Abstract PS2-32: Incidental malignant findings on pre-admission chest computed tomography scan for coronavirus disease screening in patients with breast cancer or other cancers
Authors: Masuda Jun , Kataoka Akemi , Oikado Katsunori , Uehiro Natsue , Ozaki Yukinori , Inagaki Lina , Kato Chieko , Morizono Hidemoto , Takano Toshimi , Ueno Takayuki , Ohno Shinji 
Published: February 2021

Abstract
Background: Amidst the coronavirus disease (COVID-19) pandemic, pre-admission chest computed tomography (CT) screening has been performed for all patients (pts) scheduled for cancer surgery to prevent the nosocomial spread of COVID-19 at our cancer center in Tokyo. This strategy was employed owing to a shortage of polymerase chain reaction assay opportunities and the relatively abundant availability of CT scanning in Japan. Notably, a screening CT may reveal incidental findings that are different from the original purpose of the examination. Thus far, there are no reports of incidental malignant findings on CT scans for COVID-19 screening. Methods: This single-institutional retrospective study included pts scheduled for surgery and who underwent pre-admission CT scans for COVID-19 screening between April 26, 2020, and June 12, 2020. Clinical and radiological data of pts were extracted from medical records. Clinical data included age, sex, medical history, and treatment. All CT scans for COVID-19 screening were examined one or two days before surgery and interpreted by two trained radiologists. This study aimed to reveal the ratio of incidental findings related to malignancy. Results: Between April 26, 2020, and June 12, 2020, 863 pts underwent pre-admission CT scans for COVID-19 screening. Median patient age was 58 years (range, 11-91 years), and 511 (59%) of the pts were female. The most common disease was breast cancer (n = 165, 19%), followed by colorectal cancer (n = 108, 13%), gynecological cancer (n = 107, 12%), and other cancers (n = 483, 56%). CT scan revealed radiological findings of pneumonia in 23 pts (2.7%); therefore, surgery was postponed for these pts. Incidental findings were detected in 28 pts (3.2%), including one pneumothorax and 27 findings related to malignancies. The present study included 165 pts (19%) with breast cancer and who were scheduled for curative surgery. Among them, incidental findings related to malignancies were detected in nine pts (5.5%), including small ground-glass pulmonary nodules (GGN) (n=5), pancreatic duct dilatation (n=1), suspected vertebral metastasis (n=2) and suspected liver tumor (n=1). All pts did not undergo breast surgery but underwent additional examinations after surgery. Five pts (2.5%) with GGN needed follow-up. One patient’s pancreatic duct dilatation was diagnosed as benign using ultrasound. One patient with suspected vertebral metastasis was diagnosed with degenerative changes. The other patient was diagnosed with multiple bone metastases by bone scintigraphy, and further treatment was planned. Pre-admission screening CT scan for pts with other cancers was performed in 698 pts (81%). Among them, findings related to malignancies were detected in 18 pts (2.6%), including breast nodules (n=3), lung nodules (n=5), liver metastasis (n=1), progression of metastasis (n=3), mediastinum tumor (n=1), and GGN (n=5). Two of the three pts with breast nodules were diagnosed with invasive breast cancer and planned for breast surgery after the current cancer treatment. Two pts developed new lung metastasis, and the surgical strategy was changed. The progression of known liver or lung metastasis was detected in three pts, which led to the addition of systemic chemotherapy without modification of surgical treatment. One patient had a mediastinum tumor, and an MRI evaluation after surgery revealed an athymic cyst. Five pts were determined to have GGN, and follow-up was required. Conclusion: The proportion of pts for whom pre-admission CT for COVID-19 revealed incidental findings was 3.2%. Incidental breast cancer was found in 0.4% of female pts. GGNs needed follow-up examination in 2.5% of operable breast cancer pts. Physicians and surgeons should be aware of incidental malignant findings in the COVID-19 screening CT scan.
Citation Format: Jun Masuda, Akemi Kataoka, Katsunori Oikado, Natsue Uehiro, Yukinori Ozaki, Lina Inagaki, Chieko Kato, Hidemoto Morizono, Toshimi Takano, Takayuki Ueno, Shinji Ohno. Incidental malignant findings on pre-admission chest computed tomography scan for coronavirus disease screening in patients with breast cancer or other cancers [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS2-32.