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K. Hjorthaug
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P3.13 - Radiology/Staging/Screening (ID 729)
- Event: WCLC 2017
- Type: Poster Session with Presenters Present
- Track: Radiology/Staging/Screening
- Presentations: 3
- Moderators:
- Coordinates: 10/18/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)
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P3.13-014 - Prediction of Survival with 18F-FDG-PET/CT Early during Erlotinib Treatment in NSCLC Patients – a Comparison of Four Evaluation Methods (ID 8902)
09:30 - 09:30 | Author(s): K. Hjorthaug
- Abstract
Background:
Erlotinib treatment is offered to NSCLC patients in a palliative setting also in EGFR wildtype (EGFR-wt) patients because we know that some of these patients will benefit, However, in order to evaluate the effect of treatment, we wait for 8-12 weeks before performing a CT scan, since the effect is rather subtle especially in EGFR-wt patients. The purpose of this study was to evaluate which method for evaluating change in 18F-FDG uptake is the best predictor for survival.
Method:
18F-FDG-PET/CT scans from 56 NSCLC patients (48 EGFR-wt and 8 EGFR mutated) performed before and after 7-10 days of erlotinib treatment were analysed with four different methods for response to treatment including visual evaluation, and three semi quantitative methods measuring % change in SULpeak, SULmax and TLG, with a range of cut-off levels determining response, stable disease and progression. A direct comparison of the semi-quantitative parameters was performed using univariate cox regression, linear regression and ROC analysis for progression free survival (PFS) and overall survival (OS) < the median. Kaplan-Meier analysis was used to estimate PFS and OS for the response categories.
Result:
Both %SULpeak, % SULmax and %TLG were correlated to PFS and OS. The strongest linear correlation was found for %TLG (R=0.51, p< 0.001). The ROC analysis showed the highest AUC for predicting OS for %TLG (0.70 (0.56-0.85) with a sensitivity of 0.68 and a specificity of 079. All the semi-quantitative methods showed a statistical overall difference in PFS for the three response categories at some cut-off levels for %SULmax both at 15 and 25%, for %SULpeak at 20 and 25% and for %TLG at 45/75, 50, 30, 25 and 20% cut-off. Visual evaluation failed to differentiate between response categories. For OS %TLG at 4 different cut-off levels and SULpeak at the three lowest cut-off levels showed a statistical overall difference in OS, both visual and %SULmax did not.
Conclusion:
The choice of method for analysis is not clear-cut, but %TLG as suggested by the PERCIST 1.0 is not inferior to other methods, and visual evaluation seems to be the least sensitive at this very early time-point. A lower cut-off level for discriminating between response categories seems to be relevant, we find that 20-25% change for both response and progression is optimal.
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P3.13-015 - 18F-FDG-PET/CT after Induction Chemotherapy for Prediction of Survival after Radical Chemo-Radiotherapy in Locally Advanced NSCLC Patients (ID 8914)
09:30 - 09:30 | Author(s): K. Hjorthaug
- Abstract
Background:
The use of 18F-FDG-PET/CT is increasing for radiotherapy planning. We wanted to investigate whether 18F-FDG-PET/CT scans at this time-point can be a tool for selecting patients with locally advanced NSCLC who are likely not to benefit from radical chemo-radiotherapy in order to avoid the potentially harmful side effects in patients undergoing futile treatment, by predicting progression free survival (PFS) and overall survival.
Method:
18F-FDG-PET/CT scans before and after 2 cycles of induction chemotherapy (carboplatin/vinorelbine) from 91 patients enrolled in a Danish randomized controlled multicenter study (the NARLAL study) was retrospectively evaluated using visual evaluation. Following the induction chemotherapy patients received radical radiotherapy (66 or 66 Gy) with concomitant vinorelbine treatment as according to the NARLAL protocol. Estimates of median OS and PFS was calculated with Kaplan-Meier analysis for the response categories resulting from the visual evaluation, both considering all four response categories and separate analyses for the SMD and PMR groups. Statistical significance was tested using the log rank test, and a significance level of 0.05 was applied.
Result:
The median OS was 25.3 months (95% CI: 21.0-29.6 months), median PFS was 8.6 months (95% CI: 7.9-9.4 months). Overall survival did not differ for PFS or OS when considering all four response categories (p = 0.424 for PFS and p= 0.245 for OS). Considering only partial metabolic response (PMR) and stable metabolic disease (SMD) no difference for PFS, but we found a median OS of 22.6 (95% CI: 18.9-26.3) months for PMR and 32.4 (28.4-36.3) months for SMD (p=0.036). Stratified by histology, the effect was seen in the adenocarcinomas only.
Conclusion:
The median overall survival in patients with a partial response by 18F-FDG-PET/CT evaluation is shorter than for patients with stable disease, in adenocarcinomas. This is surprising and may suggest a differentiation of the treatment for patients with locally advanced NSCLC.
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P3.13-016 - 18F-FDG-PET/CT for Prediction of Survival after Induction Chemotherapy in Locally Advanced NSCLC – a Comparison of Methods (ID 8915)
09:30 - 09:30 | Author(s): K. Hjorthaug
- Abstract
Background:
In patients with inoperable, locally advanced NSCLC, radical chemo-radiotherapy is the preferred treatment, and 18F-FDG-PET/CT is increasingly used for radiotherapy planning. Despite the introduction of the PERCIST criteria for evaluation of response with 18F-FDG-PET/CT, various methods are being used making comparisons of studies a difficult task. The aim of this study was to investigate which method for analyses of 18F-FDG-PET/CT provided the best prediction of survival.
Method:
18F-FDG-PET/CT scans before and after 2 cycles of chemotherapy from 91 patients enrolled in a Danish randomized controlled multicenter study was retrospectively evaluated using four different methods. The change in 18F-FDG-uptake was measured in a single lesion a) SULpeak (according to PERCIST) and b) SULmax (according to the EORTC criteria), c) total disease evaluation qualitatively (visual), and d) total lesion glycolysis measured in all involved measurable lesions with a 45% decrease as cut-off for response and 75% increase as cut-off for progression as according to PERCIST (%TLG). Univariate cox regression was used to evaluate a direct correlation between 18F-FDG uptake at baseline, follow-up and %change and survival (PFS and OS). Estimates of median OS and PFS was calculated with Kaplan-Meier analysis for the response categories from all four methods and, a log rank test performed for evaluation of the statistical significance. A Bonferroni correction for comparison of four methods was applied rendering a p < 0.013 the considered level for statistical significance.
Result:
There was no clear correlation between survival (neither PFS nor OS) and % change in FDG-uptake (independent of analysis method), but TLG at baseline showed the strongest correlation to both PFS (p= 0.02) and OS (p= 0.03). %TLG was the only method to show a statistically significant difference in OS, (p=0.004). Visual evaluation and change in SULpeak both succeeded in discriminating between the two largest response groups, PMR and SMD, with median OS for visual evaluation: PMR: 22.6 (95% CI: 18.9-26.3) months versus 32.4 (95% CI: 28.4-36.3) months for SMD; SULpeak: PMR: 20.6 (95% CI: 18.0-23.2) months versus 29.7 (95% CI: 24.2-35.1) months for SMD. Change in SUL max and TLG showed no difference.
Conclusion:
There was no clear correlation between PFS or OS and percentage change in FDG-uptake. The response categories for SULpeak and TLG (PERCIST criteria for cut-off), and visual evaluation predicts OS at various levels. SULmax categories as according to the EORTC criteria did not successfully predict OS. None of the methods predicts PFS.
