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123 Breath-hold technique during radical radiotherapy for non-small-cell lung cancer (NSCLC)
Poster abstracts of the 14th Annual British Thoracic Oncology Group Conference 2016 / Lung Cancer 91, Suppl. 1 (2016) S1–S71
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acute toxicity, where 6 patients had grade 1 and the remaining 6 had grade 2 (CTCAE version 4.03). None of these 12 patients had any worsening of dyspnoea or noticeable pneumonitis. Median follow-up is 15.24 months and median overall survival has not been reached. Estimated mean progression-free survival is 10.5 months. Estimated 12-month and 18-month survival rates are both 72.9%. At the time of analysis, 2 patients had local failure, 3 had distant failure and 1 had both local and distant failure. Three out of 12 patients have died from disease. Table 1. Planning parameters for CHART patients treated using VMAT Mean
Median
Standard Minimum Maximum deviation value value
GTV volume (ml) 229.4 PTV volume (ml) 858.5 Cranio-caudal PTV length (cm) 12.7 Whole lung volume (ml) 2872.9 PTV:whole lung volume ratio 0.308 Minimum dose to at least 5% of PTV (Gy) 56.34 Minimum dose to at least 95% of PTV (Gy) 51.20 Spinal canal max dose (Gy) 37.7 Spinal canal PRV max dose (Gy) 41.8 MLD (Gy) 12.4 V30 lung (%) 13.3 V20 lung (%) 22.3 V10 lung (%) 39.9 V5 lung (%) 58.9 Heart mean dose (Gy) 16.3 V30 heart (%) 24.5 Oesophagus mean dose (Gy) 23.4 Conformity number 0.84 Conformity index 1.03 Dose homogeneity index (DHI) 1.10
127.0 700.1 12.5 2723.7 0.252
234.5 466.7 3.10 690.2 0.180
43.2 345.6 7.5 1900.4 0.148
849.8 1970.6 18.5 4008.7 0.780
56.13
0.80
55.33
57.77
51.63 38.1 42.4 13.0 14.4 22.4 40.2 63.4 17.3 22.9 24.4 0.88 1.04 1.09
1.70 4.1 4.7 3.2 5.7 8.0 10.5 12.7 8.8 14.7 6.4 0.07 0.10 0.04
47.97 28.9 33.1 8.2 5.1 11.4 25.2 39.22 1.6 3.4 10.4 0.72 0.82 1.07
53.79 44.2 51.1 16.3 20.8 32.7 56.4 73.7 26.7 47.0 33.8 0.92 1.19 1.20
Conclusion: Although a small series with early data, CHART using VMAT was well tolerated with manageable and reversible oesophageal toxicity. Clinical impact of Accelerated Hyperfractionation with VMAT in lung cancer needs to be evaluated further for toxicity, local control and survival. Disclosure: All authors have declared no conflicts of interest. 122
To determine ideal gross tumour volumes and PTV expansion using four-dimensional computed tomography for the treatment of lung cancer
N. Goyal 1 , M. Ingle 1 , N. Bhuva 2 , D. Power 1 , C. Lewanski 3 . Charing Cross Hospital, London, United Kingdom; 2 Oncology, Mount Vernon Cancer Centre, Middlesex, United Kingdom; 3 Charing Cross Hospital (imperial), Charing Cross Hospital (Imperial), London, United Kingdom 1 Radiotherapy,
Introduction: To determine the ideal protocol to determine Gross Tumour Volume (GTV) using Four-Dimensional Computed Tomography (4DCT) in the treatment of lung cancers. To then determine the optimal Planning Target Volume (PTV) expansion volume using ontreatment Cone Beam CT (CBCT) verification data. Methods: 4DCT data for 13 consecutively treated patients with lung cancer (stage I: 3, stage II: 5, stage III: 5). The GTV was determined from the 4DCT data on each individual patient using the following methods: 1) GTV was determined individually on all 10 phases (GTVMERGE ); 2) defining GTV from 3DCT alone (GTV3DCT ) 3) defining GTV from MIP data alone (GTVMIP ); 4) combining GTV data from MIP and two extreme respiratory phases (0% and 50%) (GTVMODMIP ). We used the GTVMERGE as our reference GTV and compared volume and orthogonal positioning to the other three GTV volumes. Using the GTVMODMIP dataset, PTV volumes of 3mm, 5mm, 7mm and 10mm were created (assuming a standard GTV to ITV growth of 5mm). These were then overlain onto on-treatment CBCT images to determine our department’s ideal PTV expansion.
