Prognostic Implications of 68Ga-FAPI-46 PET/CT-Derived Parameters on Overall Survival in Various Types of Solid Tumors.

Tumoral fibroblast activation protein expression is associated with proliferation and angiogenesis and can be visualized by PET/CT. We examined the prognostic value of [68Ga]Ga-fibroblast activation protein inhibitor (FAPI) (68Ga-FAPI)-46 PET/CT for different tumor entities in patients enrolled in 2 prospective imaging studies (NCT05160051, n = 30; NCT04571086, n = 115). Methods: Within 4 wk, 145 patients underwent 68Ga-FAPI-46 and [18F]FDG (18F-FDG) PET/CT. The association between overall survival (OS) and sex, age, tumor entity, total lesion number, highest SUVmax, and the presence of each nodal, visceral, and bone metastasis was tested using univariate Cox regression analysis. Multivariate analyses were performed for prognostic factors with P values of less than 0.05. Results: In the univariate analysis, shorter OS was associated with total lesion number and the presence of nodal, visceral, and bone metastases on 68Ga-FAPI-46 PET/CT (hazard ratio [HR], 1.06, 2.18, 1.69, and 2.05; P < 0.01, < 0.01, = 0.04, and = 0.02, respectively) and 18F-FDG PET/CT (HR, 1.05, 2.31, 1.76, and 2.30; P < 0.01, < 0.01, = 0.03, and < 0.01, respectively) and with SUVmax on 68Ga-FAPI-46 PET/CT (HR, 1.03; P = 0.03). In the multivariate analysis, total lesion number on 68Ga-FAPI-46 PET/CT was an independent risk factor for shorter OS (HR, 1.05; P = 0.02). In patients with pancreatic cancer, shorter OS was associated with total lesion number on 68Ga-FAPI-46 PET/CT (HR, 1.09; P < 0.01) and bone metastases on 18F-FDG PET/CT (HR, 31.39; P < 0.01) in the univariate analysis and with total lesion number on 68Ga-FAPI-46 PET/CT (HR, 1.07; P = 0.04) in the multivariate analyses. In breast cancer, total lesion number on 68Ga-FAPI-46 PET/CT (HR, 1.07; P = 0.02), as well as bone metastases on 18F-FDG PET/CT (HR, 9.64; P = 0.04), was associated with shorter OS in the univariate analysis. The multivariate analysis did not reveal significant prognostic factors. In thoracic cancer (lung cancer and pleural mesothelioma), the univariate and multivariate analyses did not reveal significant prognostic factors. Conclusion: Disease extent on 68Ga-FAPI-46 PET/CT is a predictor of short OS and may aid in future risk stratification by playing a supplemental role alongside 18F-FDG PET/CT.

Diagnostic Accuracy of 68Ga-FAPI Versus 18F-FDG PET in Patients with Various Malignancies.

To assess the diagnostic accuracy of 68Ga-labeled fibroblast activation protein inhibitor (FAPI) and 18F-labeled FDG PET for the detection of various tumors, we performed a head-to-head comparison of both imaging modalities across a range of tumor entities as part of our ongoing 68Ga-FAPI PET observational trial. Methods: The study included 115 patients with 8 tumor entities who received imaging with 68Ga-FAPI for tumor staging or restaging between October 2018 and March 2022. Of those, 103 patients received concomitant imaging with 68Ga-FAPI and 18F-FDG PET and had adequate lesion validation for accuracy analysis. Each scan was evaluated for the detection of primary tumor, lymph nodes, and visceral and bone metastases. True or false positivity and negativity to detected lesions was assigned on the basis of histopathology from biopsies or surgical excision, as well as imaging validation. Results: 68Ga-FAPI PET revealed higher accuracy than 18F-FDG PET in the detection of colorectal cancer (n = 14; per-patient, 85.7% vs. 78.6%; per-region, 95.6% vs. 91.1%) and prostate cancer (n = 22; per-patient, 100% vs. 90.9%; per-region, 96.4% vs. 92.7%). 68Ga-FAPI PET and 18F-FDG PET had comparable per-patient accuracy in detecting breast cancer (n = 16, 100% for both) and head and neck cancers (n = 10, 90% for both modalities). 68Ga-FAPI PET had lower per-patient accuracy than 18F-FDG PET in cancers of the bladder (n = 12, 75% vs. 100%) and kidney (n = 10, 80% vs. 90%), as well as lymphoma (n = 9, 88.9% vs. 100%) and myeloma (n = 10, 80% vs. 90%). Conclusion: 68Ga-FAPI PET demonstrated higher diagnostic accuracy than 18F-FDG PET in the diagnosis of colorectal cancer and prostate cancer, as well as comparable diagnostic performance for cancers of the breast and head and neck. Accuracy and impact on management will be further assessed in an ongoing prospective interventional trial (NCT05160051).

