AI Algorithm Outperforms Radiologists in Measuring Cancer Spread on CT Scans

By MedImaging International staff writers
Posted on 24 Oct 2022

Image: The new AI algorithm demonstrated superior accuracy in measuring extent of cancer spread (Photo courtesy of Pexels)

Head and neck cancers and their standard treatments - surgery, radiation, or chemotherapy - carry significant morbidity. They affect how a person looks, talks, eats, or breathes. Therefore, there is great interest in developing less intense treatment strategies for patients. Among the factors that determine the cancer stage are the size of the original tumor, the number of lymph nodes involved, and extranodal extension - when malignant cells spread beyond the borders of the neck lymph nodes into the surrounding tissue. Now, new research has demonstrated that artificial intelligence (AI) can augment current methods to predict the risk that head and neck cancer will spread outside the borders of neck lymph nodes.

In a study by researchers with the ECOG-ACRIN Cancer Research Group (ECOG-ACRIN, Philadelphia, PA, USA), a customized deep learning algorithm using standard computed tomography (CT) scan images and associated data contributed by patients who participated in the E3311 phase 2 trial showed promise, especially for patients with a new diagnosis of human papillomavirus (HPV)-related head and neck cancer. The E3311 validated dataset carries the potential to contribute to the more accurate staging of disease and prediction of risk. The completed E3311 phase 2 trial showed that low-dose radiation at 50 Gray (Gy) without chemotherapy following transoral surgery led to very high survival and outstanding quality of life in patients at medium risk for recurrence.

The researchers developed and validated a neural network-based deep learning algorithm based on diagnostic CT scans, pathology, and clinical data. The source was the cohort of participants in the E3311 trial who were assessed at high risk of recurrence by standard pathologic and clinical measures. In E3311, patients were assessed as high risk if there was ≥1 mm extranodal extension (ENE). These patients were assigned to chemotherapy and high-dose radiation (66 Gy) following transoral surgery.

The researchers obtained pre-treatment CT scans and corresponding surgical pathology reports from the E3311 high-risk cohort, as available. From 177 collected scans, 311 nodes were annotated: 71 (23%) with ENE and 39 (13%) with ≥1 mm ENE. The tool showed high performance in predicting ENE, substantially outperforming the reviews by expert head and neck radiologists. The team now plans to evaluate the dataset as part of future treatment trials for head and neck cancer. The algorithm will be assessed for its potential to improve upon current disease staging and risk assessment methods.

“The deep learning algorithm accurately classified 85% of the nodes as having ENE compared to 70% by the radiologists,” said Benjamin Kann, MD, who led the study for ECOG-ACRIN. “As to specificity and sensitivity, the deep learning algorithm was 78% accurate versus 62% by the radiologists.”

"Our ability to develop biomarkers from standard CT scan images is an exciting new area of clinical research and provides the hope that we will be able to better tailor treatment for individual patients, including deciding when to best use surgery and in whom to reduce the extent of treatment," added senior author Barbara A. Burtness, MD.

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ECOG-ACRIN