[Evaluation of radionuclide therapy for the residue after surgery in papillary thyroid carcinoma].

OBJECTIVE: To assess the efficacy of radioactive iodine (RAI) for the treatment of residual papillary thyroid cancer (PTC) after surgery. METHODS: A total of 20 patients diagnosed with PTC and underwent 2-6 courses of RAI therapy for residual PTC after surgery in other hospitals were included our study. Of these, 13 were in stage I, 3 in stage III and 4 in stage IV. All the cases were operated again due to the presence of suspicious residual tumors indicated by CT. Excision of thyroid tumor residue was performed in 5 cases and neck dissection in 15 cases (20 sides). The suspicious thyroid or neck residual tumors were examined pathologically after surgery. Response Evaluation Criteria in Solid Tumors (RECIST) was used to evaluate the efficacy of surgery treatment on residual tumor. T-test was used to identify variables associated to RAI and to calculate the propensity score to receive RAI after surgery. RESULTS: The patients aged 22-58 years, with a median age of 40 years. The mean times of surgeries received before RAI was 1.5 and the mean dose of applied RAI was 318 mCi (210-660 mCi). No significant difference in tumor size between pre-RAI and post-RAI was found (t = 1.177, P > 0.05). With postoperative pathological examination, the suspicious thyroid or neck residual tumors were confirmed as PTC or the cervical lymph metastasis of PTC. CONCLUSIONS: For the residue or metastasis of PTC after operation, reoperation should be a priority, while RAI therapy has no obvious therapeutic effect and it should be limited to selected cases such as those with distant metastasis or unsuitable for operation but with iodine uptake function, or taken as an adjuvant treatment after radical resection of cervical lesions.

[CME: Radioactive iodine therapy in thyroid cancer]. / CME: Radiojodbehandlung des Schilddrüsenkarzinoms.

Differentiated thyroid carcinomas represent about 90% of all thyroid tumors and are divided in papillary and follicular carcinomas. Their prognosis is good, however, recurrences are not rare. Their ability to accumulate iodine is used for the radioactive iodine treatment. The aim of the postoperative radioactive iodine ablation therapy is the complete elimination of remnant thyroid cells and sensitive staging (Fig. 1). The recurrence rate decreases after a complete thyroid ablation. Furthermore, thyroglobulin can be used as a sensitive tumor marker. Radioactive iodine treatment by itself describes the therapy of metastases. An exception is the papillary microcarcinoma, which in general is treated by a lobectomy alone.

Radioiodine-remnant ablation in low-risk differentiated thyroid cancer: pros.

Differentiated thyroid carcinomas are typically treated with total thyroidectomy as initial therapy. Subsequent radioactive iodine (RAI) ablation destroys post-surgical thyroid remnants, can additionally provide adjuvant therapy of residual and metastatic thyroid cancers, and enhances the sensitivity and specificity of further diagnostic studies. There is current controversy regarding whether a large number of patients, broadly considered to have "low-risk" disease, should be provided RAI ablation. This is consequent to over-reliance on short-term studies, under-appreciation of the value of RAI remnant ablation, and inflation of the side effects of RAI therapy. A balanced assessment of all of these issues provides justification to utilize post-surgical radioiodine ablation, even in cases that are considered low risk on the basis of surgical findings.

Recombinant human thyroid stimulating hormone-assisted radioactive iodine remnant ablation in thyroid cancer patients at intermediate to high risk of recurrence.

