Dual-Time-Point 18F-Fluorocholine PET/CT Improves Characterization of Thyroid Nodules in Patients Referred for Primary Hyperparathyroidism: A Proof of Concept Study

PURPOSE

Thyroid nodules frequently coexist with primary hyperparathyroidism (pHPT). Because of the increasing use of 18F-fluorocholine (18F-FCH) PET/CT in patients with pHPT, evaluation of its clinical utility for thyroid nodules characterization in this population is of paramount importance. Herein, we investigate the value of dual-point 18F-FCH PET/CT in the diagnosis of thyroid cancer in patients referred for pHPT imaging who have thyroid nodules.

PATIENTS AND METHODS

All pHPT patients who underwent a dual-time point 18F-FCH PET/CT (at 5 and 60 minutes postinjection) between July 2019 and December 2020 were analyzed. Only those with a thyroid nodule greater than 10-mm and pathological analysis (criterion standard) were included. Nodule-to-thyroid SUVmax ratio was calculated at the 2 study points, as well as the 18F-FCH washout index (WO%).

RESULTS

Twenty-seven patients (32 nodules) were included in this study. The final diagnoses were as follows: 27 benign nodules including 2 NIFTPs (noninvasive follicular thyroid neoplasm with papillary-like nuclear features) and 5 cancers of follicular origin. Early uptake ratio was significantly higher in malignant lesions than in benign nodules (P = 0.0008). Thyroid cancers were also characterized by a marked 18F-FCH washout index (WO% benign vs cancer: 2.9% ± 4.1% vs 45.5% ± 13.4%, P = 0.0001). Using a WO% threshold of 22.1%, 25/27 benign nodules and 5/5 malignant lesions were accurately classified (sensitivity of 100%, specificity of 92.6%, positive predictive value of 71.4%, and negative predictive value of 100%). The false-positive findings were related to the 2 NIFTPs that share similarities with thyroid cancer.

CONCLUSIONS

Our preliminary results suggest to perform a dual-time-point PET/CT acquisition protocol in pHPT patients with uncharacterized centimeter thyroid nodules. However, the real impact of these promising results should be assessed by prospective studies on a larger cohort of patients.

Bone metastases from a 1p/19q codeleted and IDH1-mutant anaplastic oligodendroglioma: a case report

BACKGROUND

Oligodendroglioma is a rare type of primary brain tumor which, like other malignant gliomas, metastasizes very rarely even when in high-grade form.

CASE REPORT

A 36-year-old white man diagnosed 29 months previously as having 1p/19q codeleted anaplastic oligodendroglioma presented bilateral cruralgia and lower limb motor deficits. A computed tomography scan showed multiple osteoblastic bone lesions. The presence of oligodendroglial cells was revealed by bone marrow biopsy and confirmed by immunohistochemical analyses. A positon emission tomography-computed tomography scan confirmed the exclusive involvement of bones.

CONCLUSION

This case joins less than 20 other reported cases of oligodendroglioma bone marrow metastasis, and is one of only a handful of cases of diffuse bone metastases beyond the axial skeleton. To the best of our knowledge, the early relapse of 1p/19q codeleted anaplastic oligodendroglioma with this distribution of metastases has never been described in the literature.

Contribution of three-dimensional conformal intensity-modulated radiation therapy for women affected by bulky stage II supradiaphragmatic Hodgkin disease

Purpose

To analyze the outcome and dose distribution of intensity-modulated radiation therapy (IMRT) by helical tomotherapy in women treated for large supradiaphragmatic Hodgkin’s disease.

Material and methods

A total of 13 patients received adjuvant radiation at a dose of 30 Gy to the initially involved sites with a boost of 6 Gy to those areas suspected of harboring residual disease on the simulation CT scan.

