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C.S. Pramesh
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P2.14 - Radiotherapy (ID 715)
- Event: WCLC 2017
- Type: Poster Session with Presenters Present
- Track: Radiotherapy
- Presentations: 1
- Moderators:
- Coordinates: 10/17/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)
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P2.14-005 - Determination of Optimal Cut off SUV Threshold for Auto-Contouring of GTV Using PETCT for Early Stage NSCLC (ID 8812)
09:30 - 09:30 | Author(s): C.S. Pramesh
- Abstract
Background:
[18]F-Fluorodeoxyglucose positron emission tomography-computed tomography ([18]F-FDG-PET-CT) has the potential to increase the precision in contouring of gross tumour volume (GTV). However, detection of tumour edge in the halo around the tumour has been a problem. A surgical histopathological examination is the current gold standard for tumour size estimation in NSCLC. The aim of this study was to determine an optimal cut-off of standardized uptake value (SUV) on FDG-PET-CT images that correlates best with tumour size on surgical histopathology examination.
Method:
From January 2013- July 2014, 25 consecutive patients with diagnosed early NSCLC (pT1-pT3,N0M0) who underwent surgical resection (either a lobectomy or pneumonectomy) were accrued. GTVs were delineated on a preoperative FDG-PET-CT scan (acquired within 8 weeks before surgery) by automatic delineation using % threshold SUV at 20%, 30%, 40%, 50% of maximal uptake and threshold as absolute SUV 2, 2.5, 3, 3.5 and 4. The maximum tumour size was recorded from the surgical histopathology reports. First order linear regression was used to obtain values of optimal cut off SUV for each patient at which maximum size of GTV on FDG-PET-CT matched with maximum tumor size on histopathology. Different SUV thresholds of GTV delineation were compared with histopathology with respect to the estimation of maximum tumour size using Bland-Altman plots. The above methodology was carried out in 25 patients in test set. 12 additional patients were used to validate the results of the test set.
Result:
On analysis of 25 patients in the test set using first order linear approximation, the mean optimal cut-off values for GTV delineation on FDG-PET-CT images were 35.6 % ± 18.6 for % threshold SUV and a 4.35 ± 1.7 for absolute SUV. On analysis of 12 more patients in the validation set, the mean optimal cut-off values for GTV delineation on FDG-PET-CT images were 36.9 ± 16.9 % threshold SUV and a 4.1 ± 1.6 absolute SUV. After combined analysis of all 37 patients, the mean optimal cut-off values for GTV delineation on FDG-PET-CT images were 36 ± 17.9 % threshold SUV and a 4.27 ± 1.7 absolute SUV. On comparing various methods of delineation by Bland-Altman plots, auto-contouring with percentage threshold of 40% and absolute SUV 4 were in greater agreement with the histopathological tumour size.
Conclusion:
Auto-contouring of GTV in NSCLC with the help of optimal cut-off SUV in FDG-PET-CT will improve precision in delineation, reduce inter-observer variability and importantly will save time.
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P3.02 - Biology/Pathology (ID 620)
- Event: WCLC 2017
- Type: Poster Session with Presenters Present
- Track: Biology/Pathology
- Presentations: 2
- Moderators:
- Coordinates: 10/18/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)
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P3.02-036 - Feasibility Study to Evaluate Patterns of Metastases and Effect of Surgery on Lung Cancer Xenografts with Differing Sensitivity to EGFR TKI (ID 8660)
09:30 - 09:30 | Author(s): C.S. Pramesh
- Abstract
Background:
Lung cancer cell lines with differing sensitivities to the epidermal growth factor receptor tyrosine kinase inhibitor, Erlotinib have different invasive and metastatic potential. Surgical intervention may play a role in altering the pattern of metastases and survival. Studying these patterns may help in designing trials to evaluate the efficacy of peri-operative EGFR inhibition.
Method:
Two lung cancer cell lines with known different sensitivity to Erlotinib were selected; A549 known to be resistant to Erlotinib (sensitive to Everolimus) and HCC 827, known to be sensitive to Erlotinib. 12 NOD SCID mice were injected with A549 and 17 NOD SCID with HCC 827 as xenografts in the thigh. FDG-18 PET scans were performed in all mice thrice, at 7-10 days, 4 weeks and at 6 weeks. 8 of the 12 mice with A549 cell line and 12 of the 17 with HCC 827 cell line underwent surgery for local tumour at 4-5 weeks from inoculation. The rest of the mice; 4 in A549 group and 5 in HCC 827 group served as controls. All mice were subjected to autopsy at death.
Result:
For the mice with the HCC 827 cell line: Local invasive potential was 90%. 40% of the mice in the control group and 33.3% of the mice in the operated group produced metastases. Survival was similar in operated and control groups (126 versus 127 days). For the mice with A549 cell line: Local invasion and metastases were seen in all mice. The survival in the group undergoing surgery was 129 days versus 107 days in the control group.
Conclusion:
Both the cell lines have good invasive potential, A549 cell line scored over HCC827 in producing metastases. All the metastases were noted only in the lungs. This study can serve as a background to evaluate the role of peri-operative inhibition with epidermal growth factor receptor tyrosine kinase inhibitors and/or mTor inhibitors.
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P3.02-081 - Nutritional Status Assessment in Treatment Naïve Patients with Lung Cancer (ID 8900)
09:30 - 09:30 | Author(s): C.S. Pramesh
- Abstract
Background:
Malnutrition is multifactorial and frequently co-exists in patients with cancer. Cancer-related anorexia, cachexia and side effects of anticancer therapy can lead to inadequate nutrient intake and subsequent malnutrition. Lung cancer is the leading cause of cancer and cancer-related mortality globally and most patients present in an advanced stage. Nutritional status has a direct effect on the performance status, tolerance to treatment and outcomes.
Method:
We performed a cross-sectional, observational study in the outpatient department of a tertiary referral cancer hospital involving nutritional assessment of treatment-naïve patients with lung cancer. Patients who consented were assessed by two nutritionists using the patient reported subjective global assessment(SGA) and mini nutritional assessment (MNA) tools. Data collected included history, physical and anthropometric measurements. Assuming a prevalence of 33%, the required sample size was calculated to be 400.
Result:
400 patients were recruited between August 2015 and January 2016. The mean age of patients was 58 years and 72% were male. The mean body weight was 57 kilograms and the mean body mass index (BMI) was 21.9 kg/m2. The mean hemoglobin was 12.4 gm% and the mean albumin was 3.9 gm%. 50% of patients were smokers, and 34.7% of the smokers also chewed tobacco. 95% of the smokers were male; 21% consumed alcohol. 64.5% of patients had lost weight, and 60% had anorexia. Most patients presented in advanced stages, with 60.75% in stage IV and 24% in stage III. Nutritional status assessed by the Subjective Global Assessment (SGA) score showed that 24.5% were well nourished (SGA “A”), 64.5% were at risk of malnutrition (SGA “B”) and 11% were malnourished (SGA “C”). Using the Mini Nutritional Assessment (MNA) score, 80.7% of patients were found to be malnourished or at risk of malnutrition with 19.3% patients considered to have normal nutritional status. No significant correlation was found between age, ECOG status, smoking, disease stage or weight loss and the nutritional status scores. There was moderate agreement between the SGA and MNA scores with a kappa coefficient of 0.44.
Conclusion:
Malnutrition is widely prevalent in patients with lung cancer. Formal nutritional assessment using universally acceptable tools like the SGA or MNA should be a part of the work up of the patient along with staging and diagnosis. Early identification can guide nutritional intervention in order to improve the performance status and enable patients to receive and tolerate cancer directed therapy.
