Small-cell carcinoma of the lung detected by CT screening: Stage distribution and curability

Trends in Stage I Lung Cancer

INTRODUCTION

The American Cancer Society has recently reported an increase in the percentage of patients with localized lung cancer from 2004 to 2018, coinciding with the initial lung cancer screening guidelines issued in 2013. We conducted a National Cancer Database (NCDB) study to further evaluate the trends in stage I according to patient and tumor characteristics.

METHODS

We selected patients with lung cancer from the NCDB Public Benchmark Report diagnosed between 2010 and 2017. Patients with stages I to IV according to the AJCC seventh edition were evaluated according to the year of diagnosis, histology, age, sex, race, and insurance.

RESULTS

Among the 1,447,470 patients identified in the database, 56,382 (3.9%) were excluded due to stage 0 or unknown, or incorrect histology, leaving 1,391,088 patients eligible. The percentage of patients with stage I increased from 23.5% in 2010 to 29.1% in 2017 for all lung cancers, from 25.9% to 31.8% in non-small-cell lung cancer (NSCLC), and from 5.0% to 5.4% in small-cell lung cancer (SCLC). Patients younger than 70 years, males and blacks had lower percentages of stage I compared to older patients, females, and nonblacks respectively. Patients with no insurance had the lowest percentage of stage I.

CONCLUSIONS

There has been a significant increase in the percentage of stage I lung cancer at diagnosis from 2010 to 2017, which occurred mostly in NSCLC. Although the staging shift was observed in all subsets of patients, there were noticeable imbalances according to demographic factors.

Machine Learning Radiomics Model for Early Identification of Small-Cell Lung Cancer on Computed Tomography Scans

PURPOSE

Small-cell lung cancer (SCLC) is the deadliest form of lung cancer, partly because of its short doubling time. Delays in imaging identification and diagnosis of nodules create a risk for stage migration. The purpose of our study was to determine if a machine learning radiomics model can detect SCLC on computed tomography (CT) among all nodules at least 1 cm in size.

MATERIALS AND METHODS

Computed tomography scans from a single institution were selected and resampled to 1 × 1 × 1 mm. Studies were divided into SCLC and other scans comprising benign, adenocarcinoma, and squamous cell carcinoma that were segregated into group A (noncontrast scans) and group B (contrast-enhanced scans). Four machine learning classification models, support vector classifier, random forest (RF), XGBoost, and logistic regression, were used to generate radiomic models using 59 quantitative first-order and texture Imaging Biomarker Standardization Initiative compliant PyRadiomics features, which were found to be robust between two segmenters with minimum Redundancy Maximum Relevance feature selection within each leave-one-out-cross-validation to avoid overfitting. The performance was evaluated using a receiver operating characteristic curve. A final model was created using the RF classifier and aggregate minimum Redundancy Maximum Relevance to determine feature importance.

RESULTS

A total of 103 studies were included in the analysis. The area under the receiver operating characteristic curve for RF, support vector classifier, XGBoost, and logistic regression was 0.81, 0.77, 0.84, and 0.84 in group A, and 0.88, 0.87, 0.85, and 0.81 in group B, respectively. Nine radiomic features in group A and 14 radiomic features in group B were predictive of SCLC. Six radiomic features overlapped between groups A and B.

CONCLUSION

A machine learning radiomics model may help differentiate SCLC from other lung lesions.

Pulmonary nodule radiological diagnostic algorithm in lung cancer screening

Publications of the final results of the two largest randomized lung cancer screening (LCS) trials in the United States and Europe confirmed the reduction in the mortality rate associated with the use of screening with low-dose computed tomography (LDCT). Results of these trials led to widespread acceptance of LCS in properly defined high-risk populations, and its implementation in the clinical practice. Many countries started preparation for national LCS and refreshed still open debate about lung nodule management. Detection of lung cancer in the early stage with a reduction of lung cancer mortality requires dedicated programs with optimized protocols, including a specified pulmonary nodule diagnostic algorithm. The screening protocol should be clear with a precise nodule diameter or volume threshold, based on which a positive screen result is defined. The application of risk-prediction models and the introduction of the semiautomated assessment of detected nodules improves screening accuracy and should be applied in LCS protocols as verified tools to aid radiological diagnosis. In this review, we have summarized recent data about the radiological protocols from the most important LCS programs and pulmonary diagnostic algorithms. These protocols should be taken into consideration in the ongoing and planned LCS programs.

