THYROID MALIGNANCY RISK OF INCIDENTAL THYROID NODULES IN PATIENTS WITH NON-THYROID CANCER

Retrospective study of qualitative assessment in detecting synchronous and metachronous malignancies in adult cancer patients by 18 F-FDG PET/CT

OBJECTIVES

The study aimed to evaluate the frequency of incidental suspicious lesions detected by flourine-18 fluorodeoxyglucose PET/computed tomography ( 18 F-FDG PET/CT) scans done for staging or restaging in adult cancer patients. We further determined the detection rate of synchronous and metachronous malignancies in these suspicious lesions after further investigations.

MATERIALS AND METHODS

This retrospective analysis evaluated the consecutive patients with 18 F-FDG PET/CT scans done in Queen Elizabeth Hospital (QEH), Hong Kong between July 2021 and June 2022. The adult cancer patients who underwent staging or restaging 8 F-FDG PET/CT were included while the remaining were excluded. Patients' demographics, primary cancer type, tumor markers, and pathological analyses for the incidental suspicious lesions were reviewed to establish the detection rate of synchronous and metachronous malignancies.

RESULTS

A total of 2054 patients fulfilled inclusion criteria with age ranging from 18 to 93 years old. Out of the 2054 patients, 304 (14.8%) were found to have incidental suspicious lesions. Of these, 206 patients (67.8%) underwent further investigations including pathological analyses. Subsequently, 84 of these 206 patients (40.8%) had pathologically proven synchronous or metachronous malignancies.

CONCLUSION

The detection rate of incidental suspicious lesions in adult cancer patients who underwent 18 F-FDG PET/CT scans for staging or restaging was 14.8% and the rate of synchronous and metachronous malignancies in these suspicious lesions was 40.8%. The treatment plan of these patients may potentially be altered, which should be included in the cost-benefit analysis of using this imaging modality.

NEW PROPOSED FORMULA OF TI-RADS CLASSIFICATION BASED ON ULTRASOUND FINDINGS

Introduction

The present study aimed to introduce a new formula for classification of nodules in TI-RADS and describe ultrasonography features of benign and malignant thyroid nodules.

Methods

This study was conducted on thyroid mass in 1033 patients. The incidence of malignancy for thyroid nodules was determined by selecting malignancy coefficients. Then the patients were first classified using conventional TI-RADS classification criteria and once again according to a new proposed formula.

Results

Among ultrasonography features of thyroid nodules, the irregular shape (46.7%), unclear margin (47.3%), extension to the capsule (irregular and infiltrative margin) (85%), the marked hypo-echoic nodules (63.8%), micro-calcification (49%), and to have vertical axis (74.0%) were associated with high incidence of malignancy.

Conclusion

According to the proposed new formula for TI-RADS, there are four coefficients of 7, 3, 1 and 0 for incidence of malignancy of each one of ultrasound findings that help to standardization and unifying of TI-RADS classification. The incidence of malignancy in TI-RADS classification according to the new proposed formula was achieved as follows: group 2: 0.0%, group 3: 0.7%, groups 4a, 4b, 4c: 16.7%, 43.4%, 68.5%, and group 5: 95.2%, respectively.