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Angela Tijhuis
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P3.16 - Treatment of Early Stage/Localized Disease (Not CME Accredited Session) (ID 982)
- Event: WCLC 2018
- Type: Poster Viewing in the Exhibit Hall
- Track:
- Presentations: 1
- Moderators:
- Coordinates: 9/26/2018, 12:00 - 13:30, Exhibit Hall
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P3.16-17 - Cardiac Sparing in Stereotactic Body Radiotherapy of Early Stage NSCLC Patients (ID 13855)
12:00 - 13:30 | Author(s): Angela Tijhuis
- Abstract
Background
In NSCLC patients who receive radiotherapy, cardiac toxicity was not well established as a possible factor until the results of the RTOG 0617 showed associations between cardiac dose and survival. These associations have been confirmed both in early and in locally advanced stage NSCLC patients. Cardiac sparing is not yet systematically pursued, and there is currently no agreement on cardiac constraints to be used. We investigated the feasibility of cardiac sparing in early stage NSCLC patients who receive SBRT.
a9ded1e5ce5d75814730bb4caaf49419 Method
Ten patients with early stage NSCLC in a middle or lower lobe, treated to 3x18 Gy between 2015 and 2017 using a dual arc VMAT technique were randomly selected. Retrospectively, clinical plans were adapted to minimize the maximum heart dose, while clinical constraints were respected. Mean Lung Dose (MLD) and cardiac doses Dmax, Dmean and V5Gy were compared between clinical and cardiac spared plans using a paired t-test.
4c3880bb027f159e801041b1021e88e8 Result
Median GTV was 3.05cc (range 0.54-23.2cc), 7 left sided tumors, 3 right sided. All cardiac spared plans fulfilled the clinical constraints on tumor coverage, conformity and organs at risk. All cardiac parameters were significantly decreased; a reduction in max heart dose of 8.2 Gy, reduction in mean heart dose of 1.0 Gy, and reduction in heart V5Gy of 10.3%, with p-values <0.001, 0.008 and 0.014 respectively. MLD was increased by a mean of 0.51 Gy (p-value 0.002). Results are shown in table 1.
8eea62084ca7e541d918e823422bd82e ConclusionDifference in cardiac and lung doses between clinical plans and cardiac spared plans. Patient Difference Heart_Dmax (Gy) Difference Heart_Dmean (Gy) Difference Heart_V5 (%) Difference MLD (Gy) 1
-6.1
-0.2
-2.5
0.2
2
-6.6
-0.9
-6.8
0.5
3
-2.8
0
-0.1
0.1
4
-8
-0.5
-3.7
0.8
5
-8
-0.2
-1.9
0.7
6
-8.6
-1.8
-13.4
0.2
7
-12.8
-2.9
-34.9
1.3
8
-12.4
-0.4
-5.6
0.2
9
-7.4
-1.4
-14.8
0.6
10
-9.4
-1.9
-19.5
1
Average
-8.21
-1.02
-10.32
0.56
Cardiac sparing is feasible for early stage NSCLC patients treated with SBRT, without compromising target coverage, and with minimal increase in mean lung dose. As cardiac exposure is associated with increased mortality, cardiac sparing has the potential to increase survival, and should be considered for all early stage NSCLC patients treated with radiotherapy. These data will need to be confirmed in a larger, prospective cohort.
6f8b794f3246b0c1e1780bb4d4d5dc53