Prioritization and Resource Allocation in the Context of the COVID-19 Pandemic: Recommendations for Colorectal and Pancreatic Cancer in Germany.

In the context of the COVID-19 pandemic, there has been a scarcity of resources with various effects on the care of cancer patients. This paper provides an English summary of a German guideline on prioritization and resource allocation for colorectal and pancreatic cancer in the context of the pandemic. Based on a selective literature review as well as empirical and ethical analyses, the research team of the CancerCOVID Consortium drafted recommendations for prioritizing diagnostic and treatment measures for both entities. The final version of the guideline received consent from the executive boards of nine societies of the Association of Scientific Medical Societies in Germany (AWMF), 20 further professional organizations and 22 other experts from various disciplines as well as patient representatives. The guiding principle for the prioritization of decisions is the minimization of harm. Prioritization decisions to fulfill this overall goal should be guided by (1) the urgency relevant to avoid or reduce harm, (2) the likelihood of success of the diagnostic or therapeutic measure advised, and (3) the availability of alternative treatment options. In the event of a relevant risk of harm as a result of prioritization, these decisions should be made by means of a team approach. Gender, age, disability, ethnicity, origin, and other social characteristics, such as social or insurance status, as well as the vehemence of a patient's treatment request and SARS-CoV-2 vaccination status should not be used as prioritization criteria. The guideline provides concrete recommendations for (1) diagnostic procedures, (2) surgical procedures for cancer, and (3) systemic treatment and radiotherapy in patients with colorectal or pancreatic cancer within the context of the German healthcare system.

Attitude towards and perception of individual safety after SARS-CoV-2 vaccination among German cancer patients.

PURPOSE: Refusal to receive SARS-CoV-2 vaccination poses a threat to fighting the COVID-19 pandemic. Little is known about German cancer patients' attitude towards and experience with SARS-CoV-2 vaccination. METHODS: Patients were enrolled between 04-11/2021. They completed a baseline questionnaire (BLQ) containing multiple choice questions and Likert items ranging from 1 ("totally disagree") to 11 ("totally agree") regarding their attitude towards vaccination and COVID-19. A follow-up questionnaire (FUQ) was completed after vaccination. RESULTS: 218 patients (43% female) completed BLQ (110 FUQ; 48% female). Most patients agreed to "definitely get vaccinated" (82%) and disagreed with "SARS-CoV-2 vaccination is dispensable due to COVID-19 being no serious threat" (82%; more dissent among men, p = 0.05). Self-assessment as a member of a risk group (p = 0.03) and fear of COVID-19 (p = 0.002) were more common among women. Fear of side effects was more common among women (p = 0.002) and patients with solid or GI tumors (p = 0.03; p < 0.0001). At FUQ, almost all (91%) reported their vaccination to be well tolerated, especially men (p = 0.001). High tolerability correlated with confidence in the vaccine being safe (r = 0.305, p = 0.003). Most patients would agree to get it yearly (78%). After vaccination, patients felt safe meeting friends/family (91%) or shopping (62%). Vacation (32%) or work (22%) were among others considered less safe (less frequent among men, p < 0.05). CONCLUSION: Acceptance of SARS-CoV-2 vaccination is high and it is well tolerated in this sensitive cohort. However, concerns about vaccine safety remain. Those and gender differences need to be addressed. Our results help identify patients that benefit from pre-vaccination consultation.

