Somatostatin analogue treatment is associated with lack of progression of pNETs <20mm in size in patients with MEN1

Isolda Frizelle; Anand Velusamy; Barbara McGowan; Louise Breen; Emma Duncan; Louise Izatt; Dimitra Christodoulou; Mamta Joshi; Carroll Paul

doi:10.1530/endoabs.90.P167

Introduction: Pancreatic neuroendocrine tumours (pNETs) are the main cause of mortality in patients with multiple endocrine neoplasia type 1 (MEN1). The CLARINET study demonstrated that somatostatin analogue treatment improved progression free survival in patients with enteropancreatic NETs but little is known about the role of SSA in preventing progression of pNETs in MEN1 (1). Many centres have started using SSA treatment in MEN1 patients with enlarging pNETs or tumours >15 mm. This is current practice in our centre.

Objective: This observational study examined the effectiveness of somatostatin analogue (SSA) treatment in preventing progression of pNETS in MEN1.

Methods: Using our database of MEN1 patients, electronic patient records were individually reviewed to document the radiological, biochemical and clinical behaviour of pNETs over time. Patients were treated with SSA if tumours had documented growth, were > 15 mm in size or were associated with metastases. We compared pNET size/ growth in patients treated and untreated with SSA (overwhelmingly lanreotide autogel 120 mg 4 weekly).

Results:

Demographics
	Total MEN1 cohort
n	57
Gender	37F: 20M
Age (y)	45 (16)
PNETs documented	44 (12 surgical)
Deceased (n)	8
Mean age of death, y (range)	59 (41-84)
SSA use (%)	35.1
Metastases N (%)	4 (7.02)
Surgical intervention? N (%)	16 (28.1)
Other Rx (n)	Peptide receptor radiotherapy (PRRT) (n=2)

Included patients treated with SSA compared with untreated patients
	MEN1 cohort with pNETs on SSA	MEN1 cohort with pNETs not on SSA
n	20	12
Gender	12F: 8M	8F:4M
Age (y)	42.2 (12.9)	41.6 (17.6)
Deceased (n)	3	2
Mean age of death (y)	56	51
Cause of deaths	Metastatic pNET x2, metastatic gastrinoma	ACC, metastatic pNET
Surgical intervention? (n)	3	1
PNET size (mm)(SD)	15 (8)	8 (4)
Stable disease	11	8
Progression	1	1
Improvement	4	0
Data unavailable	4	3
Duration of SSA use	4- 120 (mean: 48)(SD 24)	N/A
Duration of total surveillance (mths)	61.9 (25.2)	34.8 (24.6)
SEs reported	Minimal reporting-GI Symptoms, GB sludge, ?pancreatitis	N/A
Other Rx	1 patient had PRRT

Conclusion: These data indicate that mean duration of 4 years SSA treatment is associated with stable size or reduction (20%) in pNETs averaging 1.5 cm in patients with MEN1. Multi-centre collaboration, including comparison of a larger untreated cohort would clarify the effectiveness of SSA preventing progression on pNETs in MEN1.

Reference: Caplin ME, et al. Lanreotide in metastatic enteropancreatic neuroendocrine tumors. N Engl J Med. 2014;371:224–233.

Endocrine Abstracts

P167