Endocrine Abstracts

Background: Peptide receptor radionuclide therapy (PRRT) is well-established for patients with gastroenteropancreatic neuroendocrine tumours (GEP-NET). At our centre there has been an increase in referrals for complex patients who are higher risk for complications, or who require special considerations for therapy. We aimed to review the characteristics of such patients at our centre.

Methods: A single centre prospective study of patients discussed at our NET MDM who were recommended for PRRT between October 2023 to October 2024 was conducted. Data collected included patient and tumour characteristics, complications, initial response and presence of special considerations. Special considerations included requirement for corticosteroids at the time of therapy, measured GFR (mGFR) prior to proceeding (patients with eGFR <70 ml/ml/1.73m² ), requirement for inpatient admission, presence of carcinoid syndrome (CS) or carcinoid heart disease (CHD).

Results: 76 patients had MDM outcome recommending PRRT. 36 patients were included after excluding trials (n = 5), patients referred to other centres for treatment (n = 24) and patients who chose alternative therapies (n = 9). Median age was 66, 53% male. 61% of tumours originated from the small bowel, 47.2% were grade 2, with a median tumour grade 5.9%. Median time from diagnosis was 24.7 months, and in 83% of patients PRRT was second line systemic therapy after somatostatin analogues. 15 patients had special considerations; 4 required mGFR, 8 corticosteroids, 3 inpatient admission, 14 CS and 1 CHD. 29 patients completed 4 cycles. Not completing therapy was due to side effects in 2 patients, 2 due to progressive disease (PD), 3 from complications. 71.4% not completing therapy had special considerations. Initial response in 29 patients who completed 4 cycles, 51.7% had stable disease (SD), 34.5% had partial response (PR) and 3.4% had PD. For 13 patients with ≥6 months follow-up 76.9% still had SD. Median PFS was 34.2 months with follow-up of 40 months. Of 6 patients who died, 66.7% had not completed 4 cycles and 83% had special considerations.

Conclusions: In our cohort, patients with special considerations were less likely to complete therapy and more likely to experience complications. Those with special considerations who did complete therapy had SD at initial follow-up.