Queensland Lung Cancer Screening Study: rationale, design and methods

Australia-wide cross-sectional survey of general practitioners' knowledge and practice of lung cancer screening

BACKGROUND

Low-dose computed tomography (LDCT) screening can reduce lung cancer deaths in high-risk individuals, yet current Australian guidelines do not recommend screening. Little is known about current screening practices in Australia.

AIM

To evaluate the proportion of general practitioners who report ordering lung cancer screening for their patients, identify factors associated with ordering lung cancer screening and assess general practitioners (GP) rationale for recommending screening and preference of composition of any future national targeted screening programme.

METHODS

A survey was distributed to a nationally representative sample of 4000 Australian GP. The questionnaire included respondent demographics, self-reported screening practices, knowledge of screening recommendations, recent screening education, preference for recruitment methodologies for potential screening programmes and potential factors influencing the screening practices of GP. Two logistic regression models identified factors associated with self-reported chest X-ray (CXR) and LDCT screening within the past 12 months.

RESULTS

A total of 323 GP completed the survey (participation rate 8.1%). Participants were mostly females (50.6%), from collective/group (79.1%) and metropolitan-based practices (73.5%). Despite the majority of responders understanding that screening is not recommended by Australian professional societies (71.2%), a substantial proportion of participants requested a CXR or LDCT screening (46.4% and 20.8% respectively). A variety of shared (GP reassurance, affordability of screening, believing screening is funded) and unique practice, educational and cognitive factors were associated with self-reported LDCT and CXR screening, with the strongest association being recent education about screening from radiology practices (odds ratio (aOR) for LDCT screening 10.4, P < 0.001).

CONCLUSION

In Australia, lung cancer screening occurs outside a coordinated programme, and there is discordance between practice and national recommendations. This highlights an urgent need for clearer guidance from national and professional bodies.

Interstitial lung abnormalities in the Queensland Lung Cancer Screening Study: prevalence and progression over 2 years of surveillance

BACKGROUND

We report the prevalence and progression of incidentally detected interstitial lung abnormalities (ILA) in the Queensland Lung Cancer Screening Study cohort.

METHODS

About 256 volunteers aged 60-74, with ≥30 pack years smoking history and forced expiratory volume in 1 s (FEV1) ≥50% predicted underwent low-dose computed tomography (CT) chest screening. Electronic search of baseline (T0) and 2-year follow-up (T2) CT reports identified candidate cases using Fleischner Society interstitial terminology. Candidate CT were reviewed in a randomised order by two experienced radiologists and a senior respiratory medicine trainee blinded to the existing reports. Scans were evaluated for the presence and extent of ILA using an in-house score, and graded for progression.

RESULTS

ILA were detected in 20/256 baseline cases (7.8%) with no incident cases detected at T2 surveillance imaging. Of these 20 cases, 9 (45%) had reticulation, 18 (90%) had ground glass change, 1 had traction bronchiectasis and 1 had randomly distributed nodularity. Seven cases with ground glass changes also had areas of reticulation, and only two had reticulation alone. All ILA were graded as minor except for traction bronchiectasis, which was moderate. Only one case progressed on T2 imaging. ILA were associated with the presence of auscultatory crackles (50% vs 11.6%, P = 0.001) and a lesser degree of emphysema (mean % volumetric emphysema 6.7% vs 9.8%, P = 0.009). No relationship was observed between baseline and serial lung function parameters.

CONCLUSION

ILA are frequent incidental findings in lung cancer screening. In the majority of cases these abnormalities do not appear to change significantly over a 2-year period of surveillance.

Cost of screening for lung cancer in Australia

BACKGROUND

Lung cancer screening can reduce lung cancer mortality. Australian cost estimates are important to inform policy but remain uncertain.

AIM

To describe the first direct medical costs associated with lung cancer screening in Australia.

METHODS

Single-centre prospective screening cohort. Healthy volunteers (age 60-74 years, current or former smokers quit <15 years prior to enrolment, ≥30 pack-years exposure) underwent baseline and two annual incidence computed tomography (CT) screening scans. Health status and healthcare usage data were collated for 5 years. The main outcome measures were: rates of lung cancer; individual healthcare resource use derived from multiple data sources adjusted to 2018 Australian Medicare Benefits Schedule values.

