CT Texture Analysis of Tumors May Be a Valuable Biomarker in Localized Esophageal Cancer

Released: 2/8/2013 3:00 PM EST
Source Newsroom: American Society for Radiation Oncology (ASTRO)
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Citations 2013 Cancer Imaging and Radiation Therapy Symposium

Newswise — Orlando, Fla., February 8, 2013 – CT texture analysis of primary tumors may be a potential imaging biomarker in localized esophageal cancer following neoadjuvant chemotherapy, according to research being presented at the 2013 Cancer Imaging and Radiation Therapy Symposium. This Symposium is sponsored by the American Society for Radiation Oncology (ASTRO) and the Radiological Society of North American (RSNA).

This study evaluated the tumoral texture analysis on baseline and post-treatment CT scans of 31 patients with localized resectable esophageal cancer patients with a median age of 63 and who received neoadjuvant chemotherapy between 2007 and 2010. CT scans were performed before and after the use of chemotherapy and prior to surgery. All patients received platinum and fluorouracil-based chemotherapy followed by surgery. Texture parameters (mean-grey level intensity (MGI), entropy, uniformity, kurtosis, skewness and standard deviation of histogram (SDH)) were derived for four filter values to highlight structures of different spatial width: 1.0 (fine texture), 1.5-2.0 (medium) and 2.5 (coarse). Median follow-up was 21.9 months. Primary tumors became more homogenous following chemotherapy, as entropy decreased and uniformity increased. Smaller change in skewness following chemotherapy was a significant prognostic factor—median overall survival was 36.1 months vs. 11.1 months. Lower baseline entropy and lower post-treatment MGI were also associated with improved survival, although they demonstrated only a trend toward significance.

Texture analysis of the CT scans is a post-processing step, which was done utilizing proprietary software (TexRAD) that enhances the images in ultra-fine detail not visible to the human eye. Certain tumoral features changed consistently following chemotherapy, and some features were associated with overall survival.

“Though these results are for a very small number of patients, they suggest that the tumoral texture features may provide valuable information that could help us to distinguish which patients will do well following chemotherapy and which ones will do poorly,” said Connie Yip, MD, the lead study author, a clinical research fellow at King’s College London, United Kingdom and an associate consultant in radiation oncology at the National Cancer Centre, Singapore. “As a biomarker for treatment efficacy, this technique could save patients from unnecessary surgery and provide more definitive guidance in developing patient treatment plans with improved outcomes.”

The abstract, “CT Tumoral Heterogeneity as a Prognostic Marker in Primary Esophageal Cancer Following Neoadjuvant Chemotherapy,” will be presented in detail during a scientific session at 8:00 a.m. Eastern time on Saturday, February 9, 2013. To speak with Connie Yip, MD, call Michelle Kirkwood on February 8-9, 2013, in the Press Office at the Hilton Orlando Lake Buena Vista in the Walt Disney World Resort at 407-560-2314 or email michellek@astro.org.

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2013 Cancer Imaging and Radiation Therapy Symposium
Abstracts of Interest News Briefing, Saturday, February 9, 2013, 7:00 a.m. – 7:45 a.m. ET

Oral Presentation: Saturday, February 9, 8:00 a.m. Eastern time

7 CT Tumoral Heterogeneity as a Prognostic Marker in Primary Esophageal Cancer Following Neoadjuvant Chemotherapy

Author Block:
C. S. P. Yip1, F. Davnall1, R. Kozarski2, D. Landau11, 3, R. Mason1, J. Lagergren1, G. Cook4, V. Goh1, 3,
1Guy's & St Thomas' NHS Foundation Trust, London, United Kingdom, 2University of Hertfordshire, Hatfield, United Kingdom, 3Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom, 4Division of Imaging Sciences and Biomedical Engineering, King’s College London, London, United Kingdom

Abstract Body:
Purpose/objectives: Outcome following curative surgery remains poor in early stage esophageal cancer, thus neoadjuvant chemotherapy is advocated to improve local and distant control. At present, there is no established imaging or histological biomarker that identifies responders or good prognosis patients who would benefit from surgery. We hypothesized that CT texture analysis which assesses intratumoral heterogeneity may prognosticate in patients treated with neoadjuvant chemotherapy for primary esophageal cancer.

Methods/materials: 31 patients (median age 63 years, range 49-77; 19 males; 22 adenocarcinoma, 9 SCC; 1 stage I, 12 stage II, 17 stage III, 1 stage IV) who received neoadjuvant chemotherapy for esophageal cancer in our centre between 2007-2010 were identified retrospectively from our institutional database. All patients received platinum and fluorouracil-based chemotherapy (ECF, ECX or PF) followed by surgery. 11 patients received adjuvant treatment. CT texture analysis of the primary tumor was performed using proprietary software (TexRAD, University of Sussex) on staging and post-chemotherapy scans. Texture parameters (mean-grey level intensity (M), entropy, uniformity, kurtosis, skewness and standard deviation of histogram (SD)) were derived for 4 filter values to highlight structures of different spatial width: 1.0 (fine texture), 1.5-2.0 (medium) and 2.5 (coarse). Overall survival was estimated using Kaplan-Meier method and comparison between dichotomized texture parameters was performed with log-rank test. A subgroup of 26 patients were grouped as responders and non-responders based on pathological Mandard score (score 1-3 vs. 4-5 respectively). The association between treatment response and texture parameters was done using Mann-Whitney U (MWU) and Fisher exact test. A p value ≤0.01 was considered significant.

Results: Median follow-up was 24.7 months (range 9.6-56.9). Baseline texture parameters: lower entropy (filter 2.5: median OS 34.1mo vs. 9.3mo, p=0.01), lower SD (filter 2.5: MOS 34.1mo vs. 8.1mo, p<0.001) and higher uniformity (filter 2.5: MOS 34.1mo vs. 9.3mo, p=0.01); and post-treatment parameters: lower M (filter 1.0: MOS 36.1mo vs. 10.5mo, p<0.001) and negative skewness (filter 2.0: MOS 34.1mo vs. 4.3mo, p<0.001) were significant positive prognostic factors. There were 11 responders: 5 complete, 6 partial; and 15 non-responders. Baseline SD (filter 1.5, p=0.006) and post-treatment SD (filter 1.0, p=0.009) as continuous variables had significant associations with pathological tumor response.

Conclusions: CT texture analysis has the potential to be a prognostic biomarker following neoadjuvant therapy in esophageal cancer.

Author Disclosure Block:
C.S.P. Yip: None. F. Davnall: None. R. Kozarski: None. D. Landau: None. R. Mason: None. J. Lagergren: None. G. Cook: None. V. Goh: None.


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