Lessons on Tumour Response: Imaging during Therapy with (177)Lu-DOTA-octreotate. A Case Report on a Patient with a Large Volume of Poorly Differentiated Neuroendocrine Carcinoma.

Favourable outcomes of peptide receptor radiotherapy (PRRT) of neuroendocrine tumours have been reported during the last years. Still, there are uncertainties on the radionuclides to be used, the treatment planning, and the indication in patients with a high proliferation rate.This case report describes a patient with a high tumour burden of poorly differentiated neuroendocrine carcinoma of unknown primary with a proliferation rate in liver metastases up to 50%, undergoing fractionated treatment with 7 cycles of (177)Lu-DOTA-octreotate (7.4 GBq each) after disease progression on two different chemotherapy regiments. Based on initial staging scintigraphy, somatostatin receptor expression was very high.Longitudinal dosimetry studies during therapy indicated ongoing increases in tumour-to-organ ratios that coincided with an objective response.We conclude that fractionated therapy with (177)Lu-DOTA-octreotate should be considered a treatment option also for those patients with large tumours, high proliferation, and high receptor expression.

Intra- and inter-rater reliability of endonasal activity estimation in granulomatosis with polyangiitis (Wegener´s).

OBJECTIVES: Granulomatosis with polyangiitis (GPA) frequently starts with an affection of the nasal and paranasal mucosa. Localised GPA of the nasal mucosa or persistent disease activity ('grumbling disease') is often encountered even under immunosuppressive therapy. Necessity for reconstructive surgery is common and careful scheduling to prevent failure and minimise revision rates is crucial. Therefore, reliable estimation of GPA activity in the upper airways using a score is mandatory for diagnosis, follow-up and scheduling reconstructive surgery. METHODS: Fifty endoscopic, endonasal images of 45 patients with GPA were used. Twelve (4 German, 8 Mexican) experienced (n=7) and inexperienced (n=5) physicians assessed GPA-activity at two times (T1/T2) in dichotomy and in a grading approach (none, mild, moderate and high activity) using the novel ENT Activity Score (ENTAS). All documents were written in English. RESULTS: Estimation of activity in dichotomy (none vs. mild/moderate/high): Cohen's Kappa (κ) for intra-rater reliability T1/T2 in inexperienced and experienced physicians was κ=0.58 (agreement 85%) and κ=0.72 (agreement 91%). The inter-rater reliability (Fleiss's κ) T1/T2 for inexperienced and experienced physicians was κ=0.62/κ=0.59 and κ=0.50/κ=0.58 respectively. Estimation of activity in grading approach (none, mild, moderate, high): for inexperienced physicians the intra-rater reliability T1/T2 was κ=0.67 (agreement 56%) and the inter-rater reliability at T1/T2 was κ=0.29 (intraclass correlation coefficient, ICC=0.69) and κ=0.27 (ICC=0.59). For experienced physicians the intra-rater reliability T1/T2 was κ=0.80 (agreement 67%) and the inter-rater reliability at T1 and T2 was κ=0.41 (ICC=0.77) and κ=0.39 (ICC=0.75) respectively. CONCLUSIONS: Intra-rater reliability is high in decision in dichotomy and even in grading activity. There is no difference for experienced or inexperienced physicians. Inter-rater reliability is high in dichotomy, but low for activity grading. Thus, the ENTAS provides a reliable instrument for assessing, documenting and following GPA-related disease activity in the upper respiratory tract. The relationship of activity and following damage needs to be investigated in further studies.

Comparative evaluation of synthetic anti-HER2 Affibody molecules site-specifically labelled with 111In using N-terminal DOTA, NOTA and NODAGA chelators in mice bearing prostate cancer xenografts.

