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Can VMAT-based SBRT Be an Option in Patients Unsuitable for Intracavitary Brachytherapy in Locally Advanced Cancer of the Cervix?
S442
International Journal of Radiation Oncology Biology Physics
Conclusions: The pathological volume provided the more accurate tumor volume. This study determined the optimal SUV for PET by use of GTV as a “golden standard” for cervical cancer target volume delineation. Author Disclosure: Y. Zhang: None.
VMAT based SBRT as an alternative option in patients unsuitable for ICRT. Materials/Methods: CT Data sets of ten patients who underwent ICRT were used in the study. In all these patients a total Dose of 7 Gy was prescribed to Point A. Rectum Bladder and other normal structures were contoured on the ICRT CT data set, which were transferred to TPS along with the 150% ,100% (7 Gy Volume taken as PTV for VMAT Plan),80% and 50% Isodose volumes. VMAT plans were generated in TPS with 2 coplanar full Arc. Dosimetric parameters such as Conformity Index (CI100), Homogeneity Index (HI), were calculated for PTV whereas for Rectum and Bladder Mean dose (Dmean), 1cc, 2cc, and 5cc volume doses were used for evaluation. The treatment time was compared between the 2 techniques to understand its impact on intra fraction motion. A paired T test was used for plan comparisons. Results: The average CI100 for RA plans were 1.11 0.07 whereas averages HI were 1.549 0.19 and 8.61 0.15 for RA and ICRT plans respectively. As shown in the table-1 the average 1cc, 2cc, 5cc volume and mean doses of bladder for RA plans were 1.83 Gy, 0.98 Gy, 0.54 Gy, and 0.40 Gy less than ICRT plans. Similarly, the average 1cc, 2cc, 5cc volume and mean doses of rectum for RA plans were 0.30 Gy, 0.43 Gy, 0.80 Gy, and 0.94 Gy less than ICRT plans. The average actual beam on time for VMAT plans (DR 600 MU/ Min) was 1.93 min less than the ICRT plans (source strength is 10 Ci). Conclusions: The dosimetric results obtained in our study suggest that image guided SBRT can be used for patients with significant residual disease at the end of External Radiation therapy. Apart from variation in quality of application geometry, the CT based ICRT with Point A dose prescription has several limitations. In addition, VMAT-SBRT can be used for patients with parametrial disease extending up to lateral pelvic wall. The above facts and the results from this study have encouraged us to start a limited clinical study evaluating VMAT based SBRT using MR guided target delineation for patients unwilling to undergo or unsuitable for interstitial brachytherapy at the end of external radiation therapy after being declared unsuitable for ICRT. Author Disclosure: S. Vallinayagam: None. M. Kathirvel: None. C. Srinivas: None. S. Thirumalai Swamy: None. G. Arun: None.
