Abstract Library

#4666 Merkel cell neuroendocrine carcinoma of the skin: High response rates to short course palliative radiotherapy – Typical clinical scenarios

Introduction: Merkel cell carcinomas (MCC) are a rare, aggressive skin neuroendocrine carcinomas, with peak incidence in the elderly. MCC often presents as a firm, red/purple painless nodule with a short history of increasing size. Surgery is considered the 1st line treatment but elderly patients, in particular, have comorbidities which may preclude radical surgery requiring reconstruction. In advanced MCC, immunotherapy (IO) is 1st line systemic treatment. Chemotherapy is used 2nd line or if contraindications for IO but can be challenging in an elderly population. There may be an emerging role for PRRT due to the presence of somatostatin receptors on MCC. Radiotherapy (RT) can be used for non-surgical candidates, or those with unresectable or metastatic disease. Adjuvant post-operative irradiation (PORT) may provide additional benefit in risk reduction and improves local control.

Conference:

Presenting Author:

Authors: Saunders E, Sizer B, Collins J, Skelly R, Srinivasan G,

Keywords: Merkel cell, skin, radiotherapy,

#4657 Should we use the growth modulation index (GMI) in response assessment in G2 neuroendocrine tumours (NETs)?

Introduction: Grade 2 (G2) neuroendocrine tumours (NETs) exhibit diverse behaviours ranging from indolent to aggressive malignancies. Growth Modulation Index (GMI) is the ratio between time to progression (TTP) with a line of therapy (TTPn) and that of the previous line of therapy (TTPn-1). A GMI value equal to or greater than 1,33 has been suggested as an indicator of clinical effectiveness beyond traditional metrics.

Conference:

Presenting Author: Bertuzzi A

Authors: Bertuzzi A, Ferrillo G, Laffi A, Evangelista L, Jandric J,

Keywords: growth modulation index (GMI), G2 gastroenteropancreatic neuroendocrine tumour (GEP-NET), tumour response assessment,

#4625 Efficacy and safety of capecitabine-temozolomide (CAPTEM) regimen in patients with neuroendocrine neoplasms – A systematic review and experience from NETwerk, a Belgian ENETS Center of Excellence

Introduction: Current treatment guidelines remain inconclusive due to scarcity of data regarding the optimal systemic treatment for metastatic gastroenteropancreatic (GEP) neuroendocrine tumours (NET) grade 3 and aggressive GEP-NET grade 2. Similarly, for metastatic pulmonary typical (TC) and atypical carcinoids (AC), the indication for chemotherapy is unclear. Recent evidence highlights a promising role for CAPTEM, combining temozolomide (TEM) with capecitabine (CAP), showing encouraging antitumoural activity and safety profiles for these indications.

Conference:

Presenting Author: Chhajlani S

Authors: Chhajlani S, Lambrechts C, Islam O, de Weerdt C, Verbruggen L,

Keywords: capecitabine, temozolomide, CAPTEM, GEP-NET, pulmonary NEN, safety, efficacy, systematic review,

#4622 Elucidating the role of high mobility group box 3 (Hmgb3) during progression and response to radiation therapy in pancreatic neuroendocrine tumours

Introduction: We have recently demonstrated that HMGB3 is upregulated during the pancreatic neuroendocrine tumours (PanNETs) transition via dedifferentiation from a relatively benign molecular subtype to an aggressive and highly metastatic molecular subtype. HMGB3 expression has recently been linked to resistance to therapy, metastasis, and poor prognosis in patients with various solid cancers.

Conference:

Presenting Author: Kulathunga N

Authors: Kulathunga N, Wang Z, Qureshi A, Lok B, Tyryshkin K,

Keywords: pancreatic neuroendocrine tumour, HMGB3, tumour progression,

#4618 The exceptionally rare phenomenon of well-differentiated colon neuroendocrine tumours

Introduction: Colonic neuroendocrine tumours (NETs), excluding rectal NETs, are often described as relatively common and aggressive, with inferior median survival compared to other gastrointestinal (GI) primary sites. However, epidemiological databases may conflate well-differentiated NETs with poorly differentiated NECs, leading to unclear data on prevalence, clinical behaviour, and prognosis of well-differentiated colonic NETs.

Conference:

Presenting Author: Al-Toubah T

Authors: Al-Toubah T, Strosberg J,

Keywords: colon, neuroendocrine tumour, caecum, sigmoid, neuroendocrine neoplasm,