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Quantification of Inter-Fractional Organ Motion and Deformation Using Megavoltage Computed Tomography Images From Helical Tomotherapy
Proceedings of the 49th Annual ASTRO Meeting
2582
Differences in Pattern of Practice in Radiation Therapy for Patients With Non-Small Cell Lung Cancer (NSCLC) Between Physicians in China and the United States (US)
L. Wang1, G. Jiang2, F. Kong3 1 3
Peking Union Medical University, Cancer Hospital, Beijing, China, 2Fudan University Cancer Hospital, Shanghai, China, Michigan University, Ann Arbor, MI
Purpose/Objective(s): To study the pattern of practice in radiation therapy (RT) for NSCLC patients in China and compare the results with that of US. Materials/Methods: Study questionnaires were designed by a panel of 8 Board certified radiation oncologists. The survey was sent through email to radiation oncologist members of American Society of Therapeutic Radiology and Oncology (ASTRO) in September, 2006, and to Chinese radiation oncologists in January, 2007. The results were collected online in March, 2007. There were a total of 492 responses: 425 from the US and 67 from China. Results: Chinese respondents saw an average of 14 new cases monthly, significantly more than US physicians (p \ 0.001). The choices of treatment decision and RT prescription were heterogeneous among respondents. There was a significant difference in choices of radiation regimens for stage I peripherally located disease: 20% Chinese vs 34% of US chose conventional fractionated RT (p\0.00), 43% Chinese vs 19% of US chose stereotactic RT (p\0.001), 0% Chinese vs 14% of US chose stereotactic RT 1820 Gy 3, and 23% Chinese vs 1.5% of US chose 6 Gy 10 (p \ 0.001). For stage I centrally located disease, the majority of respondents selected conventional fractionated RT in both countries: 28% of Chinese vs 8% of US chose stereotactic RT (p \ 0.001). For stage II disease, a majority of respondents chose concurrent chemoradiation (64% Chinese vs 85% of US, p \ 0.001), with radiation dose of 60–70 Gy in 1.8–2 Gy daily fractions (79% of US vs 69% Chinese). For stage III patients with a performance score of 70–100%, the dominant pattern of practice was concurrent chemoradiation followed by adjuvant chemotherapy (61% Chinese vs 85% of US respondents, p\0.001); 16% Chinese vs 1% of US chose sequential chemoradiation (p\0.001). For patients with performance score of 50–60%, 36% of Chinese and 41% of US respondents chose fractionated RT alone, 0% Chinese vs 11% of US chose concurrent chemoradiation followed by adjuvant chemotherapy, 22% Chinese vs 17% of US chose chemotherapy followed by RT, 13% Chinese vs 20% of US chose RT followed by chemotherapy (p \ 0.001). Regarding choices of dose fractionation, 45% Chinese vs 79% of US respondents (p \ 0.001) chose 60–70 Gy in 1.8–2 Gy daily fractions, 48% Chinese vs 13% of US chose exactly 60 Gy in 2 Gy daily fractions (p \ 0.001). For stage IV disease with good performance score, 50% Chinese 27% of US respondents chose 2 Gy 30 (p = 0.001), fewer Chinese respondents chose lower doses or no radiation (p = 0.001). For patients with stage IV with hemoptysis or obstructive lung disease with asymptomatic distant metastasis, Chinese respondents tended to choose chemotherapy followed by RT (39%) more than 3 Gy 10 followed by chemotherapy (10%), which is the opposite of respondents of the US (5% vs 43%, p \ 0.001). Conclusions: There is a significant difference in the pattern of practice for NSCLC patients between radiation oncologists from China and the US. Fewer Chinese physicians selected larger fraction size for stereotactic RT, higher total dose for fractionated RT, and concurrent chemoradiation for stage II/III NSCLC, and aggressive RT for stage IV diseases. Author Disclosure: L. Wang, None; G. Jiang, None; F. Kong, None.
