Boen L.R. Kam

Peptide-receptor radionuclide therapy for endocrine tumors

Peptide-receptor radionuclide therapy (PRRT) with radiolabeled somatostatin analogs is a promising option for the treatment of somatostatin-receptor-positive endocrine tumors. Treatment with somatostatin analogs labeled with 111In, 90Y or 177Lu can result in symptomatic improvement, although tumor remission is seldom achieved with 111In-labeled analogs. In this Review, the findings of several studies on the use of PRRT for endocrine tumors are evaluated. Large variation in the antitumor effects of 90Y-octreotide was reported between studies: an objective response (≥50% tumor regression) was achieved in 9–33% of patients. After treatment with 177Lu-octreotate, an objective response was achieved in 29% of patients and a minor response (25–50% tumor regression) was achieved in 16% of patients; stable disease was present in 35% of patients. Treatment with 177Lu-octreotate resulted in a survival benefit of several years and markedly improved quality of life. Serious, delayed adverse effects were rare after PRRT. Although randomized, clinical trials have not yet been performed, data on the use of PRRT compare favorably with those from other treatment approaches, such as chemotherapy. If these results can be replicated in large, controlled trials, PRRT might become the preferred option in patients with metastatic or inoperable gastroenteropancreatic neuroendocrine tumors.

Salvage Therapy with 177Lu-Octreotate in Patients with Bronchial and Gastroenteropancreatic Neuroendocrine Tumors

Regular therapy with the radiolabeled somatostatin analog 177Lu-octreotate (22.2–29.6 GBq) in patients with gastroenteropancreatic or bronchial neuroendocrine tumors results in tumor remission in 46% of patients, including minor response. We present the effects of additional therapy with 177Lu-octreotate in patients in whom progressive disease developed after an initial benefit from regular therapy. Methods: Thirty-three patients with progressive disease after an initial radiologic or clinical response were treated with additional cycles of 177Lu-octreotate. The intended cumulative dose of additional therapy was 14.8 GBq in 2 cycles. Responses were evaluated using Southwest Oncology Group criteria, including minor response (tumor size reduction of ≥25% and <50%). Results: Median time to progression (TTP) after regular therapy was 27 mo. In 4 patients, the intended cumulative dose was not achieved (2 had progressive disease, 2 had long-lasting thrombocytopenia). Hematologic toxicity grade 3 was observed in 4 patients, and grade 4, in 1. The median follow-up time was 16 mo (range, 1–40 mo). No kidney failure or myelodysplastic syndrome was observed. Renewed tumor regression was observed in 8 patients (2 partial remission, 6 minor response), and 8 patients had stable disease. Median TTP was 17 mo. Treatment outcome was less favorable in patients with a short TTP after regular cycles. Treatment effects in patients with pancreatic neuroendocrine tumors were similar to those in patients with other gastroenteropancreatic neuroendocrine tumors. Conclusion: Most patients tolerated additional cycles with 177Lu-octreotate well. None developed serious delayed adverse events. Additional cycles with 177Lu-octreotate can have antitumor effects, but effects were less than for the regular cycles. This may be because of a worse clinical condition, more extensive tumor burden, or changed tumor characteristics. We conclude that this salvage therapy can be effective and is safe.

Hormonal crises following receptor radionuclide therapy with the radiolabeled somatostatin analogue [177Lu-DOTA0,Tyr3]octreotate

IntroductionReceptor radionuclide therapy is a promising treatment modality for patients with neuroendocrine tumors for whom alternative treatments are limited. The aim of this study was to investigate the incidence of hormonal crises after therapy with the radiolabeled somatostatin analogue [177Lu-DOTA0,Tyr3]octreotate (177Lu-octreotate).Materials and methodsAll 177Lu-octreotate treatments between January 2000 and January 2007 were investigated. Four hundred seventy-six patients with gastroenteropancreatic neuroendocrine tumors and three patients with metastatic pheochromocytoma were included for analysis.ResultsFour hundred seventy-nine patients received a total of 1,693 administrations of 177Lu-octreotate. Six of 479 patients (1%) developed severe symptoms because of massive release of bioactive substances after the first cycle of 177Lu-octreotate. One patient had a metastatic hormone-producing small intestinal carcinoid; two patients had metastatic, hormone-producing bronchial carcinoids; two patients had vasoactive intestinal polypeptide-producing pancreatic endocrine tumors (VIPomas); and one patient had a metastatic pheochromocytoma. With adequate treatment, all patients eventually recovered.ConclusionHormonal crises after 177Lu-octreotate therapy occur in 1% of patients. Generally, 177Lu-octreotate therapy is well tolerated.

