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S. Saeteng



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    P1.19 - Poster Session 1 - Imaging (ID 179)

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Imaging, Staging & Screening
    • Presentations: 1
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      P1.19-011 - Correlation between the tumor size measured by using chest radiograph and CT chest comparison to the pathologic size (ID 3037)

      09:30 - 09:30  |  Author(s): S. Saeteng

      • Abstract

      Background
      The size of the tumor is an important prognostic factor in cancer patient. It is ultimately based on the pathologic measurement of gross specimen from surgical resection. However, the preoperative tumor size could be determined by direct measurement of palpable superficial lesion or radiologic imaging such as chest radiograph or computed tomography (CT) in both lung window setting and mediastinal window setting. To our knowledge, there is no definite method to measure tumor’s size on radiographic imaging, moreover, the correlation between pulmonary tumor size measured by using radiographic imaging and pathologic size has not been studied in Thailand yet. The Northern Thailand Thoracic Group (NT-TOG) would like to determine the correlation between tumor size measured by using chest radiograph and CT chest comparison to the pathological tumor size.

      Methods
      After institutional review board approval, the retrospectively analytic cross sectional study from pathological records of all patients who underwent surgery in Chiang Mai University Hospital were reviewed. All cases that achieved CT imaging in the department of radiology were included. Finally 60 pulmonary tumors were collected to measure their sizes on chest radiograph and 98 pulmonary tumors were gather to measure their sizes on mediastinal and lung window sets and compared to the pathological sizes. The location of the tumor and histological cell type were recorded. Data analysis was performed using STATA software to find out the correlation between sizes that had been measured on chest radiograph and on CT images comparison to the tissue pathologic size.

      Results
      The tumor locations were common in the RUL and LUL. Adenocarcinoma was the most common histological type, followed by squamous cell carcinoma and metastasis respectively. The mean radiologic tumor sizes on chest radiograph, CT using mediastinal and lung window settings were 4.8 cm, 4.8 cm and 5.1 cm in maximal diameters, respectively. The mean pathologic tumor size was 4.7 cm in maximal diameter. The mean errors of chest radiographic measurement, CT measurement using mediastinal and lung window settings were 0.25 cm, 0.04 cm and 0.41 cm, respectively. The error of tumor size measured by using CT in mediastinal window setting was statistically significant less than that of using lung window setting (p<0.001). There was a statistically significant difference between tumor size measured by using CT in mediastinal window setting and pathologic tumor size (p<0.001). Predicted tumor size was calculated by using the equation “calculated tumor size (cm) = 1+(0.78xtumor size on CT in mediastinal window (cm)).

      Conclusion
      Although there is a statistically significant difference between CT measurement and pathologic tumor size, the tumor size measured by using CT in mediastinal window setting is seemly more accurate than in lung window setting or chest radiograph.

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    P1.20 - Poster Session 1 - Early Detection and Screening (ID 172)

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Imaging, Staging & Screening
    • Presentations: 1
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      P1.20-005 - Comparison between Chest Radiography, Chest Tomosynthesis and Computed Tomography to Detect Pulmonary Nodules: A Phantom study and clinical experience. (ID 2327)

      09:30 - 09:30  |  Author(s): S. Saeteng

      • Abstract

      Background
      It is true that treatment in the early stage of lung cancer provides the best benefit, so many researchers have actively sought a good screening test for early detection. Although, chest radiography (CXR) is commonly used for evaluating patient with pulmonary disease. There are some limitations in early detection small nodule. Computed Tomography (CT) can easily solve this problem. However, the disadvantages of the CT are high cost and high radiation dose. Recently, there is a new technique called digital tomosynthesis, which can reconstruct sectional images at arbitrary depths by collecting a number of projection images at different angles using a digital detector. The overlapping anatomy of the section images is much less than the standard projection radiograph. Currently, many articles have presented the benefits of DT. The learning curve for interpretation of the technology is also important. The purpose of this study is to find the detection rate of nodule by using CXR, chest digital tomosynthesis (CDT) and CT examination with phantoms and preliminary clinical application in Maharaj Nakorn Chiang Mai hospital.

