Preoperative Positron Emission Tomography Research Articles

Radiologic Parameters Predicting the Histologic Invasiveness of Pure Ground-glass Nodules

BackgroundThis study aimed to investigate the diagnostic performance of combined computed tomography (CT) and fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) for predicting histologic invasiveness of pure ground-glass nodules (pGGNs). MethodsThe study analyzed 91 patients who underwent resection of pGGNs and examined the correlation of pathologic invasiveness with preoperative CT and FDG PET findings. ResultsOverall, 24, 36, and 31 patients had adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA), and invasive adenocarcinoma (IAD), respectively. Compared with AIS and MIA, IAD was significantly correlated with larger CT size (P = .001), maximum CT value (P = .026), and high maximum standardized uptake value (SUVmax; P < .001). Multivariable logistic analyses revealed that CT size (odds ratio [OR], 3.848; P = .019) and SUVmax (OR, 4.968; P = .009) were independent predictors of histologic invasiveness. Receiver operating characteristic curve analysis revealed that a cutoff CT size value of 18 mm predicted histologic invasiveness with a sensitivity and specificity of 65% and 80%, respectively; similarly, a cutoff SUVmax value of 1.5 predicted histologic invasiveness with a sensitivity and specificity of 61% and 90%, respectively. Of 20 lesions with CT size ≥18 mm and SUVmax ≥1.5, 16 (80%) were IAD. Of 54 lesions with CT size <18 mm and SUVmax <1.5, 46 (85%) were non-IAD lesions. Furthermore, all pGGNs with SUVmax ≥2.5 were IAD. ConclusionsCT size and SUVmax were significantly correlated with the histologic invasiveness of pGGNs. These factors may aid in determining optimal surgical procedures.

Identifying G6PC3 as a Potential Key Molecule in Hypoxic Glucose Metabolism of Glioblastoma Derived from the Depiction of 18F-Fluoromisonidazole and 18F-Fluorodeoxyglucose Positron Emission Tomography.

Glioblastoma is the most aggressive primary brain tumor, characterized by its distinctive intratumoral hypoxia. Sequential preoperative examinations using fluorine-18-fluoromisonidazole (18F-FMISO) and fluorine-18-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) could depict the degree of glucose metabolism with hypoxic condition. However, molecular mechanism of glucose metabolism under hypoxia in glioblastoma has been unclear. The aim of this study was to identify the key molecules of hypoxic glucose metabolism. Using surgically obtained specimens, gene expressions associated with glucose metabolism were analyzed in patients with glioblastoma (n = 33) who underwent preoperative 18F-FMISO and 18F-FDG PET to identify affected molecules according to hypoxic condition. Tumor in vivo metabolic activities were semiquantitatively evaluated by lesion-normal tissue ratio (LNR). Protein expression was confirmed by immunofluorescence staining. To evaluate prognostic value, relationship between gene expression and overall survival was explored in another independent nonoverlapping clinical cohort (n = 17) and validated by The Cancer Genome Atlas (TCGA) database (n = 167). Among the genes involving glucose metabolic pathway, mRNA expression of glucose-6-phosphatase 3 (G6PC3) correlated with 18F-FDG LNR (P = 0.03). In addition, G6PC3 mRNA expression in 18F-FMISO high-accumulated glioblastomas was significantly higher than that in 18F-FMISO low-accumulated glioblastomas (P < 0.01). Protein expression of G6PC3 was consistent with mRNA expression, which was confirmed by immunofluorescence analysis. These findings indicated that the G6PC3 expression might be facilitated by hypoxic condition in glioblastomas. Next, we investigated the clinical relevance of G6PC3 in terms of prognosis. Among the glioblastoma patients who received gross total resection, mRNA expressions of G6PC3 in the patients with poor prognosis (less than 1-year survival) were significantly higher than that in the patients who survive more than 3 years. Moreover, high mRNA expression of G6PC3 was associated with poor overall survival in glioblastoma, as validated by TCGA database. G6PC3 was affluently expressed in glioblastoma tissues with coincidentally high 18F-FDG and 18F-FMISO accumulation. Further, it might work as a prognostic biomarker of glioblastoma. Therefore, G6PC3 is a potential key molecule of glucose metabolism under hypoxia in glioblastoma.

