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P1.03-042 Nodule Size is Poorly Represented by Nodule Diameter in Low-Dose CT Lung Cancer Screening
January 2017
[NS]), offering LCS to the whole population would not encourage smokers to continue smoking. The table shows lay persons’ and physicians’ replies concerning possible target populations within the whole population and among smokers.
Conclusion: Lay persons are more inclined to suggest generalizing LCS to the whole population, independently of current smoking status or quitting issues. Lay persons and physicians alike agree with generalizing LCS to all smokers, regardless of their tobacco consumption. Keywords: screening organisation, screening efficacy, opinion, target population
P1.03-041 Do Several Rounds of Negative Screening Low Dose CT Scans Influence the Risk to Develop Lung Cancer? Topic: Screening Heidi Schmidt,1 John Kavanagh,1 Geoffrey Liu,2 Ming Tsao,3 Frances Shepherd2 1Joint Department of Medical Imaging, University Health Network, Toronto/ ON/Canada, 2Princess Margaret Cancer Centre, Toronto/ ON/Canada, 3Research, Princess Margaret Hospital and Ontario Cancer Institute, Mg L/ON/Canada Background: The purpose of this study was to assess whether several years of negative screening low-dose computed tomography (LDCT) scans predict a subsequent lower risk of developing lung cancer. This would have implications for recommended intervals and duration of LDCT lung cancer screening. Methods: The cohort was an at-risk population who had previous negative screening LDCTs and had not been screened for at least 5 years. Between 2003 and 2009, 4782 individuals had been enrolled in a lung cancer screening study based on age and smoking alone. At this time, their risk was re-calculated using a multifactorial assessment model, and they were contacted in
Abstracts
S567
decreasing order of their re-calculated risk. An initial phone interview assessed interim history, general health, interim diagnosis of lung cancer or interim chest CT. Those participants without lung cancer or recent CT were invited for a single LDCT (40mA, 135kV, 1mm axial reconstructions). Subsequent investigation was recommended depending on the LDCT findings: negative, no new or growing nodules (no further recommendation), positive, low suspicion for malignancy (follow up CT in 3-6 months) or positive, high suspicion for malignancy (referral to the local lung cancer rapid diagnostic assessment program). Results: To date, 361 individuals or family members have been contacted. Fifty-five individuals had passed away (20 from lung cancer), 24 were alive with lung cancer. 129 did not qualify for a LDCT scan (declined participation, or recent CT). A total of 153 have attended for LDCT, on average 7 years after their last LDCT. Ninety-one (59%) studies were reported as negative. Forty-five (29%) LDCTs were positive with low suspicion and a follow up scan was recommended; in 13 cases nodules had resolved on follow up imaging, the remaining 32 are awaiting surveillance LDCTs. Seventeen (11%) LDCTs were reported as positive with high suspicion; 11 of those have a subsequently biopsy proven lung cancer and 6 are currently undergoing further investigations or LDCT surveillance. All lung cancers diagnosed were either stage I or II. Of the 11 individuals with biopsy proven cancers, 7 had normal previous CTs, 4 had a preexisting ground glass nodules in the tumor location on the most recent exam. The overall prevalence of lung cancer in this cohort is 15.2% (55/361) and it may increase. The detection rate of LDCT to date is 7.2% (11/153). Conclusion: Lung cancer risk remains high despite several negative annual screening LDCT scans. Continued screening beyond three years is recommended in high risk individuals. Keywords: Low dose computed tomography, lung cancer, Screening
P1.03-042 Nodule Size is Poorly Represented by Nodule Diameter in Low-Dose CT Lung Cancer Screening Topic: Screening Marjolein Heuvelmans,1 Rozemarijn Vliegenthart,1 Peter Van Ooijen,1 Harry De Koning,2
S568