BACKGROUND: Multiple studies have demonstrated successful radioactive iodine remnant ablation (RRA) following preparation with recombinant human thyroid stimulating hormone (rhTSH). Short-term studies in relatively low-risk patients have also suggested that rhTSH-stimulated RRA can have an effective adjuvant therapy function in destroying residual microscopic thyroid cancer cells. However, very few of these studies have included a significant number of intermediate or high-risk patients. The goal of this study was to examine clinical outcomes after rhTSH stimulated RRA in a larger cohort of thyroid cancer patients at higher risk of recurrence and disease-specific mortality. METHODS: A retrospective chart review identified 586 thyroid cancer patients prepared for RRA with either a thyroid hormone withdrawal (THW) (n=321) or rhTSH preparation (n=265). The primary end points included both the best response to initial therapy and the clinical status at final follow-up. Clinical outcomes were compared within each of the American Thyroid Association (ATA) risk groups (low, intermediate, and high) and American Joint Committee on Cancer (AJCC) stages (I-IV) based on the method of preparation for RRA (THW vs. rhTSH). RESULTS: Preparation with rhTSH was more likely to be associated with an excellent response to therapy (39.4% for rhTSH vs. 30% for TWH, p=0.03) and fewer additional therapies (29% for rhTSH vs. 37% for TWH, p=0.05) than THW. However, after a median follow-up period of 9 years, the final clinical outcomes were not significantly different with respect to recurrence rates (1.5% for rhTSH vs. 1.2% for TWH), likelihood of having persistent disease (46% for rhTSH vs. 48% for THW) or likelihood of having no evidence of disease (53% for rhTSH vs. 52% for TWH). Furthermore, clinical outcomes were similar between rhTSH and THW preparation across all ATA risk groups and AJCC stages. CONCLUSIONS: rhTSH preparation for RRA is associated with a small, but statistically significant improvement in an initial response to therapy and similar final clinical outcomes across a wide range of risk of recurrence and risk of disease-specific mortality. These data suggest that rhTSH preparation for RRA can be effectively used in intermediate and high-risk patients without known distant metastases.

Prognostic impact of postoperative, pre-irradiation (18)F-fluoroethyl-l-tyrosine uptake in glioblastoma patients treated with radiochemotherapy.

BACKGROUND AND PURPOSE: Resection is considered as essential for the efficacy of modern adjuvant treatment of glioblastoma multiforme (GBM). Previous studies have indicated that amino acid PET is more specific than contrast enhancement on MRI for detecting residual tumor tissue after surgery. In a prospective study we investigated the prognostic impact of postoperative tumor volume and tumor/brain ratios (TBR) in PET using O-(2-[(18)F]fluoroethyl)-l-tyrosine (FET) in comparison with MRI. MATERIALS AND METHODS: Forty-four patients with GBM were investigated by FET PET and MRI after surgery. Tumor volume in FET PET with a tumor/brain ratio (TBR)>1.6 and a TBR>2, mean and maximum TBR and gadolinium contrast-enhancement on MRI (Gd-volume) were determined. Thereafter patients received a fractionated radiotherapy with concomitant temozolomide (RCX). The median follow-up was 15.4 (3-35) months. The prognostic value of postoperative residual tumor volume in FET PET, TBR(mean,) TBR(max) and Gd-volume was evaluated using Kaplan-Maier estimates for disease-free survival (DFS) and overall survival (OS). RESULTS: Postoperative tumor volume in FET PET had a significant independent influence on OS and DFS (OS 20.0 vs. 6.9 months; DFS 9.6 vs. 5.1 months, p<0.001; cut-off 25 ml). Similar results were observed when a TBR ≥ 2 (cut-off 10 ml) was used to define the tumor volume in (18)F-FET PET. The TBR(mean) and TBR(max) of FET uptake had a significant influence on DFS (p<0.05). Gd-volume in MRI had significant effect on OS and DFS in the univariate analysis. No independent significant influence in OS or DFS could be observed for Gd-volume in MRI. CONCLUSIONS: Our data indicate that the tumor volume in FET PET after surgery of GBM has a strong prognostic impact for these patients. FET PET appears to be helpful to determine the residual tumor volume after surgery of GBM and may serve as a valuable tool for optimal planning of radiation treatment.

The continuous debate in literature about the usage of iodine-131 dosing for the ablation of thyroid remnants and metastases.

