Prognostic value of [18F]-FDG PET/CT in patients with meta-static breast cancer treated with cyclin-dependent inhibitors

Objective

The addition of cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) to endocrine therapy impressively improved the outcome of patients with hormone receptor-positive metastatic breast cancer. Despite their great efficacy, not all patients respond to treatment and many of them develop acquired resistance. The aim of this retrospective study was to assess the role of [18F]-FDG PET/CT in predicting PFS and OS in breast cancer patients treated with CDK4/6i.

Methods

114 patients who performed an [18F]-FDG PET/CT scan before (PET1) and 2-6 months (PET2) after starting treatment were retrospectively enrolled. Metabolic response was evaluated by EORTC, PERCIST and Deauville Score and correlated to PFS and OS.

Results

In patients who did not progress at PET2 (n = 90), PFS rates were not significantly different between classes of response by EORTC and PERCIST. Conversely, patients showing a Deauville score ≤3 had a longer PFS (median PFS 42 vs 21.0 months; p = 0.008). A higher total metabolic tumor volume at PET1 (TMTV1) was also associated with a shorter PFS (median 18 vs 42 months; p = 0.0026). TMTV1 and Deauville score were the only independent prognostic factors for PFS at multivariate analysis and their combination stratified the population in four definite classes of relapse risk. Conversely, the above parameters did not affect OS which was only influenced by a progressive metabolic disease at PET2 (3-years survival rate 29.8 vs 84.9%; p<0.0001).

Conclusion

TMTV and metabolic response by Deauville score were significant prognostic factors for PFS in patients with breast cancer treated with CDK4/6i. Their determination could help physicians to select patients who may need a closer follow up.

Comparison between MIBI-based radiopharmaceuticals for parathyroid scintigraphy: quantitative evaluation and correlation with clinical-laboratory parameters

OBJECTIVE

Parathyroid scintigraphy is mandatory for the identification of hyperfunctioning parathyroid glands in hyperparathyroidism (HPT). The use of ^99mTc-methoxy-isobutyl-isonitrile (MIBI) as radiopharmaceutical for parathyroid scintigraphy is considered the most valid and useful considering its uptake mechanism. Several MIBI-based radiopharmaceuticals are commercially available (i.e., MediMIBI, TechneMIBI, Stamicis). They seem to have similar physico-chemical characteristics and the choice between them is based on commercial criteria, even though some differences in qualitative scintigraphic results have been appreciated. Aims of the study were: first, to compare the scintigraphic quantitative data of MediMIBI, TechneMIBI, and Stamicis, particularly in the view of a personalized medicine approach; second, to investigate the potential effect of clinical-laboratory data on image quality using one of these radiopharmaceuticals.

METHODS

Patients with diagnosis of HPT, who underwent a parathyroid scintigraphy using one of the three MIBI-based radiopharmaceuticals between December 2018 and October 2020, have been retrospectively identified. Parameters derived from regions of interest (ROIs) drawn on three different sites were obtained: a reasonable parathyroid lesion detected, an area in the lateral neck considered as the background, and the hepatic dome as the site of MIBI physiological uptake. Laboratory and clinical data, such as serum calcium, PTH, vitamin D, and creatinine levels, as well as possible drug-mediated interferences were considered.

RESULTS

Among 250 patients included, 83 (33.2%) had the parathyroid scintigraphy using MediMIBI, 84 (33.6%) using TechneMIBI and 83 (33.2%) using Stamicis. The ROIs on the parathyroid uptake at early images, on the background, and on the hepatic dome were statistically different among the three groups (p < 0.05). No significant differences were found in the remaining semi-quantitative parameters among the three groups, not even considering clinical-laboratory data.

CONCLUSIONS

Some differences in semi-quantitative parameters emerged among MIBI-based radiopharmaceuticals for parathyroid scintigraphy. This might justify the different qualitative scintigraphic results obtained using one or another of the cited radiopharmaceuticals.