2583
Effect of Different Concurrent Chemotherapy Regimens on Locally Advanced Non-Small Cell Lung Carcinoma
H. Ren, L. Wang Cancer Hospital of Chinese Academy of Medical Science, Beijing, China Purpose/Objective(s): To retrospectively analyze the effects of different concurrent chemotherapy regimens on locally advanced non-small-cell lung carcinoma (NSCLC). Materials/Methods: Data were analyzed from 106 patients pathologically diagnosed as NSCLC(IIIa: 29 IIIb: 77) and received concurrent external beam radiotherapy with various chemotherapy regimens. Analysis was performed for overall survival, progression-free survival, freedom from local-regional progression survival, and toxicity (grade$2). Results: Paclitaxel based chemotherapy regimen was delivered in 55 patients (51.9%), whereas 21 patients (19.8%) with topotecan regimen and 26 patients (24.5%) with PE (cisplatin and etopside) regimen, 4 patients had other chemotherapy regimens. The median follow-up time for surviving patients was 14.4 months, the median survival time was 18.6 months, the overall 1-, 2- and 3-year survival rate were 72.2%, 41.1% and 27.5%, respectively. Survival and toxicity analysis were performed in 102 patients which include paclitaxel, topotecan and PE groups, the median survival time was 16.3 months, 27.3 months and 29.1 months, respectively. The overall survivals of topotecan and PE groups were superior to paclitaxol based group, but not signifcant (p = 0.32). However, when topotecan and PE group were combined (47 patients) and compared to paclitaxel based regimen group, the median survival was poorer in patients with paclitaxol based regimen (16.3 months vs. 27.3 months), and both in univariate and multivariate analysis paclitaxol based chemotherapy regimen was significantly associated with poorer survival (p \ 0.05). N stage was significant in the COX multivariate regression model. Paclitaxel based regimen was associated with more acute radiation pneumonitis, 27.3% versus 10.6%, (p = 0.03), less blood toxicity (16.4% vs 29.8%) (p = 0.108) and almost same esophagitis (29.1% vs 34.0%). Conclusions: This retrospective analysis showed a correlation between concurrent chemotherapy regimens with survival and toxicity in patients with locally advanced NSCLC. Further study for chemotherapy regimens in concurrent chemoradiation is needed. Author Disclosure: H. Ren, None; L. Wang, None.
2584
Quantification of Inter-Fractional Organ Motion and Deformation Using Megavoltage Computed Tomography Images From Helical Tomotherapy
L. Lin1,2, C. Shi1,2, G. Swanson1, N. Papanikolaou1,2 1 University of Texas Health Science Center at San Antonio, San Antonio, TX, 2Cancer Therapy and Research Center, San Antonio, TX Purpose/Objective(s): Planning for radiation therapy with modern equipment is very precise, although targeting remains a major challenge because of inter-fractional organ motion and deformation. We sought to quantify those parameters utilizing multiple
S527
S528
I. J. Radiation Oncology d Biology d Physics
Volume 69, Number 3, Supplement, 2007
daily megavoltage computed tomography (MVCT) imaging with helical tomotherapy (HT) over the course of the treatment. Multiple daily imaging should give a unique opportunity to quantify motion and deformation. Anatomy site-specific margins for targets and critical structures were identified. Materials/Methods: Six representative patients who underwent HT treatment were analyzed retrospectively. The treatment sites included two of each: lung, prostate, and pancreas. MVCT images were obtained daily prior to each treatment. Targets and clinical structures were contoured for all data sets. The center of mass (COM), shifts in right-left (RL), superior-inferior (SI), and anterior-posterior (AP) directions, and volume change (DV) for selected treatment fractions were used as surrogates to measure organ shifts and deformation. The planning target volume (PTV) and critical structures margins were calculated based on ICRU 71 guidelines. Results: The means and standard deviations of the COM of inter-fractional targets and critical structures in RL, SI, and AP directions during the entire treatment course are tabulated (Table). The liver displayed the largest mean shift and shape change in both the SI and AP directions. The largest DV (±50%) was found for the bladder. The largest motion of the lung targets was observed in the AP direction with the maximum 17.0 mm in absolute value. The largest shift of prostate targets was observed in the AP direction with a value of 11.8 mm. The statistical analysis for 25 fractions indicated that the inter-fraction anatomic variations were site-specific in RL (p = 0.0001), SI (p \ 0.001), AP (p \ 0.001) directions. For the same patient, the inter-fractional variations of target and critical structures were uncorrelated. Based on the maximum deviations of the COM in the three directions, the PTV margins for lung and prostate were calculated as 15.6 mm and 7.7 mm respectively if no consideration was given to account for organ motion. Conclusions: Daily MVCT images from tomotherapy can be used to effectively evaluate inter-fractional anatomic variations during treatment (Fig.). The inter-fractional variations in shape and positions of both targets and critical structures are substantial and site-specific. The use of a non-uniform margin for PTV definitions is recommended considering the different characteristics of organ motion in each of the three measured directions.