NIMG-53. IMAGING FEATURES AND CONSIDERATION OF PROGRESSION PATTERN OF DIFFUSE HEMISPHERIC GLIOMAS, H3 G34-MUTANT

Abstract BACKGROUND Diffuse hemispheric gliomas, H3 G34-mutant (DHGs-G34m) are newly recognized pediatric-type diffuse high-grade gliomas. We describe detail imaging features of seven cases of DHGs-G34m and consider about progression pattern of DHGs-G34m. RESULTS H3 G34R or H3 G34V was detected by sanger sequencing in all tumors. Mean age of onset was 16.5 years (range: 10-26). Tumors were located on frontal (2), parietal (2), temporal lobe (1) and insular cortex (1), respectively. In one case, gliomatosis cerebri-like multiple lesions involving the cortex and basal ganglia occurred. Magnetic resonance imaging showed T2/FLAIR high lesions with poor contrast enhancement in all cases. All tumors harbored restriction of diffusion. Cystic component and hemorrhage were observed in five and three cases, respectively. Six patients underwent preoperative positron emission tomography. Strong accumulation of methionine and partial accumulation of FDG in all cases. All tumors harbored T2/FLAIR high lesions in the deep white matter, most of which showed methionine accumulation. All patients underwent surgery (total resection in one case, partial resection in five cases, and biopsy in one case) followed by radiation chemotherapy. The mean progression free survival was 9.9 months (range: 1.6-33.1 months). All tumors harbored diffuse infiltration along the white matter, which was temporarily reduced by bevacizumab, but eventually invaded into cerebral peduncle via pyramidal tract and into contralateral brain via corpus callosum or anterior commissure in six cases. Extensive infiltration of tumor cells into the contralateral brain and brain stem was confirmed histopathologically in the autopsy brain of one case. The mean overall survival was 21.6 months (range: 8.9-48.3 months). CONCLUSION DHGs-G34m showed deep white matter infiltration from the time of initial onset, which made gross total resection difficult. Residual lesions extensively infiltrated along the white matter and eventually invaded the brainstem and contralateral brain, leading to death.

Preoperative predictors for recurrence sites associated with poor post-recurrence survival after surgery of non-small cell lung cancer: a multicenter study

BackgroundThe recurrence site that influences post-recurrence survival (PRS) in patients with non-small cell lung cancer (NSCLC) undergoing surgery and the preoperative predictors of recurrence remain unclear.MethodsCohorts 1 and 2 had 4520 (who underwent complete resection for p-stage 0-IIIA NSCLC) and 727 (who experienced recurrence after surgery) patients, respectively. The initial sites of recurrence were the lungs (309 cases), thoracic lymph nodes (225 cases), pleura (112 cases), bone (110 cases), central nervous system (86 cases), adrenal gland (25 cases), abdomen (60 cases), cervical and axillary lymph nodes (38 cases), chest wall (13 cases), skin (5 cases), and eye and tongue (3 cases). For cohort 2 analysis, the initial recurrence site that resulted in poor PRS was analyzed by multivariable analysis using a Cox proportional hazard model. For cohort 1 analysis, the preoperative predictors of recurrence patterns with poor PRS were analyzed by multivariable analysis using a logistic regression model.ResultsIn cohort 2 analysis, recurrence in the central nervous system (hazard ratio [HR], 1.70; p < 0.001), bone (HR, 1.75; p < 0.001), abdomen (HR, 2.39; p < 0.001), and pleura (HR, 1.69; p < 0.001) were independent poor prognostic recurrent sites for PRS and they were high-risk sites (HRS). Intrathoracic lymph nodes, cervical and axillary lymph nodes, lungs, chest wall, adrenal gland, eye and tongue, and skin were low-risk sites (LRS) that did not affect PRS. Patients with multiple LRS without HRS recurrence had a worse prognosis than those with a single LRS without HRS recurrence (5-year PRS 20.2% vs. 37.7%, p < 0.001) and were comparable to those with HRS recurrence (p = 1.000). In cohort 1 analysis, preoperative predictors for HRS and multiple LRS recurrences were positron emission tomography (PET) maximum standardized uptake value (maxSUV) ≥ 3.2 (HR, 5.09; p < 0.001), clinical nodal metastasis (HR, 2.00; p < 0.001), tumor size ≥ 2.4 cm (HR, 1.96; p < 0.001) and carcinoembryonic antigen (CEA) ≥ 5 ng/ml (HR, 1.41; p = 0.004). The cumulative incidence rates of HRS and multiple LRS recurrences within 5 years were 55.9%, 40.9%, 26.3%, 11.1%, and 3.5% (p < 0.001) in patients with 4, 3, 2, 1 and 0 of the above risks, respectively.ConclusionsHRS and multiple LRS were vital recurrences associated with poor PRS. Preoperative PET maxSUV, clinical nodal metastasis, tumor size, and CEA level predicted the incidence of vital recurrence.

Accuracy of DOTATATE PET imaging in the preoperative planning of small bowel neuroendocrine tumor resection.

