Imaging and clinicopathological features contributing to second primary breast cancer visibility in contrast-enhanced chest CT

Purpose We aimed to evaluate the utility of surveillance contrast-enhanced chest computed tomography (CT) in detecting second primary breast cancer among breast cancer survivors, focusing on imaging and clinicopathological features contributing to tumor visibility. Additionally, we sought to provide insights into which patient populations benefit from contrast-enhanced chest CT. Methods We retrospectively analyzed records of patients diagnosed with in-breast recurrence through biopsy during surveillance follow-up after curative breast cancer surgery between January 2016 and August 2022. Patients who underwent contrast-enhanced chest CT within 1 month of diagnosis were included. Two radiologists reviewed chest CT scans for breast cancer lesions by consensus, and their findings were validated by two other radiologists blinded to tumor locations. Statistical analyses were performed to evaluate associations among clinicopathological factors, image features, and visibility. Results Eighty-nine recurrent tumors in 85 patients were included. Of these, 58 recurrent tumors were identified by the unblinded radiologists. The blinded radiologists independently identified 50 and 56 recurrences, with substantial inter-observer agreement. The visible group had a higher rate of invasive ductal carcinoma (IDC) and larger tumor sizes than those of the non-visible group. Tumors in fatty backgrounds exhibited greater visibility on chest CT than those in glandular tissues. Logistic regression analysis revealed that mastectomy patients had significantly increased visibility of recurrent tumors on chest CT. Conclusion Contrast-enhanced chest CT is valuable for detecting recurrent breast cancer, especially in mastectomy patients. Tumors in fatty backgrounds, larger tumors, mass-type tumors, and IDC are better visible on chest CT.