Endocrine Abstracts

Background: New nuclear medicine imaging techniques have improved diagnosis, staging and treatment planning for BC. ⁶⁸Ga-DOTA PET is preferable to standard somatostatin receptor scintigraphy where available (ENETS guidelines); however, its role in the management of BC remains unclear.

Methods: All consecutive patients diagnosed with BC from two ENETS Centres of Excellence were identified retrospectively; patients with high grade tumours or lacking biopsy confirmation were excluded. Primary objective: to assess the impact of ⁶⁸Ga-DOTANOC on clinical management in patients with BC.

Results: Of 166 patients screened, 46 were eligible: 52% female, median age 57 years (range 21–86). Type of BC: DIPNECH (4%), typical (44%), atypical (35%), not reported (17%); median Ki67 and mitotic count were 3 and 1, respectively. Stage at time of referral for ⁶⁸Ga-DOTANOC was: localised (63%), locally advanced (13%) and metastatic (17%). Provided treatment: 27 patients (59%) had curative resection; 18 (39%) received palliative treatment; one patient did not have information available regarding treatment. A total of 47 ⁶⁸Ga-DOTANOC PETs were performed with the following rationale: confirmation of neuroendocrine malignancy (4; 9%), identification of primary tumour (2; 4%), post-surgical re-staging (“cancer free” patients) (19; 40%), staging (patients with known BC present at time of ⁶⁸Ga-DOTANOC) (19; 40%) and consideration of Peptide Receptor Radionuclide Therapy (PRRT) (3; 7%). Twenty-seven (57%) scans showed evidence of non-physiological uptake: median SUVmax 7.2 (range 1.42–53). ⁶⁸Ga-DOTANOC provided additional information in 37% (95%CI 22–51) of patients and impacted on management in 26% (95%CI 12–41). A total of 9 patients (21%) were identified to have occult sites of metastases: 3 of whom had the ⁶⁸Ga-DOTANOC performed as post-surgical re-staging (3/19; 16%). No factors predictive of changes in management were identified (univariate logistic regression): type of BC (OR 2.3 (95%CI 0.5–11.6); P-value 0.308), stage (OR 1.4 (95%CI 0.5–3.7); P-value 0.474), previous curative resection (OR 1.3 (95%CI 0.3–6.2); P-value 0.744); other factors such as aim of the ⁶⁸Ga-DOTANOC, Ki67, mitotic count and sites of metastases were also not significant (all P-values >0.05).

Conclusions: Our results support the use of ⁶⁸Ga-DOTANOC in patients with BC for planning treatment, including post-surgical re-staging due to potential for identifying occult metastases.