2593 Correlation Between Proliferation Activity, Glucose Metabolism, and Tumor Volume in Patients With Cervical Cancer, Measured by 18F-FLT-PET and 18F-FDG-PET – Preliminary Results A. Roszak, E. Burchardt, W. Cholewinski, and B. Urbanski; Great Poland Cancer Centre, Pozna n, Poland Purpose/Objective(s): PET/CT studies can provide various information related to tumor molecular activity. Glucose metabolism and proliferation are well known factors, which have a significant impact on treatment planning, treatment response and patients prognosis. The aim of the study was to compare pretreatment tumor volume, FDG, and FLT uptake in the cervix cancer tumor before radiation therapy planning. Material/Methods: The study population comprised on 12 pts (aged 57 14 years) with histologically confirmed cervical cancer. All pts were injected with 185MBq of [(18)F]-fluoro-3-deoxy-L-thymidine ([(18)F] FLT) and 370MBq of 2- [(18)F]-fluoro-2-deoxy-D-glucose ([18)F]FDG) on two separated days. The acquisitions over abdomen and pelvis were performed twice using PET/CT scanner. The collected data were reconstructed using dedicated workstation. On reconstructed images the tumor borders are drawn using semiautomatic dedicated software based on 30% threshold method (other methods were also evaluated). Metabolic parameters of the tumor tissue and the tumor volume were evaluated on each nuclear image. For statistical analysis, the T-test was used. Results: There was no significant difference (p>0.05) in the tumor volume calculated on FDG images (77.5 56.6cc) and FLT images (78.4 62.68cc). The maximum standardized uptake values (SUV) of the tumor were similar in both examination- SUVmaxFDGZ 10.1 2.5, SUVmaxFLTZ7.9 3.5; p>0.05). However the mean SUV values in FDG images showed significantly higher values than on FLT images (SUVmeanFDGZ4.91.3, SUVmeanFLTZ3.41.0; p<0.05). No correlation was observed between glucose metabolism and proliferation activity in the evaluated patients (rZ0.4). Conclusions: The proliferation activities do not correlate with glucose metabolism in cervical cancer tumor. This phenomenon should be further evaluated in radiation therapy strategy planning and prognosis. Author Disclosure: A. Roszak: None. E. Burchardt: None. W. Cholewi nski: None. B. Urba nski: None.
2595 Impact of Concomitant Chemotherapy on the Effects of Treatment Prolongation in Cervical Cancer N. Shaverdian,1 V. Gondi,1 K.L. Sklenar,1 E.F. Dunn,1 S.M. Bentzen,1 D.G. Petereit,1,2 M.R. Straub,1 and K.A. Bradley1; 1Department of Human Oncology, University of Wisconsin Comprehensive Cancer Center, Madison, WI, 2John T. Vucurevich Cancer Care Institute, Rapid City Regional Hospital, Rapid City, SD
2594
Purpose/Objective(s): Prior reports have demonstrated adverse effects of treatment prolongation on pelvic control and survival outcomes in cervical cancer patients treated with radiation therapy alone (RT). In this study, we seek to assess whether treatment prolongation has similarly adverse effects in the setting of concomitant chemoradiation therapy (CRT). Methods/Materials: From 1989 to 2009, 480 consecutive cervical cancer patients treated at a single institution with RT or CRT for curative intent were retrospectively analyzed. Relapse was defined as in-field or out-offield, with patients censored at the time of first relapse. The effects of treatment duration (TD) on in-field and out-of-field relapse rates, diseasefree survival (DFS) and overall survival (OS) were assessed continuously
Can VMAT-based SBRT Be an Option in Patients Unsuitable for Intracavitary Brachytherapy in Locally Advanced Cancer of the Cervix? S. Vallinayagam, M. Kathirvel, C. Srinivas, S. Thirumalai Swamy, and G. Arun; Yashoda Hospitals, Hyderabad, India Purpose/Objective(s): On institutional retrospective audit, it was found that there was a large degree of noncompliance among patients advised interstitial Brachytherapy at the end of external radiation therapy after being declared unsuitable for ICRT. Hence a study was initiated to evaluate
Poster Viewing Abstract 2594; Table 1cc
2cc
5cc
Mean
Structure
Parameters
VMAT
ICRT
VMAT
ICRT
VMAT
ICRT
ICRT
ICRT
Bladder
Avg.Mean p Value Avg.Mean p Value
5.51 (2.73)
7.34 (4.30)
5.20 (2.62)
6.18 (3.34)
1.77 (0.92)
2.17 (0.88)
2.17 (0.88)
2.17 (0.88)
5.82 (2.15)
2.79 (2.33)
Rectum
0.36 2.86 (2.58) 0.71 D95
PTV Avg.Mean SD
0.56
2.05 1.17
3.98 2.59
1.89 1.18
4.79 (1.97)
0.56 Dmean 3.38 1.99
0.68 1.03 (0.68) 1.52 (0.91) 0.19 CI100 0.57 1.22 0.52 0.43
0.42 1.52 (0.91) 1.52 (0.91) 0.0042 HI 1.22 1.22 0.43 0.43
International Journal of Radiation Oncology Biology Physics
Conclusions: The pathological volume provided the more accurate tumor volume. This study determined the optimal SUV for PET by use of GTV as a “golden standard” for cervical cancer target volume delineation. Author Disclosure: Y. Zhang: None.
