Melanoma of the middle ear: initial presentation, Fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography imaging and follow up

Abstract Background: We present a rare case of primary mucosal melanoma of the middle ear imaged with 18F-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography (FDG-PET/CT). Method: Clinical, radiological, intra-operative and histological findings are discussed. Results: An 88-year-old woman presented with intermittent otorrhoea of the left ear for several months. Otoscopy revealed a livid protrusion of the tympanic membrane. Melanoma was not suspected initially, but was established on transmembranous biopsy. Pre-operative 18F-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography revealed a mass lesion in the left tympanic cavity with high fluoro-deoxyglucose uptake, as well as an ipsilateral intraparotid lymph node metastasis. The patient underwent surgical treatment. The diagnosis of melanoma was confirmed histologically. Conclusion: In this rare case, clinical, radiological and surgical findings led to the diagnosis of a primary mucosal melanoma of the middle ea

Prediction of pelvic lymph node metastases and PSMA PET positive pelvic lymph nodes with multiparametric MRI and clinical information in primary staging of prostate cancer

PURPOSE To compare the accuracy of multiparametric MRI (mpMRI), $^{68}$Ga-PSMA PET and the Briganti 2019 nomogram in the prediction of metastatic pelvic lymph nodes (PLN) in prostate cancer, to assess the accuracy of mpMRI and the Briganti nomogram in prediction of PET positive PLN and to investigate the added value of quantitative mpMRI parameters to the Briganti nomogram. METHOD This retrospective IRB-approved study included 41 patients with prostate cancer undergoing mpMRI and $^{68}$Ga-PSMA PET/CT or MR prior to prostatectomy and pelvic lymph node dissection. A board-certified radiologist assessed the index lesion on diffusion-weighted (Apparent Diffusion Coefficient, ADC; mean/volume), T2-weighted (capsular contact length, lesion volume/maximal diameters) and contrast-enhanced (iAUC, k$_{ep}$, K$^{trans}$, v$_{e}$) sequences. The probability for metastatic pelvic lymph nodes was calculated using the Briganti 2019 nomogram. PET examinations were evaluated by two board-certified nuclear medicine physicians. RESULTS The Briganti 2019 nomogram performed superiorly (AUC: 0.89) compared to quantitative mpMRI parameters (AUCs: 0.47-0.73) and $^{68}$Ga-PSMA-11 PET (AUC: 0.82) in the prediction of PLN metastases and superiorly (AUC: 0.77) in the prediction of PSMA PET positive PLN compared to MRI parameters (AUCs: 0.49-0.73). The addition of mean ADC and ADC volume from mpMRI improved the Briganti model by a fraction of new information of 0.21. CONCLUSIONS The Briganti 2019 nomogram performed superiorly in the prediction of metastatic and PSMA PET positive PLN, but the addition of parameters from mpMRI can further improve its accuracy. The combined model could be used to stratify patients requiring ePLND or PSMA PET

Impact of Bayesian penalized likelihood reconstruction on quantitative and qualitative aspects for pulmonary nodule detection in digital 2-[18F]FDG-PET/CT

To evaluate the impact of block sequential regularized expectation maximization (BSREM) reconstruction on quantitative and qualitative aspects of 2-[18F]FDG-avid pulmonary nodules compared to conventional ordered subset expectation maximization (OSEM) reconstruction method. Ninety-one patients with 144 2-[18F]FDG-avid pulmonary nodules (all ≤ 20 mm) undergoing PET/CT for oncological (re-)staging were retrospectively included. Quantitative parameters in BSREM and OSEM (including point spread function modelling) were measured, including maximum standardized uptake value (SUVmax). Nodule conspicuity in BSREM and OSEM images was evaluated by two readers. Wilcoxon matched pairs signed-rank test was used to compare quantitative and qualitative parameters in BSREM and OSEM. Pulmonary nodule SUVmax was significantly higher in BSREM images compared to OSEM images [BSREM 5.4 (1.2–20.7), OSEM 3.6 (0.7–17.4); p = 0.0001]. In a size-based analysis, the relative increase in SUVmax was more pronounced in smaller nodules (≤ 7 mm) as compared to larger nodules (8–10 mm, or > 10 mm). Lesion conspicuity was higher in BSREM than in OSEM (p < 0.0001). BSREM reconstruction results in a significant increase in SUVmax and a significantly improved conspicuity of small 2-[18F]FDG-avid pulmonary nodules compared to OSEM reconstruction. Digital 2-[18F]FDG-PET/CT reading may be enhanced with BSREM as small lesion conspicuity is improved