We assessed the accuracy of preoperative gallium-68 DOTA-Tyr3-octreotate (DOTATATE) positron emission tomography (PET) imaging in estimating multifocality and nodal metastases of small bowel neuroendocrine tumors (sbNETs). A multicenter analysis was performed on patients with sbNETs who underwent preoperative DOTATATE PET imaging and surgical resection, with manual palpation of the entire length of the small bowel, between January 2016 and August 2022. Preoperative imaging reports and blinded secondary imaging reviews were compared to the final postoperative pathology reports. Descriptive statistics were applied. One-hundred and four patients met inclusion criteria. Pathology showed 53 (51%) patients had multifocal sbNETs and 96 (92%) had nodal metastases. The original preoperative DOTATATE PET imaging identified multifocal sbNET in 28 (27%) patients and lymph node(LN) metastases in 80 (77%) patients. Based on original radiology reports, sensitivity for multifocal sbNET identification was 45%, specificity was 92%, positive predictive value (PPV) was 86%, and negative predictive value (NPV) was 62%. For the identification of LN metastases, sensitivity was 82%, specificity was 88%, PPV was 99%, and NPV was 29%. Although DOTATATE PET imaging is specific and relatively accurate, sensitivity and NPV are insufficient to guide surgical planning. Preoperative use should not replace open palpation to identify additional synchronous lesions or to omit regional lymphadenectomy.

Prognostic prediction using maximum standardized uptake value ratio of lymph node-to-primary tumor in preoperative PET-CT for oral squamous cell carcinoma

This study aimed to calculate the ratio of maximum standardized uptake values of cervical lymph nodes to maximum standardized uptake values of primary tumors measured by preoperative fluorodeoxyglucose positron-emission tomography in oral cancer patients, and to retrospectively examine the prognostic association and evaluate whether it could be a prognostic factor. We retrospectively examined consecutive Japanese patients diagnosed with oral squamous cell carcinoma who underwent oral cancer resection and cervical dissection between January 2014 and December 2018. The study included 52 patients aged 39–89 years (median age 66.5 years), excluding non-cervical dissection surgery and/or non-underwent preoperative positron-emission tomography. The maximum standardized uptake value of the cervical lymph nodes and primary tumor was measured, and the ratio of maximum standardized uptake values of the lymph nodes to that of the primary tumor was calculated. The median follow-up of 52 patients was 1,465 days (198–2,553 days), and overall survival was significantly worse in patients with a high lymph node-to-tumor standardized uptake values ratio (>0.4739) (5 years, 58.8% vs. 88.2%; P<0.05). Pretreatment lymph node-to-tumor standardized uptake values ratio can be easily calculated, and as a predictor of prognosis, it may be of assistance when considering the treatment strategy for oral cancer.

Role of minimally invasive secondary cytoreduction in patients with recurrent ovarian cancer

ObjectiveRetrospective series have shown minimally invasive secondary cytoreductive surgery is a feasible approach in selected cases of recurrent ovarian cancer. However, no predictors of minimally invasive secondary cytoreductive surgery feasibility...

The oncological characteristics of non-prostate-specific membrane antigen (PSMA)-expressing primary prostate cancer on preoperative PSMA positron emission tomography/computed tomography.

The oncological characteristics of non-prostate-specific membrane antigen (PSMA)-expressing primary prostate cancer on preoperative PSMA positron emission tomography/computed tomography.

Retrospective audit: Utility of PET scan in routine preoperative rectal cancer staging.

Accurate staging for rectal cancer is pertinent with recent introduction of rectum-sparing approaches for patients showing complete clinical response on restaging. Positron emission tomography(PET) is used in detection of recurrence or metastasis, but its value in routine preoperative rectal cancer staging remains unclear. Studies report that preoperative PET altered the stage in 39% and changed the management in 17-27% of patients. Our study aims to look at the utility of PET in routine preoperative staging of rectal cancer within 2 two colorectal units, and to determine if PET did result in a change in management. Patients in Nepean Hospital (NSW) and Peter MacCallum Cancer Centre (VIC) who were diagnosed with rectal cancer between 1 January 2017 and 31 December 2021 were included in this retrospective study. All patients who did not have a PET scan were excluded. PET scan results were then compared with MRI and CT results. Three hundred and fifty-seven patients were included in the study. 30.3% of the patients had Stage 3 rectal cancer. 71.7% received neoadjuvant therapy. PET scan provided additional information in 55.5% of patients when compared with CT and MRI alone; 18.2% of the PET findings resulted in an altered management for the patient. PET scan can be a valuable tool in accurate staging, especially for ambiguous or equivocal lesions on CT. Our study demonstrated that additional information from PET scan resulted in an altered management plan in 18.2% of the patients. PET/MRI as a newer modality may be more accurate with reduced radiation exposure.