PURPOSE: In disseminated prostate cancer, expression of human epidermal growth factor receptor type 2 (HER2) is one of the pathways to androgen independence. Radionuclide molecular imaging of HER2 expression in disseminated prostate cancer might identify patients for HER2-targeted therapy. Affibody molecules are small (7 kDa) targeting proteins with high potential as tracers for radionuclide imaging. The goal of this study was to develop an optimal Affibody-based tracer for visualization of HER2 expression in prostate cancer. METHODS: A synthetic variant of the anti-HER2 Z(HER2:342) Affibody molecule, Z(HER2:S1), was N-terminally conjugated with the chelators DOTA, NOTA and NODAGA. The conjugated proteins were biophysically characterized by electrospray ionization mass spectroscopy (ESI-MS), circular dichroism (CD) spectroscopy and surface plasmon resonance (SPR)-based biosensor analysis. After labelling with (111)In, the biodistribution was assessed in normal mice and the two most promising conjugates were further evaluated for tumour targeting in mice bearing DU-145 prostate cancer xenografts. RESULTS: The HER2-binding equilibrium dissociation constants were 130, 140 and 90 pM for DOTA-Z(HER2:S1), NOTA-Z(HER2:S1) and NODAGA-Z(HER2:S1), respectively. A comparative study of (111)In-labelled DOTA-Z(HER2:S1), NOTA-Z(HER2:S1) and NODAGA-Z(HER2:S1) in normal mice demonstrated a substantial influence of the chelators on the biodistribution properties of the conjugates. (111)In-NODAGA-Z(HER2:S1) had the most rapid clearance from blood and healthy tissues. (111)In-NOTA-Z(HER2:S1) showed high hepatic uptake and was excluded from further evaluation. (111)In-DOTA-Z(HER2:S1) and (111)In-NODAGA-Z(HER2:S1) demonstrated specific uptake in DU-145 prostate cancer xenografts in nude mice. The tumour uptake of (111)In-NODAGA-Z(HER2:S1), 5.6 ± 0.4%ID/g, was significantly lower than the uptake of (111)In-DOTA-Z(HER2:S1), 7.4 ± 0.5%ID/g, presumably because of lower bioavailability due to more rapid clearance. (111)In-NODAGA-Z(HER2:S1) provided higher tumour-to-blood ratio, but somewhat lower tumour-to-liver, tumour-to-spleen and tumour-to-bone ratios. CONCLUSION: Since distant prostate cancer metastases are situated in bone or bone marrow, the higher tumour-to-bone ratio is the most important. This renders (111)In-DOTA-Z(HER2:S1) a preferable agent for imaging of HER2 expression in disseminated prostate cancer.

Minor changes in effective half-life during fractionated 177Lu-octreotate therapy.

AIMS: Fractionated (177)Lu-DOTA-octreotate therapy has been reported to be an effective treatment option for patients with generalized neuroendocrine tumors. In our clinic, full individual dosimetry is performed during the first therapy cycle, while dosimetry at later cycles is based on the 24 h uptake measurement assuming an unchanged effective half-life. Our aim was to evaluate this assumption and the variation in the 24 h uptake during therapy. PATIENTS: Thirty patients, 13 women and 17 men, were included in the study. METHODS: During the first therapy cycle the (177)Lu-concentration was measured with SPECT/CT over the abdomen at 24 h, 96 h and 168 h after infusion. The effective half-life was determined for the kidneys, liver and spleen. The procedure was repeated at cycle 4 or 5. RESULTS: The median ratio between the effective half-lives of the latter and the first cycle was 0.97 and 1.01 for the right and left kidney, with a range of 0.89-1.01 (1st-3rd quartile) and 0.93-1.05, respectively. DISCUSSION: The mean value of the ratios was slightly lower than one, indicating a tendency towards increased activity elimination during therapy. In individual patients, significant changes were found for all organs, often when a large tumor burden reduction occurred during treatment. Possible contributing factors appeared to be larger amounts of non-tumor bound tracer, improved organ function (kidneys), decrease of vessel obstruction (spleen), less scatter from large tumors and reduction of small metastases (liver and spleen). CONCLUSION: With most patients it is safe to estimate absorbed doses to kidneys, liver and spleen from 24 h activity concentration assuming an unchanged effective half-life during therapy. Patients with risk factors for kidney dysfunction need to be monitored in more detail. Simplified dosimetry based on the assumption of unchanged effective half-life can function as guidance to the number of therapy cycles an individual patient can tolerate.

Individualized dosimetry in patients undergoing therapy with (177)Lu-DOTA-D-Phe (1)-Tyr (3)-octreotate.

