in VMAT plans were higher than those of IMRT (P<0.05). (2) For cervical cases, the V5, V10, V15 and mean doses of lungs were significantly higher in VMAT plans (P<0.05). (3) For upper-thoracic cases, the V30 and mean doses of heart were significantly higher in VMAT plans (P<0.05). However, the maximum dose of spinal cord in VMAT plans was lower than IMRT (P<0.05). (4) For middle-thoracic cases, the V10, V15, V20 of the lungs were lower in plans of VMAT (P<0.05). (5) There were no significant differences between the comparison of VMAT and IMRT plans for lower-thoracic esophageal cancers. (6) The 3mm/3% Gamma pass rates for VMAT and IMRT plans were 92.75% and 92.98%, respectively. (8) The average MUs of VMAT and IMRT plans were 460.66 and 522.55, respectively, the former was significantly smaller than the latter, t Z -3.870, P Z 0.001. The treatment delivery times of VMAT and IMRT plans were 139.6s and 298.73s, respectively, t Z -16.943, P Z 0.000. Conclusions: VMAT plans of esophageal carcinoma could afford similar dose distribution as IMRT plans and even could afford better CI. The implementation of Synergy is stable and reliable. Compared with IMRT, the execution of VMAT plans need fewer MUs, shorten treatment delivery time, and therefore had potential advantage of biological effects enhancement. Author Disclosure: C. Han: None. L. Liu: None. L. Wang: None. J. Zhang: None. H. Tian: None.
Risk Factors of Lymph Node Micrometastasis in Negative Node of Esophageal Squamous Cell Carcinoma Detected by Conventional Pathological Technique, and Its Relationship With Primary Tumor FDG PET/CT Uptake D. Han, Y. Yuan, Z. Fu, D. Mu, and J. Yu; Shandong Cancer Hospital and Institute, Jinan, China Purpose/Objective(s): To evaluate risk factors of micro-metastasis in negative lymph node in esophageal squamous cell carcinoma detected by conventional pathological technique, further investigate its relationship with primary tumor FDG PET/CT uptake, for a successful prediction could be helpful in screening appropriate candidates for definite radiation therapy or surgery. Materials/Methods: We have prospectively enrolled 49 patients who diagnosed as esophageal squamous cell carcinoma and detected by (18)FFDG PET/CT from January 2008 to July 2013. All patients underwent radical surgery and systematic lymph node dissection and preoperative (18)F-FDG PET/CT scanning. For the objective of this study, several additional sections (4 mm in thickness and contiguous) of all resected nodes as negative detected by conventional pathological technique, were obtained from archived paraffin embedded lymph node tissue. For the immunohistochemical analysis, a previously validated technique (anticytokeratin AE1/AE3) was used. This immunoperoxidase staining works by exposing the lymph node tissue to a monoclonal antibody directed against a spectrum of cytokeratins, allowing for identification of epithelial cells. The prevalence of lymph node micro-metastasis was analyzed according to clinicopathologic factors such as tumor site, grade of differentiation, longitudinal length, invasion depth and primary tumor maximum standard uptake value (SUVmax). Results: Lymph node micro-metastasis was detected in 26.53% (13/49) of the patients. SUV(max) of the primary tumor and T stage were independent predictors of occult nodal metastasis for patients with negative node by both conventional pathological detected and FDG PET/CT. Accordingly we divided all patients into three teams: team 1 (low-risk) without metastasis or micro-metastasis; team 2 (moderate-risk) with micrometastasis but no metastasis; team 3 (high-risk) macro-metastasis with or without micro-metastasis. The mean value of SUVmax were 8.242.25, 13.23.28, and 13.1711.18, respectively, there are significant differences among those teams (P less than 0.05). Conclusions: The patients underwent PET/CT scanning showed higher SUV(max) and deeper invasion depth constitutes a high-risk group for occult nodal metastasis. The combined information of primary tumor SUV (max) and invasion depth have potential values in the clinic. These findings would be helpful in selection for benefit from definite radiation therapy or surgery candidates. Author Disclosure: D. Han: None. Y. Yuan: None. Z. Fu: None. D. Mu: None. J. Yu: None.
2321 The Application of Volumetric Modulated Arc Therapy (VMAT) in Esophageal Carcinoma C. Han, L. Liu, L. Wang, J. Zhang, and H. Tian; Department of radiation oncology, the fourth hospital of Hebei Medical University, Shijiazhuang, China Purpose/Objective(s): To compare the dosimetric difference between the technology of volumetric modulated arc therapy (VMAT) and static intensity modulated radiation therapy(IMRT) for Esophageal Carcinoma, and to investigate the feasibility and potential advantage of VMAT. Materials/Methods: Thirty patients were selected for this study which including 5 cases of cervical esophageal cancers, 10 cases of upperthoracic esophageal cancers, 10 of middle-thoracic esophageal cancers and 5 of lower-thoracic esophageal cancers. VMAT plans with single arc and IMRT plans with five fields were designed for each patients and a treatment planning system was used. The prescription dose was 60Gy (2Gy per fraction). Delta4 was used for dosimetric verification, radiation doses
2322 Feasibility of Endoscopic Guided Placement of Markers in Patients With Esophageal Tumors M. Machiels, J. van Hooft, T. Alderliesten, P. Jin, and M.C.C. Hulshof; AMC Amsterdam, Amsterdam, Netherlands Purpose/Objective(s): Fiducial markers have been successfully used in the management of various tumor sites to improve radiation accuracy. Fiducials placed at the margins of esophageal tumors are potentially useful to facilitate both radiation therapy (RT) target delineation and image-guided RT (IGRT). In this pilot study we investigated the feasibility, safety, visibility and stability of endoscopic guided placement of two different types of fiducial markers in patients with esophageal tumors referred for RT. Materials/Methods: Sixteen esophageal cancer patients underwent endoscopic ultrasound (EUS) guided implantation. The first 7 patients received Cook gold markers and consecutive 9 patients Visicoil markers. The length of the Cook markers was 5 mm (pre-loaded system), but length of Visicoils varied from 3 to 10 mm (back loaded). Pain and toxicity were scored after implantation. Visibility and stability were evaluated on simulation CT scan and on weekly cone-beam CT (CBCT) images during the course of radiation. Results: A total of 41 fiducials were placed (18 Cooks and 23 Visicoils). Technical success was achieved in 15 out of 16 patients. In one patient the implantation failed because of a non-preloaded needle system (Cook) and was left out of analyses. Two grade 1 complications were noticed. Visibility on CT scan of both types of implanted markers was adequate for tumor delineation. Of the Cook markers, 50% remained visible during the whole course of radiation compared to 65% of the Visicoil markers. However, when selecting only Visicoils with a length of >5 mm, all (15/ 15) remained stable and visible on CBCT scan between implantation and end of radiation. Conclusions: EUS-guided placement of gold fiducials is both safe and feasible for esophageal tumors and adequate for tumor delineation and positional verification. The results imply an advantage of Visicoil markers over Cook markers in terms of stability over time, but the effects of a learning curve should be ruled out. Visicoil markers have to be at least 5 mm in length for visibility on CBCT scan. Author Disclosure: M. Machiels: None. J. van Hooft: None. T. Alderliesten: None. P. Jin: None. M.C.C. Hulshof: None.