Raffaella Bertolotti

Lung cancer screening with low-dose computed tomography: A non-invasive diagnostic protocol for baseline lung nodules

BACKGROUND Indeterminate non-calcified lung nodules are frequent when low-dose spiral computed tomography (LD-CT) is used for lung cancer screening. We assessed the diagnostic utility of a non-invasive work-up protocol for nodules detected at baseline in volunteers enrolled in our single-centre screening trial, and followed for at least 1 year. METHODS 5201 high-risk volunteers, recruited over 1 year from October 2004, underwent baseline LD-CT; 4821 (93%) returned for the first repeat LD-CT. Nodules <or=5mm underwent repeat LD-CT at 1 year; nodules 5.1-8mm underwent LD-CT 3 months later; lesions >8mm received combined CT-positron emission tomography (CT-PET). A subset of nodules >8mm was studied by CT with contrast. Protocol failures were delayed diagnosis with disease progression beyond stage I, and negative surgical biopsy. RESULTS 2754 (53%) volunteers presented one or more non-calcified nodules. Ninety-two lung cancers were diagnosed: 55 at baseline and 37 at annual screening (66% stage I). Among the 37 incident cancers, 17 had a baseline nodule that remained stage I, 7 had a baseline nodule that progressed beyond stage I, and 13 presented a new malignant nodule. Baseline and annual cancers were 79 (1.5%) and 13 (0.2%), respectively. In 15 of 104 (14%) invasive diagnostic procedures, the lesion was benign. Sensitivity, and specificity were 91 and 99.7%, respectively, for the entire protocol; 88 and 93% for CT-PET; and 100 and 59% for CT with contrast. CONCLUSIONS The protocol limits invasive diagnostic procedures while few patients have diagnosis delay, supporting the feasibility of lung cancer screening in high-risk subjects by LD-CT. Nevertheless further optimization of the clinical management of screening-detected nodules is necessary.

Estimating overdiagnosis in low-dose computed tomography screening for lung cancer: a cohort study.

BACKGROUND Lung cancer screening may detect cancer that will never become symptomatic (overdiagnosis), leading to overtreatment. Changes in size on sequential low-dose computed tomography (LDCT) screening, expressed as volume-doubling time (VDT), may help to distinguish aggressive cancer from cases that are unlikely to become symptomatic. OBJECTIVE To assess VDT for screening-detected lung cancer as an indicator of overdiagnosis. DESIGN Retrospective estimation of the VDT of cancer detected in a prospective LDCT screening cohort. SETTING Nonrandomized, single-center screening study involving persons at high risk for lung cancer enrolled between 2004 and 2005 who received LDCT annually for 5 years. PATIENTS 175 study patients diagnosed with primary lung cancer. MEASUREMENTS VDT was measured on LDCT and classified as fast-growing (<400 days), slow-growing (between 400 and 599 days), or indolent (≥600 days). RESULTS Fifty-five cases of cancer were diagnosed at baseline, and 120 were diagnosed subsequently. Of the latter group, 19 cases (15.8%) were new (not visible on previous scans) and fast-growing (median VDT, 52 days); 101 (84.2%) were progressive, including 70 (58.3%) fast-growing and 31 (25.8%) slow-growing (15.0%) or indolent (10.8%) cases. Lung cancer-specific mortality was significantly higher (9.2% per year) in patients with new compared with slow-growing or indolent (0.9% per year) cancer. Sixty percent of fast-growing progressive cancer and 45% of new cancer were stage I, for which survival was good. LIMITATIONS This is a retrospective study. Volume-doubling time can only indicate overdiagnosis and was estimated for new cancer from 1 measurement (a diameter of 2 mm assumed the previous year). CONCLUSION Slow-growing or indolent cancer comprised approximately 25% of incident cases, many of which may have been overdiagnosed. To limit overtreatment in these cases, minimally invasive limited resection and nonsurgical treatments should be investigated. PRIMARY FUNDING SOURCE Italian Association for Cancer Research.

Lung Cancer Risk Prediction to Select Smokers for Screening CT—a Model Based on the Italian COSMOS Trial

