Virtual Library
Start Your Search
H. Raziee
Author of
-
+
P1.14 - Radiotherapy (ID 700)
- Event: WCLC 2017
- Type: Poster Session with Presenters Present
- Track: Radiotherapy
- Presentations: 1
- Moderators:
- Coordinates: 10/16/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)
-
+
P1.14-016 - Assessing the Feasibility of FLT-PET for Evaluation of Non-Small Cell Lung Cancer (NSCLC) Treated with Stereotactic Body Radiotherapy (SBRT) (ID 8455)
09:30 - 09:30 | Author(s): H. Raziee
- Abstract
Background:
Distinguishing fibrosis from tumor recurrence following lung SBRT remains a clinical challenge since CT has poor sensitivity and specificity for detecting recurrence. 18F-Fluoro-L-thymidine-PET (FLT-PET) uptake correlates with cell proliferation. The purpose of this study is to investigate the feasibility of FLT-PET as an imaging biomarker for lung SBRT response assessment.
Method:
In this prospective study, three groups were included: 1) newly-diagnosed biopsy-proven NSCLC pre-SBRT, 2) established post-SBRT mass-like fibrosis on serial follow-up CT scans by co-investigators’ consensus, and 3) biopsy-proven locally-recurrent NSCLC after SBRT. Non-gated, helical gated (3D-CT/4D-PET) and phase-matched (4D-CT/4D-PET) FLT-PET images were obtained. Group-1 underwent fluorodeoxyglucose (FDG)-PET scan according to clinical guidelines. FLT uptake was measured by SUV95 and SUV50 (95% and 50% of maximum pixel value plus average background value, respectively), SUV2Dpeak and SUV3Dpeak (1cm diameter circular or spherical around region of interest, respectively), SUVmean and SUVmax. Descriptive statistics were gathered. Kolmogorov–Smirnov test was used to determine normality. Statistical significance was reported using student’s t-test.
Result:
27 patients were included, with 19 primary tumors (group-1), 12 established fibrosis (group-2) and 1 recurrence (group-3). In group-1, 16 tumors were T1. Group-1, mean FDG-PET SUVmax, SUV95, SUV50, SUV2Dpeak, SUV3Dpeak and SUVmean were 7.40, 5.88, 2.39, 5.59, 6.02 and 2.78, respectively. Mean FLT-PET values for group-1 were 3.43, 2.84, 1.71, 2.9, 2.82 and 1.78, respectively. Group-2 SBRT dose was either 48Gy in 4 fractions (83%) or 60Gy in 8 fractions. Median time from radiation to FLT-PET scan in group-2 was 19.5 months (5.8-83.8mos). The patient in group-3 had SUV50, SUV95, SUV2Dpeak, SUV3Dpeak, SUVmean and SUVmax of 2.27, 3.85, 6.37, 6.05, 2.39 and 7.64, respectively. Mean FLT-PET SUVmax for groups 1 and 2 was significantly different (p=0.03) at 3.42(1.14-7.04) and 2.34(1.23-4.35) respectively. Similarly, mean (range) of SUV50, SUV95 and SUVmean for group-1 was 1.8(0.74-3.43), 2.97(1.03-5.83), 1.87(0.73-3.44), and for group-2 was 1.22(0.81-2.26), 1.85(1.13-3.8) and 1.25(0.83-2.39), respectively (p<0.01, <0.01 and <0.01). There was no statistically-significant difference between SUV2Dpeak and SUV3Dpeak between groups 1 and 2, with a mean of 2.97(0.99-6.30) and 2.91(0.90-6.11) for group-1 and 2.10(1.11-3.91) and 2.03(1.00-3.86) for group-2 (p=0.06 and 0.06), respectively. There was no statistically significant difference between the 3D and 4D image acquisition in group-1. There were no FLT-PET-related toxicities.
Conclusion:
FLT-PET is feasible in SBRT patients pre- and post-treatment, and may assist in distinguishing fibrosis from recurrent tumor. Further validation studies are needed.
-
+
P3.14 - Radiotherapy (ID 730)
- Event: WCLC 2017
- Type: Poster Session with Presenters Present
- Track: Radiotherapy
- Presentations: 1
- Moderators:
- Coordinates: 10/18/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)
-
+
P3.14-013 - Outcomes According to Marginal Tumor Dose Prescription for Small- to Medium-Sized Brain Metastases from Lung Cancer (ID 10416)
09:30 - 09:30 | Author(s): H. Raziee
- Abstract
Background:
At our institution, we commonly treat brain metastases (BM) adjacent to critical structures with a smaller dose prescription (DP) to reduce the likelihood of toxicity. We sought to evaluate the impact of DP on LF and RN for small- to medium-sized BM (≤ 2 cm) from lung cancer.
Method:
A prospective registry of BM patients treated with gamma knife SRS between 2008 and 2016 was interrogated to determine per lesion rates of LF and RN. Each lesion was followed until LF or RN or at last MRI follow-up. Defined criteria were used to differentiate LF from RN. Whole brain irradiation (WBI) was a censoring event.
Result:
From 1,465 potential subjects, 345 small- to medium-sized BM from 151 lung cancer patients were evaluated. Median radiographic follow-up was 10.2 months. Median lesion volume and diameter were 0.17 cm[3], and 0.81 cm, respectively. The DP for 71 lesions (21%) was 15 Gy, and ≥ 20 Gy (median 21 Gy; 20-24Gy) for 274(79%). Most lesions were ≤ 1 cm (65%). Median number of SRS was 2 (1-4) and 36 patients received salvage WBI. Sixteen lesions (4%) developed LF and 12 (3%) developed RN. Freedom from local failure at 1 year (FFLF) for 15 Gy, and ≥ 20 Gy, was 80%, and 95%, respectively (p=0.02). FFLF for lesions ≤1cm, and >1 cm, was 95%, and 78%, respectively (p<0.01). Freedom from RN at 1-year (FFRN) for DP 15 Gy, and ≥ 20 Gy, was 98%, and 96%, respectively (p=0.3). FFRN for lesions ≤ 1cm, and > 1 cm, was 98%, and 93%, respectively (p=0.01). FFLF and FFRN for lesions ≤1 cm and >1 cm, according to DP, are shown in Table 1.Lesion size ≤1 cm P value >1 cm P value DP DP 15 Gy ≥20 Gy 15 Gy ≥20 Gy FFLF 88.8% 96.4% 0.42 53.4% 88.2% 0.08 FFRN 100% 98% -- 98% 92% 0.43
Conclusion:
Our results suggest that, particularly for lesions >1 cm, DP ≥ 20 Gy correlates with improved FFLF, and similar FFRN rates, compared to DP 15 Gy.