RESULTS

A total of 256, 239, 233 participants was screened at each round respectively; 12 participants were diagnosed with lung cancer during screening and 2 during follow-up: 9 underwent surgery, 4 received concurrent chemoradiation, 1 received palliative chemotherapy. One surgical case died from lymphoma 1407 days after diagnosis, all other surgical cases survived >5 years. Non-surgical median survival post-diagnosis was 654 days. Gross trial cost was Australian dollar (AU$) 965 665 (AU$397 396 CT scans; AU$29 303 false-positive scan work-up; AU$96 340 true-positive scan workup; AU$336 914 lung cancer treatment; AU$104 712 lung cancer follow-up post-treatment). Average total direct medical cost per participant was AU$3 768. Average direct cost of surgery was AU$22 659; average non-surgical cost was AU$47 395 (radiotherapy, chemotherapy, palliative care).

CONCLUSIONS

Advanced cancer cost more to treat and had worse survival than early cancer. Screening costs are similar to international studies and suggest that lung cancer early detection could limit treatment costs and improve outcomes.

Is Digital Tomosynthesis on Par With Computed Tomography for the Detection and Measurement of Pulmonary Nodules?

Chest digital tomosynthesis (DT) has potential advantages compared to computed tomography (CT) such as radiation dose reduction. However, the role of DT in pulmonary nodule management remains investigative. We compared DT against CT for pulmonary nodule detection and size measurement. A clinical population comprising 54 nodules from 30 patients and a screening population comprising 42 nodules from 52 patients were included. Scans were independently read by two radiologists. Agreement in nodule measurements between readers and between modalities was assessed by Bland-Altman analysis using a 95% level of significance. The DT true positive fraction for the two readers was 0.44 and 0.39 in the clinical population, and 0.10 and 0.05 in the screening population. No significant inter-modality bias was observed between DT and CT measurements of nodule size, but the range of variation between modalities was approximately 30%. Inter-reader DT measurements also showed no significant bias, with a range of variation of approximately 15%. We conclude that DT has poor nodule detection sensitivity compared to CT. However, DT showed good measurement reproducibility and may be useful for monitoring growth of existing pulmonary nodules.

Estimating the Cost-Effectiveness of Lung Cancer Screening with Low-Dose Computed Tomography for High-Risk Smokers in Australia

INTRODUCTION

Health economic evaluations of lung cancer screening with low-dose computed tomography (LDCT) that are underpinned by clinical outcomes are relatively few.

METHODS

We assessed the cost-effectiveness of LDCT lung screening in Australia by applying Australian cost and survival data to the outcomes observed in the U.S. National Lung Screening Trial (NLST), in which a 20% lung cancer mortality benefit was demonstrated for three rounds of annual screening among high-risk smokers age 55 to 74 years. Screening-related costs were estimated from Medicare Benefits Schedule reimbursement rates (2015), lung cancer diagnosis and treatment costs from a 2012 Australian hospital-based study, lung cancer survival rates from the New South Wales Cancer Registry (2005-2009), and other-cause mortality from Australian life tables weighted by smoking status. The health utility outcomes, screening participation rates, and lung cancer rates were those observed in the NLST. Incremental cost effectiveness ratios (ICER) were calculated for a 10-year time horizon.

RESULTS

The cost-effectiveness of LDCT lung screening was estimated at AU$138,000 (80% confidence interval: AU$84,700-AU$353,000)/life-year gained and AU$233,000 (80% confidence interval: AU$128,000-AU$1,110,000)/quality-adjusted life year (QALY) gained. The ICER was more favorable when LDCT screening impact on all-cause mortality was considered, even when the costs of incidental findings were also estimated in sensitivity analyses: AU$157,000/QALY gained. This can be compared to an indicative willingness-to-pay threshold in Australia of AU$30,000 to AU$50,000/QALY.

CONCLUSIONS

LDCT lung screening using NLST selection and implementation criteria is unlikely to be cost-effective in Australia. Future economic evaluations should consider alternative screening eligibility criteria, intervals, nodule management, the impact and cost of new therapies, investigations of incidental findings, and incorporation of smoking cessation interventions.

Screen-detected subsolid pulmonary nodules: long-term follow-up and application of the PanCan lung cancer risk prediction model

OBJECTIVE

To report the long-term follow-up of subsolid nodules (SSNs) detected in participants of a prospective low-dose CT lung cancer screening cohort, and to investigate the utility of the PanCan model in stratifying risk in baseline SSNs.