UNLABELLED: Radioiodine plays an important role in the treatment of thyroid cancer. It is used for thyroid remnant ablation as well as for treatment of metastatic disease. Despite the fact that it is used all over the world for these indications, the exact administered dose is still a subject for DISCUSSION: Two methods are widely available: the so-called fixed empiric method and the dosimetric one. This review will highlight the aspects of radioiodine in treatment of thyroid cancer and discuss the advantages and disadvantages of the several methods for the calculation of the administered dose.

Patterns of relapse following radiotherapy for differentiated thyroid cancer: implication for target volume delineation.

INTRODUCTION: Post-operative residual disease in differentiated thyroid cancer is an indication for external beam radiotherapy (EBRT) especially if there is poor radioiodine uptake by the residual disease. There are no standardized guidelines or consensus in target delineation for radiotherapy in thyroid cancer. AIMS: To determine the pattern of recurrence in patients with well differentiated thyroid cancer who received adjuvant or definitive radiotherapy as well as radioiodine ablation following surgery or biopsy with a view to better defining future target volume delineation for radiotherapy. MATERIALS AND METHODS: Forty-nine patients with differentiated thyroid cancer received radical external beam radiotherapy and radioiodine ablation (3.5GBq) following thyroidectomy or biopsy between 1990 and 2000. Nineteen patients had macroscopic residual (11) or inoperable disease (8), whilst 30 patients had clear (5) or microscopic positive resection margin (24), and 1 patient the resection margin status was unknown. All the patients were deemed high risk for local recurrence or progressive disease. The thyroid bed and regional nodes were irradiated using two radiotherapy techniques: (1) non co-planar lateral fields (NCLF) in coronal plane using 6MV photons to a dose of 45-50Gy in 16 fractions over 22 days and (2) anterior-posterior parallel pair of 6MV photons to a dose of 40-42.5Gy in 16 fractions over 22 days. There was no attempt to irradiate the lymph nodes in that part of the anterior and posterior mediastinum extending from the brachiocephalic veins to the carina. RESULTS: The median follow-up was 5.4 years (range 0.9-12.4 years). The actuarial 5-year cause-specific survival and local control for the whole group was 75.7% and 81.4%, respectively. Of the 4 patients with mediastinal recurrence, all had neck recurrences and two had distant metastases. All the medisastinal recurrences occurred in superior mediastinum (level VII) and all were treated with NCLF in coronal plane radiotherapy technique. Furthermore, mediastinal recurrences did not occur in isolation. The 5-years loco-regional control rate was 89.1% for those with clear or microscopic positive margins and 69.2% for those with macroscopic residual or inoperable disease. Five-year cause specific survival was 58.3% for patients with macroscopic residual or inoperable disease and 91.4% for those with clear or microscopic positive margins. CONCLUSION: The status of postoperative margin relating to bulk of disease influences local control and cause specific survival. Surgical resection in locally advanced thyroid cancer should be performed by an experienced surgeon to achieve macroscopic clearance where possible. The majority of recurrences were loco-regional. The few superior mediastinal recurrences did not occur in isolation. All the mediastinal recurrences occurred in the superior mediastinum (level VII). We recommend the target volume should encompass the thyroid bed and regional neck nodes and the superior mediastinum level VII excluding the lymph nodes on both sides of the trachea within the anterior and posterior mediastinum extending from the brachiocephalic veins to the carina (compartment 4). Thus, this should facilitate dose escalation to improve loco-regional control and avoiding radiation induced mediastinal toxicity.

Sentinel lymph node biopsy performed after neoadjuvant chemotherapy is accurate in patients with documented node-positive breast cancer at presentation.