Predicting time to treatment in follicular lymphoma on watchful waiting using baseline metabolic tumour burden

PURPOSE

Asymptomatic patients with follicular lymphoma (FL) and a low tumour burden can be followed without initial therapy, a strategy called watchful waiting (WW). Prediction of the time to treatment (TTT) is still a challenge. We investigated the prognostic value of baseline total metabolic tumour volume (TMTV) and whole-body total lesion glycolysis (WB-TLG) to predict TTT in patients with FL on WW.

METHODS

We conducted a retrospective study of 54 patients with FL (grade 1-3a) diagnosed between June 2013 and December 2019, staged with FDG PET/CT, and managed on WW. Median age was 62 years (range 34-85), stage was advanced (III-IV) in 57%, and FLIPI score was intermediate to high (≥ 2) in 52% of the patients.

RESULTS

The median TMTV and WB-TLG were 7.1 and 43.3, respectively. With a median follow-up of 59 months, 41% of patients started immuno-chemotherapy. The optimal cut-points to identify patients with TTT within 24 months were 14 for TMTV (AUC 0.70; 95% CI 51-88) and 64 for WB-TLG (AUC 0.71; 95% CI 52-89) (p < 0.005). The probability of not having started treatment within 24 months was 87% for TMTV < 14 and 53% for TMTV ≥ 14 (p < 0.005). TMTV was independent of the FLIPI score for TTT prediction. Patients with both FLIPI ≥ 2 and TMTV ≥ 14 had only an 18% probability of not having started treatment at 36 months, while this probability was 75% in patients with TMTV < 14.

CONCLUSION

Metabolic tumour volume parameters may add information to clinical scores to better predict TTT and better stratify patients for interventional studies.

Oropharyngoesophageal Scintigraphy in a Case of Complex Swallowing Disorders After a Major Oral Surgery

ABSTRACT

A 75-year-old woman had an occasional finding of a left tonsil mass for dysphagia, which resulted a high-grade squamous carcinoma. Therefore, the patient was sent to have a left pharyngectomy. After the pharyngectomy, the patient reported persistent swallowing disorders and nasal reflux. Consequently, she had an oropharyngoesophageal scintigraphy, demonstrating irregular oral and pharyngeal swallowing phases and confirming reflux episodes into the rhinopharynx and into the oropharynx. In line with these findings, the patient was send to rehabilitation; the abnormal functional mechanisms, previously identified by the scintigraphy, allowed to guide the speech therapy, with a progressive clinical improvement.

Clinical characteristics of metabolic associated fatty liver disease (MAFLD) in subjects with myotonic dystrophy type 1 (DM1)

BACKGROUND

Myotonic dystrophy type 1 (DM1) is a rare inherited neuromuscular disease associated with insulin resistance, and its association with metabolically associated fatty liver disease (MAFLD) has never been explored in prospective studies. The aim of this study was to assess the clinical features of MAFLD in DM1 patients.

METHODS

We investigated the prevalence and the diagnostic features of MAFLD in a cohort of 29 outpatient fully characterized DM1 patients; afterward, we compared the selected cohort of DM1-MAFLD individuals with a propensity-matched cohort of non-DM1-MAFLD RESULTS: 13/29 (44.83%) DM1 patients received a clinical diagnosis of MAFLD. Compared to DM1 patients with normal liver, DM1-MAFLD individuals showed a higher male prevalence (p = 0.008), BMI (p = 0.014), HOMA score (p = 0.012), and GGT levels (p = 0.050). The statistical comparison showed that the DM1-MAFLD group had a more severe MAFLD according to the FIB4 score than non-DM1-MAFLD patients. This association of a more severe form of liver disease with DM1 remained significant after logistic regression analysis (OR: 6.12, 95% CI 1.44- 26.55).

