Computed Tomography Screening For Cancer Research Articles

Trends in oncological imaging during the COVID-19 pandemic through the vaccination era.

This study examines the impact that the COVID-19 pandemic has had on computed tomography (CT)-based oncologic imaging utilization. We retrospectively analyzed cancer-related CT scans during four time periods: pre-COVID (1/5/20-3/14/20), COVID peak (3/15/20-5/2/20), post-COVID peak (5/3/20-12/19/20), and vaccination period (12/20/20-10/30/21). We analyzed CTs by imaging indication, setting, and hospital type. Using percentage decrease computation and Student's t-test, we calculated the change in mean number of weekly cancer-related CTs for all periods compared to the baseline pre-COVID period. This study was performed at a single academic medical center and three affiliated hospitals. During the COVID peak, mean CTs decreased (-43.0%, p < 0.001), with CTs for (1) cancer screening, (2) initial workup, (3) cancer follow-up, and (4) scheduled surveillance of previously treated cancer dropping by 81.8%, 56.3%, 31.7%, and 45.8%, respectively (p < 0.001). During the post-COVID peak period, cancer screenings and initial workup CTs did not return to prepandemic imaging volumes (-11.4%, p=0.028; -20.9%, p=0.024). The ED saw increases in weekly CTs compared to prepandemic levels (+31.9%, p=0.008), driven by increases in cancer follow-up CTs (+56.3%, p < 0.001). In the vaccination period, cancer screening CTs did not recover to baseline (-13.5%, p=0.002) and initial cancer workup CTs doubled (+100.0%, p < 0.001). The ED experienced increased cancer-related CTs (+75.9%, p < 0.001), driven by cancer follow-up CTs (+143.2%, p < 0.001) and initial workups (+46.9%, p=0.007). The pandemic continues to impact cancer care. We observed significant declines in cancer screening CTs through the end of 2021. Concurrently, we observed a 2× increase in initial cancer workup CTs and a 2.4× increase in cancer follow-up CTs in the ED during the vaccination period, suggesting a boom of new cancers and more cancer examinations associated with emergency level acute care.

1607P Trends in cancer imaging by indication, care setting, and hospital type during the COVID-19 pandemic and recovery

Background: The delivery of cancer care has been greatly affected by the COVID pandemic. We aim to investigate the effect of the pandemic on computed tomography (CT) imaging of cancer. Methods: Cancer-related CT exams were retrospectively analyzed during three periods of 2020: pre-COVID (1/5/20-3/14/20), COVID peak (3/15/20-5/2/20) and post-COVID peak (5/3/20-11/14/20). Volumes were assessed by 1) Imaging indication: cancer screening, initial workup, active cancer, surveillance;2) Care setting: outpatient, inpatient, ED;3) Hospital type: quaternary academic center (QAC), university-affiliated community hospital (UACH), sole community hospitals (SCHs). Results: During the COVID peak, a significant drop in CT volumes was observed (-42·2%, p<0·0001), with cancer screening, initial workup, active cancer and cancer surveillance experiencing declines by 81·7%, 54·8%, 30·7% and 44·7% respectively (p<0·0001, Figure 1). The emergency department (ED) was the only setting with stable cancer-related CT volumes. In the post-COVID peak period, CT volumes for cancer screening and for initial workup did not recover (-11·7%, p=0·037;-20·0%, p=0·031), with the outpatient setting particularly affected. CT volumes for active cancer recovered post-peak, but inconsistently across hospital types with the QAC experiencing a 9·4% decline (p=0·022) and the UACH a 41·5% increase (p<0·001). Outpatient CTs recovered during the post-peak period, but a shift in utilization away from the QAC (-8·7%, p=0·020) toward the UACH (+13·3%, p=0·013) was observed. Inpatient and ED-based cancer-related CTs increased post-peak (+20·0%, p=0·004 and +33·2%, p=0·009, respectively). Conclusions: COVID severely impacted cancer imaging care. CTs for cancer screening and initial workup did not recover to pre-COVID levels well into 2020, a finding that suggests higher numbers of patients with advanced cancers may present in the future. A redistribution of imaging utilization away from the QAC and outpatient settings, toward the community hospitals and inpatient setting/ED was observed. The ED has remained a dependable healthcare delivery setting for patients with cancer throughout the pandemic. Legal entity responsible for the study: The authors. Funding: Has not received any funding. Disclosure: J. Brink: Financial Interests, Institutional, Member of the Board of Directors: Accumen, Inc. All other authors have declared no conflicts of interest.

Trends in cancer imaging by indication, care setting, and hospital type during the COVID-19 pandemic and recovery at four hospitals in Massachusetts.