BACKGROUND: The optimal strategy for incorporating lymphatic mapping and sentinel lymph node biopsy into the management of breast cancer patients receiving neoadjuvant chemotherapy remains controversial. Previous studies of sentinel node biopsy performed following neoadjuvant chemotherapy have largely reported on patients whose prechemotherapy, pathologic axillary nodal status was unknown. We report findings using a novel comprehensive approach to axillary management of node-positive-patients receiving neoadjuvant chemotherapy. METHODS: We evaluated 54 consecutive breast cancer patients with biopsy-proven axillary nodal metastases at the time of diagnosis that underwent lymphatic mapping with nodal biopsy as well as concomitant axillary lymph node dissection after receiving neoadjuvant chemotherapy. All cases were treated at a single comprehensive cancer center between 2001 and 2005. RESULTS: The sentinel node identification rate after delivery of neoadjuvant chemotherapy was 98%. Thirty-six patients (66%) had residual axillary metastases (including eight patients that had undergone resection of metastatic sentinel nodes at the time of diagnosis), and in 12 cases (31%) the residual metastatic disease was limited to the sentinel lymph node. The final, post-neoadjuvant chemotherapy sentinel node was falsely negative in three cases (8.6%). The negative final sentinel node accurately identified patients with no residual axillary disease in 17 cases (32%). CONCLUSIONS: Sentinel lymph node biopsy performed after the delivery of neoadjuvant chemotherapy in patients with documented nodal disease at presentation accurately identified cases that may have been downstaged to node-negative status and can spare this subset of patients (32%) from experiencing the morbidity of an axillary dissection.

18F-choline and/or 11C-acetate positron emission tomography: detection of residual or progressive subclinical disease at very low prostate-specific antigen values (<1 ng/mL) after radical prostatectomy.

OBJECTIVES: To assess the value of positron emission tomography (PET)/computed tomography (CT) with either (18)F-choline and/or (11)C-acetate, of residual or recurrent tumour after radical prostatectomy (RP) in patients with a prostate-specific antigen (PSA) level of <1 ng/mL and referred for adjuvant or salvage radiotherapy. PATIENTS AND METHODS: In all, 22 PET/CT studies were performed, 11 with (18)F-choline (group A) and 11 with (11)C-acetate (group B), in 20 consecutive patients (two undergoing PET/CT scans with both tracers). The median (range) PSA level before PET/CT was 0.33 (0.08-0.76) ng/mL. Endorectal-coil magnetic resonance imaging (MRI) was used in 18 patients. Nineteen patients were eligible for evaluation of biochemical response after salvage radiotherapy. RESULTS: There was abnormal local tracer uptake in five and six patients in group A and B, respectively. Except for a single positive obturator lymph node, there was no other site of metastasis. In the two patients evaluated with both tracers there was no pathological uptake. Endorectal MRI was locally positive in 15 of 18 patients; 12 of 19 responded with a marked decrease in PSA level (half or more from baseline) 6 months after salvage radiotherapy. CONCLUSIONS: Although (18)F-choline and (11)C-acetate PET/CT studies succeeded in detecting local residual or recurrent disease in about half the patients with PSA levels of <1 ng/mL after RP, these studies cannot yet be recommended as a standard diagnostic tool for early relapse or suspicion of subclinical minimally persistent disease after surgery. Endorectal MRI might be more helpful, especially in patients with a low likelihood of distant metastases. Nevertheless, further research with (18)F-choline and/or (11)C-acetate PET with optimal spatial resolution might be needed for patients with a high risk of distant relapse after RP even at low PSA values.

Pre-ablative diagnostic whole-body scan following total thyroidectomy for well-differentiated thyroid cancer: is it necessary?

OBJECTIVE: This study reviewed the incidence of positive pre-ablative diagnostic scan after total thyroidectomy and the efficacy of the current ablative dose. The predictive factors for outcome using a standard ablative dose and postoperative complications of total thyroidectomy were also examined. METHODS: This was a retrospective review of patients referred for radioiodine ablation after total thyroidectomy between September 1997 and September 2001. RESULTS: Forty patients were included in this study, of whom 95% had a positive scan after total thyroidectomy. Of the 30 patients who underwent standard 80-mCi radioiodine ablation, 21 (70%) had successful single ablation while the remaining nine patients needed a higher ablative dose. There were no significant differences between patients who had successful ablation with the standard dose and those who did not in terms of tumour size, patient age, lymph node status and extra-thyroidal extension. Fifteen percent suffered from permanent hypoparathyroidism requiring calcium supplementation. Three patients had documented recurrent laryngeal nerve paralysis. CONCLUSION: Bypassing the pre-ablative diagnostic scan is feasible. The present ablation dose of 80 mCi of radioiodine is effective. The relatively high postoperative morbidity after difficult total thyroidectomy suggests less aggressive excision and postoperative radioiodine ablation of the remnant tissue.