PET/NIR-II fluorescence imaging and image-guided surgery of glioblastoma using a folate receptor α-targeted dual-modal nanoprobe.

The surgery of glioblastoma (GBM) requires a maximal resection of the tumor when it is safe and feasible. The infiltrating growth property of the GBM makes it a challenge for neurosurgeons to identify the tumor tissue even with the assistance of the surgical microscope. This highlights the urgent requirement for imaging techniques that can differentiate tumor tissues during surgery in real time. Fluorescence image-guided surgery of GBM has been investigated using several non-specific fluorescent probes that emit light in the visible and the first near-infrared window (NIR-I, 700-900nm), which limit the detection accuracy because of the non-specific targeting mechanism and spectral characteristics. Targeted NIR-II (1000-1700nm) fluorescent probes for GBM are thus highly desired. The folate receptor (FR) has been reported to be upregulated in GBM, which renders it to be a promising target for specific tumor imaging. In this study, the folic acid (FA) that can target the FR was conjugated with the clinically approved indocyanine green (ICG) dye and DOTA chelator for radiolabeling with 64Cu to achieve targeted positron emission tomography (PET) and fluorescence imaging of GBM. Surprisingly it was found that the resulted bioconjugate, DOTA-FA-ICG and non-radioactive natCu-DOTA-FA-ICG, were both self-assembled into nanoparticles with NIR-II emission signal. The radiolabeled DOTA-FA-ICG, 64Cu-DOTA-FA-ICG, was found to specifically accumulate in the orthotopic GBM models using in vivo PET, NIR-II, and NIR-I fluorescence imaging. The best time window of fluorescence imaging was demonstrated to be 24h after DOTA-FA-ICG injection. NIR-II fluorescence image-guided surgery was successfully conducted in the orthotopic GBM models using DOTA-FA-ICG. All the fluorescent tissue was removed and proved to be GBM by the H&E examination. Overall, our study demonstrates that the probes, 64Cu-DOTA-FA-ICG and DOTA-FA-ICG, hold promise for preoperative PET examination and intraoperative NIR-II fluorescence image-guided surgery of GBM, respectively.

Survival after liver resection and liver transplantation for colorectal liver metastases: a comparative analysis stratified by metabolic tumor volume assessed by 18F-FDG PET/CT.

Many patients undergoing resection for colorectal liver metastases (CRLM) recur with poor survival. Overall survival (OS) following liver transplantation (LT) for CRLM is reported to be about 80% at 5 years. In this study, survival following resection versus transplantation for CRLM in patients with moderate (6-70cm3) metabolic tumor volume (MTV) from the preoperative positron emission tomography (PET) was compared. Disease-free survival (DFS), OS and post recurrence survival (PRS) following resection (n=18) and LT (n=12) was compared by using the Kaplan Meier method and log rank test for patients with moderate MTV. Patients undergoing LT had unresectable metastases, significantly lower age, higher tumor burden score and number of liver metastases, longer time from diagnosis to surgery, and more patients received neoadjuvant chemotherapy. OS at 5 years was 39% in the resection group and 83% in the LT group (P=0.012). PRS was significantly improved in patients treated with LT compared to resection with 71% alive at 5 years from recurrence compared to 17% in the resection group (P=0.017). LT for selected patients seems to be superior to resection as treatment for CRLM for patients with moderate MTV.

\u201cMYH9 mutation and squamous cell cancer of the tongue in a young adult: a novel case report\u201d

BackgroundThe incidence of tongue cancer in young adults is on the rise. This trend is more pronounced in females. Although the aetiology is still unclear, there is mounting evidence that genetic syndromes can play a key role in development of oral cancers in this patient group. We report the first case of oral squamous cell carcinoma (oSCC) in a young adult with an MYH9-related disorder (MYH9-RD).Case presentationA 19-year-old female with a germline MYH9 variant (missense variant in exon 2: c.287C > T, (p.Ser96Leu)) was referred to the head and neck surgery department for investigation of a painful, thick right tongue ulcer. She was diagnosed with Epstein syndrome, an MYH9-RD, at 12 years of age. Her main phenotypic features were profound thrombocytopenia and marked renal impairment. The tongue biopsy confirmed SCC. Preoperative positron emission tomography (PET) revealed avidity in the right tongue and ipsilateral level 2A neck lymph node. With substantial preoperative multidisciplinary input, she underwent cancer ablation and microvascular free flap reconstruction. Her pathology showed a 35 mm diameter, 14 mm thick moderately differentiated SCC with perineural and lymphovascular invasion. Two out of 38 right neck nodes were positive for metastasis with extranodal extension. None of the 34 left neck nodes was involved.She had an uneventful recovery and was discharged home on day 6 postoperative day. On day 15 postoperative day, she had catastrophic bleeding in the neck with a respiratory arrest after a forceful cough. She required an emergency tracheostomy and returned to the theatre for haemostasis. Following a short inpatient stay, she was again discharged home and underwent adjuvant therapy consisting of external beam radiotherapy of 60Gy in 30 fractions. On clinical examination and PET at 6 months after surgery, she had no evidence of disease recurrence.ConclusionsMYH9-RD can present with advanced locoregional oral cavity malignancy at an early age. The combination of profound thrombocytopenia and marked renal impairment can impact heavily on routine major head and neck cancer surgery and adjuvant treatment. This rare and challenging condition underlines the importance of early detection of cancer and multidisciplinary team input.

