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R. Soo
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P3.01 - Advanced NSCLC (ID 621)
- Event: WCLC 2017
- Type: Poster Session with Presenters Present
- Track: Advanced NSCLC
- Presentations: 1
- Moderators:
- Coordinates: 10/18/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)
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P3.01-022 - Prognostic Value of Clinical, Immune and Biochemical Markers in EGFR-Mutant NSCLC Patients Treated with First-Line EGFR TKIs (ID 8913)
09:30 - 09:30 | Author(s): R. Soo
- Abstract
Background:
Sensitizing Epidermal Growth Factor Receptor (EGFR) mutations confers a better prognosis and predicts a favorable response to treatment with EGFR tyrosine kinase inhibitors (TKIs) in patients with advanced non-small cell lung cancer (NSCLC). We sought to determine the prognostic utility of a comprehensive panel of clinical, immune and biochemical markers in EGFR-mutant advanced NSCLC patients treated with first-line EGFR TKIs.
Method:
A retrospective analysis was conducted on a cohort of NSCLC patients treated at our institution. Only patients who met the following criteria were included: NSCLC with EGFR mutations, diagnosed with Stage 4 disease at initial diagnosis or incurable disease recurrence, and received first-line EGFR TKI treatment. Statistical analysis on descriptive and survival data was performed using IBM SPSS Statistics, version 20.
Result:
We identified 74 patients based on predefined criteria. The mean age of the patients was 63.8 years with 38 (51.4%) female patients and 36 (48.6%) male patients, 51 (68.9%) were never smokers and 39 (52.7%) harbored EGFR exon 19 deletion. 15 (22.7%) out of 66 patients with available data had high serum LDH (median: 456 U/L; normal range: 250-580 U/L). In addition, 19 (25.7%) had brain metastasis, 12 (16.2%) had liver metastasis and 12 (16.2%) had adrenal metastasis at stage 4 diagnosis. These represent the descriptive data of the variables that were later identified to carry prognostic significance. The median PFS and OS for this cohort of patients were 12 and 30 months respectively. On our multivariable Cox-PH regression analysis, old age (>=60; HR = 2.35; 95% CI = 1.18-4.69, p-value = 0.015), female gender (HR = 2.05; 95% CI = 1.05-4.00, p-value = 0.036) and high LDH levels (HR = 2.45; 95% CI = 1.04-5.81, p-value = 0.041) retained their association with unfavorable PFS and only high LDH levels (HR = 2.84; 95% CI = 1.25-6.49, p-value = 0.013) is an independent prognostic indicator of unfavorable OS. Total leukocyte count, hemoglobin levels, absolute neutrophil, lymphocyte and platelet counts at diagnosis were not statistically significant for PFS or OS.
Conclusion:
We identified old age, female gender and high serum LDH levels as independent prognostic predictors of progression-free survival on multivariable analysis. The strong association between elevated LDH and unfavorable overall survival is in line with recent published studies. Further studies confirming the prognostic utility of these markers are necessary to potentially develop a prognostic scoring system that can guide risk stratification in patients with EGFR mutations treated with EGFR TKIs.
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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: 1
- Moderators:
- Coordinates: 10/18/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)
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P3.13-004 - Prospective Study of Sequential Ultra-Low then Standard Dose 18F-FDG PET/CT Scans for Lung Lesion Detectability (ID 8102)
09:30 - 09:30 | Author(s): R. Soo
- Abstract
Background:
Lung cancer screening with low-dose computed tomography (CT) is better than chest X-rays but is non-specific. Accuracy is improved with positron emission tomography (PET), at a cost of additional radiation. We had previously reported on simulated low-dose PET imaging and demonstrated that 10x10[6] net true counts is sufficient to generate images with acceptable diagnostic quality. We now hypothesize that we can maintain image quality with a 92% reduction of fluorodeoxyglucose (FDG) tracer activity from 6 mCi to 0.5 mCi.
Method:
Nine patients have been scanned with two sequential PET/CT scans on the same day. The patient is first scanned with 0.5 mCi FDG and a low-dose CT protocol, followed by a routine PET/CT with 6 mCi FDG. PET data from the standard-dose scan were manipulated to emulate various noise (dose) levels, corresponding to nine pre-defined true count levels. Data were matched to the level of the low-dose scan, to compare noise statistics to a ground truth and to directly validate our methods. The data were reconstructed, with many independent noise realizations, and the images were reviewed. Ten lesions, in seven patients, were identified as having the size and uptake consistent with those found in early disease. For a given count level, the corresponding images were determined to be acceptable if lesion detectability was comparable to that found in the full-statistic image set. Detection performance was determined automatically by machine learning, namely, convolution neural networks trained by 4 previous observer responses.
Result:
Lesion detection accuracy was evaluated in 4458 total image sub-volumes. Regions containing both target lesions (2627 samples) and healthy lung background (1831 samples) were used to assess sensitivity and specificity for the task at all noise levels. The table shows data across the 4 observer models.Mean Sensitivity & Specificity by True Count Groups
True count/ millions <0.5 0.5-1 1-2 2-5 5-10 10-20 >20 Mean sensitivity/% 0.35 18.85 62.35 85.40 95.73 96.23 96.42 Mean Specificity/% 6.64 6.93 20.43 66.54 93.55 96.87 98.25
Conclusion:
Low-dose PET can provide good performance for lesion detection within the true count range 5-10×10[6].