Thermoradiotherapy of the chest wall in locally advanced or recurrent breast cancer with marginal resection.

BACKGROUND AND PURPOSE: Evaluation of the efficacy of combined hyperthermia and radiotherapy (TRT) in high-risk breast cancer patients with microscopic involved margins (R1) after mastectomy or with resected locoregional, early recurrence with close margins or R1-resection. Main endpoint was local tumour control (LC); secondary endpoints were overall survival (OS), disease free survival (DFS) and acute toxicity. MATERIAL AND METHODS: Between 1997-2001, 50 patients were treated with TRT. Thirteen patients (group 1) received a post-operative TRT in a high-risk situation (free margin <1 cm or R1, N+), 37 patients (group 2) received TRT after close/R1 resection of a locoregional recurrence. Thirteen out of 37 patients in group 2 already had had two-to-seven recurrences prior to TRT. Median radiation dose was 60 Gy (range: 44-66.4 Gy), the additional local hyperthermia (>41 degrees C, 60 min) was given twice a week. Median follow-up for patients at risk was 28 months. All statistical tests were done using Statistica software. RESULTS: Actuarial OS for all patients at 3 years accounted for 89%, DFS for 68% and LC for 80%. Actuarial OS was 90% for group 1 and 89% for group 2, with four patients having died so far. DFS at 3 years was 64% in group 1 and 69% in group 2, actuarial 3 year LC was 75% and 81%, respectively. For patients with recurrent chest wall disease, there was no difference concerning local control between patients who underwent TRT with or without prior radiation. No prognostic factors could be detected due to the small number of patients investigated. The combined modality treatment was well tolerated. Grade IV toxicity, according to the Common Toxicity Criteria, did not occur. CONCLUSION: The results concerning local tumour control and overall survival in these high-risk patients are promising, especially for TRT for the treatment of local recurrences. A longer follow-up is needed to estimate late toxicity.

131I therapeutic efficacy is not influenced by stunning after diagnostic whole-body scanning.

PURPOSE: To determine if stunning can be seen with a 185-MBq (5-mCi) dose of iodine 131 (131I) at diagnostic whole-body scanning and, if stunning is seen, determine if there is any 131I therapeutic efficacy. MATERIALS AND METHODS: A retrospective review of findings involving 166 patients who underwent thyroidectomy for differentiated thyroid carcinoma was performed. Diagnostic 131I scans were compared with postablation scans for evidence of stunning. Stunning was defined when the diagnostic scan showed activity that was subsequently decreased on the postablation scan. The sample population was divided into two groups: group NS, patients with no stunning, and group S, patients with stunning. Patients were considered successfully treated if no functioning thyroid tissue and/or metastases were seen on follow-up diagnostic scans. Fisher exact and Student t tests were used to evaluate the statistical significance of therapy success rates, clinical characteristics, and scanning parameters between the two groups. RESULTS: Group NS included 135 (81.3%) of 166 patients, with 36 (26.7%) of 135 lost to follow-up. Group S included 31 (18.7%) of 166 patients, with eight (26%) of 31 patients lost to follow-up. There was no significant difference (P =.61) in treatment success rates between group NS (87 of 99, 88%) and group S (21 of 23, 91%). The treatment success rates for thyroid remnants were 87% (48 of 55) for group NS and 91% (10 of 11) for group S (P =.63). Treatment success rates for metastases (mostly lymph nodes) were 89% (39 of 44) for group NS and 83% (10 of 12) for group S (P =.55). CONCLUSION: Thyroid stunning can occur with 185 MBq of 131I in diagnostic imaging. However, data did not show any effect of stunning on the efficacy of 131I therapy for differentiated thyroid carcinoma.