11C-Methionine PET/CT in patients with primary hyperparathyroidism and inconclusive pre-operative imaging work-up: diagnostic accuracy and role of semi-quantitative analysis

OBJECTIVE

¹¹C-Methionine PET/CT (C-MET) is a promising method in detecting abnormal parathyroid glands in patients with primary hyperparathyroidism (PHPT). The first aim of the study was to evaluate which is the diagnostic role of C-MET in patients with PHPT and inconclusive pre-operative imaging. Second, we aimed to investigate whether C-MET semi-quantitative parameters may reflect biochemical and histological characteristics of involved glands.

METHODS

Patients with PHPT, undergoing C-MET after an inconclusive pre-operative imaging and having a parathyroid surgery, were retrospectively included. C-MET visual and semi-quantitative assessment was performed. Parameters, as SUV_max, SUV_peak, SUV_mean, functional lesion volume (FLV) and total lesion activity (TLA), were measured for each detected lesion; SUV_mean, FLV and TLA were calculated on 40-90% thresholds of SUV_max to define SUV_mean40-90, FLV_40-90 and TLA_40-90, respectively. Results were correlated with patients' clinical-laboratory (calcium and PTH values) and histological data (size and weight of excised glands). Mann-Whitney test was used and P value < 0.05 was considered significant.

RESULTS

Thirty-eight patients (36 female, age: 57.69 ± 15.13 years) were included. Pre-operative median calcium and PTH values were 11.1 mg/dl [interquartile range (IQR) 10.6-11.5] and 154.6 pg/ml (IQR 101.8-227.0), respectively. C-MET showed a parathyroid uptake in 30 out of thirty-eight patients (78.9%). Among 42 nodules excised, C-MET correctly detected the side of the neck (right/left) in 30/42 with sensitivity, specificity and accuracy of 79, 75 and 79%, respectively. C-MET correctly identified the exact position (superior/inferior) in 27/42 with sensitivity, specificity and accuracy of 75, 50 and 71%, respectively. SUV_peak, FLV_50-70 and TLA_40-70 were significantly (P < 0.05) higher in patients with higher PTH results. The histological size resulted significantly (P < 0.05) higher in abnormal glands with higher SUV_max, SUV_peak, FLV_40-80 and TLA_40-90, the weight was higher in glands with higher SUV_peak, SUV_mean40-50, FLV_40-80 and TLA_40-90.

CONCLUSIONS

C-MET showed a good performance in detecting hyperfunctioning parathyroid glands in PHPT patients with inconclusive pre-operative imaging. Semi-quantitative PET-derived parameters closely correlated with PTH as well as with size and weight of the excised gland, thus reflecting some biochemical and histological characteristics of involved glands.

90Y-DOTA-nimotuzumab: Synthesis of a Promising β⁻ radiopharmaceutical

BACKGROUND

Nimotuzumab is a humanized anti-epidermal growth factor receptor (EGFR) monoclonal antibody, nowadays used for tumour immunochemotherapy. This study aimed to label the conjugate DOTA-nimotuzumab with yttrium-90, in order to provide a β- emitting radioimmunoconjugate (90Y-DOTA-nimotuzumab) potentially useful to assess the feasibility of a new radio-guided surgery approach.

METHODS

The synthesis of 90Y-DOTA-nimotuzumab was performed in two days. Nimotuzumab was conjugated with a 50 fold excess of DOTA and then labelled with 90Y3+. The 90Y-DOTA-nimotuzumab preparation was optimized considering several parameters such as pH, temperature and reaction volume. Moreover, the 90Y-DOTA-nimotuzumab stability was evaluated in human plasma.

RESULTS

The radioimmunoconjugate 90Y-DOTA-nimotuzumab was obtained with a radiochemical purity greater than 96%, and showed a good stability at 20°C as well as at 37°C in human plasma.

CONCLUSIONS

The optimized conditions for a mild and easy preparation of 90Y-DOTA-nimotuzumab joined to a promising stability under physiological conditions suggest to propose this radioimmunoconjugate as a potential diagnostic radiopharmaceutical for β- radio-guided surgery.