Results: The GTV3DCT was consistently smaller and unrepresentative of the reference GTVMERGE data. GTVMIP and GTVMODMIP more closely represented the reference GTVMERGE although GTVMIP frequently underestimated the reference GTVMERGE . GTVMODMIP only slightly overestimated the reference GTVMERGE and had the smallest standard deviation. A PTV expansion of 5mm was then sufficient to accurately encompass the tumour through treatment. Over/underestimation of GTV compared to reference GTVMERGE (cm3 )
Max Min Median Mean Standard deviation
GTV3DCT
GTVMIP
GTVMODMIP
27.46 −1.18 6.25 7.79 7.61
6.48 −1.47 0.77 1.60 2.69
2.6 −5.53 −0.61 −0.74 2.08
Conclusion: Utilising GTVMODMIP allows for a representative volume and is considerably quicker to volume (3 versus 10 volumes). The use of CBCT for on-treatment verification allowed us to determine our departmental setup error and reduce PTV expansion to 5mm. Further reduction is possible for certain tumours but would require daily verification. Disclosure: All authors have declared no conflicts of interest. 123
Breath-hold technique during radical radiotherapy for non-small-cell lung cancer (NSCLC)
A.E. Hollingdale, E.J. Orchard, S.J. Treece. Haematology/Oncology Unit Box 018, Peterborough City Hospital, Peterborough, United Kingdom Introduction: Local tumour control in NSCLC is limited in part by the dose delivered, normal tissue tolerance, and prediction of tumour motion. In a patient with >1cm tumour motion requiring increased margins to ensure treatment dose is delivered, various techniques can be used to improve radiation delivery. Here we describe radical treatment using a breath hold technique with daily on-line cone beam CT (CBCT) imaging, and compare to conventional 4D planning. Methods: 3D and 4D planning CT scans were performed and reviewed for a patient with a T1bN0M0 NSCLC of the right lower lobe. Tumour motion in the superior-inferior plane was >3cm, so a scan in comfortable breath hold (BH) was obtained. The tumour was outlined in the 4D and BH scans to create an ITV (4D) and GTV (BH). Both volumes were grown isotropically by 1cm, and a Rapidarc plan created using 2 arcs, with a prescribed dose of 55Gy in 20 fractions. The treatment volumes of the PTV and doses to critical organs are compared in Table 1. Table 1
PTV (cm3 ) Mean lung dose (Gy) Lungs-PTV V18Gy (%) Liver V55Gy (cm3 ) Liver V27.5Gy (cm3 )
Rapidarc plan using 4D scan
Rapidarc plan using BH scan
151 9.3 21.2 37.3 252
85 6.0 11.0 5.4 42
Results: Use of the BH scan resulted in a significant reduction in the volume of the PTV, and liver and lung treated. Radiotherapy was delivered with daily on-line CBCT matching, with back-up respiratory gating to ensure the tumour remained within the planned volume. Conclusion: In a patient with significant tumour motion, treatment using a comfortable breath hold technique with daily on-line CBCT imaging and back-up gating allowed delivery of a radical dose of radiotherapy with reduced dose to normal tissues. This technique was easy to implement in a busy department, and well tolerated. This method has also been successfully applied in other radical treatments where reducing the normal tissue irradiated was important, for example in a patient requiring retreatment with a respiratory rate too slow for 4D scanning. Disclosure: All authors have declared no conflicts of interest.