BackgroundWe aimed to investigate the effects of COVID‐19 on computed tomography (CT) imaging of cancer.MethodsCancer‐related CTs performed at one academic hospital and three affiliated community hospitals in Massachusetts were retrospectively analyzed. Three periods of 2020 were considered as follows: pre‐COVID‐19 (1/5/20–3/14/20), COVID‐19 peak (3/15/20–5/2/20), and post‐COVID‐19 peak (5/3/20–11/14/20). 15 March 2020 was the day a state of emergency was declared in MA; 3 May 2020 was the day our hospitals resumed to non‐urgent imaging. The volumes were assessed by (1) Imaging indication: cancer screening, initial workup, active cancer, and surveillance; (2) Care setting: outpatient and inpatient, ED; (3) Hospital type: quaternary academic center (QAC), university‐affiliated community hospital (UACH), and sole community hospitals (SCHs).ResultsDuring the COVID‐19 peak, a significant drop in CT volumes was observed (−42.2%, p < 0.0001), with cancer screening, initial workup, active cancer, and cancer surveillance declining by 81.7%, 54.8%, 30.7%, and 44.7%, respectively (p < 0.0001). In the post‐COVID‐19 peak period, cancer screening and initial workup CTs did not recover (−11.7%, p = 0.037; −20.0%, p = 0.031), especially in the outpatient setting. CT volumes for active cancer recovered, but inconsistently across hospital types: the QAC experienced a 9.4% decline (p = 0.022) and the UACH a 41.5% increase (p < 0.001). Outpatient CTs recovered after the COVID‐19 peak, but with a shift in utilization away from the QAC (−8.7%, p = 0.020) toward the UACH (+13.3%, p = 0.013). Inpatient and ED‐based oncologic CTs increased post‐peak (+20.0%, p = 0.004 and +33.2%, p = 0.009, respectively).ConclusionsCancer imaging was severely impacted during the COVID‐19 pandemic. CTs for cancer screening and initial workup did not recover to pre‐COVID‐19 levels well into 2020, a finding that suggests more patients with advanced cancers may present in the future. A redistribution of imaging utilization away from the QAC and outpatient settings, toward the community hospitals and inpatient setting/ED was observed.

Artificial intelligence for detection and characterization of pulmonary nodules in lung cancer CT screening: ready for practice?

Lung cancer computed tomography (CT) screening trials using low-dose CT have repeatedly demonstrated a reduction in the number of lung cancer deaths in the screening group compared to a control group. With various countries currently considering the implementation of lung cancer screening, recurring discussion points are, among others, the potentially high false positive rates, cost-effectiveness, and the availability of radiologists for scan interpretation. Artificial intelligence (AI) has the potential to increase the efficiency of lung cancer screening. We discuss the performance levels of AI algorithms for various tasks related to the interpretation of lung screening CT scans, how they compare to human experts, and how AI and humans may complement each other. We discuss how AI may be used in the lung cancer CT screening workflow according to the current evidence and describe the additional research that will be required before AI can take a more prominent role in the analysis of lung screening CT scans.

Efficacy of low-dose computed tomography screening for lung cancer: the current state of evidence of mortality reduction.

The interim and final results of randomized controlled trials on the efficacy of lung cancer computed tomography (CT) screening have been reported recently from Western countries. The outcome of the National Lung Screening Trial (NLST) demonstrated the efficacy of low-dose thoracic CT screening for heavy smokers; however, other studies have found no apparent reduction in the mortality rate, and the outcome of the NELSON study is awaited. To date, a few studies have reported on the efficacy of lung cancer CT screening for non-/light smokers. A report from the Hitachi district, which is an ecological/time series study where non-/light smokers account for approximately half of the CT screening examinees, was published in 2012, with an outcome suggesting efficacy. Currently, a randomized controlled trial (JECS Study) is underway in Japan with non-/light smokers as the subjects, and this trial is very important in terms of cancer prevention.

Technical Note: Image filtering to make computer-aided detection robust to image reconstruction kernel choice in lung cancer CT screening.

