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L.W. Le
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OA09 - Locally Advanced NSCLC: Innovative Treatment Strategies (ID 384)
- Event: WCLC 2016
- Type: Oral Session
- Track: Locally Advanced NSCLC
- Presentations: 1
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OA09.05 - Positron Emission Tomography (PET) with 18F-Fluoroazomycin Arabinoside (FAZA) to Assess Tumor Hypoxia in Non-Small Cell Lung Cancer (NSCLC) (ID 5119)
11:45 - 11:55 | Author(s): L.W. Le
- Abstract
- Presentation
Background:
Tumor hypoxia is an adverse prognostic factor in many cancers. Hypoxia tracer [18]F-FAZA provides a non-invasive method of hypoxia imaging. This study aims to evaluate the feasibility and potential benefits of using FAZA-PET scans to assess NSCLC tumor hypoxia.
Methods:
The initial 17 patients of an ongoing study with stage II–III NSCLC have been analyzed prospectively by imaging with FAZA-PET before initiation of a radical course of radiotherapy. The hypoxic volume (HV) was defined as all voxels within the tumor with standard uptake value (SUV) more than 1.2 times the aorta SUVmean. The Tmax/Bmean ratio (T/B) was defined as maximum tumor SUV divided by aorta SUVmean. The hypoxic fraction (HF) was determined by dividing the HV by the entire gross tumor volume. Spearman correlation and Fisher’s test were used to explore potential correlations among several variables.
Results:
Median primary and nodal FAZA SUVmax were 1.7 (range: 1.0-3.8) and 1.7 (range: 1.0–3.3). Median primary and nodal T/B ratios were 1.4 (range: 1.0–2.5) and 1.3 (range: 1.0–2.2). Median primary and nodal HF were 3.9% (range: 0.0-38.2%) and 0.6% (range: 0.0-50.7%). The median time from diagnostic FDG PET to study FAZA PET scans was 28 days (range: 1–63). Median primary and nodal FDG SUVmax were 13.5 (range: 5.1–32.2) and 8.3 (range: 2.3–15.7). Larger primary tumor volume is correlated with higher FAZA-T/B (p=0.01) and higher HF (p=0.01). Primary tumors with higher T/B also had higher HF (p<0.0001). The same correlations also apply to nodal disease. Nodal FAZA SUVmax is correlated with primary FAZA SUVmax (p<0.0001). When comparing FAZA-PET with FDG-PET, nodal FDG SUVmax is correlated with nodal FAZA T/B (p=0.01) and nodal FAZA HF (p=0.01), which was not observed for primary disease. For each patient, the nodal station with the highest FAZA SUVmax correlates with the highest FDG SUVmax (p=0.02).
Conclusion:
Imaging intra-lesional hypoxia in NSCLC primary and nodal tumors is feasible and can be achieved with FAZA-PET. Larger tumor volume is correlated with higher T/B and HF in both primary and nodal masses. In the nodal volume only, higher FDG activity is correlated with higher FAZA T/B and higher HF. Ongoing trial accrual and follow-up of our patient cohort will provide more information with regards to the imaging and clinical value of FAZA-PET. This study may eventually lead to using FAZA-PET as a guiding tool to escalate dose to the hypoxic region of the tumor.
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P2.02 - Poster Session with Presenters Present (ID 462)
- Event: WCLC 2016
- Type: Poster Presenters Present
- Track: Locally Advanced NSCLC
- Presentations: 1
- Moderators:
- Coordinates: 12/06/2016, 14:30 - 15:45, Hall B (Poster Area)
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P2.02-046 - Prognostic Value of Early Tumor Regression during Chemo-Radiotherapy in Locally Advanced Non-Small Cell Lung Cancer (ID 5127)
14:30 - 14:30 | Author(s): L.W. Le
- Abstract
Background:
Volumetric changes are observed on serial cone-beam computed tomography (CBCT) images obtained for image-guidance throughout the course of radical radiotherapy for non-small cell lung cancer (NSCLC). This study aims to a) examine whether the magnitude of tumor regression is correlated with disease control and survival; b) explore the potential difference between adenocarcinoma and non-adenocarcinoma NSCLC subtypes.
Methods:
In a previous study from our institution, primary tumor volumes were assessed on weekly CBCT images of 60 NSCLC patients treated with radical radiotherapy from January 2006 to June 2007. We performed a retrospective review of these patients, documenting patient-, tumor-, and treatment-related details. Outcome measures included loco-regional failure free survival (LRFFS), distant failure free survival (DFFS), disease free survival (DFS) and overall survival (OS), which were calculated using Kaplan-Meier method. Univariable analysis (UVA) and multivariable analysis (MVA) were performed using Cox regression model. Further analysis was performed for the adenocarcinoma and non-adenocarcinoma subgroups.
Results:
Forty-five patients with locally advanced NSCLC were included in this study. Median follow-up was 22.1 months for all patients, and 90 months for alive patients (range: 0.9-108). The distribution of 7[th] ed. AJCC stage was as follows: stage II 8.9%; IIIA 66.7%; IIIB 24.4%. Twenty patients (44.4%) had adenocarcinoma, while 25 patients (55.6%) had non-adenocarcinoma. Twenty-eight patients (62.3%) received total radiation dose ≥ 60Gy, 15 patients (33.3%) received 45Gy as neoadjuvant therapy, and 2 patients (4.4%) received 58-59Gy due to missed fractions. 23 patients (51.1%) had more than 30% regression by fraction 15 and 32 patients (71.1%) by treatment completion. In UVA, adenocarcinoma (p=0.03) was associated with better LRFFS; young age was associated with better LRFFS (p=0.02), DFFS (p=0.048) and OS (p=0.04). In MVA, large regression by fraction 15 was associated with better DFS (p=0.047). For patients with adenocarcinoma, MVA showed that large regression by fraction 15 was associated with better DFFS (p=0.01), DFS (p=0.01) and OS (p=0.02). For patients with non-adenocarcinoma, larger regression by treatment completion and trimodality therapy (radiation dose of 45Gy) were associated with better LRFFS (p=0.02, 0.04).
Conclusion:
Evaluation of tumor regression on CBCT images during radiotherapy may be predictive of treatment response. Early tumor regression, as indicated by regression ≥ 30% by fraction 15, was associated with better DFS for all patients; and this was associated with better DFFS, DFS and OS for the adenocarcinoma cohort. This observation may provide insight into when and how to best utilize adaptive radiotherapy.