Small-cell lung cancer

Small-cell lung cancer (SCLC) represents about 15% of all lung cancers and is marked by an exceptionally high proliferative rate, strong predilection for early metastasis and poor prognosis. SCLC is strongly associated with exposure to tobacco carcinogens. Most patients have metastatic disease at diagnosis, with only one-third having earlier-stage disease that is amenable to potentially curative multimodality therapy. Genomic profiling of SCLC reveals extensive chromosomal rearrangements and a high mutation burden, almost always including functional inactivation of the tumour suppressor genes TP53 and RB1. Analyses of both human SCLC and murine models have defined subtypes of disease based on the relative expression of dominant transcriptional regulators and have also revealed substantial intratumoural heterogeneity. Aspects of this heterogeneity have been implicated in tumour evolution, metastasis and acquired therapeutic resistance. Although clinical progress in SCLC treatment has been notoriously slow, a better understanding of the biology of disease has uncovered novel vulnerabilities that might be amenable to targeted therapeutic approaches. The recent introduction of immune checkpoint blockade into the treatment of patients with SCLC is offering new hope, with a small subset of patients deriving prolonged benefit. Strategies to direct targeted therapies to those patients who are most likely to respond and to extend the durable benefit of effective antitumour immunity to a greater fraction of patients are urgently needed and are now being actively explored.

Bronchovascular bundle thickening on CT as a predictor of survival and brain metastasis in patients with stage IA peripheral small cell lung cancer

AIM

To determine if bronchovascular bundle (BVB) thickening on pretreatment computed tomography (CT) images helps predict survival in patients with peripheral small cell lung cancer (pSCLC) ≤3 cm.

MATERIALS AND METHODS

The pretreatment CT examinations of 79 histopathologically proven pSCLC ≤3 cm (TNM stage I, 21; II, 13; III, 22; IV, 23) were reviewed retrospectively. The CT characteristics of the nodule and associated findings, including BVB thickening, were evaluated. Progression-free survival (PFS), overall survival (OS), and brain metastasis-free survival were compared with the presence of BVB thickening using Kaplan-Meier and Cox regression analysis.

RESULTS

Among the 79 patients, 34 (43%) had BVB thickening. BVB thickening was prevalent in patients with mediastinal lymph node metastasis (50.9% versus 22.7%; p=0.024) and distant metastasis (60.9% versus 35.7%; p=0.049). Out of the 21 patients with TNM stage IA disease, the 16 patients (76.2%) without BVB thickening showed better PFS, OS, and brain metastasis-free survival (mean, 1,762 versus 483 days; p=0.019: 2,243 versus 1,328 days; p=0.038: 2,274 versus 1,287 days; p=0.038, respectively). Multivariate Cox regression analysis showed that the absence of BVB thickening (hazard ratio [HR], 7.806; 95% CI, 1.241-49.091; p=0.029) and surgery (HR, 0.075; 95% CI, 0.008-0.746; p=0.027) were independent and useful prognostic factors for PFS.

CONCLUSIONS

BVB thickening was found more frequently in patients with advanced-stage pSCLC ≤3 cm, and the PFS was more favourable in patients without BVB thickening, with a similar tendency to that of OS and brain metastasis-free survival, in stage IA pSCLC.

Characteristics and Outcomes of Small Cell Lung Cancer Detected by CT Screening

BACKGROUND

Previous studies with a limited number of patients have reported divergent findings on whether screening can detect small cell lung cancer (SCLC) at an earlier stage and whether there might be a survival benefit.