PURPOSE: In recent years, targeted radionuclide therapy with [(177)Lu-DOTA(0), Tyr(3)]octreotate for neuroendocrine tumours has yielded promising results. This therapy may be further improved by using individualized dosimetry allowing optimization of the absorbed dose to the tumours and the normal organs. The aim of this study was to investigate the feasibility and reliability of individualized dosimetry based on SPECT in comparison to conventional planar imaging. METHODS: Attenuation-corrected SPECT data were analysed both by using organ-based volumes of interest (VOIs) to obtain the total radioactivity in the organ, and by using small VOIs to measure the tissue radioactivity concentration. During the first treatment session in 24 patients, imaging was performed 1, 24, 96 and 168 h after [(177)Lu-DOTA(0), Tyr(3)]octreotate infusion. Absorbed doses in non tumour-affected kidney, liver and spleen were calculated and compared for all three methods (planar imaging, SPECT organ VOIs, SPECT small VOIs). RESULTS: Planar and SPECT dosimetry were comparable in areas free of tumours, but due to overlap the planar dosimetry highly overestimated the absorbed dose in organs with tumours. Furthermore, SPECT dosimetry based on small VOIs proved to be more reliable than whole-organ dosimetry. CONCLUSION: We conclude that SPECT dosimetry based on small VOIs is feasible and more accurate than conventional planar dosimetry, and thus may contribute towards optimising targeted radionuclide therapy.

High success rate of parathyroid reoperation may be achieved with improved localization diagnosis.

INTRODUCTION: Because of the difficulty of reoperative parathyroid surgery, preoperative imaging studies have been increasingly adopted. We report the use of consistently applied localization diagnosis to yield high success rates in parathyroid reoperations. METHODS: Parathyroid reoperation was performed after previous parathyroid surgery in 144 patients with nonmalignant hyperparathyroidism (HPT) between 1962 and 2007. From the year 2000, 46 patients who underwent parathyroid reoperation and 14 patients who were subjected to thyroid surgery before primary parathyroid operation were investigated with sestamibi scintigraphy (MIBI), 11C-methionine PET/CT (met-PET), surgeon-performed ultrasound (US), US-guided fine-needle aspiration biopsy (US-FNA), and selective venous sampling (SVS) with rapid PTH (Q-PTH) analyses. When imaging was considered adequate, additional studies were generally not obtained. RESULTS: Reversal of hypercalcemia was achieved by reoperation in 134 of 144 (93%) of all patients with previous parathyroid surgery. In patients operated from year 2000, MIBI had 90% sensitivity and 88% predictive value, met-PET 79% sensitivity and 87% predictive value, and US 72% sensitivity and 93% predictive value. SVS with Q-PTH analyses provided accurate localization or regionalization in 11 of 11 recently selected patients. Q-PTH analyses in fine-needle aspirations verified parathyroid origin of excised specimens, and intraoperative Q-PTH helped decide when operations could be terminated. In patients subjected to the algorithm of imaging procedures, reversal of hypercalcemia and apparent cure was obtained after the reoperation in 45 of 46 patients with previous parathyroid surgery, implying a success rate of 98%, and in all patients with previous thyroid surgery. CONCLUSIONS: Reoperative parathyroid surgery is challenging. Results can be improved by consistently applied sensitive methods of preoperative imaging, and reoperative procedures may then achieve nearly the same success rates as primary operations.

Nuclear imaging of neuroendocrine tumours.

The diagnosis of neuroendocrine tumours (NETs) and monitoring of therapy in many patients relies mainly on morphological imaging techniques such as computed tomography (CT), ultrasound (US) and magnetic resonance imaging (MRI). However, functional imaging modalities--such as somatostatin receptor scintigraphy (SRS)--have great impact on patient management by providing tools for better staging of the disease, visualization of occult tumour, and evaluation of eligibility for somatostatin analogue treatment. Positron emission tomography (PET) using (18)F-fluoro-deoxy-glucose (FDG) is a powerful functional modality for oncological imaging. Unfortunately, FDG is not accumulated in NETs except in the case of dedifferentiated tumours and tumours with high proliferative activity. Based on the concept of amine precursor uptake and decarboxylation (APUD), the (18)F- and (11)C-labelled amine precursors L-dihydroxyphenylalanine and 5-hydroxy-L-tryptophan (5-HTP) have been utilized for PET imaging of NETs. In comparative studies of patients with a variety of NETs, (11)C5-HTP-PET proved better than CT and SRS by visualizing additional small lesions. With carbidopa premedication orally before (11)C5-HTP-PET examination the tumour uptake could be increased and the urinary radioactivity concentration considerably reduced. This concept may also be applied to (18)F-L-DOPA-PET, a method which in a limited number of studies has gained additional diagnostic information in NET patients compared to SRS and morphological imaging. (68)Ga is available from an in-house generator and has been utilized for labelling of somatostatin analogues for PET imaging of NETs with promising results in a small number of patients. However, SRS is an established functional imaging method for patients with NETs, whereas the role for PET in the clinical routine needs further evaluation in comparative studies in larger groups of patients.