Matthijs Oudkerk1 1Center for Medical Imaging NorthEast Netherlands, University of Groningen, University Medical Center Groningen, Groningen/Netherlands, 2 Public Health, Erasmus University Medical Center, Rotterdam/Netherlands Background: In lung cancer screening, at least one pulmonary nodule is found in over 50% of participants, of which 99% is benign. As lung cancer probability in low-dose computed tomography (CT) lung cancer screening usually is based on nodule size and growth rate, accurate nodule size determination is of major importance to decrease false positive screen results. Previous studies showed that nodule size measurements based on semi-automated volume are preferred over diameter measurements. Aim of this study was to determine the correlation between nodule diameter and nodule size of nodules found in low-dose CT lung cancer screening, and to directly compare it with semi-automated volume measurements. Methods: We investigated baseline data of 2,240 solid nodules of intermediate size (volume 50-500mm3) in 1,500 lung cancer screening participants. Nodule volume, x, y, and z diameter and minimum / maximum diameter in any direction were generated by semiautomated software (LungCARE, Siemens). Range in maximum axial and mean nodule diameter per nodule volume category (50-100mm3, 100-200mm3, 200300mm3, 300-400mm3, 400-500mm3) was determined. Semi-automated nodule volume represented nodule size. Intra-nodule diameter variation was defined as maximum minus minimum nodule diameter. Results: Median participant age was 59 years, 14.1% were women. Median nodule volume was 82.4 mm3 (interquartile range [IQR], 62.9e125.4 mm3). Median nodule diameter was 6.1 mm (IQR, 5.4e7.2 mm) for mean diameter, and 6.6 mm (IQR, 5.9e7.7 mm) for maximum axial diameter. Range in mean nodule diameter per volume category varied from 8.55 mm (3.0 e 11.5 mm) for nodules with volume of 50-100 mm3 to 6.1 mm (7.2 e 13.3 mm) for nodules with volume of 200-300 mm3; range in maximum axial diameter varied from 11.2 mm (7.3 e 18.5 mm) for nodules with volume of 200-300 mm3, to 7.0 mm (9.1 e 16.1 mm) for nodules with volume of 400-500 mm3. Intra-nodule diameters varied by a median of 2.8 mm (IQR, 2.2-3.7 mm). Intra-nodule diameter variation for smaller intermediate-sized nodules (50-200 mm3) was 2.8 mm (IQR 2.2-3.5 mm), and was smaller than intranodule diameter variation for larger intermediate-sized nodules (200-500 mm3; median 3.6 mm [IQR 2.5-5.1 mm], P<0.01).
Journal of Thoracic Oncology
Vol. 12 No. 1S
Conclusion: Nodule size is poorly represented by diameter, as a nodule has an infinite number of diameters, but only one volume. Therefore, use of nodule diameter measurements may lead to misclassification of lung cancer probability. Median intra-nodule diameter variation was found to be higher as the 1.5mm LungRADS cutoff for nodule growth. Keywords: pulmonary nodule, computed tomography, Screening
P1.03-043 Practical Difficulty of Low Dose Computerized Tomography as a Lung Cancer Screening Tool in an Endemic Area of Tuberculosis Topic: Screening Natthaya Triphuridet, Sutida Singharuksa, Sirachat Vidhyakorn Medicine, Chulabhorn Hospital, Bangkok/Thailand Background: Low-dose computerized tomography (LDCT) is a current standard technique for lung cancer screening to reduce lung cancer death. Clinical and radiographic finding for lung cancer can also be found in Tuberculosis(TB). No clear evidence of benefits from lung cancer screening has been established in a high-risk population residing in an endemic area of TB. Methods: A 5-year prospective lung cancer screening using LDCT enrolled 634 former or current heavy smokers (30 pack-years) aged 50-70 years without a history of active TB within a recent year between July 2012 and January 2014 at Chulabhorn Hospital in Thailand. The results were classified as negative, indeterminate, or positive for primary lung cancer. The preliminary data demonstrated from three rounds of low-dose CT screening for lung cancer (rounds T0, T1, and T2). Results: At initial screening LDCT, 3.5% had positive test (solid/part solid nodule10$0 mm/volume >500 mm3 or consolidation, obstructive atelectasis, pleural effusion, or mediastinal lymphadenopathy). Most of participants with non-calcified lung nodule (NCN)(s) had 2-4 nodules, the higher proportion of multiple pulmonary nodules was observed in the larger size. Nine cases (1.4%) were proven lung cancer (56% stage I, 22% stage II/III, 22% stage IV) within 12 months. All cases of stage I-II had 2-10 lung nodules, while all stage III-IV lung cancers had single lung nodule. PPV of positive LDCT test, NCN(s)10 mm and GGN(s)10 mm for diagnosis
[NS]), offering LCS to the whole population would not encourage smokers to continue smoking. The table shows lay persons’ and physicians’ replies concerning possible target populations within the whole population and among smokers.