Fast and label-free automated detection of microsatellite status in early colon cancer using artificial intelligence integrated infrared imaging.

PURPOSE: Microsatellite instability (MSI) due to mismatch repair (MMR) defects accounts for 15-20% of colon cancers (CC). MSI testing is currently standard of care in CC with immunohistochemistry of the four MMR proteins representing the gold standard. Instead, label-free quantum cascade laser (QCL) based infrared (IR) imaging combined with artificial intelligence (AI) may classify MSI/microsatellite stability (MSS) in unstained tissue sections user-independently and tissue preserving. METHODS: Paraffin-embedded unstained tissue sections of early CC from patients participating in the multicentre AIO ColoPredict Plus (CPP) 2.0 registry were analysed after dividing into three groups (training, test, and validation). IR images of tissue sections using QCL-IR microscopes were classified by AI (convolutional neural networks [CNN]) using a two-step approach. The first CNN (modified U-Net) detected areas of cancer while the second CNN (VGG-Net) classified MSI/MSS. End-points were area under receiver operating characteristic (AUROC) and area under precision recall curve (AUPRC). RESULTS: The cancer detection in the first step was based on 629 patients (train n = 273, test n = 138, and validation n = 218). Resulting classification AUROC was 1.0 for the validation dataset. The second step classifying MSI/MSS was performed on 547 patients (train n = 331, test n = 69, and validation n = 147) reaching AUROC and AUPRC of 0.9 and 0.74, respectively, for the validation cohort. CONCLUSION: Our novel label-free digital pathology approach accurately and rapidly classifies MSI vs. MSS. The tissue sections analysed were not processed leaving the sample unmodified for subsequent analyses. Our approach demonstrates an AI-based decision support tool potentially driving improved patient stratification and precision oncology in the future.

Longitudinal data on humoral response and neutralizing antibodies against SARS-CoV-2 Omicron BA.1 and subvariants BA.4/5 and BQ.1.1 after COVID-19 vaccination in cancer patients.

PURPOSE: The SARS-CoV-2 Omicron variant of concern (VOC) and subvariants like BQ.1.1 demonstrate immune evasive potential. Little is known about the efficacy of booster vaccinations regarding this VOC and subvariants in cancer patients. This study is among the first to provide data on neutralizing antibodies (nAb) against BQ.1.1. METHODS: Cancer patients at our center were prospectively enrolled between 01/2021 and 02/2022. Medical data and blood samples were collected at enrollment and before and after every SARS-CoV-2 vaccination, at 3 and 6 months. RESULTS: We analyzed 408 samples from 148 patients (41% female), mainly with solid tumors (85%) on active therapy (92%; 80% chemotherapy). SARS-CoV-2 IgG and nAb titers decreased over time, however, significantly increased following third vaccination (p < 0.0001). NAb (ND50) against Omicron BA.1 was minimal prior and increased significantly after the third vaccination (p < 0.0001). ND50 titers against BQ.1.1 after the third vaccination were significantly lower than against BA.1 and BA.4/5 (p < 0.0001) and undetectable in half of the patients (48%). Factors associated with impaired immune response were hematologic malignancies, B cell depleting therapy and higher age. Choice of vaccine, sex and treatment with chemo-/immunotherapy did not influence antibody response. Patients with breakthrough infections had significantly lower nAb titers after both 6 months (p < 0.001) and the third vaccination (p = 0.018). CONCLUSION: We present the first data on nAb against BQ.1.1 following the third vaccination in cancer patients. Our results highlight the threat that new emerging SARS-CoV-2 variants pose to cancer patients and support efforts to apply repeated vaccines. Since a considerable number of patients did not display an adequate immune response, continuing to exhibit caution remains reasonable.

Mental burden and moral distress among oncologists and oncology nurses in Germany during the third wave of the COVID-19 pandemic: a cross-sectional survey.

