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OC-0266: Image-guided brachytherapy for cervical cancer patients using intracavitary and interstitial implants
S102 OC-0265 Using MRI and integrated ultrasound to guide brachytherapy for cervix cancer S. Van Dyk1, S. Kondalsamy-Chennakesavan2, M. Schneider3, K. Narayan4 1 Peter MacCallum Cancer Centre, Radiation Therapy Services, East Melbourne, Australia 2 University of Queensland, Rural Clinical School, Toowoomba, Australia 3 Monash University, Department of Medical Imaging and Radiation Science, Clayton, Australia 4 Peter MacCallum Cancer Centre, Division of Radiation Oncology, East Melbourne, Australia
ESTRO 33, 2014 Materials and Methods: The patients were treated with conformal external beam radiotherapy to a total dose of 50 Gy in combination with IGABT, using 5 fractions with a planning aim of 5 Gy per fraction. For each brachytherapy fraction 3D image guided treatment planning was performed to optimise the dose to the target volumes while keeping the dose to OAR as low as possible. Dose-volume-histogram parameters for the target volumes and OAR were recorded for each fraction and 2Gyeqivalent (EQD2) total dose were calculated using the LQ-model. Results: The mean and standard deviation for DVH parameters for all patents treated with and without needles are shown in Table 1.
Purpose/Objective: To compare measurements of the uterus and cervix obtained with MRI and ultrasound to determine: 1. changes in the brachytherapy volume over the course of treatment 2. impact on use of a single conformal plan. Materials and Methods: Data from patients undergoing curative treatment for cervix cancer with radiotherapy, between January 2007 and March 2012, were analysed. Intrauterine applicators were inserted under spinal or general anaesthesia. Trans-abdominal ultrasound was used for applicator insertion and treatment planning and performed in the brachytherapy/theatre suite. Ultrasound was used at all four fractions. MRI was used at fraction one only and necessitated the patient being moved to the MR suite after treatment. Images were obtained in the longitudinal axis of the uterus with the applicator in-situ. Four measurements were taken at both the anterior and posterior surface of the uterus at 2.0 cm intervals along the applicator, from the external os to the tip of the applicator. Measurements taken at fraction one with MRI and ultrasound were compared using Bland-Altman plots. Measurements taken with ultrasound at fraction one, two, three and four were analysed using repeated measures ANOVA and Dunnett’s multiple comparison test. The MRI measurements taken at fraction one served as the control. Mean differences (MD) between measurements on MRI and ultrasound of less than 3 mm in the cervix and 5 mm in the uterus were deemed not clinically significant. Results: One hundred and forty one patients contributed 6,047 measurements. MD and 95% CI between MRI and ultrasound at fraction one at each point on the anterior uterine surface were 2.2 mm [1.50 to2.84], 3.2 mm [2.49 to 3.87], 3.7 mm [2.83 to 4.47] and 1.4 mm [0.67 to 2.10] respectively. Measurements taken on the posterior surface were 0.07 mm [-0.73to 0.86], -0.2 mm [-0.85 to 0.52], 0.5 mm [-0.17 to 1.2] and -1.6 mm [-2.46 to-0.74] respectively. MD and 95% CI between MRI at fraction one and ultrasound at fraction four on the anterior uterine surfacewere 2.9 mm [2.08 to 3.65], 3.46 mm [2.86 to 4.09], 4.19 mm [3.53 to 4.86] and 1.64 mm [0.81 to 2.47] respectively; and on the posterior surface, 0.77 mm [0.03 to 1.52], 0.31 mm [-0.46 to 1.08], 0.93 mm [0.15 to 1.71] and -0.9 mm [-1.70 to -0.03] respectively. Changes in measurements to the posterior uterine wall over the course of brachytherapy were not statistically significant (p>0.05). All mean differences between fractions one and four were within the clinically acceptable limits. Conclusions: Ultrasound can accurately identify the cervix and uterus and can be used to assess and verify the brachytherapy volume over the course of treatment. Individualised conformal plans based on the measurements of the cervix and uterus taken with ultrasound can be used for the duration of treatment. There are considerable cost savings in using integrated ultrasound while maintaining safety and accuracy of treatment delivery. OC-0266 Image-guided brachytherapy for cervical cancer patients using intracavitary and interstitial implants B. Knutsen1, L.H. Djupvik1, K. Bruheim2, E. Nakken2, K. Skipar2, K. Sundfør3, T.P. Hellebust1 1 Oslo University Hospital, Department of Medical Physics, Oslo, Norway 2 Oslo University Hospital, Department of Cancer Treatment, Oslo, Norway 3 Oslo University Hospital, Department of Gyneacological Oncology, Oslo, Norway Purpose/Objective Image-guided adaptive brachytherapy (IGABT) is increasingly implemented as new treatment option for cervix cancer applying the GYN GEC ESTRO recommendations. A combination of intracavitary (IC) and interstitial (IS) implants are often applied in order to increase the dose to the target volumes and decrease the dose to the organs at risk (OAR). In this study data from 147 cervical cancer patients treated with 739 fractions were analysed.
