SUN-298 Ga-68 DOTANOC incidentaloma; a higher prevalence but lower rate of malignancy than expected

Abstract Disclosure: C. De Herdt: None. L. Naert: None. S. Stroobants: None. C. De Block: None. Introduction: Ga-68 DOTANOC PET/CT is increasingly performed, which may lead to an increase of incidentaloma. In 2022, Bentestuen et al. published a systematic review concerning Ga-68 DOTA incidentaloma describing a prevalence of 4% with a malignancy rate of 13%. Methodology: The results of Ga-68 DOTANOC PET/CT’s performed between 2017-2023 in adult subjects at the Antwerp University Hospital were retrospectively screened for incidentaloma, defined as an increased, non-physiological tracer uptake, not related to the indication of imaging. The aim of the study was to evaluate the prevalence of incidentaloma and describe the underlying cause, including malignancy. Results: 1571 Ga-68 DOTANOC PET/CT’s performed in 1241 subjects were analyzed. A total of 137 incidentaloma were described in 126 subjects with a mean age of 64 ± 13 years and F/M ratio of 49/77. The most frequently reported locations were the thyroid (n=37), brain (n=28), prostate (n=22) and breast (n=13). Further investigation was performed in 90 (66%) incidentaloma. Only 30% (11/37) of thyroid incidentaloma were further evaluated with ultrasound. Diffuse tracer uptake (n=2) at the thyroid was caused by an underlying multinodular goiter. Focal tracer uptake (n=9) was caused by a thyroid nodule. Punction was indicated in 5 nodules and all showed a benign cytology. MRI of the brain was performed in 23 of 28 (82%) brain incidentaloma in which a meningioma was the most frequent finding (16/23). Ultrasound was performed in 14 of 22 (64%) prostate incidentaloma, which most commonly showed benign prostate hypertrophy (9/14). One patient was diagnosed with prostate carcinoma. Further imaging (ultrasound/ MRI) was performed in 10 of 13 (77%) breast incidentaloma and led to the diagnosis of breast adenocarcinoma in 3 patients. Overall, rate of malignancy was 8% (7/90), consisting 3 breast, 2 renal cell, 1 prostate and 1 lung cancer. Conclusion: This is the largest single-center study describing the prevalence and underlying cause of Ga-68 DOTANOC incidentaloma to date. Evaluating the images of 1241 subjects a prevalence of 11% was found which is higher than the prevalence of 4% previously described. Incidentaloma were most frequently encountered in the thyroid (29%), followed by the brain (20%), prostate (16%) and breast (9%). The rate of malignancy (8%) was lower than previously described (13%) which could be explained by publication bias in the review of Bentestuen et al. No thyroid cancer was diagnosed, however, no ultrasound was performed in 67% of thyroid incidentaloma. We do not support focal thyroid tracer uptake is a risk for malignancy as previously stated. We do strongly advise to further investigate breast and renal incidentaloma as rate of malignancy was high. With this abstract we want to stimulate other centers to publish their data of DOTA-incidentaloma which can lead to a guidance in interpretation. Presentation: Sunday, July 13, 2025