Hybrid SPECT-CT: an additional technique for sentinel node detection of patients with invasive bladder cancer.

OBJECTIVES: To explore the feasibility of performing lymphoscintigraphy combined with computed tomography (CT) for preoperative detection of sentinel lymph nodes in patients with invasive bladder cancer. MATERIALS: Six consecutive patients scheduled for radical cystectomy underwent lymphoscintigraphy after transurethral injection of Albures-technetium 99m in the detrusor muscle peritumourally both with planar imaging and with single-photon emission computed tomography/CT (SPECT/CT). CT for anatomic fusion was performed directly after the SPECT/CT and both investigations were combined to a fused image. Radical cystectomy started with extended lymphadenectomy and intraoperative detection of sentinel nodes with both Geiger probe and dye marker. The conventional planar lymphoscintigraphies and the fused SPECT/CT were compared with each other and with the outcome of intraoperative sentinel node detection and final histopathologic analyses. RESULTS: The method allowed anatomically detailed preoperative visualisation of 21 sentinel nodes in five of the six patients, whereas planar pictures only visualised two sentinel nodes in two of six patients. Two patients had lymph node metastases and in the other four the nodes were negative. The combined method visualised all metastatic sentinel nodes, whereas planar lymphoscintigraphy detected only one of six node metastases. CONCLUSIONS: The combination of lymphoscintigraphy with CT enhanced preoperative anatomic localisation of sentinel nodes in bladder cancer and aided in the identification of sentinel nodes during surgery. The yield of detected sentinel nodes, both metastatic and nonmetastatic, was markedly increased using the combined method compared to conventional planar lymphoscintigraphy.

Detection of immune responses against urinary bladder cancer in sentinel lymph nodes.

OBJECTIVE: The lymphatic drainage from a tumour is received in the sentinel node where the immune system encounters tumour derived antigens. We investigated anti-tumoural lymphocyte function in sentinel nodes from patients with urinary bladder cancer. METHODS: In 14 patients undergoing cystectomy due to bladder cancer, radioactive tracer and blue dye were used to identify the sentinel node. Cell suspensions from the tumour, sentinel- and non-sentinel nodes and peripheral blood were analyzed by flow cytometry with antibodies against lymphocyte surface antigens and against the tumour cell marker cytokeratin-20. Reactivity against autologous tumour extract and the mitogen Concanavalin A was tested in proliferation assays with 3H-Thymidine incorporation. Lymphocytes were put in long-term culture with IL-2 and autologous tumour extract. RESULTS: Sentinel nodes were detected in 12 of the 14 patients. Antigen dependent proliferation in response to autologous tumour extract was detected in 6 patients, in 5 cases in sentinel nodes, in the remaining case in a non-sentinel node. Proliferation against Concanavalin A was vigorous in lymph nodes from all patients, whereas tumour infiltrating lymphocytes were unresponsive. Lymphocytes from sentinel nodes could be expanded in vitro. CONCLUSION: Tumour reactive lymphocytes are present in sentinel nodes draining human bladder cancers. These cells display immunologic function upon restimulation in vitro, and provide a promising source for expansion and subsequent adoptive T cell immunotherapy.

[Radionuclide therapy--a possible way toward an improved treatment of cancer. The obstacle is the shortage of commercially available radionuclides for clinical use]. / Radionuklidterapi--möjlig väg mot bättre behandling av cancer. Hindret är bristen på kommersiellt tillgängliga nuklider i kliniken.

About one third of all cancer develops into a spread disease that is difficult to treat. Radioimmunotherapy has during the last years proven to be of help when other therapy modalities fail in e.g. lymphomas. The development in this area is fast mainly due to substantial improvements in molecular biology and in our increasing understanding of specific receptor expressions in cancer cells. However, radionuclides used today, 131I and 90Y, are not optimal in that sense that they emit radiation mainly suitable to treat the bulk tumor and not the single cell and micrometastases present in spread disease. The article stresses the importance that radionuclides with more suitable emission of particles like 177Lu and 211At are made available for clinical research and routine.