High Prevalence and Gender-Related Differences of Gastrointestinal Manifestations in a Cohort of DM1 Patients: A Perspective, Cross-Sectional Study

Myotonic dystrophy type 1 (DM1, MIM #160900), the most common muscular dystrophy among adults, is a multisystem disorder, which affects, besides the skeletal muscle, several other tissues and/or organs, including the gastrointestinal apparatus, with manifestations that frequently affect the quality of life of DM1 patients. So far, only few, mainly retrospective studies evaluated this specific topic in DM1, so we performed a perspective study, enrolling 61 DM1 patients who underwent an extensive diagnostic protocol, including administration of the Gastrointestinal Symptom Rating Scale (GSRS), a validated patient-reported questionnaire about GI symptoms, laboratory tests, liver US scan, and an intestinal permeability assay, in order to characterize frequency and assess correlations regarding specific gastrointestinal manifestations with demographic or other DM1-related features. Our results in our DM1 cohort confirm the high frequency of various gastrointestinal manifestations, with the most frequent being constipation (45.9%). γGT levels were pathologically increased in 65% of DM1 patients and GPT in 29.82%; liver ultrasound studies showed steatosis in 34.4% of patients. Significantly, 91.22% of DM1 patients showed signs of altered intestinal permeability at the specific assay. We documented a gender-related prevalence and severity of gastrointestinal manifestations in DM1 females compared to DM1 males, while males showed higher serum GPT and γGT levels than females. Correlation studies documented a direct correlation between severity of muscle weakness estimated by MIRS score and γGT and alkaline phosphatase levels, suggesting their potential use as biomarkers of muscle disease severity in DM1.

Radioguided surgery with β- radiation in pancreatic Neuroendocrine Tumors: a feasibility study

The possibility to use β- decaying isotopes for radioguided surgery (RGS) has been recently proposed, and first promising tests on ex-vivo samples of Meningioma and intestinal Neuroendocrine Tumor (NET) have been published. This paper reports a study of the uptake of 68Ga-DOTATOC in pancreatic NETs (pNETs) in order to assess the feasibility of a new RGS approach using 90Y-DOTATOC. Tumor and healthy pancreas uptakes were estimated from 68Ga-DOTATOC PET/CT scans of 30 patients with pNETs. From the obtained SUVs (Standardised Uptake Value) and TNRs (Tumor Non tumor Ratio), an analysis algorithm relying on a Monte Carlo simulation of the detector has been applied to evaluate the performances of the proposed technique. Almost all considered patients resulted to be compatible with the application of β--RGS assuming to administer 1.5 MBq/kg of activity of 90Y-DOTATOC 24 h before surgery, and a sampling time of few seconds. In just 2 cases the technique would have required a mildly increased amount of activity or of sampling time. Despite a high physiological uptake of 68Ga-DOTATOC in the healthy pancreas, the proposed RGS technique promises to be effective. This approach allows RGS to find application also in pancreatic diseases, where traditional techniques are not viable.

Characterisation of a β detector on positron emitters for medical applications

PURPOSE

Radio Guided Surgery (RGS) is a technique that helps the surgeon to achieve an as complete as possible tumor resection, thanks to the intraoperative detection of particles emitted by a radio tracer that bounds to tumoral cells. In the last years, a novel approach to this technique has been proposed that, exploiting β^- emitting radio tracers, overtakes some limitations of established γ-RGS. In this context, a first prototype of an intraoperative β particle detector, based on a high light yield and low density organic scintillator, has been developed and characterised on pure β^- emitters, like ⁹⁰Y. The demonstrated very high efficiency to β^- particles, together with the remarkable transparency to photons, suggested the possibility to use this detector also with β⁺ emitting sources, that have plenty of applications in nuclear medicine. In this paper, we present upgrades and optimisations performed to the detector to reveal such particles.

