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G.H. De Bock
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MINI 36 - Imaging and Diagnostic Workup (ID 163)
- Event: WCLC 2015
- Type: Mini Oral
- Track: Screening and Early Detection
- Presentations: 1
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MINI36.02 - Newly Detected Solid Nodules at Incidence CT Lung Cancer Screening Rounds: Occurrence and Lung Cancer Probability (ID 1352)
18:35 - 18:40 | Author(s): G.H. De Bock
- Abstract
Background:
Lung cancer screening by low-dose computed tomography (LDCT) is now recommended for high-risk individuals by US guidelines. New nodules detected after initial baseline screening may complicate management. So far, reported results of new nodules have been inconsistent as different definitions were used. The purpose of this study was to determine the occurrence of new solid nodules and their respective lung cancer rate at incidence screening rounds of the Dutch-Belgian Randomized Lung Cancer Screening Trial (NELSON).
Methods:
The NELSON trial was approved by the Dutch Ministry of Health. All participants gave written informed consent. In total, 7,557 individuals underwent baseline LDCT screening. Incidence-screening rounds took place after 1, 3 and 5.5 years. This study included participants with solid non-calcified nodules, newly detected after baseline and also in retrospect not present on any previous screen. Lung cancer diagnosis was based on histology, and benignity was based on either histology or a stable size for at least two years. Nodule volume was generated semi-automatically by Lungcare software (Siemens, Erlangen, Germany), and the nodule detection limit was 15mm[3].
Results:
During the incidence screening rounds, 1,484 new solid nodules were detected in 949 participants (77% male), with a median age of 59 years (interquartile-range 55-63 years). At the second screening round (1 year after baseline), at least one new solid nodule was present in 4.7% (344/7,295) of participants, and at the third screening round (2 years after the second screening round) additional new nodules were found in 7.1% (491/6,922) of participants. Eventually, a new solid nodule was proven to be lung cancer in 7.9% (75/949) of participants with new solid nodules (77 cancers). A higher number of pack-years smoked increased the risk of a new nodule being cancer significantly (P=0.004). Age and gender distribution were comparable between participants with and without lung cancer detected in a new solid nodule (P=0.236 and P=0.157 respectively). The majority of cancers was diagnosed at stage I (48/77 [62.3%]). Most of the lung cancers were adenocarcinoma (30/77 [39.0%]), squamous cell carcinoma (20/77 [26.0%]) or small cell lung cancer (9/77 [11.7%]).
Conclusion:
New solid nodules are common findings in LDCT lung cancer screening and possess a comparably high risk of malignancy. Guidelines may need to consider a more stringent follow-up for new nodules. More research concerning new nodules is necessary to determine a sufficient follow-up strategy and evaluate distinguishing nodule features of benign and malignant new nodules.
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ORAL 09 - CT Screening - New Data and Risk Assessment (ID 95)
- Event: WCLC 2015
- Type: Oral Session
- Track: Screening and Early Detection
- Presentations: 1
- Moderators:J. Mulshine, J.K. Field
- Coordinates: 9/07/2015, 10:45 - 12:15, Mile High Ballroom 2a-3b
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ORAL09.01 - Discerning Malignant and Benign New Nodules at Incidence Rounds of CT Lung Cancer Screening: The Role of Volume and Predicted Volume Doubling Time (ID 1358)
10:45 - 10:56 | Author(s): G.H. De Bock
- Abstract
Background:
Newly detected nodules after baseline screen are common findings in low-dose computed tomography (LDCT) lung cancer screening, and may complicate management. So far little research focused specifically on nodules newly detected at incidence screening rounds. These nodules develop within a known time-frame and are expected to be fast-growing and potentially malignant. Even so, the majority are benign. The aim of this study was to compare volume and predicted growth rate of benign and malignant new solid nodules detected in the incidence screening rounds of the Dutch-Belgian Randomized Lung Cancer Screening Trial (NELSON).
Methods:
The NELSON trial was approved by the Dutch Ministry of Health. All participants gave written informed consent. In total, 7,557 individuals underwent baseline LDCT screening. After the baseline screening, incidence screening rounds took place after 1, 3 and 5.5 years. This study included participants with solid non-calcified nodules, newly detected after baseline and also in retrospect not present on any previous screening. Nodule volume was obtained semi-automatically by Lungcare software (Siemens, Erlangen, Germany). The growth rate at first detection was estimated by calculating the slowest predicted volume-doubling time (pVDT), according to the formula pVDT=[ln(2)*Δt]/[ln(V2/V1)], using the study’s detection limit of 15mm[3] (V1), the volume of the new nodule at first detection (V2), and the time interval between current and last screen (Δt [days]). The pVDT was calculated for nodules with a predicted volume increase of at least 25% (≥ 18.75mm[3]). Lung cancer diagnosis was based on histology. Benignity was based on histology or a stable size for at least two years. Mann-Whitney U testing was used to evaluate differences in volume and pVDT between malignant and benign nodules.
Results:
During the incidence screening rounds, 1,484 new solid nodules in 949 participants were detected of which 77 (5.2%) turned out to be malignant. At first detection, both the median volume of malignant (373mm[3], IQR 120-974mm[3]) and benign (44mm[3], interquartile-range [IQR] 22-122mm[3]) new nodules, as well as the median pVDT of malignant (144 days, IQR 116-213 days) and benign (288 days, IQR 153-566 days) new nodules differed significantly (P<0.001 for both). The calculated median pVDT of adenocarcinomas (183 days, IQR 138-299 days) and squamous-cell carcinomas (150 days, IQR 117-223 days) was similar to previously published volume doubling-times of fast-growing baseline cancers in the NELSON trial of the same histological type (196 days, IQR 135-250 days and 142 days, IQR 91-178 days, respectively).
Conclusion:
At incidence LDCT lung cancer screening, volume and pVDT can be used to differentiate between malignant and benign nature of newly detected solid nodules. The pVDT is a new measure that can assist in adjusting for time differences in screening intervals.