Quantitation of GD2 synthase mRNA by real-time reverse transcriptase polymerase chain reaction: clinical utility in evaluating adjuvant therapy in neuroblastoma.

PURPOSE: Minimal residual disease (MRD) is one of the final hurdles to cancer cure. Because therapy (myeloablation, immunotherapy, or differentiation) for MRD is applied at the time of clinical remission, objective surrogate markers are needed to gauge treatment efficacy. PATIENTS AND METHODS: Using quantitative reverse transcriptase polymerase chain reaction (RT-PCR) of GD2 synthase (beta1,4-N-acetylgalactosaminyltransferase, EC 2.4.1.92) mRNA, we evaluated MRD response to anti-GD2 monoclonal antibody 3F8 adjuvant therapy, namely, one cycle of radioimmunotherapy using iodine-131 ((131)I)-3F8 plus one cycle of unlabeled 3F8 in 45 stage 4 neuroblastoma patients (newly diagnosed or without prior relapse) on the N7 protocol at Memorial Sloan-Kettering Cancer Center. The prognostic effect of MRD in their bone marrows before and after this phase of adjuvant therapy on progression-free survival (PFS) and overall survival (OS) was also analyzed. RESULTS: Before 3F8 treatment, 24 of 45 patients were in complete remission (CR), 12 were in very good partial remission (VGPR), and nine were in partial remission (PR), according to criteria from International Neuroblastoma Staging System plus (131)I-3F8 scan; 71% had detectable tumor cells in marrow by real-time RT-PCR. Of the 32 positive patients, 20 became negative after therapy, with a 63% efficacy. When patients were stratified by CR/VGPR versus PR, GD2 synthase positivity was prognostic when detected before 3F8-targeted therapy (PFS, P =.045 and OS, P =.010). Persistent marker positivity was also predictive of PFS (P =.035) and OS (P =.027). Patients who succumbed to the disease had transcript levels four times higher than those who remain alive. CONCLUSION: GD2 synthase mRNA is a useful surrogate marker for evaluating adjuvant treatment efficacy in neuroblastoma with prognostic potential.

[Differentiated thyroid gland carcinoma in a scintigraphically hot thyroid nodule: diagnosis and interdisciplinary therapeutic management]. / Differenziertes Schilddrüsenkarzinom in einem szintigraphisch heissen Schilddrüsenknoten: Diagnostik und interdisziplinäres therapeutisches Vorgehen.

A hyperfunctioning differentiated thyroid carcinoma is a rare occurrence. Nevertheless, this diagnosis must be considered in a scintigraphically hot nodule if there is a clinical or sonographic suggestion of malignancy. The case of a 57-year old patient with hyperthyreosis and a scintigraphically hot thyroid nodule is presented. Further evaluation led to the diagnosis of a differentiated thyroid carcinoma with extensive lymph node and pulmonary metastases (pT2b, pN1b, pM1). The scintigraphically hot nodule corresponded to the primary tumor, whereas scintigraphic detection of the lymph node metastases was only possible postoperatively. Extensive resection of the lymph node metastases was achieved by the intraoperative application of a gamma probe (2nd operation). This allowed sufficient uptake of radioiodine in the pulmonary metastases for their detection and subsequent devitalisation by radioiodine therapy. Complete elimination of all tumour tissue was documented at a control follow-up after six months. Gamma probe-guided surgery may allow for additional removement of non-palpable lymph node metastases. In selected cases this may optimize the surgical results and thereby facilitate the subsequent radioiodine elimination of advanced differentiated thyroid carcinomas.

Radioimmunoguided-intraoperative radiation therapy in colorectal carcinoma: a new technique to precisely define the clinical target volume.