Targets Observed center of mass shift relative to planning CT (mm) Right-left Mean SD Min (absolute value) Max (absolute value) Superior-inferior Mean SD Min (absolute value) Max (absolute value) Anterior-posterior Mean SD Min (absolute value) Max (absolute value) Calculated PTV margins or critical structure margins (= 2s + 0.7r)
Lung
Critical Structures
Prostate
Liver
Lt kidney
Rt kidney
Bladder
Rectum
3.4 3.3 0.0 11.1
1.5 1.7 0.1 4.4
2.3 2.4 0.0 6.3
0.6 3.5 0.4 9.6
2.6 1.9 0.1 6.0
1.1 1.9 0.6 5.2
1.8 1.7 0.6 3.8
4.6 2.7 0.9 8.4
1.9 2.6 0.2 9.0
5.5 6.9 0.2 17.4
3.7 3.2 5.2 9.8
0.4 3.8 0.3 5.9
3.9 2.4 0.2 7.4
4.6 3.8 0.5 9.2
4.2 7.3 2.3 17.0
3.3 3.4 0.1 11.8
10.0 2.6 5.2 12.9
4.8 2.2 1.8 9.0
4.5 3.7 1.2 8.9
5.4 1.7 2.6 8.3
5.9 2.5 2.2 9.3
15.6
7.7
15.1
11.8
9.0
5.7
8.1
s = Systematic error. r = Random error.
Author Disclosure: L. Lin, None; C. Shi, None; G. Swanson, None; N. Papanikolaou, None.
2582
Differences in Pattern of Practice in Radiation Therapy for Patients With Non-Small Cell Lung Cancer (NSCLC) Between Physicians in China and the United States (US)
L. Wang1, G. Jiang2, F. Kong3 1 3
Peking Union Medical University, Cancer Hospital, Beijing, China, 2Fudan University Cancer Hospital, Shanghai, China, Michigan University, Ann Arbor, MI
Purpose/Objective(s): To study the pattern of practice in radiation therapy (RT) for NSCLC patients in China and compare the results with that of US. Materials/Methods: Study questionnaires were designed by a panel of 8 Board certified radiation oncologists. The survey was sent through email to radiation oncologist members of American Society of Therapeutic Radiology and Oncology (ASTRO) in September, 2006, and to Chinese radiation oncologists in January, 2007. The results were collected online in March, 2007. There were a total of 492 responses: 425 from the US and 67 from China. Results: Chinese respondents saw an average of 14 new cases monthly, significantly more than US physicians (p \ 0.001). The choices of treatment decision and RT prescription were heterogeneous among respondents. There was a significant difference in choices of radiation regimens for stage I peripherally located disease: 20% Chinese vs 34% of US chose conventional fractionated RT (p\0.00), 43% Chinese vs 19% of US chose stereotactic RT (p\0.001), 0% Chinese vs 14% of US chose stereotactic RT 1820 Gy 3, and 23% Chinese vs 1.5% of US chose 6 Gy 10 (p \ 0.001). For stage I centrally located disease, the majority of respondents selected conventional fractionated RT in both countries: 28% of Chinese vs 8% of US chose stereotactic RT (p \ 0.001). For stage II disease, a majority of respondents chose concurrent chemoradiation (64% Chinese vs 85% of US, p \ 0.001), with radiation dose of 60–70 Gy in 1.8–2 Gy daily fractions (79% of US vs 69% Chinese). For stage III patients with a performance score of 70–100%, the dominant pattern of practice was concurrent chemoradiation followed by adjuvant chemotherapy (61% Chinese vs 85% of US respondents, p\0.001); 16% Chinese vs 1% of US chose sequential chemoradiation (p\0.001). For patients with performance score of 50–60%, 36% of Chinese and 41% of US respondents chose fractionated RT alone, 0% Chinese vs 11% of US chose concurrent chemoradiation followed by adjuvant chemotherapy, 22% Chinese vs 17% of US chose chemotherapy followed by RT, 13% Chinese vs 20% of US chose RT followed by chemotherapy (p \ 0.001). Regarding choices of dose fractionation, 45% Chinese