PURPOSE: There is evidence for mental burden and moral distress among healthcare workers during the pandemic. However, there is scarcity of analyses regarding possible correlations of mental burden and moral distress in this context. This study provides data to quantify mental burden and possible associations with moral distress among physicians and nurses working in oncology in Germany. METHODS: We conducted a cross-sectional online survey with physicians and nurses working in oncology in Germany between March and July 2021. Next to sociodemographic characteristics and working conditions, mental burden and moral distress were assessed using standardized instruments. Binary multivariate logistic regression using the enter method was performed in order to explore the relationship between mental burden and moral distress. RESULTS: 121 physicians and 125 nurses were included in the study. Prevalence of clinically relevant depressive symptoms, anxiety, somatic symptoms, burnout symptoms and moral distress was 19.2, 14.5, 12.7, 46.0 and 34.7% in physicians and 41.4, 24.0, 46.8, 46.6 and 60.0% in nurses respectively. Mental burden was significantly associated with moral distress, being female/diverse, younger age < 40 and increase in workload. Nurses who felt sufficiently protected from COVID-19 reported significantly less moral distress. CONCLUSION: To improve pandemic resilience, there is a need to ensure safe working environment including psychosocial support. Further evidence on risk and protective factors for moral distress is needed to be able to develop and implement strategies to protect healthcare workers within and beyond the pandemic.

68Ga-Labeled Fibroblast Activation Protein Inhibitor (68Ga-FAPI) PET for Pancreatic Adenocarcinoma: Data from the 68Ga-FAPI PET Observational Trial.

The fibroblast activation protein (FAP) is highly expressed on carcinoma-associated fibroblasts in the stroma of pancreatic cancer and thus is a promising target for imaging and therapy. Preliminary data on PET imaging with radiolabeled FAP inhibitors (FAPIs) demonstrate superior tumor detection. Here we assess the accuracy of FAP-directed PET in patients with pancreatic cancer. Methods: Of 64 patients with suspected or proven pancreatic cancer, 62 (97%) were included in the data analysis of the 68Ga-FAPI PET observational trial (NCT04571086). All of these patients underwent contrast-enhanced CT, and 38 patients additionally underwent 18F-FDG PET. The primary study endpoint was the association of 68Ga-FAPI PET uptake intensity and histopathologic FAP expression. Secondary endpoints were detection rate, diagnostic performance, interreader reproducibility, and change in management. Datasets were interpreted by 2 masked readers. Results: The primary endpoint was met: The association between 68Ga-FAPI SUVmax and histopathologic FAP expression was significant (Spearman r, 0.48; P = 0.04). For histopathology-validated lesions, 68Ga-FAPI PET showed high sensitivity and positive predictive values (PPVs) on per-patient (sensitivity, 100%; PPV, 96.3%) and per-region (sensitivity, 100%; PPV, 97.0%) bases. In a head-to-head comparison versus 18F-FDG or contrast-enhanced CT, 68Ga-FAPI detected more tumor on a per-lesion (84.7% vs. 46.5% vs. 52.9%), per-patient (97.4% vs. 73.7% vs. 92.1%), or per-region (32.6% vs. 18.8% vs. 23.7%) basis, respectively. 68Ga-FAPI PET readers showed substantial overall agreement on the basis of the Fleiss κ: primary κ, 0.77 (range, 0.66-0.88). Minor and major changes in clinical management occurred in 5 patients (8.4%) after 68Ga-FAPI PET. Conclusion: We confirmed an association of 68Ga-FAPI PET SUVmax and histopathologic FAP expression in pancreatic cancer patients. Additionally, we found high detection rate and diagnostic accuracy, superior to those of 18F-FDG PET/CT. 68Ga-FAPI might become a powerful diagnostic tool for pancreatic cancer work-up.

Fibroblast-Activation Protein PET and Histopathology in a Single-Center Database of 324 Patients and 21 Tumor Entities.

