Incidental Breast Lesions Detected on Diagnostic CT Scans: A 4‐year Prospective Study

To the Editor: Breast cancer remains the commonest cancer affecting women in the UK. Breast symptomatic clinics and breast screening program diagnose the majority of breast cancers. Mammography and ultrasonography are the preferred radiological examination methods for the assessment of breast lesions. Computed tomography (CT) scans have not been recommended for the diagnosis of breast diseases. In the last few years, there has been an increase in cross-sectional imaging including a staggering 226% rise in the number of CT scans for chest diseases over a 5-year period (1). The entire breast tissue becomes visible on a chest CT and occult breast lesions can be revealed by such scans performed for pathologies other than breast. With greater than ever usage of chest CT scans, incidental breast lesions are increasingly being encountered (2, 3). We aimed this study to investigate the discovery of incidental breast lesions on chest CT scans done for pathologies other than breast. Prospective data were collected from January 2008 to December 2011. All patients referred to breast multi-disciplinary meeting after radiologist reporting certain incidental breast abnormalities on chest CT scans done for various nonmammary reasons were entered in this study. All patients were assessed by clinical breast examination coupled with mammography, ultrasonography, and tissue biopsy if indicated. Data collection included indications of CT scans, referral pattern, pathologic diagnoses, treatment details, and follow-up. An increasing trend has been seen in the total number of thoracic CT scans with 4,388 scans in 2008 and 6,409 scans in 2011 resulting in 46% rise in the total number of scans over this 4-year period. During this time, 21,127 chest CT scans were carried out. Forty patients (0.19%) shown to have incidental breast lesions were referred to breast multi-disciplinary meeting becoming eligible to enter this study. Thirty-nine of these 40 patients were women, one was man. Their age ranged from 50 to 92 (median 78) years. All CT scans were done for nonmammary indications (Table 1). Of the total 40 patients in this group, 20 (50%) were primary breast cancers, 19 (47.5%) were benign, and one (2.5%) had lymphoma (Table 2). Among the breast cancers, 17 had invasive ductal carcinoma, two had lobular carcinoma, and one had mucinous carcinoma. Benign pathologies included 12 fibrocystic diseases, four fibroadenomata, two cysts, and one gynaecomastia. Of 20 breast cancer patients in this group, only four were operable, three had breast-conserving surgery, and one had mastectomy. Among the 16 inoperable patients, 10 (50%) had metastases at the time of diagnosis, and six patients were frail and elderly. All sixteen inoperable patients were estrogen receptor positive, hence given anti-estrogen therapy, two had palliative chemotherapy, and two had palliative radiotherapy. The follow-up for breast cancer patients ranges from 1 to 39 months (median 21 months). There have been seven deaths overall in these 40 patients (17.5%), six in malignant group and one in the benign group. With growing usage of CT scans and improving image quality, there has been an increase in the frequency of detecting “incidental findings or inciden-