Diagnostic performance of positron emission tomography in the staging of pseudomyxoma peritonei

BackgroundPseudomyxoma peritonei (PMP) is a rare clinical entity, commonly derived from a mucin-producing tumour of the appendix. International consensus is unclear on the role of positron emission tomography (PET) in preoperative staging. This study aimed to assess the ability of preoperative PET in predicting the histological grade of PMP. MethodsAll patients scheduled for cytoreductive surgery (CRS) +/− hyperthermic intraperitoneal chemotherapy (HIPEC) for PMP who underwent preoperative PET at a single centre between June 2007 and June 2020 were included. A nuclear medicine physician, blinded to patient outcomes, retrospectively reviewed imaging studies to assess for maximum tumour standardised uptake value (SUV) to mean liver SUV ratio (SUVTLR) and maximum porta hepatis SUV to mean liver SUV ratio (SUVPLR). ResultsBetween April 2007 and December 2020, a total of 204 patients underwent surgical intervention for PMP. Of these, 124 (60.8%) met the inclusion criteria. Median peritoneal carcinomatosis index for the entire cohort was 9 and complete cytoreduction (CC0/1) was achieved in 109 (88%) patients. Patients with high-grade PMP were more likely to have diffuse peritoneal disease (p < 0.001) and higher SUVTLR (p<0.001). The area under the ROC curve (AUC) of SUVTLR in predicting high-grade pathology was 71% (p = 0.003). Patients with a SUVTLR ≤ 0.78 had improved disease-free survival (p = 0.042). ConclusionPreoperative PET showed positive correlation with high-grade PMP and acceptable sensitivity and specificity as a diagnostic tool. PET should be considered a useful adjunct to standard imaging for predicting histological grade in the staging of patients with PMP.

Primary Diffuse Leptomeningeal Atypical Teratoid/Rhabdoid Tumor Initially Masquerading as Guillain–Barré Syndrome: A Case Report and Literature Review

AbstractA 10-year-old male child patient was admitted with a chief complaint of progression of lower limb weakness lasting for 5 weeks. An initial clinical picture was reminiscent of Guillain–Barré syndrome. Repeated cerebrospinal fluid (CSF) cytological examinations were negative for neoplastic cells, but leptomeningeal biopsy targeting positron emission tomography (PET) avid lesion confirmed the invasion of tumor cells which were negatively stained with Brahma-related gene 1. An extensive literature review identified five cases of primary diffuse leptomeningeal atypical teratoid/rhabdoid tumors, and the clinical characteristics, including ours, were characterized as follows: (1) there was a bimodal age distribution in young children and adolescents with a male predominance, (2) roughly half of the patients fulfilled the diagnostic criteria of albuminocytologic dissociation and CSF cytology was neither sensitive nor specific to establish a definitive diagnosis, and (3) cerebrospinal magnetic resonance imaging findings were mostly indistinguishable from those of infectious or inflammatory diseases. We would like to suggest that primary leptomeningeal tumor should be included in the differential diagnosis of progressive polyneuropathy even in the absence of CSF cytological findings and implementation of preoperative PET may enhance the diagnostic accuracy of such a miscellaneous central nervous system tumor.