      Methods
      After institutional review broad approval, in-house chest phantom was made from acrylic, plaster and catheters. The plastic beads, diameter size 1-2 mm., 3-4 mm., 5-6 mm., 7-8 mm. and 9-10 mm. were implanted to represent pulmonary nodules in a phantom. None to 20 nodules were randomly embedded in each model and photographed by digital chest radiograph (CXR), chest digital tomosynthesis (CDT) and chest computed tomography (CT). Two thoracic radiologists were blinded to review and label nodules on each image. Percentage of nodular detection in each study was calculated and compared between each other. After gain experience from phantom study, CDT was preliminary applied to the surgical cases for preoperative evaluation.

      Results
      There were 332 nodules in the 34 phantom-models. Nodule detection rate from each modality was 75.3% of CXR, 91.0% of CDT and 98.8% of CT, respectively. CT could detect all nodules, which were larger than 3 mm in diameter. There were over 90 % of detected nodules from CDT that diameter were larger than 5mm. Percentages of nodular detection of CDT and CT were not statistically significant difference in 5-10 mm sized nodules. Poor nodular detection areas on CXR were mediastinal and hilar regions, while on CDT was costophrenic sulcus. Clinical examinations were shown.

      Conclusion
      CT showed the highest percentage of nodular detection, followed by CDT and digital CXR, respectively. The percentage of detection in nodules size 5 – 10 mm between CT and CDT was not statistically significant difference.

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    P2.19 - Poster Session 2 - Imaging (ID 180)

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Imaging, Staging & Screening
    • Presentations: 1
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      P2.19-013 - Pilot study of low dose computed tomography screening in first relative of lung cancer patient (preliminary report) (ID 3052)

      09:30 - 09:30  |  Author(s): S. Saeteng

      • Abstract

      Background
      Screening lung cancer with low dose computed tomography (CT) improved the likelihood of detection of small non-calcified nodules, and thus lung cancer might be detected earlier with more potential for a cure. The National Lung Screening Trial (NLST) showed that screening with low-dose helical computed tomography (CT) rather than with chest radiography reduced mortality from lung cancer. However, the cost-effectiveness of using low dose CT screening was still debatable in the normal population even in the smoking population. The Northern Thailand Thoracic Oncology Group (NT-TOG) would like to study focusing on the first relative of lung cancer patients which may benefit from low dose CT screening.

      Methods
      From January 2013 to May 2013, a prospective cohort study was performed at Chiang Mai University Hospital. We enrolled asymptomatic participants, 20 to 65 years of age who were the first relative of lung cancer patients and received a structural interview and informed consent. Low-dose CT scan and chest radiography were performed on the same day for each participant. Nodules or other suspicious findings were classified as positive results. Nodules or suspicious findings from either low-dose CT or chest radiography which have a high risk of malignancy will be worked up rapidly for tissue pathology whereas low risk nodules will be followed up with low-dose CT and chest radiography every six months, for two years. This study reports findings from the initial screening examination.

      Results
      There were 14 (45.2%) cases of positive nodule from low- dose CT screening out of a total of 31 cases, whereas, there were no positive nodules from the chest radiography. The average number of nodules was 2.1 nodules and the average size of nodule was 0.4 cm in diameter. There was ground-glass opacity (GGO) in seven cases (22.6 %), subsegmental atelectasis in 14 cases (45.2 %), traction bronchiectasis in four cases (12.9 %), and a lung cyst in one case with subcentimeter lymphadenopathy in 26 cases (83.9 %). The average size of the mediastinal lymph node was 0.7 cm in diameter (range 0.2-0.9 cm).

      Conclusion
      This study reported initial findings from low-dose CT and chest radiography. These results demonstrated that low-dose CT screen may be a valuable method for screening in the first relative of lung cancer patients compared with chest radiography. However, all of the positive cases need to be worked up for a definite tissue diagnosis in order to have an earlier diagnosis of lung cancer and potentially more curative treatment or at least to be closely monitored. This study will be continued and more participants will be recruited and evaluated.