Conclusion: Lay persons are more inclined to suggest generalizing LCS to the whole population, independently of current smoking status or quitting issues. Lay persons and physicians alike agree with generalizing LCS to all smokers, regardless of their tobacco consumption. Keywords: screening organisation, screening efficacy, opinion, target population
P1.03-041 Do Several Rounds of Negative Screening Low Dose CT Scans Influence the Risk to Develop Lung Cancer? Topic: Screening Heidi Schmidt,1 John Kavanagh,1 Geoffrey Liu,2 Ming Tsao,3 Frances Shepherd2 1Joint Department of Medical Imaging, University Health Network, Toronto/ ON/Canada, 2Princess Margaret Cancer Centre, Toronto/ ON/Canada, 3Research, Princess Margaret Hospital and Ontario Cancer Institute, Mg L/ON/Canada Background: The purpose of this study was to assess whether several years of negative screening low-dose computed tomography (LDCT) scans predict a subsequent lower risk of developing lung cancer. This would have implications for recommended intervals and duration of LDCT lung cancer screening. Methods: The cohort was an at-risk population who had previous negative screening LDCTs and had not been screened for at least 5 years. Between 2003 and 2009, 4782 individuals had been enrolled in a lung cancer screening study based on age and smoking alone. At this time, their risk was re-calculated using a multifactorial assessment model, and they were contacted in
Abstracts
S567
decreasing order of their re-calculated risk. An initial phone interview assessed interim history, general health, interim diagnosis of lung cancer or interim chest CT. Those participants without lung cancer or recent CT were invited for a single LDCT (40mA, 135kV, 1mm axial reconstructions). Subsequent investigation was recommended depending on the LDCT findings: negative, no new or growing nodules (no further recommendation), positive, low suspicion for malignancy (follow up CT in 3-6 months) or positive, high suspicion for malignancy (referral to the local lung cancer rapid diagnostic assessment program). Results: To date, 361 individuals or family members have been contacted. Fifty-five individuals had passed away (20 from lung cancer), 24 were alive with lung cancer. 129 did not qualify for a LDCT scan (declined participation, or recent CT). A total of 153 have attended for LDCT, on average 7 years after their last LDCT. Ninety-one (59%) studies were reported as negative. Forty-five (29%) LDCTs were positive with low suspicion and a follow up scan was recommended; in 13 cases nodules had resolved on follow up imaging, the remaining 32 are awaiting surveillance LDCTs. Seventeen (11%) LDCTs were reported as positive with high suspicion; 11 of those have a subsequently biopsy proven lung cancer and 6 are currently undergoing further investigations or LDCT surveillance. All lung cancers diagnosed were either stage I or II. Of the 11 individuals with biopsy proven cancers, 7 had normal previous CTs, 4 had a preexisting ground glass nodules in the tumor location on the most recent exam. The overall prevalence of lung cancer in this cohort is 15.2% (55/361) and it may increase. The detection rate of LDCT to date is 7.2% (11/153). Conclusion: Lung cancer risk remains high despite several negative annual screening LDCT scans. Continued screening beyond three years is recommended in high risk individuals. Keywords: Low dose computed tomography, lung cancer, Screening
P1.03-042 Nodule Size is Poorly Represented by Nodule Diameter in Low-Dose CT Lung Cancer Screening Topic: Screening Marjolein Heuvelmans,1 Rozemarijn Vliegenthart,1 Peter Van Ooijen,1 Harry De Koning,2
S568
