This observational study evaluates the effectiveness of computed tomography (CT) imaging surveillance after curative-intent treatment for stage I-IIIA non-small cell lung cancer (NSCLC) in a diverse U.S. population. The main questions are: How do CT surveillance use and adherence vary by race, ethnicity, and socioeconomic status? Does semi-annual CT surveillance improve outcomes compared with annual surveillance? Adults ages 20-90 with stage I-IIIA NSCLC treated between 2012 and 2026 will be identified using OneFlorida+ electronic health records, tumor registry data, claims, and clinical notes. Patients will be followed for up to five years after curative-intent therapy to evaluate surveillance patterns, recurrence, second primary lung cancers, complications, and survival.
This study, Advancing Precision Lung Cancer Surveillance and Outcomes in Diverse Populations (PLuS2), is an observational cohort study designed to evaluate real-world computed tomography (CT) imaging surveillance strategies following curative-intent treatment for early-stage non-small cell lung cancer (NSCLC). The study uses existing clinical data and does not assign interventions. The study population includes adults ages 20-90 with pathologically confirmed stage I-IIIA NSCLC who completed curative-intent therapy. Patients treated between 2012 and 2026 will be identified within the OneFlorida+ Clinical Research Consortium and followed for up to five years after treatment to assess surveillance patterns and outcomes. UF Health serves as the data coordinating site in collaboration with the OneFlorida+ Data Trust. Data sources include structured electronic health records, tumor registry data, selected claims, and unstructured clinical notes. Data extraction and cohort identification are conducted centrally using standardized definitions aligned with the PCORnet Common Data Model. The primary objectives of the study are to: 1. Describe utilization and adherence to guideline-recommended CT surveillance and evaluate determinants of use by race, ethnicity, socioeconomic status, and clinical factors. 2. Compare recurrence, second primary lung cancers, complications, and survival among patients undergoing semi-annual versus annual CT surveillance. 3. Use observational findings to inform microsimulation models that project long-term outcomes under alternative surveillance strategies. Clinical natural language processing (NLP) methods are used to classify CT scans as routine surveillance versus symptom-directed diagnostic imaging and to extract recurrence indicators, smoking history, and selected social determinants of health from unstructured clinical notes. NLP outputs are integrated with structured data to improve classification accuracy and completeness. Quality assurance procedures include automated checks for completeness, range, and internal consistency, validation against source EHR and tumor registry records, and maintenance of a standardized data dictionary defining all variables and coding systems. Standard operating procedures govern cohort assembly, quarterly data refreshes, data management, analysis, and reporting. The expected cohort size is approximately 1,700 patients, providing sufficient power to evaluate surveillance utilization patterns and outcome differences by surveillance interval. Missing data will be addressed using multiple imputation and sensitivity analyses. Statistical analyses include descriptive methods, multivariable and mixed-effects regression models, and time-to-event and competing-risk analyses. Results from the observational analyses will be used as inputs for microsimulation modeling to estimate long-term population-level outcomes associated with different CT surveillance strategies.
Study Type
OBSERVATIONAL
Enrollment
1,826
University of Florida College of Medicine
Gainesville, Florida, United States
Guideline Adherence to Chest CT Surveillance
Proportion of patients who complete guideline-recommended post-treatment chest CT surveillance within prespecified rolling surveillance windows. Guideline adherence will be defined using ±1-month and ±2-month allowable windows around each recommended surveillance time point. Semi-annual surveillance (Years 0-2) will be assessed at recommended months 6, 12, 18, and 24, with adherence defined as completing a CT within months 5-7 or 4-8, 11-13 or 10-14, 17-19 or 16-20, and 23-25 or 22-26, respectively. Annual surveillance (Years 3-5) will be assessed at recommended months 36, 48, and 60, with adherence defined as completing a CT within months 35-37 or 34-38, 47-49 or 46-50, and 59-61 or 58-62, respectively. Patients will be censored at recurrence, death, loss to follow-up, or end of study.
Time frame: Up to 5 years after treatment completion
Annual Rates of Guideline-Concordant Surveillance CT Imaging during post-treatment Years 1-5.
Surveillance begins at completion of curative-intent therapy (surgery or SBRT ± adjuvant therapy), and only routine surveillance scans are included. In Years 1-2, surveillance is guideline-concordant if CTs are completed within rolling 4-8-month intervals following either treatment completion or the prior surveillance CT. In Years 3-5, surveillance is guideline-concordant if CTs occur within rolling 10-14-month intervals from the prior CT. Patients are censored at recurrence, death, loss to follow-up, or end of study period.
Time frame: Year-specific rates are assessed annually for up to 5 years post-treatment.
Time to First Recurrence
Time from completion of curative-intent therapy to the first documented cancer recurrence (local, regional, or distant). Recurrence will be identified using structured electronic health records (EHR) recurrence fields, validated recurrence-detection algorithms, cancer registry linkage, and natural language processing (NLP) based extraction from radiology reports and clinical notes. Patients will be censored at death without recurrence, loss to follow-up, or completion of 5-year follow-up.
Time frame: Up to 5 years post-treatment.