vs 79% of US respondents (p \ 0.001) chose 60–70 Gy in 1.8–2 Gy daily fractions, 48% Chinese vs 13% of US chose exactly 60 Gy in 2 Gy daily fractions (p \ 0.001). For stage IV disease with good performance score, 50% Chinese 27% of US respondents chose 2 Gy 30 (p = 0.001), fewer Chinese respondents chose lower doses or no radiation (p = 0.001). For patients with stage IV with hemoptysis or obstructive lung disease with asymptomatic distant metastasis, Chinese respondents tended to choose chemotherapy followed by RT (39%) more than 3 Gy 10 followed by chemotherapy (10%), which is the opposite of respondents of the US (5% vs 43%, p \ 0.001). Conclusions: There is a significant difference in the pattern of practice for NSCLC patients between radiation oncologists from China and the US. Fewer Chinese physicians selected larger fraction size for stereotactic RT, higher total dose for fractionated RT, and concurrent chemoradiation for stage II/III NSCLC, and aggressive RT for stage IV diseases. Author Disclosure: L. Wang, None; G. Jiang, None; F. Kong, None.
2583
Effect of Different Concurrent Chemotherapy Regimens on Locally Advanced Non-Small Cell Lung Carcinoma
H. Ren, L. Wang Cancer Hospital of Chinese Academy of Medical Science, Beijing, China Purpose/Objective(s): To retrospectively analyze the effects of different concurrent chemotherapy regimens on locally advanced non-small-cell lung carcinoma (NSCLC). Materials/Methods: Data were analyzed from 106 patients pathologically diagnosed as NSCLC(IIIa: 29 IIIb: 77) and received concurrent external beam radiotherapy with various chemotherapy regimens. Analysis was performed for overall survival, progression-free survival, freedom from local-regional progression survival, and toxicity (grade$2). Results: Paclitaxel based chemotherapy regimen was delivered in 55 patients (51.9%), whereas 21 patients (19.8%) with topotecan regimen and 26 patients (24.5%) with PE (cisplatin and etopside) regimen, 4 patients had other chemotherapy regimens. The median follow-up time for surviving patients was 14.4 months, the median survival time was 18.6 months, the overall 1-, 2- and 3-year survival rate were 72.2%, 41.1% and 27.5%, respectively. Survival and toxicity analysis were performed in 102 patients which include paclitaxel, topotecan and PE groups, the median survival time was 16.3 months, 27.3 months and 29.1 months, respectively. The overall survivals of topotecan and PE groups were superior to paclitaxol based group, but not signifcant (p = 0.32). However, when topotecan and PE group were combined (47 patients) and compared to paclitaxel based regimen group, the median survival was poorer in patients with paclitaxol based regimen (16.3 months vs. 27.3 months), and both in univariate and multivariate analysis paclitaxol based chemotherapy regimen was significantly associated with poorer survival (p \ 0.05). N stage was significant in the COX multivariate regression model. Paclitaxel based regimen was associated with more acute radiation pneumonitis, 27.3% versus 10.6%, (p = 0.03), less blood toxicity (16.4% vs 29.8%) (p = 0.108) and almost same esophagitis (29.1% vs 34.0%). Conclusions: This retrospective analysis showed a correlation between concurrent chemotherapy regimens with survival and toxicity in patients with locally advanced NSCLC. Further study for chemotherapy regimens in concurrent chemoradiation is needed. Author Disclosure: H. Ren, None; L. Wang, None.