PURPOSE: The clinical target volume (CTV) to be irradiated by intraoperative radiation therapy (IORT) after resection is generally based on the surgeon's estimation of close margins. We have developed a new technique, radioimmunoguided-intraoperative radiation therapy (RIG-IORT), that uses an intraoperative hand-held gamma-detecting probe to define areas of residual microscopic disease containing radiolabeled monoclonal antibodies to tumor associated antigen, to more precisely delineate the CTV for IORT. METHODS AND MATERIALS: Patients were injected i.v. with 2 mCi 125I- radiolabeled CC49 antibody approximately 3 weeks before surgery. They then underwent radioimmunoguided surgery (RIGS) with maximal resection of tumor. A hand-held gamma-detecting probe (Neoprobe 1000) was used intraoperatively to detect and resect areas of high radioactivity, representing tumor. Areas with persistently high probe counts after resection were the areas of occult residual disease, and represented the CTV to be irradiated. The IORT was given with either 6-9 MeV electron beam from a dedicated linear accelerator, or with high-dose-rate brachytherapy from a remote afterloader. If all RIGS-positive tissue had been resected, or if widely disseminated disease remained, the patient was not considered for IORT. RESULT: This technique was used in 31 patients with colorectal adenocarcinoma recurrent into the pelvis (n = 23) or paraortic nodes (n = 8). The CTV for IORT was delineated by increased RIGS count in 13 of 19 patients (68%) with microscopic residual, and in 11 of 12 patients (92%) with gross residual. In the other 7 patients, the tumor area did not accumulate the radiolabeled antibody; therefore, these tumor beds were irradiated based on the surgeon's estimation of close margins. Hence, overall, the RIG-IORT technique was used to define the tumor bed for IORT in 24 of 31 patients (77%). This technical report focuses on the development of the RIG-IORT technique and does not address the outcome results of the treated patients. CONCLUSION: A new technique, RIG-IORT, which uses radiolabeled monoclonal antibodies to precisely determine the CTV for IORT, is described. Whether the use of this technique will lead to improved tumor control will only be known upon the outcome analysis of RIG-IORT-treated patients compared with those obtained using traditional IORT techniques.

[Radioiodine therapy in differentiated thyroid gland carcinoma]. / Radiojodtherapie beim differenzierten Schilddrüsenkarzinom.

The current level of knowledge about radioiodine therapy (RITh) for well-differentiated thyroid carcinoma under consideration of the recent literature is summarised. In RITh for thyroid carcinoma two major fields can be distinguished: the ablation of the thyroid remnant and the therapy of recurrences resp. local and distant metastases. New large American studies indicate, that the prophylactic post operative ablation of the thyroid remnant in primary tumours over 1.5 cm in diameter is linked with a distinct improvement of the long-term prognosis. The RITh is effective also in distant metastases, if applied early, when the tumour volume is still small. The prerequisite is an appropriate follow-up. Surveys about the application of RITh for well-differentiated thyroid carcinoma in Europe and in the USA reveal that uniform treatment recommendations designed to conform interdisciplinary demands are urgently required.

The current status of radioiodinated metaiodobenzylguanidine therapy of neuro-endocrine tumors.

The avidity of many metastatic pheochromocytomas and neuroblastomas for metaiodobenzylguanidine (MIBG) observed at diagnostic scintigraphy has led to attempts to treat these lesions with large doses of MIBG. We and others have achieved therapeutic responses with 131I-MIBG (usually partial) in about a third of malignant pheochromocytomas. A small but important subgroup of advanced, poor prognosis neuroblastomas which have been resistant to all other therapies have also shown responses including occasional long-term survival (> 5 years) and apparent complete responses to 131I-MIBG. Because the physical properties of 131I are suboptimal for the delivery of therapeutic radiation to bone marrow micrometastases, a frequent problem in neuroblastoma, we have performed preliminary studies in poor prognosis Stage III and VI neuroblastoma using 125I-MIBG which has more satisfactory emissions. This has led to prolonged tumor stabilization and survival (> 19 to > 52 months) in 5 of 10 patients. MIBG radiopharmaceutical treatment of neuroendocrine tumor patients must still be considered an experimental but nevertheless promising treatment modality.