Results

With a median follow-up of 23 months, the two-year progression-free survival was 91.6%, and the 2- and 3-year overall survivals were 100%. We did not report any heart or lung acute side effects. The conformity index of PTV (Planning Target Volume) was better for IMRT than for 3D-CRT (p=0.001). For the breasts, lungs, heart, thyroid and esophagus, the volume distributions favored the IMRT plans. For the breasts, the V_20Gy, V_25Gy and V_30Gy were 1.5, 2.5 and 3.5 times lower, respectively, for IMRT than for 3D-CRT. For the lung tissues, the V_20Gy and V_30Gy were 2 times and 4.5 times lower, respectively, for IMRT than for 3D-CRT. For the heart, the V_20Gy and V_30Gy were 1.4 and 2 times lower, respectively, for IMRT than for 3D-CRT. For the esophagus, the V_35Gy was 1.7 lower for IMRT than for 3D-CRT, and for the thyroid, the V_30Gy was 1.2 times lower for IMRT.

Conclusion

IMRT by helical tomotherapy improved the PTV coverage and dramatically decreased the dose in organs at risk. The treatment was well tolerated, but a longer follow-up is necessary to prove a translation of these dosimetric improvements in the outcome of the patients.

An open-label randomized, multicenter, phase II study on neoadjuvant treatment with trastuzumab plus docetaxel versus trastuzumab plus docetaxel plus bevacizumab according to positron emission tomography (PET) value modification in patients with early stage HER2-positive breast cancer (AVATAXHER): Design description

TPS646

Background: For patients with early HER2+ breast cancer at diagnosis, addition of trastuzumab (T) to 6 cycles of preoperative docetaxel (D) can reach a pathological complete response (pCR) in ~50% of cases, and a high rate of conservative surgery. pCR can be predicted by changes of Fluorodeoxyglucose (FDG) tumor uptake evaluated by Positon Emission Tomography (PET) after one cycle of therapy. In order to increase this pCR rate, adding an antiangiogenic compound could be considered. Pre-clinical and phase I-II data support that the combination of bevacizumab (B) and T is synergistic and safe when patients are chemotherapy naïve. The neoadjuvant AVATAXHER trial (EUDRACT 2009-013410-26) investigates the potential increase of pCR rate by combining B with T and D for patients with HER2+ breast cancer who are not predicted for pCR by FDG PET. Methods: In this multicenter, open-label, phase II trial, 2 phases are planned after a selection period: phase I: all patients receive two cycles of therapy combining T (8 mg/kg at the first cycle, then 6 mg/kg) and D (100 mg/m2). FDG PET is also performed within 7 days before cycle 1 (baseline) and less than 3 days before cycle 2 in order to calculate changes of the tumor FDG uptake between baseline and after cycle 1 (ΔSUV). Phase 2: if ΔSUV≥70%, patients will continue to receive T and D for (cycles 3 to 6: D 100 mg/m2 + T 6 mg/kg); if ΔSUV<70%, patients are randomized 2:1 to arm A (cycles 3 to 6 D 100 mg/m2 + T 6 mg/kg + B 15 mg/kg) or arm B ( cycles 3 to 6: D 100 mg/m2 + T 6 mg/kg). The primary endpoint is pCR rate evaluated post-surgery 4 to 6 weeks after the last treatment of cycle 6. Enrolment began in May 2010 and 125 patients were to be recruited in 26 sites. According to the hypothesis that 60% of patients will have a ΔSUV<70%, it is presumed that 72 patients will be randomized. There are currently 107 patients included (as of 06 January 2012 ), 95 of them reached the phase 1; 52 of them (55%) showed a ΔSUV<70% and after randomization 34 were included in arm A and 18 in arm B.

High-frequency ultrasound detection and follow-up of Wilms' tumor in the mouse

The goal of this study was to validate high-frequency (24 MHz) ultrasound imaging techniques for early detection and follow-up of renal tumors in a murine Wilms' tumor model (n = 26). For 11 mice, maximum tumor dimensions were estimated from images along three orthogonal axes for comparison with posteuthanasia caliper and histologic measurements. Tumor size in the 15 remaining mice was checked biweekly. The mice were then euthanized and histologic study assessed tumor position and nature. Tumors were detected in vivo between 7 to 14 days after injection of tumor-inducing cells. Tumor maximum cross-sectional area varied from 0.07 mm2 to 5.7 mm2 at the time of initial detection. The relative r.m.s. error between ultrasonic and histologic estimations of maximum cross-sectional area was estimated to be 19%. Results demonstrate feasibility of noninvasive ultrasound biomicroscopy early detection and characterization of renal tumor development for longitudinal monitoring of the same animal.

