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O05 - Cancer Control (ID 130)
- Event: WCLC 2013
- Type: Oral Abstract Session
- Track: Prevention & Epidemiology
- Presentations: 1
- Moderators:N. Van Zandwijk, A. McWilliams
- Coordinates: 10/28/2013, 10:30 - 12:00, Bayside Auditorium A, Level 1
O05.03 - Screening of Lung Cancer by Low-Dose CT (LDCT), Digital Tomosynthesis (DT) and Chest Radiography (CR) in a High Risk Population: A Comparison of Detection Methods (ID 3018)
10:30 - 12:00 | Author(s): S. Singharuksa
LDCT has recently been recommended as a screening tool for lung cancer in a high risk population, provided a 20% reduction in lung-cancer specific mortality. Nevertheless, LDCT has some limitations with respect to its high false positive rate, accumulated radiation exposure and relatively high cost. Digital tomosynthesis (DT) is a multisection imaging technique which can improve detection ability of small lung nodules and renders much lower radiation dosage and operation costs.
Thai heavy smokers (>30 pack-years) were enrolled in a prospective study starting from July 2012 to April 2013 (n=580). LDCT, DT and CR were utilized as a screening tool for lung cancer screening. All participants underwent imaging studies on the same day and the results were independently reviewed within a 1-week interval. Abnormal findings were categorized into 3 groups: negative, indeterminate (maximum diameter of pulmonary nodule >5- 9.9 mm), and suspicious for malignancy (maximum diameter of pulmonary nodule > 10 mm, consolidation, obstructive atelectasis, pleural effusion or mediastinal lymphadenopathy).
At baseline, LDCT and DT classified 16/580 cases as suspicious for primary lung cancer while CR detected 15/580 cases. Seven cases with positive LDCT and DT findings were tissue-proven primary lung cancer including 3 - stage I cancers, 1 - stage III cancer and 3 - stage IV cancers. CR detected only 3 proven cases of primary lung cancer and all of them were stage IV cancer. The lung cancer detection rate for pulmonary nodule > 10 mm and other suspicious findings was 1.2%, 1.2%, and 0.5% by LDCT, DT, and CR, respectively. LDCT classified 67 cases as indeterminate while DT and CR classified 21 and 11 as such cases, respectively. Two additional primary lung cancer cases were detected at a 3-month follow-up LDCT of the indeterminate group by LDCT (2 cases), DT (1 case) and CR (0 case), respectively. The lung cancer detection rate for pulmonary nodule > 5 mm and other suspicious findings was 1.6%, 1.4%, and 0.5% by LDCT, DT, and CR, respectively. The positive predictive value (PPV) for pulmonary nodule >10 mm and other suspicious findings by LDCT, DT and CR was 43.8%, 43.8%, and 20.0%, respectively, while the PPV for pulmonary nodules of> 5 mm and other suspicious for malignancy findings by LDCT, DT and CR were 10.8%, 21.6%, and 11.5%, respectively. The sensitivity and specificity was 100% and 87%, respectively, for LDCT, and 88.9% and 94.9%, respectively, for DT, and 33.3% and 96%, respectively, for CR.
DT is a lung cancer screening modality that is comparable to LDCT, particularly for pulmonary lesions that are larger than 10 mm. and other suspicious for malignancy findings while CR was far inferior to DT and LDCT.
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P3.20 - Poster Session 3 - Early Detection and Screening (ID 174)
- Event: WCLC 2013
- Type: Poster Session
- Track: Imaging, Staging & Screening
- Presentations: 1
- Coordinates: 10/30/2013, 09:30 - 16:30, Exhibit Hall, Ground Level
P3.20-010 - Low Dose Computerized Tomography (LDCT) as a Lung Cancer Screening Tool in an Endemic Area of Tuberculosis: A Preliminary Report (ID 3333)
09:30 - 16:30 | Author(s): S. Singharuksa
Thailand is among the countries with a high burden of tuberculosis (TB) with 137 new cases per 100,000 persons per year reported. The radiographic findings of TB can mimic lung cancer even after a complete anti-TB treatment. Currently, no clear evidence of benefits from lung cancer screening has been established in a high-risk population residing in an endemic area of TB.
A prospective study was started in July 2012 to determine the role of low-dose computerized tomography (LDCT) as a lung cancer screening tool in Thai heavy smokers (>30 pack-years) without a history of active TB within a recent year. Abnormal LDCT findings were categorized into 3 groups: negative, indeterminate, and suspicious for malignancy according to the baseline nodular volume and volume doubling time in a follow-up LDCT.
As of April 2013, 580 subjects were enrolled. At baseline, 406 cases (70%) had abnormal LDCT findings including 16 cases (2.8%) suspicious for primary lung cancer. Two hundred and forty-five cases (42%) had benign characteristic nodules, 78 cases (13.4%) had inflammation or infection patterns, and 67 cases (11.6%) were indeterminate for malignancy. Of the suspicious primary lung cancer group, 3 cases had a previous lung nodule without any evidence of nodule progression, 13 cases underwent tissue biopsy with resulting lung cancers in 7 cases, caseous granuloma in 2 cases, and negative results in 4 cases. Two cases with the inflammation/infection pattern had asymptomatic progressive lesions in a 2-month follow-up LDCT and underwent bronchoscopy. One case was proven pulmonary TB while the other was culture-negative TB; both of them responded well to anti-TB drugs. Two additional primary lung cancer cases were detected at a 3-month follow-up LDCT yielding a total of 9 positive lung cancer cases (1.5% of total subjects) which consisted of 4 - stage I cancer, 1 - stage II cancer, 1 - stage III cancer, and 3 - stage IV cancers. Early-stage cases (5/9) received potentially curative surgery. Notably, 7 and 2 lung cancer cases were detected from suspicious and indeterminate group, respectively. Three other malignancies were also detected including 1 mediastinal lymphoma, 1 small cell of unknown primary and 1 cholangiocarcinoma.
Our preliminary result revealed that despite a high burden of TB in Thailand, LDCT screening in heavy smokers could yield a high rate of primary lung cancer in this population at risk.