Screening with low-dose helical computed tomography (CT) has been shown to significantly reduce lung cancer mortality but the optimal target population and time interval to subsequent screening are yet to be defined. We developed two models to stratify individual smokers according to risk of developing lung cancer. We first used the number of lung cancers detected at baseline screening CT in the 5,203 asymptomatic participants of the COSMOS trial to recalibrate the Bach model, which we propose using to select smokers for screening. Next, we incorporated lung nodule characteristics and presence of emphysema identified at baseline CT into the Bach model and proposed the resulting multivariable model to predict lung cancer risk in screened smokers after baseline CT. Age and smoking exposure were the main determinants of lung cancer risk. The recalibrated Bach model accurately predicted lung cancers detected during the first year of screening. Presence of nonsolid nodules (RR = 10.1, 95% CI = 5.57–18.5), nodule size more than 8 mm (RR = 9.89, 95% CI = 5.84–16.8), and emphysema (RR = 2.36, 95% CI = 1.59–3.49) at baseline CT were all significant predictors of subsequent lung cancers. Incorporation of these variables into the Bach model increased the predictive value of the multivariable model (c-index = 0.759, internal validation). The recalibrated Bach model seems suitable for selecting the higher risk population for recruitment for large-scale CT screening. The Bach model incorporating CT findings at baseline screening could help defining the time interval to subsequent screening in individual participants. Further studies are necessary to validate these models. Cancer Prev Res; 4(11); 1778–89. ©2011 AACR.

Screening-Detected Lung Cancers: Is Systematic Nodal Dissection Always Essential?

Background: To address whether systematic lymph node dissection is always necessary in early lung cancer, we identified factors predicting nodal involvement in a screening series and applied them to nonscreening-detected cancers. Methods: In the 97 patients with clinical T1–2N0M0 lung cancer (<3 cm), enrolled in the Continuous Observation of Smoking Subjects computed tomography (CT) screening study, who underwent curative resection with radical mediastinal lymph node dissection, we examined factors associated with hilar extrapulmonary and mediastinal nodal involvement. Nodule size plus positive/negative positron emission tomography (PET)-CT (usually as maximum standard uptake value [maxSUV]) were subsequently evaluated retrospectively for their ability to predict nodal involvement in 193 consecutive patients with nonscreening-detected clinical stage I lung cancer. Results: Among Continuous Observation of Smoking Subjects patients, 91 (94%) were pN0, and six (6.2%) were pN+. All patients with maxSUV <2.0 (p = 0.08) or pathological nodule ≤10 mm (p = 0.027) were pN0 (62 cases). Nodal metastases occurred in 6 cases among the 29 (17%) patients with lung nodule >10 mm and maxSUV ≥2.0 (p = 0.002 versus the other 62 cases). In the nonscreening series, 42 of 43 cases with negative PET-CT (usually maxSUV <2.0) or nodule ≤10 mm were pN0; 33 of 149 (22%) cases with positive PET-CT (usually maxSUV ≥ 2.0) and nodule >10 mm were pN+ (p = 0.001 versus the 43 cases). Conclusions: This limited experience suggests that in early-stage clinically N0 lung cancers with maxSUV <2.0 or pathological nodule size ≤10 mm, systematic nodal dissection can be avoided as the risk of nodal involvement is very low.

Diagnostic performance of low-dose computed tomography screening for lung cancer over five years.

Introduction: Low-dose computed tomography (LD-CT) screening can reduce lung cancer mortality; however, it is essential to improve nodule management protocols. We analyze the performance of the diagnostic protocol of the Continuous Observation of SMOking Subjects single-center screening study, after long-term follow-up. Methods: Between 2004 and 2005, 5203 asymptomatic high-risk individuals (≥20 pack-years, aged 50 years or older) were enrolled to undergo annual LD-CT for 5 years. Nodules 5 mm or smaller underwent repeat LD-CT a year later. Nodules larger than 5.0 mm and 8.0 mm or smaller received LD-CT 3 to 6 months later. Nodules larger than 8.0 mm or growing underwent CT-positron emission tomography. True positives were any stage prevalent lung cancer, progressing nodules diagnosed at stage 1, localized multifocal cancer, or new nodules diagnosed at any stage. False negatives were progressing nodules diagnosed at stage >1. False positives were benign nodules resected surgically. Results: Compliance was 79% over 5 years; 175 primary lung cancers were detected (0.76% per year), 136 (77.7%) were N0M0 and three were interval cancers. Eleven second primary lung cancers were diagnosed. Resectability was 87.4%; postoperative mortality 0.6%. Recall was 6.4% overall, 10.1% at baseline. False negatives were 14 of 175 (8%). Protocol sensitivity was 158 of 175 (90%); specificity 4994 of 5028 (99.4%); positive predictive value was 158 of 187 (84.5%); and negative predictive value was 4994 of 5016 (99.7%). Twenty-nine of 204 (14.2%) benign lesions were diagnosed surgically. Five-year overall and cancer-specific survival were 78% (95% confidence interval, 72–84) and 82% (95% confidence interval, 76%–88%) respectively. Conclusions: The performance of the CT protocol was satisfactory with an acceptable number of benign lesions biopsied surgically, low recall rate, and good oncological outcomes. However, interval and advanced cancers, and misdiagnoses, need to be reduced, perhaps by risk modeling and use of serum markers.