In lung cancer computed tomography (CT) screening, the performance of a computer-aided detection (CAD) system depends on the selection of the image reconstruction kernel. To reduce this dependence on reconstruction kernels, the authors propose a novel application of an image filtering method previously proposed by their group. The proposed filtering process uses the ratio of modulation transfer functions (MTFs) of two reconstruction kernels as a filtering function in the spatial-frequency domain. This method is referred to as MTFratio filtering. Test image data were obtained from CT screening scans of 67 subjects who each had one nodule. Images were reconstructed using two kernels: fSTD (for standard lung imaging) and fSHARP (for sharp edge-enhancement lung imaging). The MTFratio filtering was implemented using the MTFs measured for those kernels and was applied to the reconstructed fSHARP images to obtain images that were similar to the fSTD images. A mean filter and a median filter were applied (separately) for comparison. All reconstructed and filtered images were processed using their prototype CAD system. The MTFratio filtered images showed excellent agreement with the fSTD images. The standard deviation for the difference between these images was very small, ∼6.0 Hounsfield units (HU). However, the mean and median filtered images showed larger differences of ∼48.1 and ∼57.9 HU from the fSTD images, respectively. The free-response receiver operating characteristic (FROC) curve for the fSHARP images indicated poorer performance compared with the FROC curve for the fSTD images. The FROC curve for the MTFratio filtered images was equivalent to the curve for the fSTD images. However, this similarity was not achieved by using the mean filter or median filter. The accuracy of MTFratio image filtering was verified and the method was demonstrated to be effective for reducing the kernel dependence of CAD performance.

CT screening for lung cancer: Is the evidence strong enough?

The prevailing questions at this time in both the public mind and the clinical establishment is, do we have sufficient evidence to implement lung cancer Computed Tomography (CT) screening in Europe? If not, what is outstanding? This review addresses the twelve major areas, which are critical to any decision to implement CT screening and where we need to assess whether we have sufficient evidence to proceed to a recommendation for implementation in Europe. The readiness level of these twelve categories in 2015 have been with colour coded, where green indicates we have sufficient evidence, amber is borderline evidence and red requires further evidence. Recruitment from the 'Hard to Reach' community still remains at red, while mortality data, cost effectiveness and screening interval are all categorised as amber. The integration of smoking cessation into CT screening programmes is still considered to be category amber. The US Preventive Services Task Force have recommended that CT screening is implemented in the USA utilising the NLST criteria, apart from continuing screening to 80 years of age. The cost effectiveness of the NLST was calculated to be $81,000/QALY, however, its well recognised that the costs of medical care in the USA, is far higher than that of Europe. Medicare have agreed to cover the cost of screening but have stipulated a number of stringent requirements for inclusion. To date we do not have good CT screening mortality data available in Europe and eagerly await the publication of the NELSON trial data in 2016 and then the pooled UKLS and NELSON data thereafter. However in the meantime we should start planning for implementation in Europe, especially in the areas of the radiological service provision and accreditation, as well as identifying novel mechanisms to recruit from the hardest to reach communities.

Feasible Method to Assess the Performance of a Lung Cancer CT Screening CAD System in Clinical Practice: Dependence on Nodule Size and Density

Detection of small pulmonary nodules is the goal of lung cancer screening. Computer-aided detection (CAD) systems are recommended to use in lung cancer computed tomography (CT) screening to increase the accuracy of nodule detection. Size and density of lung nodules are primary factors in determining the risk of malignancy. Therefore, purpose of this study is to apply computer-simulated virtual nodules based on the point spread function (PSF) measured in same scanner (maintaining spatial resolution condition) to assess the CAD system performance dependence on nodule size and density. Virtual nodules with density differences between lung background and nodule density (ΔCT) values (200, 300 and 400 HU) and different sizes (4 to 8 mm) were generated and fused on clinical images. CAD detection was performed and free-response receiver operating characteristic (FROC) curves were obtained. Results show that both density and size of virtual nodules can affect detection efficiency. Detailed results are possible to use for quantitative analysis of a CAD system performance. This study suggests that PSF-based virtual nodules could be effectively used to assess the lung cancer CT screening CAD system performance dependence on nodule size and density.

Clinical Statement on the Role of the Surgeon and Surgical Issues Relating to Computed Tomography Screening Programs for Lung Cancer

The National Lung Screening Trial (NLST) recently provided the first definitive evidence that screening for lung cancer with low-dose computed tomography (LDCT) decreases lung cancer mortality in certain high-risk groups [1]. Several surgical and nonsurgical organizations, including the National Comprehensive Cancer Network (NCCN), International Association for the Study of Lung Cancer (IASLC), American Association for Thoracic Surgery (AATS), American College of Chest Physicians (ACCP), American Thoracic Society (ATS), and American Society of Clinical Oncology (ASCO), have outlined guidelines on lung cancer computed tomography (CT) screening, which have been recently published or are currently in print with the aim of addressing the specifics of the CT screening process while identifying the ideal target population for lung cancer screening [2–4].

