The Watch the Spot Trial (WTS)

August 11, 2025 updated by: Michael K Gould, MD, Kaiser Permanente

The Watch the Spot Trial: A Pragmatic Trial of More Versus Less Intensive Strategies for Active Surveillance of Patients With Small Pulmonary Nodules

This study will compare two clinically accepted protocols for surveillance imaging in individuals who are found to have a small pulmonary nodule on chest computed tomography (CT) scans.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

The investigators will conduct an unblinded, prospective, pragmatic, cluster-randomized, comparative effectiveness trial of more intensive versus less intensive CT surveillance of patients found to have small pulmonary nodules in diverse health care settings. The goal of this pragmatic clinical trial is to identify the surveillance strategy that will maximize early diagnosis for individuals with cancerous nodules, while minimizing unnecessary surveillance of patients without cancer that can result in emotional stress, exposure to harmful ionizing radiation, and the discovery of incidental findings that may lead to unnecessary treatment.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
34686

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • California
      • Pasadena, California, United States, 91011
        • Kaiser Permanente Southern California

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

35 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

The target population includes adults with small lung nodules that may represent a new diagnosis of lung cancer, who typically would be managed by CT surveillance in usual clinical practice. Thus, we will enroll all patients:

  • aged ≥35 years
  • at least one nodule measuring ≤15 mm in average diameter on chest CT.

Exclusion Criteria:

  • Pregnant Women
  • Age <35 years
  • Known diagnosis of cancer (except non-melanoma skin cancer) within 5 years

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Diagnostic
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: More Frequent CT Surveillance
Chest CT scans to be repeated at 3, 6, 12 and/or 24 months, depending on patient risk factors and nodule size and attenuation (density)
Other: More Frequent Surveillance Strategy
Chest CT scans to be repeated at 3, 6, 12 and/or 24 months, depending on patient risk factors and nodule size and attenuation (density)
Active Comparator: Less Frequent CT Surveillance
Chest CT scans to be repeated at 3, 6, 12 and/or 24 months, depending on patient risk factors and nodule size and attenuation (density). Overall, participants in the less frequent arm are expected to undergo 30% fewer surveillance imaging tests.
Other: Less Frequent Surveillance Strategy
Chest CT scans to be repeated at 3, 6, 12 and/or 24 months, depending on patient risk factors and nodule size and attenuation (density). Overall, participants in the less frequent arm are expected to undergo 30% fewer surveillance imaging tests.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Proportion of cancerous nodules with tumor (T) stage greater than T1a disease by the AJCC staging system, 7th edition
Time Frame: 24 months after enrollment
Among individuals with small pulmonary nodules identified either incidentally or by screening, compare more versus less intensive surveillance to determine the number of cancerous nodules that progress beyond T stage T1a.
24 months after enrollment

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Number of days from date of nodule identification to date of cancer diagnosis
Time Frame: Up to 2 years
Ongoing, final analysis in year 5
Up to 2 years
Survival time from date of cancer diagnosis until death or end of study
Time Frame: Up to 4 years
Ongoing, final analysis in year 5
Up to 4 years
Emotional distress, measured with the Impact of Events Scale
Time Frame: Measured at 2 months, 13 months, and 25 months following nodule identification
Compare patient-reported emotional distress
Measured at 2 months, 13 months, and 25 months following nodule identification
Anxiety, measured with the State Anxiety Inventory, 6-item
Time Frame: Measured at 2 months, 13 months, and 25 months following nodule identification
Compare patient-reported anxiety
Measured at 2 months, 13 months, and 25 months following nodule identification
General health status, measured with a single question
Time Frame: Measured at 2 months, 13 months, and 25 months following nodule identification
Compare patient-reported general health status
Measured at 2 months, 13 months, and 25 months following nodule identification
Numbers of imaging tests, biopsy tests and surgical procedures, measured by review of electronic health records
Time Frame: Measured from date of nodule identification until date of cancer diagnosis or completion of 24 months of follow-up
Compare resource utilization.
Measured from date of nodule identification until date of cancer diagnosis or completion of 24 months of follow-up
Exposure to ionizing radiation, using the computed tomography dose index (CTDIvol), measured in mGy (milliGray)
Time Frame: Measured from date of nodule identification to date of cancer diagnosis or completion of 24 months of follow-up
Compare effective radiation doses received.
Measured from date of nodule identification to date of cancer diagnosis or completion of 24 months of follow-up
Exposure to ionizing radiation, using the the dose length product (DLP), measured in mGy*cm
Time Frame: Measured from date of nodule identification to date of cancer diagnosis or completion of 24 months of follow-up
Compare effective radiation doses received.
Measured from date of nodule identification to date of cancer diagnosis or completion of 24 months of follow-up
Numbers of CT scans recommended by the assigned protocol that were not ordered by the ordering provider, and/or not completed by the patient
Time Frame: Measured from date of nodule identification to date of cancer diagnosis or completion of 24 months of follow-up
Compare adherence to the recommended protocols for CT surveillance, and adherence to use of low radiation dose techniques.
Measured from date of nodule identification to date of cancer diagnosis or completion of 24 months of follow-up

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Kaiser Permanente

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Patient-Centered Outcomes Research Institute
University of California, Davis
University of California, San Francisco

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Michael K Gould, MD, MS, Kaiser Permanente School of Medicin

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
March 6, 2017

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
September 4, 2024

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
September 4, 2024

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
December 1, 2015

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
December 3, 2015

First Posted (Estimated)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
December 8, 2015

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
August 14, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 11, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
August 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 1000001

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

We plan to share de-identified IPD for all study variables with other researchers on request as long as there is an acceptable justification

IPD Sharing Time Frame

De-identified IPD will be made available within 6-12 months following study completion, to allow time for the primary study team to complete manuscripts that report on each of the 4 study aims.

IPD Sharing Access Criteria

Interested researchers will be required to submit a formal request with justification and aims to the study Data Coordinating Center. Requests will be reviewed and approved by the study Executive Committee. Relevant data use or data transfer agreements will need to be completed.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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