S44
acute toxicity, where 6 patients had grade 1 and the remaining 6 had grade 2 (CTCAE version 4.03). None of these 12 patients had any worsening of dyspnoea or noticeable pneumonitis. Median follow-up is 15.24 months and median overall survival has not been reached. Estimated mean progression-free survival is 10.5 months. Estimated 12-month and 18-month survival rates are both 72.9%. At the time of analysis, 2 patients had local failure, 3 had distant failure and 1 had both local and distant failure. Three out of 12 patients have died from disease. Table 1. Planning parameters for CHART patients treated using VMAT Mean
Median
Standard Minimum Maximum deviation value value
GTV volume (ml) 229.4 PTV volume (ml) 858.5 Cranio-caudal PTV length (cm) 12.7 Whole lung volume (ml) 2872.9 PTV:whole lung volume ratio 0.308 Minimum dose to at least 5% of PTV (Gy) 56.34 Minimum dose to at least 95% of PTV (Gy) 51.20 Spinal canal max dose (Gy) 37.7 Spinal canal PRV max dose (Gy) 41.8 MLD (Gy) 12.4 V30 lung (%) 13.3 V20 lung (%) 22.3 V10 lung (%) 39.9 V5 lung (%) 58.9 Heart mean dose (Gy) 16.3 V30 heart (%) 24.5 Oesophagus mean dose (Gy) 23.4 Conformity number 0.84 Conformity index 1.03 Dose homogeneity index (DHI) 1.10
127.0 700.1 12.5 2723.7 0.252
234.5 466.7 3.10 690.2 0.180
43.2 345.6 7.5 1900.4 0.148
849.8 1970.6 18.5 4008.7 0.780
56.13
0.80
55.33
57.77
51.63 38.1 42.4 13.0 14.4 22.4 40.2 63.4 17.3 22.9 24.4 0.88 1.04 1.09
1.70 4.1 4.7 3.2 5.7 8.0 10.5 12.7 8.8 14.7 6.4 0.07 0.10 0.04
47.97 28.9 33.1 8.2 5.1 11.4 25.2 39.22 1.6 3.4 10.4 0.72 0.82 1.07
53.79 44.2 51.1 16.3 20.8 32.7 56.4 73.7 26.7 47.0 33.8 0.92 1.19 1.20
Conclusion: Although a small series with early data, CHART using VMAT was well tolerated with manageable and reversible oesophageal toxicity. Clinical impact of Accelerated Hyperfractionation with VMAT in lung cancer needs to be evaluated further for toxicity, local control and survival. Disclosure: All authors have declared no conflicts of interest. 122
To determine ideal gross tumour volumes and PTV expansion using four-dimensional computed tomography for the treatment of lung cancer
N. Goyal 1 , M. Ingle 1 , N. Bhuva 2 , D. Power 1 , C. Lewanski 3 . Charing Cross Hospital, London, United Kingdom; 2 Oncology, Mount Vernon Cancer Centre, Middlesex, United Kingdom; 3 Charing Cross Hospital (imperial), Charing Cross Hospital (Imperial), London, United Kingdom 1 Radiotherapy,
Introduction: To determine the ideal protocol to determine Gross Tumour Volume (GTV) using Four-Dimensional Computed Tomography (4DCT) in the treatment of lung cancers. To then determine the optimal Planning Target Volume (PTV) expansion volume using ontreatment Cone Beam CT (CBCT) verification data. Methods: 4DCT data for 13 consecutively treated patients with lung cancer (stage I: 3, stage II: 5, stage III: 5). The GTV was determined from the 4DCT data on each individual patient using the following methods: 1) GTV was determined individually on all 10 phases (GTVMERGE ); 2) defining GTV from 3DCT alone (GTV3DCT ) 3) defining GTV from MIP data alone (GTVMIP ); 4) combining GTV data from MIP and two extreme respiratory phases (0% and 50%) (GTVMODMIP ). We used the GTVMERGE as our reference GTV and compared volume and orthogonal positioning to the other three GTV volumes. Using the GTVMODMIP dataset, PTV volumes of 3mm, 5mm, 7mm and 10mm were created (assuming a standard GTV to ITV growth of 5mm). These were then overlain onto on-treatment CBCT images to determine our department’s ideal PTV expansion.
