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S. Harrow
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MA 09 - The Current Status of Radiation Oncology (ID 666)
- Event: WCLC 2017
- Type: Mini Oral
- Track: Locally Advanced NSCLC
- Presentations: 1
- Moderators:Tomoki Kimura, Yong Chan Ahn
- Coordinates: 10/17/2017, 11:00 - 12:30, Room 316
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MA 09.11 - Isotoxic Intensity Modulated Radiotherapy (IMRT) in Stage III Non-Small Cell Lung Cancer (NSCLC) – a Feasibility Study (ID 7978)
12:10 - 12:15 | Author(s): S. Harrow
- Abstract
- Presentation
Background:
The majority of stage III patients with non-small cell lung cancer (NSCLC) are unsuitable for concurrent chemoradiotherapy. Alternative treatment options include sequential chemoradiotherapy and radiotherapy (RT) alone. As the rate of local failure is high there is a rationale for treatment intensification.
Method:
Isotoxic Intensity Modulated Radiotherapy (IMRT) is a multicentre feasibility study combining a number of intensification strategies; dose escalation, acceleration and hyperfractionation. Patients with inoperable stage III NSCLC, ECOG performance status (PS) 0-2, unsuitable for concurrent chemoradiotherapy were recruited. A minimum of 2 cycles of induction chemotherapy was mandated before RT. The dose of radiation was increased until one or more of the organs at risk (OAR) met predefined constraints or the maximum dose of 79.2Gy was reached. RT was delivered twice-daily in 1.8 Gy fractions. A RT quality assurance programme was in place. The primary end point was feasibility (>80% of patients achieving >60Gy EQD2 i.e. total biologically equivalent in 2 Gy fraction), with acute/late toxicity (CTCAE version 4.0), local control and overall survival as secondary end points.
Result:
Between June 2014 and March 2016, 37 patients were enrolled from 7 UK centres. Median age = 67 years (range 46-86). Male:female ratio = 18:19. ECOG PS=0, 5 (13.51%), PS=1, 29 (78.38%), PS=2, 3 (8.11%). Stage IIIa:IIIb ratio 23 (62.2%):14 (37.8%). Out of 37 patients, 2(5.4%) failed to achieve EQD2 >60Gy due to large tumour size and inability to meet OAR constraints, they received standard RT. This was due to large tumour size and inability to meet OAR constraints. Median prescribed tumour dose was 77.4Gy (61.2 – 79.2Gy) with the maximum dose of 79.2Gy delivered to 14 (37.8%) patients. All patients completed RT as scheduled except one due to disease progression. Grade (G)3 acute toxicities included: dysphagia 1 (2.9%), dypsnoea 2 (5.7%), lung infection 3 (5.7%) and radiation oesophagitis 2 (5.7%). There were three G5 events: radiation pneumonitis, trachea-oesophageal fistula and bronchopulmonary haemorrhage, which were probably treatment related. G3 late toxicities included: fatigue 1 (2.9%), dyspnoea 3 (8.6%) and 1 (2.9%) case of late G4 lung infection. At time of analysis median follow-up was 12.8 months for 20 survivors. Overall survival and progression-free survival at 1 year was 75% and 59% respectively.
Conclusion:
In the majority, treatment intensification using isotoxic IMRT is feasible. This regime will be tested alongside other intensified treatments against standard sequential chemoradiotherapy in the ADSCAN study (ISRCTN47674500).
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P3.09 - Mesothelioma (ID 725)
- Event: WCLC 2017
- Type: Poster Session with Presenters Present
- Track: Mesothelioma
- Presentations: 1
- Moderators:
- Coordinates: 10/18/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)
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P3.09-002 - Can We Do Better? Feasibility Dosimetric Study for Upfront Radical Radiotherapy in Mesothelioma (ID 10141)
09:30 - 09:30 | Author(s): S. Harrow
- Abstract
Background:
Standard treatment for mesothelioma (surgery+/-chemotherapy+/-radiotherapy) does not provide satisfactory oncologic results in view of the lack of evidence for a preferred treatment option in such a rare disease with little published evidence. We aim to assess the feasibility of delivering radical doses of radiotherapy in mesothelioma patients. We would also like to evaluate the dosimetric parameters to establish organs at risk and optimal dose potentially delivered if radiotherapy is a sole agent.
Method:
Patients with Mesothelioma were chosen from the SYSTEMS-1 and SYSTEMS-2 trial cohort. Treatment volumes and organs at risk were performed on the Eclipse planning system. The treatment volumes outlined were CTV Pleural cavity and GTV bulky disease. Doses were prescribed as follows: PTV pleural cavity (CTV + 0.8 cm) 45Gy/ 25# and PTV Bulky disease (GTV+5mm) 55Gy/25#. Physics planning was carried on the Eclipse 13.6.23 treatment planning system, by using VMAT technique with either 2 or 3 arcs, 6MV beams at a dose rate of 600MU/min. We calculated overlap volumes between PTV and Organs at Risk (OAR’s) in view of their proximity, prioritizing heart and liver dose constraints over PTV coverage.