Positron emission tomography in the diagnostic work-up of screening-detected lung nodules

Low-dose computed tomography (CT) screening for lung cancer can reduce lung cancer mortality, but overdiagnosis, false positives and invasive procedures for benign nodules are worrying. We evaluated the utility of positron emission tomography (PET)-CT in characterising indeterminate screening-detected lung nodules. 383 nodules, examined by PET-CT over the first 6 years of the COSMOS (Continuous Observation of Smoking Subjects) study to diagnose primary lung cancer, were reviewed and compared with pathological findings (surgically-treated patients) or follow-up (negative CT for ⩾2 years, considered negative); 196 nodules were malignant. The sensitivity, specificity and accuracy of PET-CT for differentially diagnosing malignant nodules were, respectively, 64%, 89% and 76% overall, and 82%, 92% and 88% for baseline-detected nodules. Performance was lower for nodules found at repeat annual scans, with sensitivity ranging from 22% for nonsolid to 79% for solid nodules (p=0.0001). Sensitivity (87%) and specificity (73%) were high for nodules ⩾15 mm, better (sensitivity 98%) for solid nodules ⩾15 mm. PET-CT was highly sensitive for the differential diagnosis of indeterminate nodules detected at baseline, nodules ⩾15 mm and solid nodules. Sensitivity was low for sub-solid nodules and nodules discovered after baseline for which other methods, e.g. volume doubling time, should be used. PET-CT is good at differentially diagnosing large, solid and baseline-detected lung nodules in the screening setting http://ow.ly/A1amh

Computed tomography screening for lung cancer: Results of ten years of annual screening and validation of cosmos prediction model

INTRODUCTION It is unclear how long low-dose computed tomographic (LDCT) screening should continue in populations at high risk of lung cancer. We assessed outcomes and the predictive ability of the COSMOS prediction model in volunteers screened for 10 years. MATERIALS AND METHODS Smokers and former smokers (>20 pack-years), >50 years, were enrolled over one year (2000-2001), receiving annual LDCT for 10 years. The frequency of screening-detected lung cancers was compared with COSMOS and Bach risk model estimates. RESULTS Among 1035 recruited volunteers (71% men, mean age 58 years) compliance was 65% at study end. Seventy-one (6.95%) lung cancers were diagnosed, 12 at baseline. Disease stage was: IA in 48 (66.6%); IB in 6; IIA in 5; IIB in 2; IIIA in 5; IIIB in 1; IV in 5; and limited small cell cancer in 3. Five- and ten-year survival were 64% and 57%, respectively, 84% and 65% for stage I. Ten (12.1%) received surgery for a benign lesion. The number of lung cancers detected during the first two screening rounds was close to that predicted by the COSMOS model, while the Bach model accurately predicted frequency from the third year on. CONCLUSIONS Neither cancer frequency nor proportion at stage I decreased over 10 years, indicating that screening should not be discontinued. Most cancers were early stage, and overall survival was high. Only a limited number of invasive procedures for benign disease were performed. The Bach model - designed to predict symptomatic cancers - accurately predicted cancer frequency from the third year, suggesting that overdiagnosis is a minor problem in lung cancer screening. The COSMOS model - designed to estimate screening-detected lung cancers - accurately predicted cancer frequency at baseline and second screening round.

Long-term outcomes of a pilot CT screening for lung cancer.

Background: Low-dose computed tomography (CT) screening can detect early stage lung cancer in high-risk populations. However, no data on repeated annual screening over more than 5 years are available, and the impact of screening on lung cancer mortality is controversial. Methods: We analysed outcomes in high-risk asymptomatic volunteers (smokers and former smokers, >50 years) enrolled in a pilot study over 1 year from June 2000, who received annual low-dose CT for 7 years. Cumulative lung cancer incidence and survival were represented by Kaplan–Meier curves. Standardized incidence and mortality ratios were used to estimate risks relative to the general Italian and US population. Results: Compliance was 86% at the end of the seventh year in 1035 recruited volunteers (71% men, mean age 58 years). Lung cancer was diagnosed in 54 (5.3%); radical surgery was possible in 48/54 (87%); 39/54 (72%) had stage I disease. Five-year survival was 63% overall, 89% for stage I cases. During 6308 person-years of observation, 47 participants had died versus 75 expected in the Italian general population standardised for age and sex. Fourteen lung cancer deaths were registered versus 27 expected in a standardised US smoker population. Conclusions: Seventy percent of screening-diagnosed patients had stage I disease, and the survival of screen-detected cancer patients was high. Lung cancer mortality was favourable compared to age- and sex-matched population of US smokers, suggesting that mortality can be lowered by screening, although larger trials with longer follow-up are necessary to confirm these findings.