Patterns of metastatic spread and tumor burden in unselected cancer patients using PET imaging: Implications for the oligometastatic spectrum theory

INTRODUCTION AND BACKGROUND: Metastatic disease has been proposed as a continuum, with no clear cut-off between oligometastatic and polymetastatic disease. This study aims to quantify tumor burden and patterns of spread in unselected metastatic cancer patients referred for PET-based staging, response assessment of restaging. MATERIALS AND METHODS: All oncological fluorodeoxyglucose (FDG-) and prostate-specific membrane antigen (PSMA-) positron emission tomography (PET) scans conducted at a single academic center in 2020 were analyzed. Imaging reports of all patients with metastatic disease were reviewed and assessed. RESULTS: For this study, 7,000 PET scans were screened. One third of PET scans (n = 1,754; 33 %) from 1,155 unique patients showed presence of metastatic disease from solid malignancies, of which 601 (52 %) and 554 (48 %) were classified as oligometastatic (maximum 5 metastases) and polymetastatic (>5 metastases), respectively. Lung and pleural cancer, skin cancer, and breast cancer were the most common primary tumor histologies with 132 (23.8 %), 88 (15.9 %), and 72 (13.0 %) cases, respectively. Analysis of the number of distant metastases showed a strong bimodal distribution of the metastatic burden with 26 % of patients having one solitary metastasis and 43 % of patients harboring >10 metastases. Yet, despite 43 % of polymetastatic patients having >10 distant metastases, their pattern of distribution was restricted to one or two organs in about two thirds of patients, and there was no association between the number of distant metastases and the number of involved organs. CONCLUSION: The majority of metastatic cancer patients are characterized by either a solitary metastasis or a high tumor burden with >10 metastases, the latter was often associated with affecting a limited number of organs. These findings support both the spectrum theory of metastasis and the seed and soil hypothesis and can support in designing the next generation of clinical trials in the field of oligometastatic disease

PET/CT radiomics for prediction of hyperprogression in metastatic melanoma patients treated with immune checkpoint inhibitors

PurposeThis study evaluated pretreatment 2[18F]fluoro-2-deoxy-D-glucose (FDG)-PET/CT-based radiomic signatures for prediction of hyperprogression in metastatic melanoma patients treated with immune checkpoint inhibition (ICI).Material and methodFifty-six consecutive metastatic melanoma patients treated with ICI and available imaging were included in the study and 330 metastatic lesions were individually, fully segmented on pre-treatment CT and FDG-PET imaging. Lesion hyperprogression (HPL) was defined as lesion progression according to RECIST 1.1 and doubling of tumor growth rate. Patient hyperprogression (PD-HPD) was defined as progressive disease (PD) according to RECIST 1.1 and presence of at least one HPL. Patient survival was evaluated with Kaplan-Meier curves. Mortality risk of PD-HPD status was assessed by estimation of hazard ratio (HR). Furthermore, we assessed with Fisher test and Mann-Whitney U test if demographic or treatment parameters were different between PD-HPD and the remaining patients. Pre-treatment PET/CT-based radiomic signatures were used to build models predicting HPL at three months after start of treatment. The models were internally validated with nested cross-validation. The performance metric was the area under receiver operating characteristic curve (AUC).ResultsPD-HPD patients constituted 57.1% of all PD patients. PD-HPD was negatively related to patient overall survival with HR=8.52 (95%CI 3.47-20.94). Sixty-nine lesions (20.9%) were identified as progressing at 3 months. Twenty-nine of these lesions were classified as hyperprogressive, thereby showing a HPL rate of 8.8%. CT-based, PET-based, and PET/CT-based models predicting HPL at three months after the start of treatment achieved testing AUC of 0.703 +/- 0.054, 0.516 +/- 0.061, and 0.704 +/- 0.070, respectively. The best performing models relied mostly on CT-based histogram features.ConclusionsFDG-PET/CT-based radiomic signatures yield potential for pretreatment prediction of lesion hyperprogression, which may contribute to reducing the risk of delayed treatment adaptation in metastatic melanoma patients treated with ICI

Recognition of and treatment recommendations for oligometastatic disease in multidisciplinary tumor boards

