68Ga-DOTA-TATE PET/CT - Is this the holy grail of glomus tumors imaging?

Objectives Glomus tumors are rare benign and slow growing lesions of vascular nature that commonly involve the middle ear, mastoid, jugular bulb and base of skull. Radiotherapy is used for long-term control but tumors rarely disappear. Somatostatin receptor ligands can be used in imaging glomus tumors. The combination of PET with CT has the advantage of providing exact anatomical localization of the visualized tumor activity on PET, thus a better morphologic characterization of the tumors.

Methods We retrospectively reviewed imaging of patients with glomus tumors who underwent PET/CT imaging with 68Ga-DOTA-TATE to assess extent of disease activity and determine potential implications of the tumor uptake. There were patients who were treated with radiation therapy but clinically remained with persistent disease. All images were evaluated visually and the maximum standardized uptake value (SUVmax) was used for quantification of the tumor activity.

Results There were nine patients, all were female and their ages ranged from 46 to 77 years old (mean: 60.22 +/- 9.74). The images with 68Ga-DOTA-TATE PET/CT demonstrated evidence of active disease in all patients. This high intensity of 68Ga-DOTA-TATE was quantified using SUVmax and the calculated mean uptake was 109.74. The extent of disease activity was also well characterized with PET/CT that showed associated bone erosion (destruction) in 7 of the 9 patients.

Conclusions 68Ga-DOTA-TATE PET/CT appears to be a highly sensitive metabolic imaging modality for the detection of persistent/residual disease activity in patients with glomus tumors. The modality may be considered for evaluating response to radiotherapy and in symptomatic patients with persistent disease on PET/CT after treatment with radiotherapy, the intensity of 68Ga-DOTA-TATE activity may have a potential role in deciding for alternative targeted therapy with 177Lu-DOTA-TATE.