Follow-up of Benign Thyroid Nodules-Can We Do Less?

OBJECTIVE: To determine the incidence of malignancy, follow-up ultrasound (US), and repeat fine needle aspiration (FNA) in thyroid nodules that have been previously biopsied as benign. METHODS: This is a retrospective, descriptive study of benign thyroid nodules evaluated by US between 2010-2011. We determined the frequency of follow-up ultrasounds and FNAs, mean years of follow-up, interval between follow-up US, change in nodule size, reasons for repeat FNA (rFNA), frequency of thyroidectomy, and thyroid malignancy during 5 years of follow-up. RESULTS: A total of 733 benign thyroid nodules were reviewed in 615 patients. Mean years of US follow-up was 3.47 ± 1.65 years; 275 (37.5%) had no follow-up US; 109 (14.9%) had 1 follow-up US; 93 (12.7%) had 2 follow-up US; and 256 (34.9%) had 3 or more follow-up US. Assessment of thyroid nodule size showed that 215 (28.8%) nodules decreased in size, 145 (19.4%) increased in size by less than 50%, and 91 (12.1%) increased in size by more than 50%. Of the 733 nodules, 17 nodules (2.3%) underwent thyroidectomy for which the pathology result of 9 (1.2%) showed malignancy, and 65 (8.9%) thyroid nodules underwent rFNA. When applying the 2015 recommendations for repeat FNA, 35% were done unnecessarily. CONCLUSION: In our sample of initially benign thyroid nodules, only 9 patients (1.2%) had pathology-proven malignancy after a mean follow-up of 3.5 years. Over 30% of patients had more than 3 rUSs. Decreased interval and frequency of rUS should be considered in future guidelines for thyroid management.

Retrospective Application of the 2015 American Thyroid Association Guidelines for Ultrasound Classification, Biopsy Indications, and Follow-up Imaging of Thyroid Nodules: Can Improved Reporting Decrease Testing?

INTRODUCTION: Thyroid ultrasound has been widely used to determine which nodules need further investigation. The goal of this study is to determine if using an ultrasonographic features checklist based on 2015 American Thyroid Association (ATA) guidelines can improve reporting and decrease unnecessary further testing. METHODS: In this retrospective study, ultrasonographic images of all nodules biopsied at our institution in 2014 and 2015 were reviewed by radiologists blinded to fine needle aspiration (FNA) biopsy result using a checklist. The checklist was prepared based on 2015 ATA guidelines. The ultrasonographic characteristics of thyroid nodules were compared with the result of biopsy to determine positive predictive value (PPV), negative predictive value (NPV), sensitivity, and specificity for predicting malignancy. Radiologists also made an overall recommendation on need for FNA. RESULTS: A total of 425 thyroid nodule ultrasound scans were reviewed by radiologists. Biopsy results of 31 nodules were malignant and 394 were non-malignant. Malignant nodules showed higher frequency of solid composition, hypoechoechogenicity, and cervical lymph node involvement compared to benign nodules. Solid nodule composition had the highest PPV (13%) and NPV (94.7%). Extra-thyroid extension had the highest specificity (90.1%). Lesion vascularity had the highest sensitivity (83.8%), followed by hypoechogenicity (65.6%). Overall, the checklist had a positive predictive value of 9%, negative predictive value of 97.5%, sensitivity of 96.8%, and specificity of 11.14%. Radiologists determined that 10% of the nodules were very low-risk and did not require FNA. CONCLUSION: Using a checklist based on 2015 ATA guideline thyroid nodule ultrasonographic features is a sensitive tool with high NPV to predict benign thyroid nodule, thereby preventing unnecessary FNAs.

Rapid MRI of the breast in evaluating lesions discovered on screening.

BACKGROUND: In Canada, breast MRI has traditionally been reserved for evaluation of disease extent in patients with known breast malignancy. More recently, MRI has been emerging as an instrument for breast screening. However, its utilization is limited by increased relative cost and increased reader time. In this study, we evaluate a rapid MRI protocol for breast cancer screening within a breast screening population. METHODS: A series of 100 MRI studies performed in a high-risk breast cancer population were selected, ensuring a mix of malignant and benign pathology and normal cases. These were presented as full and abbreviated MRI protocols to 3 breast-trained radiologists. Each case was evaluated for Breast Imaging Reporting and Data Systems (BIRADS) category and the presence or absence of cancer. The time taken to complete and interpret each study was also recorded. RESULTS: Of the 100 cases, 17 were of histopathology-proven invasive carcinoma, 6 were ductal carcinoma in situ, 33 were benign, and 44 were normal cases. Sensitivity using the rapid protocol was 69.6% (CI: 47.1-86.8) vs 83% (CI: 61.2-95.1) using the full protocol. Specificity using the rapid protocol was 77.9% (CI: 67.0-86.6) vs 83% (CI: 61.2-95.1) using the full protocol. Intra-observer agreement of BIRADS category and cancer detection was very good (0.82-0.93 weighted Kappa and 0.81-0.9 weighted Kappa, respectively). Inter-observer variability of BIRADS category and cancer detection was moderate (0.54-0.59 and 0.53-0.58, respectively). CONCLUSION: Our study suggests that a rapid MRI protocol is comparable in performance to that of a standard MRI protocol. In addition, breast imagers are unlikely to change their BIRADS assessment of a study based on the additional sequences provided by the lengthier study. The use of a rapid MRI protocol can improve accessibility, thus making breast MRI a more utilized tool for breast cancer screening.

Breast MRI as an adjunct to mammography for breast cancer screening in high-risk patients: retrospective review.

OBJECTIVE: In July 2011, the provincial government of Ontario, Canada, approved funding for the addition of annual breast MRI to mammography screening for all women 30-69 years old considered to be at high risk for breast cancer. The purpose of this study was to evaluate the diagnostic performance of screening breast MRI as compared with mammography in a population-based high-risk screening program. MATERIALS AND METHODS: A retrospective review identified 650 eligible high-risk women who underwent screening breast MRI and mammography between July 2011 and January 2013 at one institution. Results of 806 screening rounds (comprising both MRI and mammography) were reviewed. RESULTS: Malignancy was diagnosed in 13 patients (invasive cancer in nine, ductal carcinoma in situ in three [one with microinvasion], and chest wall metastasis in one). Of the 13 cancers, 12 (92.3%) were detected by MRI and four (30.8%) by mammography. In nine of these patients, the cancer was diagnosed by MRI only, resulting in an incremental cancer detection rate of 10 cancers per 1000 women screened. MRI screening had significantly higher sensitivity than mammography (92.3% vs 30.8%) but lower specificity (85.9% vs 96.8%). MRI also resulted in a higher callback rate for a 6-month follow-up study (BI-RADS category 3 assessment) than mammography (119 [14.8%] vs 13 [1.6%]) and more image-guided biopsies than mammography (95 [11.8%] vs 19 [2.4%]). CONCLUSION: MRI is a useful adjunct to mammography for screening in high-risk women, resulting in a significantly higher rate of cancer detection. However, this was found to be at the cost of more imaging and biopsies for lesions that ultimately proved to be benign.