Changes in treatment intent and target definition for preoperative radiotherapy after 18F-Fluorodeoxyglucose positron emission tomography in rectal cancer: A Meta-analysis

PurposeTo evaluate the impact of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) on changes in treatment plan and target definition for preoperative radiotherapy in patients with rectal cancer. MethodsEmbase, PubMed, and Cochrane Library were searched up to November 2020 for all studies investigating the role of preoperative FDG PET in patients who underwent neoadjuvant radiotherapy before curative-intent surgery. The proportion of patients whose treatment plan (curative vs. palliative intent) or target definition was changed after FDG PET was analyzed. A random-effects model was used for pooled analysis. The change in target definition was compared between conventional radiological imaging-based target volume [gross tumor volume (GTV) or planning target volume (PTV)] and PET-based target volume (GTV or PTV) using the standardized mean difference (SMD) and 95% confidence interval (CI). ResultsA total of 336 patients from twelve studies were included. In eight studies, PET changed either the treatment intent or target definition in 24.8% of patients (95% CI 15.1% to 37.9%, I2 = 69%). In ten studies, the PET-based GTV was lower than the conventional imaging-based target volume (SMD −7.0, 95% CI −1.39 to −0.01). However, there was no significant difference between conventional imaging-based and PET-based PTV (SMD −0.07, 95% CI −0.75 to 0.62). In six studies evaluating the initial staging based on PET, the initial staging (nodal or metastasis status) was changed in 53 of 229 patients (23.1%). Newly detected or additional distant metastases were identified in 22 patients (9.6%) after FDG PET. ConclusionThe use of FDG PET influences radiotherapy planning in a fourth of patients with rectal cancer. FDG PET can provide additive information for accurate tumor delineation, although PET-based PTV did not significantly change. These findings suggest that FDG PET may be beneficial to patients with rectal cancer before establishing a radiotherapy plan.

Development and Validation of a Radiomics Model Based on 18F-FDG PET of Primary Gastric Cancer for Predicting Peritoneal Metastasis.

ObjectivesThe aim of this study was to develop a preoperative positron emission tomography (PET)-based radiomics model for predicting peritoneal metastasis (PM) of gastric cancer (GC).MethodsIn this study, a total of 355 patients (109PM+, 246PM-) who underwent preoperative fluorine-18-fludeoxyglucose (18F-FDG) PET images were retrospectively analyzed. According to a 7:3 ratio, patients were randomly divided into a training set and a validation set. Radiomics features and metabolic parameters data were extracted from PET images. The radiomics features were selected by logistic regression after using maximum relevance and minimum redundancy (mRMR) and the least shrinkage and selection operator (LASSO) method. The radiomics models were based on the rest of these features. The performance of the models was determined by their discrimination, calibration, and clinical usefulness in the training and validation sets.ResultsAfter dimensionality reduction, 12 radiomics feature parameters were obtained to construct radiomics signatures. According to the results of the multivariate logistic regression analysis, only carbohydrate antigen 125 (CA125), maximum standardized uptake value (SUVmax), and the radiomics signature showed statistically significant differences between patients (P<0.05). A radiomics model was developed based on the logistic analyses with an AUC of 0.86 in the training cohort and 0.87 in the validation cohort. The clinical prediction model based on CA125 and SUVmax was 0.76 in the training set and 0.69 in the validation set. The comprehensive model, which contained a rad-score and the clinical factor (CA125) as well as the metabolic parameter (SUVmax), showed promising performance with an AUC of 0.90 in the training cohort and 0.88 in the validation cohort, respectively. The calibration curve showed the actual rate of the nomogram-predicted probability of peritoneal metastasis. Decision curve analysis (DCA) also demonstrated the good clinical utility of the radiomics nomogram.ConclusionsThe comprehensive model based on the rad-score and other factors (SUVmax, CA125) can provide a novel tool for predicting peritoneal metastasis of gastric cancer patients preoperatively.