Result:
5 patients with confirmed epitheliod mesothelioma. Ages ranged from 55 - 72 years, 4/5 patients were male. A Cisplatin or Carboplatin-Pemetrexed doublet was given to all the patients prior to the CT Scan. The table below shows the dosimetry data gathered from the plans done.Objectives Patient 1 Patient 2 Patient 3 Patient 4 Patient 5 TNM stage T4N2M0 T3N2M0 T4N3M0 T4N2M0 T4N2M0 PTV Pleural cavity Volume (cc) D~99%~ (% of the prescribed dose) D~95%~ (% of the prescribed dose) V~105%~ (%) V~95%~ (%) Median Dose (Gy) Dose prescribed 45Gy/25# - - >95% - >95% 1615 78.6 94.3 80.7 94.6 51 2276 77 108 96 97.6 53 1465 82.8 96 58.5 96.1 47.9 3701 58 91 87.1 93.2 53.4 1840 72 89 79.7 89 48.9 PTV Bulky disease Volume (cc) D~99%~ (% of the prescribed dose) D~95%~ (% of the prescribed dose) V~105%~ (%) V~95%~ (%) Median Dose (Gy) Dose prescribed 55Gy/25# - - >95% - >95% 2905 72 89.3 15.7 90 55 3104 79 89.6 15.2 81.2 54.6 4924 56 87.7 10.7 75.9 53.6 764 83 89 4.5 74 54.3 3104 79 89.6 15 81 54.6 Contralateral lung Volume(cc) Overlap with PTV (cc) Mean lung dose (Gy) V~20Gy~ (%) V~5Gy~ (%) - - ≤8-10 to 20 ≤4-10 to 35 ≤75 1637 0.1 12.2 11.3 98.6 1636 0 18.4 35.6 100 1247 0 13 18.3 92.6 2391 10.4 16.4 25.4 100 2082 0 17.5 31.3 100 Heart Volume(cc) Overlap with PTV (cc) Mean Heart Dose (Gy) V~35Gy~ (%) - - <22-26 <35 776 44.4 33.5 33.6 619 94.9 25.5 30 790 150 27.8 28.8 681 111.7 31.1 34.7 822 65.8 32.9 34.7 Liver Volume(cc) Overlap with PTV (cc) Mean liver dose (Gy) V~30Gy~ (%) - - 28-30 ≤40 1657 232 32.3 55.1 1544 0 17.3 4.0 1534 0 89.9 0.1 1931 485 32 57.2 1333 230 31.9 54.4 Oesophagus Volume (cc) Overlap with PTV (cc) Max dose (Gy) V~50Gy~ (%) - - ≤50-55 <40 28 5.3 55.6 8.3 33.5 0 53.4 5.9 30.5 1 55.6 13.4 193 48.7 60.9 26.6 43 7.7 56.3 13 Spinal cord Volume(cc) Overlap with PTV (cc) Max dose (Gy) - - <50 70.3 0 45.7 80.4 0 52.7 55.5 0 50.7 87.6 1.9 54.5 75 0 49.6 Contralateral Kidney Volume(cc) Overlap with PTV (cc) Max dose (Gy) - - <5 279 0 17.4 115 0 20 116 0 4.4 177 0 30.1 163 0 21.9 Ipsilateral Kidney Volume(cc) Overlap with PTV (cc) V~30Gy~ (%) Mean Dose (Gy) - - <50 ≤30 N/A N/A N/A N/A 118 0 29.6 17.4 89.8 0 0 2.1 134 2.8 23.3 18.9 239 20.5 44.6 29 Small Bowel Volume(cc) Overlap with PTV (cc) Max dose (Gy) - - ≤45 183 0 18.3 348 0 27.9 307 0 10.7 672.5 0 33.2 309 0 23.4 Stomach Volume(cc) Overlap with PTV (cc) Max Dose (Gy) - - ≤45 168 0.8 33.3 352 6.4 56.7 235 5.9 45.7 182.1 0 52.4 631 0 40.4
Conclusion:
Radical radiotherapy doses are achievable in mesothelioma by respecting organs at risk adequately, despite the challenging large volumes and complex disease anatomical pattern. VMAT is a promising technique allowing to potentially treat mesothelioma with radical doses of radiotherapy. Further trials are needed to assess the feasibility of radiotherapy as an upfront treatment for these patients.