METHODS

Laboratory measurement have been performed on liquid Ga68 source, and were used to validate and tune a Monte Carlo simulation.

RESULTS

The upgraded detector has an ~80% efficiency to electrons above ~110keV, reaching a plateau value of ~95%. At the same time, the probe is substantially transparent to photons below ~200keV, reaching a plateau value of ~3%.

CONCLUSIONS

The new prototype seems to have promising characteristics to perform RGS also with β⁺ emitting isotopes.

Parathyroid scintigraphy in primary hyperparathyroidism: comparison between double-phase and subtraction techniques and possible affecting factors

PURPOSE

Parathyroid scintigraphy is superior to other imaging techniques in detecting hyperfunctioning parathyroid glands. It is mainly performed using double-phase or dual-tracer subtraction methods. Neither of the techniques is perfect and different protocols are being used. We aimed to evaluate the accuracy of double-phase and subtraction methods in detecting abnormal gland as well as the potential effects of coexisting thyroid disease and clinical-laboratory data.

METHODS

We considered patients with primary hyperparathyroidism who underwent parathyroid surgery, after a parathyroid scintigraphy between April 2015 and February 2017. Sixty-eight patients were included; in 45 cases (66.2%), a thyroid disease was coexistent. Diagnostic performances of the two techniques were compared. The effect of thyroid disease and clinical-pathological data on examination interpretation was considered.

RESULTS

Double-phase scintigraphy showed higher sensitivity and accuracy in detecting the exact abnormal gland compared to the digital subtraction (90% and 75% vs. 76% and 66%, respectively). For double-phase technique, sensitivity and accuracy were higher in cases with no thyroid disease when compared to those with thyroid disease (92% and 86% vs. 88% and 69%, respectively). Similarly, for digital subtraction, sensitivity and accuracy were higher in the absence of thyroid disease compared to their presence (84% and 79% vs. 70% and 58%, respectively). There was no significant variation in the performance of both techniques, considering clinical-laboratory data.

CONCLUSIONS

Double-phase scintigraphy has been more accurate than digital subtraction. The presence of thyroid disease could be a possible limit, affecting the subtraction more than the double-phase technique. Clinical data did not influence the scintigraphic outcome.

Radioguided surgery with β radiation: a novel application with Ga68

Radio Guided Surgery is a technique helping the surgeon in the resection of tumors: a radiolabeled tracer is administered to the patient before surgery and then the surgeon evaluates the completeness of the resection with a handheld detector sensitive to emitted radiation. Established methods rely on γ emitting tracers coupled with γ detecting probes. The efficacy of this technique is however hindered by the high penetration of γ radiation, limiting its applicability to low background conditions. To overtake such limitations, a novel approach to RGS has been proposed, relying on β⁻ emitting isotopes together with a dedicated β probe. This technique has been proved to be effective in first ex-vivo trials. We discuss in this paper the possibility to extend its application cases to ⁶⁸Ga, a β⁺ emitting isotope widely used today in nuclear medicine. To this aim, a retrospective study on 45 prostatic cancer patients was performed, analysing their ⁶⁸Ga-PSMA PET images to asses if the molecule uptake is enough to apply this technique. Despite the expected variability both in terms of SUV (median 4.1, IQR 3.0–6.1) and TNR (median 9.4, IQR 5.2–14.6), the majority of cases have been found to be compatible with β-RGS with reasonable injected activity and probing time (5 s).

Bile Collection Detected With BrIDA Scintigraphy in a Patient With Hepatocellular Carcinoma

A 47-year-old man, with a history of anabolic steroid abuse, developed hepatic adenomatosis and multifocal hepatocellular carcinoma. He underwent ultrasound and CT follow-up, showing multiple solid and fluid hepatic lesions. Consequently, hospitalization was required because of high fever (up to 39°C), weakness, and anorexia. An abdominal CT scan revealed an enlargement of one of the intrahepatic fluid collections. Biochemical and microbiological analyses of a fluid sample showed bilirubin and bile acids as well as Streptococcus cristatus and Enterobacter cloacae. Thus, the patient underwent Tc-trimethylbromo-iminodiacetic acid scintigraphy, demonstrating bile collection in the lesion with a flow from a bile duct.