MP11-14 VERY LOW PROSTATE PET CT PSMA EXPRESSION MAY BE MISLEADING IN STAGING PROSTATECTOMY CANDIDATES

You have accessJournal of UrologyProstate Cancer: Staging (MP11)1 Sep 2021MP11-14 VERY LOW PROSTATE PET CT PSMA EXPRESSION MAY BE MISLEADING IN STAGING PROSTATECTOMY CANDIDATES Rennen Haramaty, Alon Lazarovich, Asaf Shvero, Miki Haifler, Jonathan Gal, Shay Golan, Sagi Shpitzer, Azik Hoffman, Omri Nativ, Yuval Freifeld, Rani Zreik, Zohar Dotan, and Barak Rosenzweig Rennen HaramatyRennen Haramaty More articles by this author , Alon LazarovichAlon Lazarovich More articles by this author , Asaf ShveroAsaf Shvero More articles by this author , Miki HaiflerMiki Haifler More articles by this author , Jonathan GalJonathan Gal More articles by this author , Shay GolanShay Golan More articles by this author , Sagi ShpitzerSagi Shpitzer More articles by this author , Azik HoffmanAzik Hoffman More articles by this author , Omri NativOmri Nativ More articles by this author , Yuval FreifeldYuval Freifeld More articles by this author , Rani ZreikRani Zreik More articles by this author , Zohar DotanZohar Dotan More articles by this author , and Barak RosenzweigBarak Rosenzweig More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000001984.14AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: 68Ga-labeled prostate-specific membrane antigen (PSMA) positron-emission tomography (PET) computed tomography (CT) imaging quickly earns an important role in staging radical prostatectomy candidates. While PSMA is generally weakly expressed in normal prostate tissue, it is strongly upregulated in prostate cancer. However, some clinically significant prostate cancers exemplify low reads on PSMA PET CT. In the current work we evaluate this unique sub-population of patients with ‘negative’ prostate PSMA PET CT reads. METHODS: We retrospectively reviewed 392 patients who underwent radical prostatectomy between September 2014 to July 2019 in 5 medical centres.Patients with pre-operative PSMA PET CT imaging were included. We collected data on baseline characteristics including demographics, comorbidities, prostate specific antigen (PSA) and rectal exam, prior biopsies, imaging results, and biopsies and radical prostatectomy histology. An index group of patients with ‘negative’ PSMA PET CT prostate read was defined as “scarce” uptake and/or numerically maximal standardized uptake value (SUVmax) below physiologic uptake. For control we used patients with PSMA PET CT prostate read defined as “intense” and/or numerically as SUVmax above physiologic uptake. RESULTS: 97 patients had PSMA PET CT imaging prior surgery, 52 (54%) of whom fitted with the index group inclusion criteria and 45 (46%) with the control group. All pre-operative characteristics did not significantly differ in-between groups except lesion size and SUVmax per PSMA PET CT (Table1). Prostatectomy specimen’s histology analysis significantly differed in-between groups, for ISUP score, seminal vesicles invasion, T stage and positive margins rates (p<0.05).Nonetheless, 50 (96%) of the index group patients harbored clinically significant disease (ISUP>=2) with extra-prostatic disease showed in 24 (46%) and peri-neural invasion in 35 (67%).Positive lymph nodes were found in 4 (8%) of index group patients. CONCLUSIONS: While prostate cancer aggressiveness was generally correlated with intense uptake of PSMA on pre-operative PSMA/PET CT, a subpopulation of patients with clinically significant cancer and aggressive characteristics show weak reads only on this imaging. These data raise concern applying PSMA PET CT for staging of prostatectomy candidates. Source of Funding:- © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e184-e184 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Rennen Haramaty More articles by this author Alon Lazarovich More articles by this author Asaf Shvero More articles by this author Miki Haifler More articles by this author Jonathan Gal More articles by this author Shay Golan More articles by this author Sagi Shpitzer More articles by this author Azik Hoffman More articles by this author Omri Nativ More articles by this author Yuval Freifeld More articles by this author Rani Zreik More articles by this author Zohar Dotan More articles by this author Barak Rosenzweig More articles by this author Expand All Advertisement Loading ...

Radiopharmaceutical and Eu3+ doped gadolinium oxide nanoparticles mediated triple-excited fluorescence imaging and image-guided surgery

Cerenkov luminescence imaging (CLI) is a novel optical imaging technique that has been applied in clinic using various radionuclides and radiopharmaceuticals. However, clinical application of CLI has been limited by weak optical signal and restricted tissue penetration depth. Various fluorescent probes have been combined with radiopharmaceuticals for improved imaging performances. However, as most of these probes only interact with Cerenkov luminescence (CL), the low photon fluence of CL greatly restricted it’s interaction with fluorescent probes for in vivo imaging. Therefore, it is important to develop probes that can effectively convert energy beyond CL such as β and γ to the low energy optical signals. In this study, a Eu3+ doped gadolinium oxide (Gd2O3:Eu) was synthesized and combined with radiopharmaceuticals to achieve a red-shifted optical spectrum with less tissue scattering and enhanced optical signal intensity in this study. The interaction between Gd2O3:Eu and radiopharmaceutical were investigated using 18F-fluorodeoxyglucose (18F-FDG). The ex vivo optical signal intensity of the mixture of Gd2O3:Eu and 18F-FDG reached 369 times as high as that of CLI using 18F-FDG alone. To achieve improved biocompatibility, the Gd2O3:Eu nanoparticles were then modified with polyvinyl alcohol (PVA), and the resulted nanoprobe PVA modified Gd2O3:Eu (Gd2O3:Eu@PVA) was applied in intraoperative tumor imaging. Compared with 18F-FDG alone, intraoperative administration of Gd2O3:Eu@PVA and 18F-FDG combination achieved a much higher tumor-to-normal tissue ratio (TNR, 10.24 ± 2.24 vs. 1.87 ± 0.73, P = 0.0030). The use of Gd2O3:Eu@PVA and 18F-FDG also assisted intraoperative detection of tumors that were omitted by preoperative positron emission tomography (PET) imaging. Further experiment of image-guided surgery demonstrated feasibility of image-guided tumor resection using Gd2O3:Eu@PVA and 18F-FDG. In summary, Gd2O3:Eu can achieve significantly optimized imaging property when combined with 18F-FDG in intraoperative tumor imaging and image-guided tumor resection surgery. It is expected that the development of the Gd2O3:Eu nanoparticle will promote investigation and application of novel nanoparticles that can interact with radiopharmaceuticals for improved imaging properties. This work highlighted the impact of the nanoprobe that can be excited by radiopharmaceuticals emitting CL, β, and γ radiation for precisely imaging of tumor and intraoperatively guide tumor resection.