VMAT based SBRT as an alternative option in patients unsuitable for ICRT. Materials/Methods: CT Data sets of ten patients who underwent ICRT were used in the study. In all these patients a total Dose of 7 Gy was prescribed to Point A. Rectum Bladder and other normal structures were contoured on the ICRT CT data set, which were transferred to TPS along with the 150% ,100% (7 Gy Volume taken as PTV for VMAT Plan),80% and 50% Isodose volumes. VMAT plans were generated in TPS with 2 coplanar full Arc. Dosimetric parameters such as Conformity Index (CI100), Homogeneity Index (HI), were calculated for PTV whereas for Rectum and Bladder Mean dose (Dmean), 1cc, 2cc, and 5cc volume doses were used for evaluation. The treatment time was compared between the 2 techniques to understand its impact on intra fraction motion. A paired T test was used for plan comparisons. Results: The average CI100 for RA plans were 1.11 0.07 whereas averages HI were 1.549 0.19 and 8.61 0.15 for RA and ICRT plans respectively. As shown in the table-1 the average 1cc, 2cc, 5cc volume and mean doses of bladder for RA plans were 1.83 Gy, 0.98 Gy, 0.54 Gy, and 0.40 Gy less than ICRT plans. Similarly, the average 1cc, 2cc, 5cc volume and mean doses of rectum for RA plans were 0.30 Gy, 0.43 Gy, 0.80 Gy, and 0.94 Gy less than ICRT plans. The average actual beam on time for VMAT plans (DR 600 MU/ Min) was 1.93 min less than the ICRT plans (source strength is 10 Ci). Conclusions: The dosimetric results obtained in our study suggest that image guided SBRT can be used for patients with significant residual disease at the end of External Radiation therapy. Apart from variation in quality of application geometry, the CT based ICRT with Point A dose prescription has several limitations. In addition, VMAT-SBRT can be used for patients with parametrial disease extending up to lateral pelvic wall. The above facts and the results from this study have encouraged us to start a limited clinical study evaluating VMAT based SBRT using MR guided target delineation for patients unwilling to undergo or unsuitable for interstitial brachytherapy at the end of external radiation therapy after being declared unsuitable for ICRT. Author Disclosure: S. Vallinayagam: None. M. Kathirvel: None. C. Srinivas: None. S. Thirumalai Swamy: None. G. Arun: None.
2593 Correlation Between Proliferation Activity, Glucose Metabolism, and Tumor Volume in Patients With Cervical Cancer, Measured by 18F-FLT-PET and 18F-FDG-PET – Preliminary Results A. Roszak, E. Burchardt, W. Cholewinski, and B. Urbanski; Great Poland Cancer Centre, Pozna n, Poland Purpose/Objective(s): PET/CT studies can provide various information related to tumor molecular activity. Glucose metabolism and proliferation are well known factors, which have a significant impact on treatment planning, treatment response and patients prognosis. The aim of the study was to compare pretreatment tumor volume, FDG, and FLT uptake in the cervix cancer tumor before radiation therapy planning. Material/Methods: The study population comprised on 12 pts (aged 57 14 years) with histologically confirmed cervical cancer. All pts were injected with 185MBq of [(18)F]-fluoro-3-deoxy-L-thymidine ([(18)F] FLT) and 370MBq of 2- [(18)F]-fluoro-2-deoxy-D-glucose ([18)F]FDG) on two separated days. The acquisitions over abdomen and pelvis were performed twice using PET/CT scanner. The collected data were reconstructed using dedicated workstation. On reconstructed images the tumor borders are drawn using semiautomatic dedicated software based on 30% threshold method (other methods were also evaluated). Metabolic parameters of the tumor tissue and the tumor volume were evaluated on each nuclear image. For statistical analysis, the T-test was used. Results: There was no significant difference (p>0.05) in the tumor volume calculated on FDG images (77.5 56.6cc) and FLT images (78.4 62.68cc). The maximum standardized uptake values (SUV) of the tumor were similar in both examination- SUVmaxFDGZ 10.1 2.5, SUVmaxFLTZ7.9 3.5; p>0.05). However the mean SUV values in FDG images showed significantly higher values than on FLT images (SUVmeanFDGZ4.91.3, SUVmeanFLTZ3.41.0; p<0.05). No correlation was observed between glucose metabolism and proliferation activity in the evaluated patients (rZ0.4). Conclusions: The proliferation activities do not correlate with glucose metabolism in cervical cancer tumor. This phenomenon should be further evaluated in radiation therapy strategy planning and prognosis. Author Disclosure: A. Roszak: None. E. Burchardt: None. W. Cholewi nski: None. B. Urba nski: None.