2584
Quantification of Inter-Fractional Organ Motion and Deformation Using Megavoltage Computed Tomography Images From Helical Tomotherapy
L. Lin1,2, C. Shi1,2, G. Swanson1, N. Papanikolaou1,2 1 University of Texas Health Science Center at San Antonio, San Antonio, TX, 2Cancer Therapy and Research Center, San Antonio, TX Purpose/Objective(s): Planning for radiation therapy with modern equipment is very precise, although targeting remains a major challenge because of inter-fractional organ motion and deformation. We sought to quantify those parameters utilizing multiple
S527
S528
I. J. Radiation Oncology d Biology d Physics
Volume 69, Number 3, Supplement, 2007
daily megavoltage computed tomography (MVCT) imaging with helical tomotherapy (HT) over the course of the treatment. Multiple daily imaging should give a unique opportunity to quantify motion and deformation. Anatomy site-specific margins for targets and critical structures were identified. Materials/Methods: Six representative patients who underwent HT treatment were analyzed retrospectively. The treatment sites included two of each: lung, prostate, and pancreas. MVCT images were obtained daily prior to each treatment. Targets and clinical structures were contoured for all data sets. The center of mass (COM), shifts in right-left (RL), superior-inferior (SI), and anterior-posterior (AP) directions, and volume change (DV) for selected treatment fractions were used as surrogates to measure organ shifts and deformation. The planning target volume (PTV) and critical structures margins were calculated based on ICRU 71 guidelines. Results: The means and standard deviations of the COM of inter-fractional targets and critical structures in RL, SI, and AP directions during the entire treatment course are tabulated (Table). The liver displayed the largest mean shift and shape change in both the SI and AP directions. The largest DV (±50%) was found for the bladder. The largest motion of the lung targets was observed in the AP direction with the maximum 17.0 mm in absolute value. The largest shift of prostate targets was observed in the AP direction with a value of 11.8 mm. The statistical analysis for 25 fractions indicated that the inter-fraction anatomic variations were site-specific in RL (p = 0.0001), SI (p \ 0.001), AP (p \ 0.001) directions. For the same patient, the inter-fractional variations of target and critical structures were uncorrelated. Based on the maximum deviations of the COM in the three directions, the PTV margins for lung and prostate were calculated as 15.6 mm and 7.7 mm respectively if no consideration was given to account for organ motion. Conclusions: Daily MVCT images from tomotherapy can be used to effectively evaluate inter-fractional anatomic variations during treatment (Fig.). The inter-fractional variations in shape and positions of both targets and critical structures are substantial and site-specific. The use of a non-uniform margin for PTV definitions is recommended considering the different characteristics of organ motion in each of the three measured directions.
Targets Observed center of mass shift relative to planning CT (mm) Right-left Mean SD Min (absolute value) Max (absolute value) Superior-inferior Mean SD Min (absolute value) Max (absolute value) Anterior-posterior Mean SD Min (absolute value) Max (absolute value) Calculated PTV margins or critical structure margins (= 2s + 0.7r)
Lung
Critical Structures
Prostate
Liver
Lt kidney
Rt kidney
Bladder
Rectum
3.4 3.3 0.0 11.1
1.5 1.7 0.1 4.4
2.3 2.4 0.0 6.3
0.6 3.5 0.4 9.6
2.6 1.9 0.1 6.0
1.1 1.9 0.6 5.2
1.8 1.7 0.6 3.8
4.6 2.7 0.9 8.4
1.9 2.6 0.2 9.0
5.5 6.9 0.2 17.4
3.7 3.2 5.2 9.8
0.4 3.8 0.3 5.9
3.9 2.4 0.2 7.4
4.6 3.8 0.5 9.2
4.2 7.3 2.3 17.0
3.3 3.4 0.1 11.8
10.0 2.6 5.2 12.9
4.8 2.2 1.8 9.0
4.5 3.7 1.2 8.9
5.4 1.7 2.6 8.3
5.9 2.5 2.2 9.3
15.6
7.7
15.1
11.8
9.0
5.7
8.1
s = Systematic error. r = Random error.
Author Disclosure: L. Lin, None; C. Shi, None; G. Swanson, None; N. Papanikolaou, None.