Evaluation of OTL38-Generated Tumor-to-Background Ratio in Intraoperative Molecular Imaging-Guided Lung Cancer Resections.

Cancer surgery has multiple challenges including localizing small lesions, ensuring negative margins, and identifying synchronous cancers. One of the tools proposed to address these issues is intraoperative molecular imaging (IMI). An important consideration in IMI is the quantification of the tumor fluorescence during the procedure and using that data to add clinical value. Currently, the most commonly cited measure of quantification is the tumor-to-background ratio (TBR). Our goal was to evaluate the clinical value of TBR measured with OTL38 NIR tracer during a lung cancer resection. Intraoperative data was retrospectively reviewed from a prospectively collected 5-year database. Between 2015 and 2020, 279 patients were included in the study. For standardization, all patients underwent infusion of the same targeted molecular optical contrast agent (OTL38) for lung cancer resections; then, the mean fluorescence intensity of the tumors and background tissues were calculated. To evaluate the clinical efficacy of the TBR calculation, the results were correlated with patient, biologic, tumor, and technological factors. For pulmonary surgery, patient factors such as gender, age, smoking history, and time from infusion of OTL38 to surgery did not have any statistical significance in predicting the TBR during surgery. In addition, TBR measurements did not correlate with location of the tumor in the lung (p= 0.123). There was no statistical correlation of preoperative positron emission tomography measurements (standardized uptake value) with intraoperative TBR. However, there was statistically significant negative correlation of in situ TBR measurement and the distance of the lesion from the surface of the organ (p< 0.001). Adenocarcinoma spectrum lesions overall had statistically significant correlation with in situ fluorescence compared to other NSCLC malignancies (p< 0.01) but TBR measurements could not identify histopathologic subtype on univariate analysis (p= 0.089). There was a tendency for in situ fluorescence for moderately and well-differentiated adenocarcinoma spectrum lesions, but this was not statistically significant. When comparing the in situ TBR of benign to malignant nodules in the lung, there was no statistically significant association (p= 0.145). In subset analysis, adenocarcinoma spectrum lesions tend to fluoresce at brighter with OTL38 compared to other histologic subtypes. In our various iterations, the results of our retrospective analysis did not show that TBR measurements during OTL38-guided surgery provide clinically useful information about the nature of the nodule or cancer. The true value of IMI is in the ability for the surgeon to use the fluorescence to guide the surgeon to the tumor and margins, but that sophisticated quantification of the amount of fluorescence may not have clinical utility.

Surgical Resection After Talimogene Laherparepvec for Melanoma: Persistent Fuorodeoxyglucose Avidity on Positron Emission Tomography Despite No Viable Disease

Talimogene laherparepvec (TVEC) is an injectable attenuated oncolytic herpes simplex virus (HSV-1) used in the treatment of loco regionally metastatic melanoma. Lesions managed by TVEC are generally considered unresectable at time of initiation of intralesional therapy; however, a subset of patients go on to have surgical resection of loco regionally controlled disease. We sought to review our experience with surgical excision of treated lesions to offer an insight into the radiologic correlate, treatment effect, and pathological findings of intralesional TVEC therapy. This is a retrospective descriptive case series of patients who underwent TVEC injection at Mayo Clinic, Rochester, MN, between October 2016 and July 2020. Institutional Institutional Review Board approval was obtained. Twenty-one patients underwent intralesional TVEC, met inclusion criteria, and were included in this series. Seven went on to surgical excision of the injected lesions after an initial course of TVEC. Of those 7 patients, 4 had residual melanoma in the specimen on final pathology, while 3 had a complete pathologic response. All 3 patients who had no residual disease on pathology continued to have fluorodeoxyglucose (FDG) avidity on preoperative positron emission tomography scan of the excised lesions. Despite ongoing FDG avidity on PET scan, patients who have well-controlled disease and stability over time of the injected lesions may benefit from surgical excision following a course of TVEC. This may render the patient clinically disease free and/or allow them a reprieve from TVEC treatment.