METHODS

This study examined the characteristics of SCLC detected by using low-dose CT (LDCT) screening in the National Lung Screening Trial, a randomized study of individuals at high risk for developing lung cancer comparing LDCT imaging vs chest radiography. SCLC was denoted as screen detected if diagnosed ≤ 1 year of a positive screen or after a longer period but with no time gap between diagnostic procedures of > 1 year; interval detected if diagnosed ≤ 1 year of a negative screen; and nonscreen detected if the subject did not receive any screens or otherwise as postscreening.

RESULTS

A total of 143 cases of SCLC were diagnosed, including 49 (34.2%) screen detected, 15 (10.5%) interval detected, and 79 (55.2%) nonscreened/postscreening. Of the screening phase-diagnosed cases (ie, screen or interval detected), a higher proportion of SCLC cases compared with NSCLC cases were interval detected (23% vs 5%; P < .0001). A higher proportion of all SCLC cases compared with NSCLC cases were advanced stage (III/IV: 86% vs 36%; P < .0001). The unfavorable SCLC stage distribution extended across screen-detected (80% stage III/IV), interval-detected (86%), and nonscreened/postscreening (90%) cancers. Among screen-detected SCLC, only 63.3% had ≥ 1 noncalcified nodule in the cancer lobe compared with 85.4% of NSCLC cases (P < .0001). Even with very small LDCT screen-detected nodules, a high proportion of SCLC cases were late stage. There was no significant difference in survival between screen- and interval-detected or postscreening SCLC.

CONCLUSIONS

"Early detection" with the use of LDCT imaging had no impact on SCLC outcomes. A successful screening modality should ideally detect SCLC earlier than when it can be detected on LDCT scans.

Cost-utility analysis of a potential lung cancer screening program for a high-risk population in Germany: A modelling approach

BACKGROUND

Lung cancer is the leading cause of cancer death in Germany. Although several randomized trials in Europe have evaluated the effectiveness of lung cancer screening programs, evidence on the cost-effectiveness of lung cancer screening is scarce.

OBJECTIVE

To evaluate the cost-effectiveness of a population-based lung cancer screening program from the perspective of a German payer.

METHODS

We conducted a cost-effectiveness analysis from the public payer perspective for a high-risk population defined as heavy former and current smokers (≥20 cigarettes per day) between 55 and 75 years of age. The underlying model consisted of two Markov models. We differentiated between a population-based annual screening program and standard clinical care. Depending on stage at diagnosis, simulated patients were assigned to one of five treatment paths according to the German clinical guideline for the diagnosis and treatment of lung cancer. Costs, life years saved, and quality adjusted life years (QALYs) were used as outcomes. Values for input parameters were taken from the literature. The model was run for 60 cycles with a cycle length of three months. Deterministic and probabilistic sensitivity analyses were conducted.

RESULTS

In the base case, annual lung cancer screening led to an increase in incremental costs (€ 1,153 per person) compared to standard clinical care. However, the screening approach was associated with an incremental gain in life years (0.06 per person) and QALYs (0.04 per person). Thus, the incremental cost-effectiveness ratio (ICER) was € 19,302 per life year saved and € 30,291 per QALY. A probabilistic sensitivity analysis with 10,000 draws resulted in average ICERs of € 22,118 per life year and € 34,841 per QALY.

CONCLUSION

We provide evidence that lung cancer screening for a high-risk population may be more effective, but also more costly, than standard clinical care from the perspective of a German payer.

Adjuvant Chemotherapy Following Surgical Resection Improves Survival in Patients With Early Stage Small Cell Lung Cancer