We present an overview of our prospective fibroblast-activation protein inhibitor (FAPI) registry study across a 3-y period, with head-to-head comparison of tumor uptake in 68Ga-FAPI and 18F-FDG PET, as well as FAP immunohistochemistry. Methods: This is an interim analysis of the ongoing 68Ga-FAPI PET prospective observational trial at our department. Patients who underwent clinical imaging with 68Ga-FAPI PET between October 2018 and October 2021 were included. Tracer uptake was quantified by SUVmax for tumor lesions and by SUVmean for normal organs. PET tumor volume (40% isocontour) and tumor-to-background ratios were calculated. Correlation between SUVmax and FAP staining in tissue samples was analyzed. Results: In total, 324 patients with 21 different tumor entities underwent 68Ga-FAPI imaging; 237 patients additionally received 18F-FDG PET. The most common tumor entities were sarcoma (131/324, 40%), pancreatic cancer (67/324, 21%), and primary tumors of the brain (22/324, 7%). The mean primary tumor SUVmax was significantly higher for 68Ga-FAPI than 18F-FDG among pancreatic cancer (13.2 vs. 6.1, P < 0.001) and sarcoma (14.3 vs. 9.4, P < 0.001), and the same was true for mean SUVmax in metastatic lesions of pancreatic cancer (9.4 vs. 5.5, P < 0.001). Mean primary tumor maximum tumor-to-background ratio was significantly higher for 68Ga-FAPI than 18F-FDG across several tumor entities, most prominently pancreatic cancer (14.7 vs. 3.0, P < 0.001) and sarcoma (17.3 vs. 4.7, P < 0.001). Compared with 18F-FDG, 68Ga-FAPI showed superior detection for locoregional disease in sarcoma (52 vs. 48 total regions detected) and for distant metastatic disease in both sarcoma (137 vs. 131) and pancreatic cancer (65 vs. 57), respectively. Among 61 histopathology samples, there was a positive correlation between 68Ga-FAPI SUVmax and overall FAP immunohistochemistry score (r = 0.352, P = 0.005). Conclusion: 68Ga-FAPI demonstrates higher absolute uptake in pancreatic cancer and sarcoma, as well as higher tumor-to-background uptake along with improved tumor detection for pancreatic cancer, sarcoma, and other tumor entities when compared with 18F-FDG. 68Ga-FAPI is a new tool for tumor staging with theranostic potential.

The CIRCULATE Trial: Circulating Tumor DNA Based Decision for Adjuvant Treatment in Colon Cancer Stage II Evaluation (AIO-KRK-0217).

BACKGROUND: Guidance regarding adjuvant treatment decisions in stage II colorectal cancer (CRC) remains uncertain due to lack of predictive clinical or molecular markers. Recently, postoperative circulating tumour (ct)DNA has been demonstrated to be a strong prognostic marker in early colon cancer. PATIENTS AND METHODS: CIRCULATE enrols patients with stage II microsatellite stable CRC in Germany (AIO) and Austria (ABCSG). Within the AIO, screening is supported by ColoPredict Plus 2.0, a molecular registry, and screening platform for interventional trials. Patient-specific mutations are centrally analysed by next generation sequencing in the resected primary tumour. A postoperative plasma sample is subsequently screened for the specific mutation(s). ctDNA positive (ctDNApos) patients are randomised (2:1) chemotherapy (capecitabine, oxaliplatin added an investigator's choice) or to follow-up (control group). ctDNA negative (ctDNAneg) patients are randomised (1:4) to be followed-up within CIRCULATE (control group) or outside the trial. Patients in the control group remain blinded to the ctDNA results. The primary objective is to compare disease free survival (DFS) of ctDNApos patients with chemotherapy or control. To demonstrate a treatment effect with a hazard ratio of 0.617 (3-year DFS rates 42.5% vs. 25%), 231 ctDNApos and estimated 2079 ctDNAneg patients are randomised. Secondary aims include to compare overall survival and DFS in the ctDNApos and ctDNAneg patient cohorts and ctDNA kinetics. CONCLUSION: The CIRCULATE trial may establish ctDNA for adjuvant treatment decision in stage II colon cancer - and with the secondary objectives - support a ctDNA guided follow up in colon cancer stage II and beyond.