BACKGROUND AND INTRODUCTION Growing evidence supports a combined modality treatment strategy for patients with oligometastatic disease. However, lack of phase III trial data and uncertainties around patient selection highlight the importance of multidisciplinary tumor boards (MDT) in therapeutic decision-making. This study aimed to analyze the recognition of and treatment recommendations for oligometastatic patients by MDTs at a large comprehensive cancer center in order to better understand current treatment patterns of oligometastasis. MATERIALS AND METHODS For this retrospective single-center cross-sectional study, oligometastatic patients were identified by screening oncological PET and concurrent brain MRI scans conducted at our center in 2020. MDT discussions and recommendations within four weeks of the imaging diagnosis of oligometastasis were analyzed. Logistic regression analysis was used to identify predictors for the addition of local therapy to standard-of-care. RESULTS A total of 787 oligometastatic cases were identified. Lung cancer and mesothelioma, skin cancer, and prostate cancer were the most common histologies with 231 (29 %), 160 (20 %), and 84 (11 %) cases, respectively. Almost half of the cases (46 %) had one distant metastasis on imaging only. More than half (56 %) of all oligometastatic cases were discussed at an MDT. In 47 % of cases, for which a therapeutic recommendation was reached in an MDT, local therapy was part of the therapeutic strategy. On logistic regression analysis, oligometastatic skin cancer was significantly associated with a recommendation for local therapy (p < 0.05), whereas the number of oligometastases was not (p = 0.202). CONCLUSION More than half of oligometastatic cases were discussed in MDTs, of which more than every second received a recommendation including the addition of local therapy. This frequency of MDT use underscores the importance of multidisciplinary decision-making, yet efforts should be increased to standardize reporting and use standard nomenclature on oligometastasis in MDTs to better frame multidisciplinary discussion

Improved Survival Prediction by Combining Radiological Imaging and S-100B Levels Into a Multivariate Model in Metastatic Melanoma Patients Treated With Immune Checkpoint Inhibition

Purpose: We explored imaging and blood bio-markers for survival prediction in a cohort of patients with metastatic melanoma treated with immune checkpoint inhibition. Materials and Methods: 94 consecutive metastatic melanoma patients treated with immune checkpoint inhibition were included into this study. PET/CT imaging was available at baseline (Tp0), 3 months (Tp1) and 6 months (Tp2) after start of immunotherapy. Radiological response at Tp2 was evaluated using iRECIST. Total tumor burden (TB) at each time-point was measured and relative change of TB compared to baseline was calculated. LDH, CRP and S-100B were also analyzed. Cox proportional hazards model and logistic regression were used for survival analysis. Results: iRECIST at Tp2 was significantly associated with overall survival (OS) with C-index=0.68. TB at baseline was not associated with OS, whereas TB at Tp1 and Tp2 provided similar predictive power with C-index of 0.67 and 0.71, respectively. Appearance of new metastatic lesions during follow-up was an independent prognostic factor (C-index=0.73). Elevated LDH and S-100B ratios at Tp2 were significantly associated with worse OS: C-index=0.73 for LDH and 0.73 for S-100B. Correlation of LDH with TB was weak (r=0.34). A multivariate model including TB change, S-100B, and appearance of new lesions showed the best predictive performance with C-index=0.83. Conclusion: Our analysis shows only a weak correlation between LDH and TB. Additionally, baseline TB was not a prognostic factor in our cohort. A multivariate model combining early blood and imaging biomarkers achieved the best predictive power with regard to survival, outperforming iRECIST

Prognostic value of different CT measurements in early therapy response evaluation in patients with metastatic colorectal cancer

OBJECTIVES: Patients with advanced stage colorectal carcinoma (CRC) display hepatic metastases on initial staging in up to 20% of cases. The effectiveness of chemotherapy is generally evaluated by computed tomography (CT) imaging using standardized criteria (RECIST). However, RECIST is not always optimal, and other criteria have been shown to correlate with pathologic response and overall survival. The aim of this study was to evaluate the prognostic value of different CT measurement for response assessment after initiation of chemotherapy in patients with synchronous colorectal cancer liver metastases. METHODS: Fifty-five patients with CRC and synchronous hepatic metastases were evaluated retrospectively at 2 academic centers. Different size, volume, ratio and attenuation parameters were determined at baseline and after 3 cycles of chemotherapy. The prognostic value of baseline measurements and of the change between baseline and second measurements was analyzed using Kaplan-Meier estimates. RESULTS: Median time to progression was 279 days, median overall survival was 704 days. In this selective patient population, neither a significant prognostic value of initial baseline CT parameters nor a prognostic value of the change between the first and the second CT measurements was found. CONCLUSION: Initial morphological response assessment using different CT measurements has no prognostic value concerning time to progression or overall survival in patients with synchronous colorectal liver metastases