Results: The GTV3DCT was consistently smaller and unrepresentative of the reference GTVMERGE data. GTVMIP and GTVMODMIP more closely represented the reference GTVMERGE although GTVMIP frequently underestimated the reference GTVMERGE . GTVMODMIP only slightly overestimated the reference GTVMERGE and had the smallest standard deviation. A PTV expansion of 5mm was then sufficient to accurately encompass the tumour through treatment. Over/underestimation of GTV compared to reference GTVMERGE (cm3 )
Max Min Median Mean Standard deviation
GTV3DCT
GTVMIP
GTVMODMIP
27.46 −1.18 6.25 7.79 7.61
6.48 −1.47 0.77 1.60 2.69
2.6 −5.53 −0.61 −0.74 2.08
Conclusion: Utilising GTVMODMIP allows for a representative volume and is considerably quicker to volume (3 versus 10 volumes). The use of CBCT for on-treatment verification allowed us to determine our departmental setup error and reduce PTV expansion to 5mm. Further reduction is possible for certain tumours but would require daily verification. Disclosure: All authors have declared no conflicts of interest. 123
Breath-hold technique during radical radiotherapy for non-small-cell lung cancer (NSCLC)
A.E. Hollingdale, E.J. Orchard, S.J. Treece. Haematology/Oncology Unit Box 018, Peterborough City Hospital, Peterborough, United Kingdom Introduction: Local tumour control in NSCLC is limited in part by the dose delivered, normal tissue tolerance, and prediction of tumour motion. In a patient with >1cm tumour motion requiring increased margins to ensure treatment dose is delivered, various techniques can be used to improve radiation delivery. Here we describe radical treatment using a breath hold technique with daily on-line cone beam CT (CBCT) imaging, and compare to conventional 4D planning. Methods: 3D and 4D planning CT scans were performed and reviewed for a patient with a T1bN0M0 NSCLC of the right lower lobe. Tumour motion in the superior-inferior plane was >3cm, so a scan in comfortable breath hold (BH) was obtained. The tumour was outlined in the 4D and BH scans to create an ITV (4D) and GTV (BH). Both volumes were grown isotropically by 1cm, and a Rapidarc plan created using 2 arcs, with a prescribed dose of 55Gy in 20 fractions. The treatment volumes of the PTV and doses to critical organs are compared in Table 1. Table 1
PTV (cm3 ) Mean lung dose (Gy) Lungs-PTV V18Gy (%) Liver V55Gy (cm3 ) Liver V27.5Gy (cm3 )
Rapidarc plan using 4D scan
Rapidarc plan using BH scan
151 9.3 21.2 37.3 252
85 6.0 11.0 5.4 42
Results: Use of the BH scan resulted in a significant reduction in the volume of the PTV, and liver and lung treated. Radiotherapy was delivered with daily on-line CBCT matching, with back-up respiratory gating to ensure the tumour remained within the planned volume. Conclusion: In a patient with significant tumour motion, treatment using a comfortable breath hold technique with daily on-line CBCT imaging and back-up gating allowed delivery of a radical dose of radiotherapy with reduced dose to normal tissues. This technique was easy to implement in a busy department, and well tolerated. This method has also been successfully applied in other radical treatments where reducing the normal tissue irradiated was important, for example in a patient requiring retreatment with a respiratory rate too slow for 4D scanning. Disclosure: All authors have declared no conflicts of interest.