A framework for falsifiable explanations of machine learning models with an application in computational pathology.

In recent years, deep learning has been the key driver of breakthrough developments in computational pathology and other image based approaches that support medical diagnosis and treatment. The underlying neural networks as inherent black boxes lack transparency and are often accompanied by approaches to explain their output. However, formally defining explainability has been a notorious unsolved riddle. Here, we introduce a hypothesis-based framework for falsifiable explanations of machine learning models. A falsifiable explanation is a hypothesis that connects an intermediate space induced by the model with the sample from which the data originate. We instantiate this framework in a computational pathology setting using hyperspectral infrared microscopy. The intermediate space is an activation map, which is trained with an inductive bias to localize tumor. An explanation is constituted by hypothesizing that activation corresponds to tumor and associated structures, which we validate by histological staining as an independent secondary experiment.

Causes of mortality in elderly UICC stage III colon cancer (CC) patients--Tumor-related death and competing risks from the German AIO colorectal study group Colopredict Plus (CPP) registry.

BACKGROUND: Colon cancer (CC) is a disease of elderly patients (pts.) with a median age of 73 years (yrs.). Lack of data about the effects of adjuvant chemotherapy (ACT) is caused by underrepresentation of this clinically relevant cohort in interventional trials. We analyzed real-world data from the German CPP registry with regard to a possible benefit of ACT in elderly (70+ yrs.) versus younger pts. (50 to <70 yrs.) taking cause-specific deaths into account. METHODS: We analyzed the effect of age and ACT on overall survival (OS) and cause-specific death of stage III pts. using Cox regression. RESULTS: In total, 1558 pts. were analyzed and follow-up was 24.6 months. 62.6% of the elderly received ACT whereas 91.1% of younger pts. (p < 0.001). Oxaliplatin combinations were significantly less often given to older than younger pts. (38.8% vs. 88.9%; p < 0.001). Mean Charlson comorbidity score was significantly lower in pts. that received ACT (0.61) than in those without ACT (1.16; p < 0.001). ACT was an independent positive prognostic factor for cancer-related death in elderly pts. even in pts. 75+ yrs. No significant difference in the effect of ACT could be observed between age groups (interaction: cancer-specific death HR = 1.7948, p = 0.1079; death of other cause HR = 0.7384, p = 0.6705). CONCLUSION: ACT was an independent positive prognostic factor for OS. There may be a cohort of elderly with less co-morbidities who benefit from ACT.

Hamartin variants that are frequent in focal dysplasias and cortical tubers have reduced tuberin binding and aberrant subcellular distribution in vitro.

Focal cortical dysplasia type IIb is characterized by epilepsy-associated malformations that are often composed of balloon cells and dysplastic neurons. There are many histopathologic similarities between focal cortical dysplasia type IIb and cortical tubers in tuberous sclerosis complex (TSC), an autosomal-dominant phakomatosis caused by mutations in the TSC1 or TSC2 genes that encode hamartin and tuberin. We previously found that an allelic variant of TSC1 (hamartin) is increased in focal cortical dysplasia type IIb. Here, we investigated the subcellular localization of hamartin and its interaction with tuberin in vitro. Coimmunoprecipitation assays with tuberin revealed reduced tuberin binding of hamartin compared with wild-type hamartin. Tuberin binding was also reduced for 2 TSC1 stop mutants (hamartin and hamartin) that are present in brain lesions of TSC patients. Colocalization assays of hamartin and tuberin were performed in HEK293T cells, and the subcellular localization of the hamartin variants were studied using immunocytochemistry. There was an impairment of tuberin binding of hamartin and aberrant nuclear distribution of hamartin in these cells, whereas hamartin and hamartin were, like wild-type tuberin, localized in the cytoplasm. These data suggest a fundamental functional impairment of hamartin and the 2 TSC1 stop mutants hamartin and hamartin in vitro. Future studies will be needed to characterize the roles of these TSC1 sequence variants in the genesis of dysplastic epileptogenic developmental brain lesions.