The purpose of this study was to determine the effects of resection coupled with standard chemotherapy on the survival prognosis of patients with early stage small cell lung carcinoma (SCLC). Patients (n = 110) with mediastinal lymph node-negative SCLC were enrolled in this study. The baseline clinical data of patients with surgery were retrospectively reviewed. Overall survival (OS) and progression-free survival (PFS) were measured by Kaplan-Meier and log-rank test analyses. Ninety-eight patients received mediastinoscopy biopsy, and pulmonary lobectomy or sublobar resection, and 67 patients underwent adjuvant chemotherapy after pulmonary lobectomy. Adjuvant chemotherapy after surgical intervention was associated with longer OS (median OS: 42.14 vs. 33.53 months, p = 0.01) and PFS (median PFS: 25.20 vs. 13.48 months, p = 0.000) compared to resection alone for all patients. Adjuvant chemotherapy was associated with improvement of survival for N1 patients with stage II (median OS: 36.42 vs. 26.68 months, p = 0.021). The median PFS was 19.02 m (16.08, 21.96) and 13.25 m (10.19, 16.30) (p = 0.031), respectively, for patients of N1 stage who received chemotherapy and those who did not. Cox regression analysis demonstrated that age, TNM stage (N stage, not T stage), and chemotherapy were independent risk factors that might affect overall survival in patients with mediastinal lymph node-negative SCLC. These findings suggest that the application of adjuvant chemotherapy following pulmonary lobectomy is associated with improvements of survival prognoses for patients with SCLC. The combination of surgical intervention with conventional therapy should be taken into consideration as a prospective multidisciplinary regimen for early stage SCLC.

The importance of the regimen of screening in maximizing the benefit and minimizing the harms

BACKGROUND

In CT screening for lung cancer, the regimen of screening is critical in diagnosing lung cancer early while limiting unnecessary tests and invasive procedures. The International Early Lung Cancer Action Program (I-ELCAP) has developed a regimen based on evidence collected in the I-ELCAP cohort of more than 70,000 participants.

METHODS

Important in the development of the regimen is the recognition of the profound difference between the first, baseline round of screening and all subsequent rounds of repeat screening. For each person undergoing screening, the baseline round happens only once while repeat rounds will be performed annually for many years. This difference needs to be clearly recognized as it is these annual rounds which allow for identification of small, early, yet aggressive, lung cancers which have high cure rates despite their aggressiveness. The importance of nodule consistency and size are key factors in the regimen. The regimen needs to be continuously updated by incorporating advances in technology and knowledge.

RESULTS

The use of the I-ELCAP regimen reduces the workup of participants in the screening program to less than 10% in the baseline round and less than 6% in the annual repeat rounds. By use of this regimen, estimated cure rate of lung cancers diagnosed under screening is 80% or higher in both baseline and annual repeat rounds.

CONCLUSIONS

The I-ELCAP collaboration provides a new paradigm that answers the 2002 NCI call for multiple approaches to address relevant questions about screening and the Institute of Medicine (IOM) Roundtable on Evidence-based Medicine from the National Academy of Science's call for a "new clinical research paradigm that takes better advantage of data generated in the course of healthcare delivery would speed and improve the development of evidence for real-world decision making".

Clinical outcomes in patients with small cell lung cancer in a single institute: Comparative analysis of radiographic screening with symptom-prompted patients

OBJECTIVES

The present study was performed to evaluate the differences in clinical characteristics and survival outcomes of patients with small cell lung cancer (SCLC) according to methods used for detecting the disease: radiographic screening or symptomatically prompted.

MATERIALS AND METHODS

The clinical findings and actual treatment outcomes were estimated according to three means of detection of SCLC: computed tomography (CT), radiographic test, and symptom-prompted cases.

RESULTS

We identified 147 patients (male/female ratio: 127/20; mean age: 68.1 years old) between 2000 and 2011. The patients were divided into three categories according to method of detection: chest CT (CT; n=24), radiographic screening (CXR; n=37), and symptom-prompted cases (symptom; n=86). There was no significant shift to early TNM stage distribution in the CT or CXR group compared with the symptom group. However, the rates of limited disease (LD)-SCLC were significantly higher in the CT and CXR groups than the symptom group. Median survival times were 17.0 months (95% confidence interval (CI): 11.6-22.4) in the CT group, 19.0 months (95%CI: 11.7-126.3) in the CXR group, and 12.0 months (95%CI: 9.6-14.4) in the symptom group. There were statistically significant differences in overall survival between CT and symptom groups (P<0.05) and between CXR and symptom groups (P<0.001). However, there was no significant difference in survival between CT and CXR groups.

CONCLUSIONS

Radiographic (CT plus CXR) testing contributes to better clinical outcome in patients with SCLC.