Table 1. Figure 1 shows the total D2cm3 for the rectum, sigmoid and bladder as a function of the total D90 for the HR-CTV for all patients. All doses are shown in EQD2.
Figure 1 We were able to achieve our D90 planning aim of 81Gya/b=10 for 86 % of the patients, while 61 % of the patients were treated with a total D90 > 85 Gya/b=10. For the OARs constraints were violated in 4 and 5 patients for the rectum and sigmoid, respectively (constraints of D2cm3 < 74 Gya/b=3 for both), while for the bladder no patients received higher dose than the constraint of D2cm3 < 90 Gya/b=3 Needles were used in 186 fractions (25%) and 53 patients (36%) were treated with at least one fraction with an IC/IS implant. An average of 2.5 needles was used per needle implant. The mean HR-CTV volume was significantly larger for the patients treated with IC/IS implants compared to the patients treated without needles (p=0.01), while the mean HRCTV D90 were significantly smaller (p=0.001). For the IC/IS patients we were able to reach a D90 of 81Gya/b=10 and 85 Gya/b=10 for 83 % and 45% of the patients, respectively. The same figures for the IC patients were 87% and 69%. Except for the sigmoid, the D2cm3 for the OARs were significantly larger for the IC/IS patients compared to the IC patients (p<0.05). However, for the 4 patients were the rectum constraints were violated, 3 patients were treated without needles. Conclusions: Using needles in combination with an intracavitary implant gives the possibility to deliver acceptable dose to large target volumes without violating the OAR constraints. To be able to give even higher target dose, a larger fraction of the patients should be treated with needles. OC-0267 Towards 4D image-guided adaptive brachytherapy (IGABT) for locally recurrent endometrial cancer L. Fokdal1, K. Tanderup1, A. Zizzo1, S. Nielsen2, L. Røhl3, E. Pedersen3, G. Ortoft4, J.C. Lindegaard4 1 Aarhus University Hospital, Department of Oncology, Aarhus C, Denmark 2 Aarhus University Hospital, Department of Medical Physics, Aarhus C, Denmark 3 Aarhus University Hospital, Department of Radiology, Aarhus C, Denmark
ESTRO 33, 2014 Materials and Methods: The patients were treated with conformal external beam radiotherapy to a total dose of 50 Gy in combination with IGABT, using 5 fractions with a planning aim of 5 Gy per fraction. For each brachytherapy fraction 3D image guided treatment planning was performed to optimise the dose to the target volumes while keeping the dose to OAR as low as possible. Dose-volume-histogram parameters for the target volumes and OAR were recorded for each fraction and 2Gyeqivalent (EQD2) total dose were calculated using the LQ-model. Results: The mean and standard deviation for DVH parameters for all patents treated with and without needles are shown in Table 1.
