Peptide receptor radionuclide therapy of differentiated thyroid cancer: efficacy and toxicity.

In rare cases of differentiated thyroid carcinoma (DTC), radioiodine treatment is no longer effective due to cell dedifferentiation. Targeting somatostatin receptors in DTC cells by radiolabelled somatostatin analogues could provide an alternative therapy option. The aim of this study was to evaluate safety and efficacy of peptide receptor radionuclide therapy (PRRT) in patients with advanced, non-iodine avid DTC. Eleven patients aged 47-81 years (median: 65 years) with a history of several courses of radioiodine therapy, increasing thyroglobulin (Tg) and negative whole body scan, were qualified to the study. After confirming receptor expression by somatostatin receptor scintigraphy, PRRT with yttrium-90 labelled analogue was initiated. Fractionated treatment protocol was used with four doses of (90)Y-DOTA-TOC in 12-week intervals. Activity of each dose was 3.7 GBq (100 mCi). Of 11 patients, 5 died before receiving the fourth course of PRRT. In the remaining six patients, morphological response, evaluated 3 months after the last course using RECIST criteria showed partial remission (PR) in one patient, stable disease (SD) in two patients and progressive disease (PD) in three patients. Biochemical response based on Tg measurements before and after PRRT showed PR in one patient, SD in four patients and PD in one patient. Median survival was 21 months from the first course of PRRT. Only minor and transient hematological toxicity was observed in some patients. We conclude that PRRT is generally well-tolerated and may be a valuable option for some patients with radioiodine-refractory DTC.

Struma ovarii maligna.

INTRODUCTION: Malignant struma ovarii is a rare ovarian neoplasm composed predominantly of mature thyroid tissue. CASE REPORT: A right ovarian tumor was discovered at ultrasound examination in a 20-year-old woman. Complete right ovariectomy was done - histopathological examination revealed papillary thyroid carcinoma arising in struma ovarii (malignant struma ovarii). Patient underwent subsequent total thyroidectomy - the thyroid was found to be without any pathological lesions. After operations the patient received ablative radioiodine treatment (200 mCi 131I). An 131I posttherapeutic whole-body radioiodine scintigraphy was performed and showed uptake in bone metastases. L-thyroxine TSH suppresive doses followed radioiodine ablation and thyroglobulin level is monitored. Next doses of radioiodine has been scheduled. DISCUSSION: Authors suggest that the management of malignant struma ovarii should be the same as differentiated thyroid cancer, so after surgical excision of ovarian neoplasm, we recommend thyroidectomy, radiotherapy with 131I and levothyroxine suppressive therapy. Long-term follow-up for the detection of metastases or tumor recurrence by serial serum thyroglobulin measurements and 131I scan may be required in patients with this rare tumor.

Combined octreotide and peptide receptor radionuclide therapy ((90)Y-DOTA-TATE) in case of malignant insulinoma.

BACKGROUND: Insulinomas are the most common functioning neuroendocrine tumours of the pancreas. Hypoglycemia due to excessive production of insulin is a main feature of this disease. Usually these neoplasms are benign and single with surgical excision as a treatment of choice. About 10% are malignant with tendency to form metastases especially to the liver then therapy requires various medical technics. CASE REPORT: 43 years old female with reccurent syncopies in course of hypoglycemia was admitted to the hospital to be diagnosed. Having suspected pathology within the pancreas the abdominal MRI was performed. It showed presence of numerous metastatic changes in the liver with no any other deviations in the abdomen including pancreas. Subsequent 18FDG PET-CT revealed metastases to the regional lymph nodes and the liver and suggested the presence of a primary lesion in the tail of the pancreas which was confirmed in EUS. Surgical excision of the tail of the pancreas was done. Pathological result: pancreatic neuroendocrine well differetiated cancer. Due to the recurrence of hypoglycemia patient was admitted to Department of Endocrinology where somatostatin analogue scintigraphy showed the presence of tracer accumulation foci in the liver. Combined long-acting somatostatin analogue (octreotide) and peptide radionuclide receptor ((90)Y-DOTA-TATE) therapy were introduced. Stable blood glucose levels with no tendency to hypoglycemia and partial regression (PR) of liver lesions according to RECIST citeria were observed in course of the treatment.

Lack of TSH stimulation in patients with differentiated thyroid cancer - possible causes.

Differentiated thyroid cancer is one of the most common endocrine cancers. Typical standard treatment includes total thyroidectomy with partial lymphadenectomy, then depending on the indications, treatment with iodine isotope 131-I. A prerequisite to conduct the therapy is to obtain endogenic thyroid-stimulating hormone (TSH) stimulation (TSH > 30 µU/ml). We describe two patients with differentiated thyroid carcinoma in whom no rise in serum TSH was observed after withdrawal of thyroxine. In one patient TSH deficiency was due to partial hypopituitarism secondary to a tumor of the pituitary gland. In the second patient the TSH level was suppressed by metabolically active thyroid tissue within bilateral ovarian teratomas. The problems with TSH growth after withdrawal of thyroxine requires additional studies to identify the cause. Above two possible reasons for the lack of TSH stimulation after withdrawal of thyroxine were presented. In the case of non-TSH stimulation due to hypopituitarism both control tests and isotope treatment should be carried out using stimulation by recombinant human TSH (rhTSH).