Feasibility of beta-particle radioguided surgery for a variety of "nuclear medicine" radionuclides

PURPOSE

Beta-particle radioguided tumor resection may potentially overcome the limitations of conventional gamma-ray guided surgery by eliminating, or at least minimizing, the confounding effect of counts contributed by activity in adjacent normal tissues. The current study evaluates the clinical feasibility of this approach for a variety of radionuclides. Nowadays, the only β^- radioisotope suited to radioguided surgery is ⁹⁰Y. Here, we study the β^- probe prototype capability to different radionuclides chosen among those used in nuclear medicine.

METHODS

The counting efficiency of our probe prototype was evaluated for sources of electrons and photons of different energies. Such measurements were used to benchmark the Monte Carlo (MC) simulation of the probe behavior, especially the parameters related to the simulation of the optical photon propagation in the scintillation crystal. Then, the MC simulation was used to derive the signal and the background we would measure from a small tumor embedded in the patient body if one of the selected radionuclides is used.

RESULTS

Based on the criterion of detectability of a 0.1 ml tumor for a counting interval of 1 s and an administered activity of 3 MBq/kg, the current probe yields a detectable signal over a wide range of Standard Uptake Values (SUVs) and tumor-to-non-tumor activity-concentration ratios (TNRs) for ³¹Si, ³²P, ⁹⁷Zr, and ¹⁸⁸Re. Although efficient counting of ⁸³Br, ¹³³I, and ¹⁵³Sm proved somewhat more problematic, the foregoing criterion can be satisfied for these isotopes as well for sufficiently high SUVs and TNRs.

Bilateral adrenalectomy: a review of 10 years' experience

INTRODUCTION The 2012 British Association of Endocrine and Thyroid Surgeons audit report showed that only 86 of 1359 patients who underwent adrenalectomy had a bilateral operation; thus the experience with this procedure remains limited. METHODS Retrospective review of patients undergoing bilateral adrenalectomy in a tertiary referral centre. RESULTS Between November 2005 and January 2016, bilateral adrenalectomy was performed in 23 patients (6 male, 17 female, age 43 ± 4 years) diagnosed with Cushing's disease (n = 13), hereditary phaeochromocytomas (n = 6), adrenocortical cancer (n = 2), colorectal metastatic disease (n = 1) and adrenocortical adenomas (n = 1). A laparoscopic transperitoneal approach was used in 17 patients, with one conversion to open. Three patients had open adrenalectomies for adrenocortical cancer and for simultaneous phaeochromocytomas and pancreatic neuroendocrine tumours in a patient with Von Hippel-Lindau syndrome. Three patients with Cushing's had a bilateral retroperitoneoscopic operation. The mean operating time was 195 ± 16 minutes for laparoscopic operations (n = 16), 243 ± 44 minutes for open adrenalectomies (n = 4) and 151 ± 12 minutes for retroperitoneal operations. It was significantly shorter for Cushing's disease than for phaeochromocytomas (162 ± 8 vs. 257 ± 39 minutes, P < 0.01). Median length of hospital stay was 5 days. Postoperative complications (Clavien-Dindo classification) included one chest infection (level 2), one postoperative haemorrhage and two chest drains for pneumothorax (level 3), two postoperative cardiac arrests (level 4) and one late cancer death from complications related to uncontrolled hypercortisolism (level 5). DISCUSSION Synchronous bilateral adrenalectomy remains an infrequent operation. The laparoscopic approach is feasible in the majority of patients. It is likely that the retroperitoneoscopic adrenalectomy will become the standard approach for bilateral operations.