Treatment of Gastroenteropancreatic Neuroendocrine Tumors with Peptide Receptor Radionuclide Therapy

The primary treatment of gastroenteropancreatic neuroendocrine tumors (GEPNETs) is surgery with curative intent or debulking of the tumor mass. In case of metastatic disease, cytoreductive options are limited. A relatively new therapeutic modality, peptide receptor radionuclide therapy (PRRT) with radiolabeled somatostatin analogs, is currently available in a number of mostly European centers. Complete and partial responses obtained after treatment with [90Y-DOTA⁰,Tyr3]octreotide are in the same range as after treatment with [177Lu-DOTA⁰,Tyr3]octreotate (i.e. 10–30%). However, significant nephrotoxicity has been observed after treatment with [90Y-DOTA⁰,Tyr3]octreotide. Options to improve PRRT may include combinations of radioactive labeled somatostatin analogs, intra-arterial administration, and the use of radiosensitizing drugs combined with PRRT. Other therapeutic applications of PRRT may include additional therapy cycles in patients with progressive disease after benefit from initial therapy, PRRT in adjuvant or neoadjuvant setting, or PRRT combined with new targeted therapies, such as sunitinib or everolimus. Randomized clinical trials comparing PRRT with other treatment modalities, or comparing various radioactive labeled somatostatin analogs should be undertaken to determine the best treatment options and treatment sequelae for patients with GEPNETs.

Peptide receptor radionuclide therapy (PRRT) for GEP-NETs

Peptide receptor radionuclide therapy (PRRT) with radiolabelled somatostatin analogues plays an increasing role in the treatment of patients with inoperable or metastasised gatroenteropancreatic neuroendocrine tumours (GEP-NETs). (90)Y-DOTATOC and (177)Lu-DOTATATE are the most used radiopeptides for PRRT with comparable tumour response rates (about 15-35%). The side effects of this therapy are few and mild. However, amino acids should be used for kidney protection, especially during infusion of (90)Y-DOTATOC. Options to improve PRRT may include combinations of radioactive labelled somatostatin analogues and the use of radiosensitising drugs combined with PRRT. Other therapeutic applications of PRRT may include intra-arterial administration, neo-adjuvant treatment and additional PRRT cycles in patients with progressive disease, who have benefited from initial therapy. Considering the mild side-effects, PRRT may well become the first-line therapy in patients with metastasised or inoperable GEP-NETs if more widespread use of PRRT can be accomplished.

Long-Term Efficacy, Survival, and Safety of [177Lu-DOTA0,Tyr3]octreotate in Patients with Gastroenteropancreatic and Bronchial Neuroendocrine Tumors

Purpose: Bronchial and gastroenteropancreatic neuroendocrine tumors (NET) are slow-growing tumors, which frequently express somatostatin receptors on their cell membranes. These receptors are targets for therapy with Lutetium-177–labeled somatostatin analogues. We have treated over 1,200 patients with peptide receptor radionuclide therapy (PRRT) with [177Lu-DOTA0,Tyr3]octreotate (177Lu-DOTATATE) since the year 2000 and present the results on efficacy, survival, and toxicity of this therapy. Experimental Design: For safety analysis, 610 patients treated with a cumulative dose of at least 100 mCi (3.7 GBq) 177Lu-DOTATATE were included. A subgroup of 443 Dutch patients who were treated with a cumulative dose of at least 600 mCi (22.2 GBq) 177Lu-DOTATATE before 2013 was further analyzed for efficacy and survival. Results: The objective response rate of the total group of patients was 39%. Stable disease was reached in 43% of patients. Progression-free survival (PFS) and overall survival (OS) for all NET patients were 29 months [95% confidence interval (CI), 26–33 months] and 63 months (95% CI, 55–72 months). Long-term toxicity included acute leukemia in four patients (0.7%) and myelodysplastic syndrome in nine patients (1.5%). No therapy-related long-term renal or hepatic failure occurred. Conclusions: PRRT with 177Lu-DOTATATE is a favorable therapeutic option in patients with metastatic bronchial and gastroenteropancreatic NETs that express somatostatin receptors. PRRT with 177Lu-DOTATATE is safe with few side-effects and shows good response rates with PFS of 29 months and OS of 63 months. Clin Cancer Res; 23(16); 4617–24. ©2017 AACR.