METHODS

Participants underwent a baseline scan, two annual incidence scans and further follow-up scans for the detected nodules. All SSNs underwent a minimum of 2 years of follow-up (unless resolved or resected). Risk of malignancy was estimated using the PanCan model; discrimination [area under the receiver-operating characteristic curve (AUC)] and calibration (Hosmer-Lemeshow goodness-of-fit test) were assessed. The Mann-Whitney U-Wilcoxon test was used to compare estimated risk between groups.

RESULTS

70 SSNs were detected in 41 (16.0%) out of 256 total participants. Median follow-up period was 25.5 months (range 2.0-74.0 months). 29 (41.4%) SSNs were transient. Five (7.1%) SSNs were resected, all found to be Stage I lung adenocarcinoma, including one SSN stable in size for 3.0 years before growth was detected. The PanCan model had good discrimination for the 52 baseline SSNs (AUC = 0.89; 95% confidence interval 0.76-1); the Hosmer-Lemeshow goodness-of-fit test was non-significant (p = 0.27). Estimated risk was significantly higher in the baseline SSNs found to be cancer vs those not found to be cancer after 2-6 years of follow-up (p < 0.01).

CONCLUSION

Our findings support a long-term follow-up approach for screen-detected SSNs for 3 years or longer. The PanCan model appeared discriminatory and well calibrated in this cohort.

ADVANCES IN KNOWLEDGE

The PanCan model may have utility in identifying low-risk SSNs which could be followed with less frequent CT scans.

Brief Tailored Smoking Cessation Counseling in a Lung Cancer Screening Population is Feasible: A Pilot Randomized Controlled Trial

INTRODUCTION

Maximizing smoking abstinence in lung cancer screening participants is important to reduce individual risk of disease and improve screening cost-effectiveness; however, the optimal strategy remains undefined. We hypothesized that a single session of tailored face-to-face counseling on the day of screening CT scan, coupled with audio and printed cessation information would be feasible to deliver in a CT screening trial.

METHODS

We randomized volunteer smokers in the Queensland Lung Cancer Screening Study to intervention (counseling session, audio quit materials, printed quit materials, Quitline contact details) or control group (printed quit materials, Quitline contact details). Participants self-reported point prevalence quit rates at 1 year.

RESULTS

Fifty-five smokers were enrolled; 28 randomized to intervention and 27 controls. Median cigarette consumption was 25/day; 54/55 smoked at least 15 cigarettes per day. Median smoking duration was 46 years. Median Fagerström dependence score was 6. In total 58% did not report any quit attempt in the prior 12 months. Mean duration of counseling was 26.5 minutes. After 1 year, four participants (14.3%) in the intervention group and five participants (18.5%) in the control group had quit (P = .74). Combined annual point prevalence quit rate was 16.4%.

CONCLUSIONS

Although feasible to deliver a single session of tailored counseling on the day of screening this intervention had no discernible impact on cessation over and above printed materials and Quitline access. As participants exhibited hardcore smoking characteristics, more intensive strategies, in larger cohorts, should be explored.

IMPLICATIONS

The optimal smoking cessation strategy within a lung cancer screening program is not known. This study demonstrates that a single session of counseling can be feasibly delivered on the day of screening but may not have been intensive enough for long-term, hard-core smokers.

Screening for lung cancer with low-dose computed tomography: a review of current status

Screening using low-dose computed tomography (CT) represents an exciting new development in the struggle to improve outcomes for people with lung cancer. Randomised controlled evidence demonstrating a 20% relative lung cancer mortality benefit has led to endorsement of screening by several expert bodies in the US and funding by healthcare providers. Despite this pivotal result, many questions remain regarding technical and logistical aspects of screening, cost-effectiveness and generalizability to other settings. This review discusses the rationale behind screening, the results of on-going trials, potential harms of screening and current knowledge gaps.

Personalizing and targeting therapy for COPD: the role of molecular and clinical biomarkers

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease characterized by persistent airflow limitation. It is the third leading cause of death worldwide, and there are currently no curative strategies for this disease. Many factors contribute to COPD susceptibility, progression and exacerbations. These include cigarette smoking, environmental and occupational pollutants, respiratory infections and comorbidities. As the clinical phenotypes of COPD are so variable, it has been difficult to devise an individualized treatment plan for patients with this complex chronic disease. This review will highlight how potential clinical, inflammatory, genomic and epigenomic biomarkers for COPD could be used to personalize treatment, leading to improved disease management and prevention for our patients.