Informed decision making does not affect health-related quality of life in lung cancer screening (NELSON trial)

Background It is believed that making an informed decision about (screening) participation is associated with better health-related quality of life (HRQoL) outcomes. This is the first study in cancer screening to explore this association in subjects participating in a lung cancer computed tomography (CT) screening trial. Methods Participants that made either an informed decision to participate ( n = 155) or not ( n = 133) were selected for this study. Differences in HRQoL, measured as generic HRQoL (Short Form 12 [SF-12] and EuroQol questionnaire [EQ-5D]), anxiety/distress (State-Trait Anxiety Inventory [STAI-6], Impact of Event Scale [IES] and Consequences of Screening-Lung Cancer [COS-LC]), were tested with Mann–Whitney U tests and ANOVA at three assessment points (when deciding about participation, before trial randomisation and 2 months after receiving the CT result). Results Subjects who made an informed decision to participate had no better scores than those who did not make an informed decision for 23 out of 24 HRQoL comparisons, except for a better mean score for mental health (Mental Component Summary (MCS) = 53.9 ± 9.2 versus 51.0 ± 10.1, p = 0.003) before randomisation. For subjects with an indeterminate CT result ( n = 64), no significant differences were found between subjects with ( n = 35) or without ( n = 29) an informed decision. Conclusion Subjects who did not make an informed decision to participate in lung cancer CT screening trial did not experience worse HRQoL during screening than subjects who did make an informed decision, either in general or after receiving an indeterminate result.

High affective risk perception is associated with more lung cancer-specific distress in CT screening for lung cancer

Screening for cancer can cause distress. People who perceive their risk of cancer as high may be more vulnerable to distress. This study evaluated whether participants of a lung cancer Computed Tomography (CT) screening trial with a high affective risk perception of developing lung cancer had a higher level of lung cancer-specific distress during CT screening. Furthermore, we evaluated whether participants perceived their risk of developing lung cancer differently 6 months after screening compared with 1 day before screening. A total of 351 subsequent participants of the NELSON-trial (Dutch-Belgian randomized controlled trial for lung cancer screening in high-risk subjects), who were randomized to the screen arm, were asked to fill in questionnaires 1 day before and 6 months after screening. Lung cancer-specific distress (Impact of Event Scale (IES)), generic health-related quality of life (SF-12) and affective risk perception were assessed. One day before screening, the participants with a high affective risk perception (n=47/321, 14.6%) had significantly higher (i.e., worse) median IES scores than participants with a low affective risk perception (11.5 vs. 2.0, p<0.01). Although median IES scores were significantly lower 6 months after screening than 1 day before screening, participants with a high affective risk perception still showed significantly higher IES scores than participants with a low affective risk perception (6.5 vs. 1.0, p<0.01). Six months after screening, significantly less participants (10.5%) felt that their risk of developing lung cancer was high than 1 day before screening (14.5%) (p<0.01). Levels of distress were not severe, but were elevated compared to participants with a low affective risk perception, and therefore, attention for this group is recommended.

2001 Plenary Session: Friday Imaging Symposium. CT Screening for Cancer.

Screening, defined as the testing of asymptomatic individuals for subclinical disease, has become a major strategy in improving patient outcome through the early detection of cancer. The purpose of screening is to differentiate among those individuals who likely have cancer from those who do not. The premise of screening is that early diagnosis will yield positive health benefits by permitting early initiation of treatment and thus a reduction in morbidity and mortality (1‐3). Screening tests differ from diagnostic tests. Diagnostic tests are generally used in patients who come to medical evaluation for symptoms. Results of diagnostic tests are often accurate enough to establish a definite diagnosis, and they can be used as a basis for initiating treatment. By comparison, screening tests are generally offered to asymptomatic populations as a means of determining whether it is probable that they have a target disease. During the past few years, many institutions have established targeted screening programs for pulmonary cancer and colorectal adenomatous polyps and also whole-body screening programs that use both single-detector and multidetector computed tomography (CT). The Radiological Society of North America recognized the importance of screening tests for cancer and dedicated an afternoon session to this topic at the 2001 annual meeting. The following two articles by Yee and Brant-Zawadzki discuss the role for virtual colonography and whole-body CT in the detection of cancer. Because screening programs for cancer detection are increasing in the United States, we believe that publication of these presentations is appropriate. Radiologists will be asked to make decisions about offering screening tests in their own practices, and thus, they must be aware of the risk/benefit and cost/benefit ratios of screening imaging procedures. These introductory comments, which emphasize the general criteria for a good screening program and the clinical and financial implications of offering CT screening directly to the consumer, provide a foundation for the articles that follow.

Spiral CT for lung cancer screening: is it ready for prime time?

Low-dose spiral computed tomography (CT) shows promise as a screening test for lung cancer, as it detects many more malignant pulmonary nodules than does standard plain radiography of the chest. Yet until more data are available we need to temper our enthusiasm. No studies have yet determined if using low-dose spiral CT as a screening test will lead to lower mortality rates. This paper reviews the issue of lung cancer screening and low-dose spiral CT.