SFEBES2021 Oral Communications Endocrine Cancer and Late Effects (6 abstracts)
1University College London Hospitals NHS Foundation Trust, London, United Kingdom; 2Great Ormond Street Hospital NHS Foundation Trust, London, United Kingdom; 3Guys and St. Thomas NHS Foundation Trust, London, United Kingdom; 4University Hospital of Leicester NHS Trust, Leicester, United Kingdom; 5East Suffolk and North Essex NHS Foundation Trust, London, United Kingdom; 6Barts Health NHS Foundation Trust, London, United Kingdom; 7Royal Marsden NHS Foundation Trust, London, United Kingdom
Background: Patients with Multiple Endocrine Neoplasia type 2 (MEN2) without previous family history often present late with advanced Medullary Thyroid Cancer (MTC). Surgery is not always curative but RET tyrosine kinase pathway is a potential target for molecular treatment for progressive MTC.
Methods: Retrospective review of clinical, genetic, biochemical (calcitonin, CEA) and imaging (US, CT/MRI, Gallium Dotate) data of children with MEN2 who developed recurrent and progressive MTC after surgery and were treated with Selpercatinib, a selective RET TK inhibitor. The main parameters were safety, efficacy and objective treatment response.
Results: Six children (3M,3-1 years) presented with palpable lymphadenopathy (5) and elevated calcitonin (median 6560 ng/l,140-46850) and were subsequently diagnosed with MEN2 (4x2B, 2x2A, RET 918,804). Five had metastatic disease on imaging. All had total thyroidectomy with unilateral (2) and bilateral (2) levels 2,3,4,5,6 lymphadenectomy and resections of JV (1), RLN (2), Vagus (1). Post-operative complications included transient (3) and permanent (1) hypoparathyroidism and Horners syndrome (2). Two children had second surgery and one external beam radiotherapy (EBRT) complicated by delayed oesophageal perforation (surgery) and stridor requiring tracheostomy (EBRT). None of the children were cured and all had disease progression evidenced by clinical deterioration, rising calcitonin and CEA (3) and worsening radiology (5). All children received Selpercatinib (92 mg/m2/dose) orally twice daily. The objective clinical, radiological and biochemical response was 100% with complete resolution of all clinical symptoms (third month) and significant decrease of calcitonin (Graph 1) and CEA within 4 weeks. Four had partial radiological response (1-3months). No child had to discontinue Selpercatinib because of a drug toxicity. Median follow up was 13 months (10-20months).
Conclusions: Children with MEN2 and advanced MTC cant be cured by surgery and EBRT alone, but Selpercatinib has shown remarkable therapeutic efficacy with clinical, biochemical and radiological improvement and minimal toxicity.