The ACR Updated Lung-RADS to Include Volumetric Measures – Are You and Your Colleagues Prepared?

By Neal Miller | October 17, 2019 | Blog

Using HealthMyne, the entire multidisciplinary team can easily follow volumes and meet the Lung-RADS 1.1 requirements in order to more accurately track and treat lung nodules.

This approach has been shown to improve the quality of care while decreasing morbidity and mortality of lung cancer screening patients.

The American College of Radiology (ACR) recently released an update to the Lung-RADS® Assessment Categories which includes six major changes:

  • Guidance for perifissural nodules
  • Increased size criteria for non-solid nodules to 30 mm
  • Addressed management of new large nodules (4B)
  • Revised instructions for mean nodule diameter measurements
  • Addition of volumetric measurements
  • Removed the C-modifier category

While radiology groups are increasingly being asked by oncologists and others on the multidisciplinary team to provide volumetric measurements of lung nodules, the addition of volume as an option in Lung-RADS version 1.1 is a significant first step toward an improved standard of care. In her August 13 webinar on Lung-RADS version 1.1, Ella Kazerooni, MD, Chair of the Lung-RADS Committee, stated that the ACR may move lung nodule reporting fully to volumetric measurements in (approximately) the next two years. She pointed to the literature that demonstrates the “tremendous error and variation” in lung nodule measurement using current methods.

There are a number of reasons for moving towards volume across all forms of cancer, but Dr. Kazerooni highlights a couple of key points during the webinar. The first one is the inherent variability that comes from using electronic calipers to measure the diameter of a lesion. In a study published in Radiology, long axis measurements differed by up to 124% between 17 readers and the authors determined that only differences greater than 7 to 10% could be considered ‘true changes.’  (McErlean, et al., 2013). In The Long and Short of It eBook, Dr. Jonathan D. Clemente, M.D., Chief of Radiology, Charlotte Radiology explained why this is so important, “A measurement that is off by 1-2 mm in any dimension could potentially change the measured volume of an index lesion, the radiologist’s interpretation of past response to treatment and the future course of treatment for that patient.”

It’s known that volume is a better predictor of tumor burden, but without accurate and easy to use tools, clinicians have used diameter as a surrogate for volumetric measurements. The problem is that since most tumors are not spherical, diametric measurements cannot accurately depict true volume. Frenette et al. showed that, on average, the actual measured volume differed by over 88% when diameter was used as the basis for estimation. (Frenette, et al., 2015) This, along with the inherent difficulties of getting accurate diametric measurements means that the treatment pathways for many patients may have been altered if the true tumor burden was known.

Along with getting more consistent and more representative measurements, it has also been shown that volumetric data more accurately represents a patient’s risk of having lung cancer. The Dutch-Belgian Randomized Lung Cancer Screening Trial (NELSON) used volume-based measurements instead of diameters, setting it apart from most other lung cancer screening studies. In comparison to the National Lung Cancer Screening (NLCS) trial, the NELSON study not only reduced false positives by over 30%, but also greatly reduced the number of patients initially diagnosed with a positive result (Zhao, et al., 2011). Using volume could greatly reduce costs, anxiety and morbidity.

Clearly volume is the better measure, not only for determination of a cancer diagnosis, but also for determining response to treatment. The ACR’s addition of volumetry in Lung-RADS version 1.1 is a step toward reducing variability and error -- and defining a new standard of care.

 

The HealthMyne Platform

Enables easy extraction of volumetric data from CT, MR and PET images. Once a clinician has identified a nodule or area of interest, HealthMyne automatically performs a full 3D segmentation. The software reports the long and short measurements and volume, including density, doubling-times and more, as well as a full radiomic profile. These measurements are then used to drive clinical workflows such as tumor board management, incidental findings and of course cancer screening.

For lung cancer, HealthMyne’s Cancer Screening Module evaluates the size of the nodule, both diameter and volume, along with the calculated solidity (percent ground glass opacity) to automatically assign the correct Lung-RADS score (using either version 1.0 or 1.1). Scores and other clinical and scheduling information is automatically pulled from the patient’s EHR record to prioritize a web-based worklist, so clinicians can easily see which patients need the most urgent attention. Coordinators or navigators track progress, communicate with both providers and patients and, with a single mouse click, upload required information to the ACR.

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