Malignant Struma Ovarii: Good Response after Thyroidectomy and 131I Ablation Therapy

Background Malignant struma ovarii is a rare malignant germ cell tumor of the ovary. Due to the rarity of this disease, treatment has not been uniform throughout the published literature. Cases We present three cases of malignant struma ovarii. Following primary surgery, all were subsequently treated with thyroidectomy and 131I ablation therapy, two patients as first line management, one following the occurrence of metastatic disease. Conclusion Histological diagnosis of malignant struma ovarii is similar to that of well differentiated thyroid carcinoma (WDTC). In line with the latest advice on treatment of WDTC, we believe that the best option for patients with malignant struma ovarii is surgical removal of the ovarian lesion followed by total thyroidectomy which allows the exclusion of primary thyroid carcinoma, and in addition, allows radioiodine (131I) ablation therapy for (micro) metastasis. After thyroidectomy, thyroglobulin can be used as a tumor marker for follow-up. Moreover, nuclear medicine imaging using radioiodine (123I) can be performed to demonstrate metastatic carcinoma. A multidisciplinary approach is essential.

Thyroid hormone and its metabolites in relation to quality of life in patients treated for differentiated thyroid cancer

Levothyroxine (LT4) is the standard of care in patients with hypothyroidism. Despite this replacement therapy, quality of life (QoL) remains impaired in a substantial amount of patients. The reasons for this are still a matter of debate. Suggested causes include lack of endogenous T3 secretion by the thyroid, changes in other thyroid hormone metabolites and interference by autoimmune processes.

[111In-DTPA]octreotide Tumor Uptake in GEPNET Liver Metastases After Intra-Arterial Administration: An Overview of Preclinical and Clinical Observations and Implications for Tumor Radiation Dose After Peptide Radionuclide Therapy

AIMS With the aim to improve peptide receptor radionuclide therapy effects in patients with gastroenteropancreatic neuroendocrine tumor (GEPNET) liver metastases we explored the effect of intra-arterial (IA) administration of [(111)In-DTPA]octreotide ((111)In-DTPAOC) on tumor uptake in an animal model and in a patient study. METHODS Preclinical study: After administering (111)In-DTPAOC intra-venously (IV) or IA, biodistribution studies were performed in rats with a hepatic somatostatin receptor subtype 2 (sst2)-positive tumor. Clinical study: 3 patients with neuroendocrine liver metastases were injected twice with (111)In-DTPAOC. The first injection was given IV, and 2 weeks later, the second was injected IA (hepatic artery). Planar images of the abdomen were made up to 72 hours after injection. Blood samples were taken and urine was collected. Pharmacokinetic modeling was performed on the IV and IA data of the same patient. Based on this model, additional (177)Lu dosimetry calculations for IV and IA administrations were performed. RESULTS The preclinical study showed a two-fold higher (111)In-DTPAOC tumor uptake after IA administration than after IV injection. Patient data showed a large variability in radioactivity increment in liver metastases after IA administration compared with IV administration. Renal radioactivity was not significantly lower after IA administration; (177)Lu dosimetry simulations in 1 patient using a maximum kidney radiation dose of 23 Gy showed IA administration resulted in a mean increase in tumor radiation dose of 2.9-fold. CONCLUSION Preclinical and clinical data both indicate that IA administration of radiolabeled somatostatin analogs via the hepatic artery can significantly increase radionuclide uptake in GEPNET, sst2-positive, liver metastases up to 72 hours postinjection, although the effect of IA administration can differ between patients.

Thyroid State Regulates Gene Expression in Human Whole Blood

Context Despite the well-recognized clinical features resulting from insufficient or excessive thyroid hormone (TH) levels in humans, it is largely unknown which genes are regulated by TH in human tissues. Objective To study the effect of TH on human gene expression profiles in whole blood, mainly consisting of T3 receptor (TR) α-expressing cells. Methods We performed next-generation RNA sequencing on whole blood samples from eight athyroid patients (four females) on and after 4 weeks off levothyroxine replacement. Gene expression changes were analyzed through paired differential expression analysis and confirmed in a validation cohort. Weighted gene coexpression network analysis (WGCNA) was applied to identify thyroid state-related networks. Results We detected 486 differentially expressed genes (fold-change >1.5; multiple testing corrected P value < 0.05), of which 76% were positively and 24% were negatively regulated. Gene ontology (GO) enrichment analysis revealed that three biological processes were significantly overrepresented, of which the process translational elongation showed the highest fold enrichment (7.3-fold, P = 1.8 × 10-6). WGCNA analysis independently identified various gene clusters that correlated with thyroid state. Further GO analysis suggested that thyroid state affects platelet function. Conclusions Changes in thyroid state regulate numerous genes in human whole blood, predominantly TRα-expressing leukocytes. In addition, TH may regulate gene transcripts in platelets.