The perinatal thyroid in iodine deficient regions: risks of radioiodines--hazards of stable iodine overload. A study in the newborn rat

Administration of large quantities of stable iodine is an effective means of reducing the radiation burden on the thyroid in the event of a nuclear power-plant accident. Such administration may involve countries with low baseline dietary iodine intake. It is questioned whether stable iodine overload is safe, and in particular, what are its effects in newborn infants? Iodine-deficient newborn rats were submitted to a single acute administration of stable iodine (100 microg) on the second day of life. The effects on thyroid structure were studied, after 24 hr and after 7 days, using light microscopy. Compared to controls, the thyroids of animals submitted to stable iodine overload showed, 7 days after treatment, signs of acute toxicity including marked desquamation of epithelial cells and rupture of a large number of thyroid follicles. Our findings in iodine deficient newborn rats suggest that stable iodine overload may have side effects during perinatal life. This prophylactic measure should, therefore, be accompanied by follow-up of thyroid function. Thyroid hormones are critical for brain development, during the first period of life.

Microscopic distribution of iodine radioisotopes in the thyroid of the iodine deficient new-born rat: insight concerning the Chernobyl accident

Thyroid cancer markedly increased in children exposed to iodine radioisotopes following the Chernobyl accident. This increase exceeded predictions based on dose estimates to the whole organ. We sought to investigate whether iodine deficiency may have influenced the pattern of microscopic distribution of radioiodines, which may be important to interpretation of the observed effects. Iodine-deficient new-born rats were injected with iodine-129 (129I) and the microscopic distribution in the thyroid tissue was studied at 24 hr and at one week after administration, using secondary ion mass spectrometry (SIMS). Twenty-four hr after administration, SIMS images showed large differences in 129I uptake among thyroid follicles, with more than a factor ten variation in the local concentration. In addition, the distribution of 129I inside follicles varied with time. At 24 hr, the highest concentration was found at the periphery of the colloid, close to the thyroid cells. There also was enhanced concentration of 129I at one pole of follicles. Distribution inside follicles was homogeneous at 7 days.

CONCLUSIONS

1/Dosimetric models, which assume uniform iodine uptake by thyroid follicles, give an oversimplified picture of radiation dosimetry in cases involving iodine deficiency, which induces patchy tissue irradiation. 2/The dynamic pattern of iodine distribution within thyroid follicles suggests that decay events from short-lived iodines will occur closer to thyroid cells than events resulting from iodine-131.

Biological consequences of irradiation by low doses of technetium 99m: ultrastructural studies, p53 protein expression and cytogenetic effects

Few studies concerning the potential genetic effects of diagnostic radionuclides used in nuclear medicine have been reported. The aim of this study was to evaluate the biological and cytogenetic consequences of two technetium 99m-labelled radiopharmaceuticals. Ultrastructural modifications of pulmonary cells were first investigated after injection of 99mTc labelled microspheres in the rat. On the same irradiated cells, nuclear expression of p53 protein was assessed using immunohistochemistry. Despite very high previously calculated doses delivered to pulmonary cells, no morpholological cell damage and no significant increase of nuclear expression of the p53 were noted. There was no correlation between the calculated dose and the ultrastructural biological damage. Secondly, a specific in vitro curve, activity/number of unstable chromosomal aberrations, corresponding to physical characteristics of 99mTc, was established to verify the potentiality of 99mTc to induce such aberrations. In vivo, cytogenetic effects were assessed on blood samples of 5 patients with various arthrosic and periarthrosic diseases obtained after bone scintigraphy. Aberration frequencies of both in vitro and in vivo irradiated lymphocytes were determined using the classical Fluorescence Plus Giemsa technique. No cytogenetic effects appeared with the routinely 99mTc injected activities as predicted by the in vitro curve.