Purpose/Objective: To compare measurements of the uterus and cervix obtained with MRI and ultrasound to determine: 1. changes in the brachytherapy volume over the course of treatment 2. impact on use of a single conformal plan. Materials and Methods: Data from patients undergoing curative treatment for cervix cancer with radiotherapy, between January 2007 and March 2012, were analysed. Intrauterine applicators were inserted under spinal or general anaesthesia. Trans-abdominal ultrasound was used for applicator insertion and treatment planning and performed in the brachytherapy/theatre suite. Ultrasound was used at all four fractions. MRI was used at fraction one only and necessitated the patient being moved to the MR suite after treatment. Images were obtained in the longitudinal axis of the uterus with the applicator in-situ. Four measurements were taken at both the anterior and posterior surface of the uterus at 2.0 cm intervals along the applicator, from the external os to the tip of the applicator. Measurements taken at fraction one with MRI and ultrasound were compared using Bland-Altman plots. Measurements taken with ultrasound at fraction one, two, three and four were analysed using repeated measures ANOVA and Dunnett’s multiple comparison test. The MRI measurements taken at fraction one served as the control. Mean differences (MD) between measurements on MRI and ultrasound of less than 3 mm in the cervix and 5 mm in the uterus were deemed not clinically significant. Results: One hundred and forty one patients contributed 6,047 measurements. MD and 95% CI between MRI and ultrasound at fraction one at each point on the anterior uterine surface were 2.2 mm [1.50 to2.84], 3.2 mm [2.49 to 3.87], 3.7 mm [2.83 to 4.47] and 1.4 mm [0.67 to 2.10] respectively. Measurements taken on the posterior surface were 0.07 mm [-0.73to 0.86], -0.2 mm [-0.85 to 0.52], 0.5 mm [-0.17 to 1.2] and -1.6 mm [-2.46 to-0.74] respectively. MD and 95% CI between MRI at fraction one and ultrasound at fraction four on the anterior uterine surfacewere 2.9 mm [2.08 to 3.65], 3.46 mm [2.86 to 4.09], 4.19 mm [3.53 to 4.86] and 1.64 mm [0.81 to 2.47] respectively; and on the posterior surface, 0.77 mm [0.03 to 1.52], 0.31 mm [-0.46 to 1.08], 0.93 mm [0.15 to 1.71] and -0.9 mm [-1.70 to -0.03] respectively. Changes in measurements to the posterior uterine wall over the course of brachytherapy were not statistically significant (p>0.05). All mean differences between fractions one and four were within the clinically acceptable limits. Conclusions: Ultrasound can accurately identify the cervix and uterus and can be used to assess and verify the brachytherapy volume over the course of treatment. Individualised conformal plans based on the measurements of the cervix and uterus taken with ultrasound can be used for the duration of treatment. There are considerable cost savings in using integrated ultrasound while maintaining safety and accuracy of treatment delivery. OC-0266 Image-guided brachytherapy for cervical cancer patients using intracavitary and interstitial implants B. Knutsen1, L.H. Djupvik1, K. Bruheim2, E. Nakken2, K. Skipar2, K. Sundfør3, T.P. Hellebust1 1 Oslo University Hospital, Department of Medical Physics, Oslo, Norway 2 Oslo University Hospital, Department of Cancer Treatment, Oslo, Norway 3 Oslo University Hospital, Department of Gyneacological Oncology, Oslo, Norway Purpose/Objective Image-guided adaptive brachytherapy (IGABT) is increasingly implemented as new treatment option for cervix cancer applying the GYN GEC ESTRO recommendations. A combination of intracavitary (IC) and interstitial (IS) implants are often applied in order to increase the dose to the target volumes and decrease the dose to the organs at risk (OAR). In this study data from 147 cervical cancer patients treated with 739 fractions were analysed.
Table 1. Figure 1 shows the total D2cm3 for the rectum, sigmoid and bladder as a function of the total D90 for the HR-CTV for all patients. All doses are shown in EQD2.
Figure 1 We were able to achieve our D90 planning aim of 81Gya/b=10 for 86 % of the patients, while 61 % of the patients were treated with a total D90 > 85 Gya/b=10. For the OARs constraints were violated in 4 and 5 patients for the rectum and sigmoid, respectively (constraints of D2cm3 < 74 Gya/b=3 for both), while for the bladder no patients received higher dose than the constraint of D2cm3 < 90 Gya/b=3 Needles were used in 186 fractions (25%) and 53 patients (36%) were treated with at least one fraction with an IC/IS implant. An average of 2.5 needles was used per needle implant. The mean HR-CTV volume was significantly larger for the patients treated with IC/IS implants compared to the patients treated without needles (p=0.01), while the mean HRCTV D90 were significantly smaller (p=0.001). For the IC/IS patients we were able to reach a D90 of 81Gya/b=10 and 85 Gya/b=10 for 83 % and 45% of the patients, respectively. The same figures for the IC patients were 87% and 69%. Except for the sigmoid, the D2cm3 for the OARs were significantly larger for the IC/IS patients compared to the IC patients (p<0.05). However, for the 4 patients were the rectum constraints were violated, 3 patients were treated without needles. Conclusions: Using needles in combination with an intracavitary implant gives the possibility to deliver acceptable dose to large target volumes without violating the OAR constraints. To be able to give even higher target dose, a larger fraction of the patients should be treated with needles. OC-0267 Towards 4D image-guided adaptive brachytherapy (IGABT) for locally recurrent endometrial cancer L. Fokdal1, K. Tanderup1, A. Zizzo1, S. Nielsen2, L. Røhl3, E. Pedersen3, G. Ortoft4, J.C. Lindegaard4 1 Aarhus University Hospital, Department of Oncology, Aarhus C, Denmark 2 Aarhus University Hospital, Department of Medical Physics, Aarhus C, Denmark 3 Aarhus University Hospital, Department of Radiology, Aarhus C, Denmark