Matthijs Oudkerk1 1Center for Medical Imaging NorthEast Netherlands, University of Groningen, University Medical Center Groningen, Groningen/Netherlands, 2 Public Health, Erasmus University Medical Center, Rotterdam/Netherlands Background: In lung cancer screening, at least one pulmonary nodule is found in over 50% of participants, of which 99% is benign. As lung cancer probability in low-dose computed tomography (CT) lung cancer screening usually is based on nodule size and growth rate, accurate nodule size determination is of major importance to decrease false positive screen results. Previous studies showed that nodule size measurements based on semi-automated volume are preferred over diameter measurements. Aim of this study was to determine the correlation between nodule diameter and nodule size of nodules found in low-dose CT lung cancer screening, and to directly compare it with semi-automated volume measurements. Methods: We investigated baseline data of 2,240 solid nodules of intermediate size (volume 50-500mm3) in 1,500 lung cancer screening participants. Nodule volume, x, y, and z diameter and minimum / maximum diameter in any direction were generated by semiautomated software (LungCARE, Siemens). Range in maximum axial and mean nodule diameter per nodule volume category (50-100mm3, 100-200mm3, 200300mm3, 300-400mm3, 400-500mm3) was determined. Semi-automated nodule volume represented nodule size. Intra-nodule diameter variation was defined as maximum minus minimum nodule diameter. Results: Median participant age was 59 years, 14.1% were women. Median nodule volume was 82.4 mm3 (interquartile range [IQR], 62.9e125.4 mm3). Median nodule diameter was 6.1 mm (IQR, 5.4e7.2 mm) for mean diameter, and 6.6 mm (IQR, 5.9e7.7 mm) for maximum axial diameter. Range in mean nodule diameter per volume category varied from 8.55 mm (3.0 e 11.5 mm) for nodules with volume of 50-100 mm3 to 6.1 mm (7.2 e 13.3 mm) for nodules with volume of 200-300 mm3; range in maximum axial diameter varied from 11.2 mm (7.3 e 18.5 mm) for nodules with volume of 200-300 mm3, to 7.0 mm (9.1 e 16.1 mm) for nodules with volume of 400-500 mm3. Intra-nodule diameters varied by a median of 2.8 mm (IQR, 2.2-3.7 mm). Intra-nodule diameter variation for smaller intermediate-sized nodules (50-200 mm3) was 2.8 mm (IQR 2.2-3.5 mm), and was smaller than intranodule diameter variation for larger intermediate-sized nodules (200-500 mm3; median 3.6 mm [IQR 2.5-5.1 mm], P<0.01).
Journal of Thoracic Oncology
Vol. 12 No. 1S
Conclusion: Nodule size is poorly represented by diameter, as a nodule has an infinite number of diameters, but only one volume. Therefore, use of nodule diameter measurements may lead to misclassification of lung cancer probability. Median intra-nodule diameter variation was found to be higher as the 1.5mm LungRADS cutoff for nodule growth. Keywords: pulmonary nodule, computed tomography, Screening
P1.03-043 Practical Difficulty of Low Dose Computerized Tomography as a Lung Cancer Screening Tool in an Endemic Area of Tuberculosis Topic: Screening Natthaya Triphuridet, Sutida Singharuksa, Sirachat Vidhyakorn Medicine, Chulabhorn Hospital, Bangkok/Thailand Background: Low-dose computerized tomography (LDCT) is a current standard technique for lung cancer screening to reduce lung cancer death. Clinical and radiographic finding for lung cancer can also be found in Tuberculosis(TB). No clear evidence of benefits from lung cancer screening has been established in a high-risk population residing in an endemic area of TB. Methods: A 5-year prospective lung cancer screening using LDCT enrolled 634 former or current heavy smokers (30 pack-years) aged 50-70 years without a history of active TB within a recent year between July 2012 and January 2014 at Chulabhorn Hospital in Thailand. The results were classified as negative, indeterminate, or positive for primary lung cancer. The preliminary data demonstrated from three rounds of low-dose CT screening for lung cancer (rounds T0, T1, and T2). Results: At initial screening LDCT, 3.5% had positive test (solid/part solid nodule10$0 mm/volume >500 mm3 or consolidation, obstructive atelectasis, pleural effusion, or mediastinal lymphadenopathy). Most of participants with non-calcified lung nodule (NCN)(s) had 2-4 nodules, the higher proportion of multiple pulmonary nodules was observed in the larger size. Nine cases (1.4%) were proven lung cancer (56% stage I, 22% stage II/III, 22% stage IV) within 12 months. All cases of stage I-II had 2-10 lung nodules, while all stage III-IV lung cancers had single lung nodule. PPV of positive LDCT test, NCN(s)10 mm and GGN(s)10 mm for diagnosis