Abstract 1573: miR-Test: a blood test for lung cancer early detection

Proceedings: AACR 106th Annual Meeting 2015; April 18-22, 2015; Philadelphia, PA Background: Lung cancer is the leading cause of cancer death worldwide. As lung cancer is asymptomatic in its early stages, the majority of patients are diagnosed with advanced disease, when the tumor is unresectable. Consequently, the survival rate is very low: 15% at 5 years. It is vital, therefore, that screening programs and novel diagnostic tools are developed, which will increase the detection of lung cancer in its early stages (stage I-II), when the tumor is still curable, to reduce lung cancer mortality. Recently, we described a serum microRNA signature diagnostic for asymptomatic, early stage, lung cancer. The availability of reliable biomarkers to identify high-risk individuals might help to reduce the size of the target population for LDCT-based programs, thereby reducing costs and probably increasing compliance Methods: We performed a large-scale validation study of a miRNA blood test based on our signature (the miR-Test) in a population of high-risk individuals (N = 1115) enrolled in the lung cancer screening program COSMOS (Continuous Observation of SMOking Subjects), and other 74 lung cancer patients diagnosed outside of screening. Results: The miR-Test showed overall accuracy, specificity and sensitivity of 75%, 78%, and 75%, respectively, with an AUC of 0.85. The test appears to have a dual origin: the first from epithelial cells (the epithelial-like component); the second from cells of hematopoietic origin (the inflammatory-like component). Of note, we found that both components are needed to maintain a good performance of the miR-Test. Conclusions: The relatively high sensitivity of the miR-Test in detecting asymptomatic lung cancer and its high negative predictive value (NPV > 99%), confirm the effectiveness of the test, both interms of its ability to identify asymptomatic lung cancer patients and to reduce significantly unnecessary CTs on healthy individuals. Citation Format: Francesca Montani, Matteo Jacopo Marzi, Fabio Dezi, Elisa Dama, Rose Mary Carletti, Giuseppina Bonizzi, Raffaella Bertolotti, Massimo Bellomi, Cristiano Rampinelli, Patrick Maisonneuve, Lorenzo Spaggiari, Giulia Veronesi, Francesco Nicassio, Pier Paolo Di Fiore, Fabrizio Bianchi. miR-Test: a blood test for lung cancer early detection. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1573. doi:10.1158/1538-7445.AM2015-1573

Estimating Overdiagnosis of Lung Cancer

TO THE EDITOR: We agree with Veronesi and colleagues (1) that risk models for lung cancer should help to identify smokers at greatest risk for aggressive lung cancer. This would minimize the investigation and treatment of indolent cancer (overdiagnosis) and improve the cost-effectiveness of computed tomography (CT) screening. Using data from the PLuSS (Pittsburgh Lung Screening Study) CT screening trial (2), we show that “low-risk” smokers are overrepresented among those with indolent lung cancer. We have previously shown that lung cancer detection rates are 4to 5-fold greater in current or former smokers with spirometry-defined chronic obstructive pulmonary disease (COPD) or CT-based emphysema than in those with normal lungs (3). The question arises, “Is lung function (or emphysema) also related to aggressiveness of lung cancer, with indolent lung cancer more prevalent in smokers without COPD?” If the answer is “yes,” then risk models selecting smokers for CT screening on the basis of a “disposition to COPD” would help to minimize overdiagnosis. We tested this hypothesis by using data from PLuSS (2) and found that the frequency of cancer with “slowgrowing” volume-doubling time (VDT) was 48% (20 of 42) in those with emphysema and 48% (10 of 21) in those without, whereas the frequency of this more indolent cancer was 38% (17 of 45) in those with COPD (Global Initiative for Chronic Obstructive Lung Disease stages I to IV) and 72% (13 of 18) in those without (P 0.01). These findings suggest that airflow limitation (COPD) is a better clinical marker of aggressive lung cancer (that is, with shorter VDT) than emphysema. A related observation from PLuSS was that 87% of cases of slow-growing VDT cancer were adenocarcinomas or bronchoalveolar carcinomas compared with 60% of cases of “rapid” or “typical” VDT cancer (P 0.001). Saghir and colleagues (4) also reported that adenocarcinomas or bronchoalveolar carcinomas account for most cases of “excess cancer” from CT screening (that is, overdiagnosed cancer); in their study, 82% were histologically confirmed adenocarcinomas or bronchoalveolar carcinomas. These results concur with studies showing that COPD prevalence is greater in cases of squamousand small-cell lung cancer than with adenocarcinoma, where lung function is consistently better (5). Taken together, these findings support the hypothesis that lung cancer associated with airflow limitation (COPD) is more likely to be aggressive (rather than indolent) and less likely to result in overdiagnosis. Of note, Veronesi and colleagues showed that early treatment of even the fastest-growing cancer had good long-term survival if identified at stage I (1). We conclude that overdiagnosis of lung cancer detected through CT screening can be minimized by targeting CT screening to smokers with the greatest risk, particularly those with an underlying tendency for or predisposition to COPD.