Time to Second Primary Lung Cancer (SPLC)
Time from completion of curative-intent therapy to diagnosis of a metachronous second primary lung cancer (SPLC). SPLC will be defined using standard criteria, including AJCC TNM staging, histologic distinction from the index tumor, cancer registry confirmation, and pathology report verification. Among patients who develop SPLC, we will evaluate stage at SPLC diagnosis, histologic subtype (including bronchioloalveolar carcinoma), and receipt of adjuvant therapy. Patients will be censored at death without SPLC, recurrence without SPLC, or completion of follow-up. This outcome will be analyzed as a time-to-event measure consistent with other survival endpoints.
Time frame: Up to 5 years or end of follow up
All-cause mortality
Time from completion of curative intent treatment to death from any cause. Vital status will be ascertained through institutional cancer registries, the National Death Index, and state death certificate data.
Time frame: Up to 5 years post-treatment (or longest available follow-up).
Lung Cancer-Specific Mortality
Time from completion of curative-intent treatment to death attributed specifically to lung cancer, analyzed under a competing-risk framework in which non-lung cancer deaths are treated as competing events. Cause of death will be determined using institutional cancer registry data and National Death Index linkage.
Time frame: Up to 5 years following treatment completion.
Mode of Recurrence Detection
Classification of recurrence mode at the time of first recurrence. Recurrences will be categorized as: 1. Surveillance detected: Identified during routine surveillance CT imaging in asymptomatic patients. 2. Symptom detected: Identified after clinical symptoms prompted diagnostic evaluation. Detection mode will be determined using electronic health record (EHR) documentation and natural language processing (NLP) extraction from radiology reports and clinical notes. Timing of recurrence (time to event) will be evaluated separately; early vs. later surveillance detection will be described, but has no clinical implications if timing windows shift.
Time frame: Assessed at the time of recurrence, up to 5 years following treatment completion.
Type of SPLC Detection
Classification of metachronous second primary lung cancer (SPLC) as either: Surveillance-detected: Identified during routine surveillance CT imaging in asymptomatic patients. Symptom-detected: Identified after new or worsening symptoms prompted diagnostic evaluation. Detection mode will be determined using EHR documentation and NLP extraction from radiology reports and clinical notes.
Time frame: At SPLC diagnosis (≤5 years following treatment completion).
Model-Projected Long-Term Survival Under Alternative Surveillance Strategies
Microsimulation-projected overall and lung cancer-specific survival under semi-annual versus annual CT surveillance schedules. The model will be calibrated using recurrence, SPLC, and mortality data from Aims 1-2 and extrapolated to national incidence patterns using SEER data. Measure Description: Difference in projected survival outcomes between semi-annual and annual surveillance strategies, reported as: 1. Mean life expectancy (life-years) 2. Five-year, ten-year, and lifetime survival probabilities 3. Hazard of lung cancer-specific death Model estimates will be derived from a calibrated Markov microsimulation model informed by Aims 1-2 and extrapolated using SEER incidence.
Time frame: At 5 years, 10 years, and over the model-projected lifetime horizon after the index surveillance decision
CT Surveillance Pattern Classification (0-5 Years)
Patients will be categorized into one of four mutually exclusive surveillance patterns based on completed post-treatment surveillance CT imaging from 0-5 years following curative intent therapy: 1. Semi-Annual Adherence: Consistent completion of surveillance CT scans within guideline-concordant 4-8 month intervals during Years 1-2, followed by 10-14 month intervals during Years 3-5. 2. Annual Only Adherence: Completion of at least annual surveillance (10-14 month intervals) during Years 1-5, but not meeting semi-annual criteria in Years 1-2. 3. Irregular/Other Surveillance: Completion of ≥1 surveillance CT scan during follow-up, but not meeting semi-annual or annual adherence definitions. 4. No Surveillance: No documented surveillance CT scan within 12 months of treatment completion.
Time frame: 0-5 years post treatment
CT Surveillance Utilization Rate
Intensity of surveillance CT use, measured as scans per person time and/or completion of guideline-recommended surveillance intervals
Time frame: Up to 5 years post treatment
False Positive Surveillance CT Results
Surveillance CT scans that trigger additional diagnostic evaluation (biopsy, PET CT, or repeat imaging) without a lung cancer diagnosis (recurrence or SPLC) within 6 months of the index scan. Results will be classified as true positive, false positive, true negative, or false negative using cancer registry data and EHR documentation
Time frame: Up to 5 years
Downstream Diagnostic Procedures After Surveillance CT
Frequency and type of diagnostic procedures, both invasive and non-invasive, performed following surveillance CT imaging, including transthoracic biopsy, transbronchial biopsy, bronchoscopy, and PET-CT.
Time frame: Up to 5 years following treatment completion
Procedure Related Complications
Complications occurring within 7 days and 30 days of invasive diagnostic procedures (transthoracic, transbronchial, or surgical biopsies), including: 1. Pneumothorax 2. Pulmonary hemorrhage 3. Acute respiratory failure 4. Acute renal failure 5. Contrast allergy requiring hospitalization 6. Acute myocardial infarction
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Time frame: Up to 5 years following treatment completion
Recurrence Site / Pattern (Registry Based)
Classification of recurrence site as local, regional, or distant, based on cancer registry definitions.
Time frame: At recurrence (≤5 years)
Receipt of Treatment Following Recurrence or SPLC
Time to treatment initiation following recurrence or SPLC diagnosis, and classification of treatment modality, including surgery, SBRT, targeted therapy, and immune checkpoint inhibitor therapy.
Time frame: At recurrence or SPLC diagnosis (≤5 years)