2595 Impact of Concomitant Chemotherapy on the Effects of Treatment Prolongation in Cervical Cancer N. Shaverdian,1 V. Gondi,1 K.L. Sklenar,1 E.F. Dunn,1 S.M. Bentzen,1 D.G. Petereit,1,2 M.R. Straub,1 and K.A. Bradley1; 1Department of Human Oncology, University of Wisconsin Comprehensive Cancer Center, Madison, WI, 2John T. Vucurevich Cancer Care Institute, Rapid City Regional Hospital, Rapid City, SD
2594
Purpose/Objective(s): Prior reports have demonstrated adverse effects of treatment prolongation on pelvic control and survival outcomes in cervical cancer patients treated with radiation therapy alone (RT). In this study, we seek to assess whether treatment prolongation has similarly adverse effects in the setting of concomitant chemoradiation therapy (CRT). Methods/Materials: From 1989 to 2009, 480 consecutive cervical cancer patients treated at a single institution with RT or CRT for curative intent were retrospectively analyzed. Relapse was defined as in-field or out-offield, with patients censored at the time of first relapse. The effects of treatment duration (TD) on in-field and out-of-field relapse rates, diseasefree survival (DFS) and overall survival (OS) were assessed continuously
Can VMAT-based SBRT Be an Option in Patients Unsuitable for Intracavitary Brachytherapy in Locally Advanced Cancer of the Cervix? S. Vallinayagam, M. Kathirvel, C. Srinivas, S. Thirumalai Swamy, and G. Arun; Yashoda Hospitals, Hyderabad, India Purpose/Objective(s): On institutional retrospective audit, it was found that there was a large degree of noncompliance among patients advised interstitial Brachytherapy at the end of external radiation therapy after being declared unsuitable for ICRT. Hence a study was initiated to evaluate
Poster Viewing Abstract 2594; Table 1cc
2cc
5cc
Mean
Structure
Parameters
VMAT
ICRT
VMAT
ICRT
VMAT
ICRT
ICRT
ICRT
Bladder
Avg.Mean p Value Avg.Mean p Value
5.51 (2.73)
7.34 (4.30)
5.20 (2.62)
6.18 (3.34)
1.77 (0.92)
2.17 (0.88)
2.17 (0.88)
2.17 (0.88)
5.82 (2.15)
2.79 (2.33)
Rectum
0.36 2.86 (2.58) 0.71 D95
PTV Avg.Mean SD
0.56
2.05 1.17
3.98 2.59
1.89 1.18
4.79 (1.97)
0.56 Dmean 3.38 1.99
0.68 1.03 (0.68) 1.52 (0.91) 0.19 CI100 0.57 1.22 0.52 0.43
0.42 1.52 (0.91) 1.52 (0.91) 0.0042 HI 1.22 1.22 0.43 0.43