18FDG-PET/CT for predicting the outcome in ER+/HER2- breast cancer patients: comparison of clinicopathological parameters and PET image-derived indices including tumor texture analysis

FDG-PET/CT and Multimodal Machine Learning Model Prediction of Pathological Complete Response to Neoadjuvant Chemotherapy in Triple-Negative Breast Cancer

Purpose: Triple-negative breast cancer (TNBC) is a biologically and clinically heterogeneous disease, associated with poorer outcomes when compared with other subtypes of breast cancer. Neoadjuvant chemotherapy (NAC) is often given before surgery, and achieving a pathological complete response (pCR) has been associated with patient outcomes. There is thus strong clinical interest in the ability to accurately predict pCR status using baseline data. Materials and Methods: A cohort of 57 TNBC patients who underwent FDG-PET/CT before NAC was analyzed to develop a machine learning (ML) algorithm predictive of pCR. A total of 241 predictors were collected for each patient: 11 clinical features, 11 histopathological features, 13 genomic features, and 206 PET features, including 195 radiomic features. The optimization criterion was the area under the ROC curve (AUC). Event-free survival (EFS) was estimated using the Kaplan-Meier method. Results: The best ML algorithm reached an AUC of 0.82. The features with the highest weight in the algorithm were a mix of PET (including radiomics), histopathological, genomic, and clinical features, highlighting the importance of truly multimodal analysis. Patients with predicted pCR tended to have a longer EFS than patients with predicted non-pCR, even though this difference was not significant, probably due to the small sample size and few events observed (p = 0.09). Conclusions: This study suggests that ML applied to baseline multimodal data can help predict pCR status after NAC for TNBC patients and may identify correlations with long-term outcomes. Patients predicted as non-pCR may benefit from concomitant treatment with immunotherapy or dose intensification.

Baseline 18F-FDG PET/CT for predicting pathological response to neoadjuvant chemotherapy and prognosis in locally advanced breast cancer patients: analysis of tumor and lymphoid organs metabolic parameters

PURPOSE

To investigate metabolic parameters from baseline 18F-FDG PET/CT as predictors of pathological complete response (pCR) to neoadjuvant chemotherapy (NAC) and disease recurrence in locally advanced breast cancer (LABC) patients.

MATERIALS AND METHODS

From 142 LABC in 137 patients (bilateral-synchronous BC: 5/137), the following parameters from baseline (pre-treatment) 18F-FDG PET/CT were retrospectively analyzed, along with clinic-histological data: primary tumor activity (SUVmax, SUVmean, SUVpeak, tumor-to-liver ratio-TLR-, MTV, TLG); lymphoid organs activity (spleen and bone marrow SUVmax and SUVmean, spleen-to-liver ratio-SLR-, bone marrow-to-liver ratio-BLR); and PET-positive lymph-nodes' number. Predictors of pCR and recurrence-free survival (RFS) were assessed by univariable logistic regression and Cox regression (significant or suggestive association: p < 0.05; p < 0.10).

RESULTS

74/142 tumors were "Luminal A/B HER2-", 44/142 "Luminal B HER2+/HER2+", 24/142 TNBC; pCR after NAC occurred in 26/142 tumors (18.3%) and disease recurrence at follow-up (45 ± 18.1 months) in 25/127 assessable patients (19.7%). Significant or suggestive predictors of NAC response, in Luminal A/B HER2-: lower spleen SUVmax and patients' age (OR 0.06; 0.93) for pCR; lower TLRmax, TLRmean and BLRmax (OR 1.33; 1.22; and 26.42) for residual disease. Significant negative RFS predictors: higher SUVmax, SUVmean, SUVpeak (HR 1.10; 1.15; 1.11), TLRmax and TLRmean (HR 1.02; 1.00), MTV and TLG (HR 1.32; 1.26) in Luminal A/B HER2-; higher spleen SUVmax, PET-positive nodes' number and patients' age (HR 6.24; 1.20; 1.08) in Luminal B HER2+/HER2+.

CONCLUSION

Primary tumor and lymphoid organs parameters at baseline 18F-FDG PET/CT resulted as predictors of NAC response and prognosis in LABC patients, respectively, reflecting the BC cells' proliferative activity and metabolic burden, and the role of tumor-induced immune-system activation on tumors' behavior and treatment responsiveness. In LABC candidates to NAC, baseline PET information could improve treatment planning and prognostic stratification.

A PET-Surrogate Signature for the Interrogation of the Metabolic Status of Breast Cancers

Metabolic alterations in cancers can be exploited for diagnostic, prognostic, and therapeutic purposes. This is exemplified by 18F-fluorodeoxyglucose (FDG)-positron emission tomography (FDG-PET), an imaging tool that relies on enhanced glucose uptake by tumors for diagnosis and staging. By performing transcriptomic analysis of breast cancer (BC) samples from patients stratified by FDG-PET, a 54-gene signature (PETsign) is identified that recapitulates FDG uptake. PETsign is independently prognostic of clinical outcome in luminal BCs, the most common and heterogeneous BC molecular subtype, which requires improved stratification criteria to guide therapeutic decision-making. The prognostic power of PETsign is stable across independent BC cohorts and disease stages including the earliest BC stage, arguing that PETsign is an ab initio metabolic signature. Transcriptomic and metabolomic analysis of BC cells reveals that PETsign predicts enhanced glycolytic dependence and reduced reliance on fatty acid oxidation. Moreover, coamplification of PETsign genes occurs frequently in BC arguing for their causal role in pathogenesis. CXCL8 and EGFR signaling pathways feature strongly in PETsign, and their activation in BC cells causes a shift toward a glycolytic phenotype. Thus, PETsign serves as a molecular surrogate for FDG-PET that could inform clinical management strategies for BC patients.

Joint EANM-SNMMI guideline on the role of 2-[18F]FDG PET/CT in no special type breast cancer : (endorsed by the ACR, ESSO, ESTRO, EUSOBI/ESR, and EUSOMA)

INTRODUCTION

There is much literature about the role of 2-[18F]FDG PET/CT in patients with breast cancer (BC). However, there exists no international guideline with involvement of the nuclear medicine societies about this subject.

PURPOSE

To provide an organized, international, state-of-the-art, and multidisciplinary guideline, led by experts of two nuclear medicine societies (EANM and SNMMI) and representation of important societies in the field of BC (ACR, ESSO, ESTRO, EUSOBI/ESR, and EUSOMA).

METHODS

Literature review and expert discussion were performed with the aim of collecting updated information regarding the role of 2-[18F]FDG PET/CT in patients with no special type (NST) BC and summarizing its indications according to scientific evidence. Recommendations were scored according to the National Institute for Health and Care Excellence (NICE) criteria.

RESULTS

Quantitative PET features (SUV, MTV, TLG) are valuable prognostic parameters. In baseline staging, 2-[18F]FDG PET/CT plays a role from stage IIB through stage IV. When assessing response to therapy, 2-[18F]FDG PET/CT should be performed on certified scanners, and reported either according to PERCIST, EORTC PET, or EANM immunotherapy response criteria, as appropriate. 2-[18F]FDG PET/CT may be useful to assess early metabolic response, particularly in non-metastatic triple-negative and HER2+ tumours. 2-[18F]FDG PET/CT is useful to detect the site and extent of recurrence when conventional imaging methods are equivocal and when there is clinical and/or laboratorial suspicion of relapse. Recent developments are promising.

CONCLUSION

2-[18F]FDG PET/CT is extremely useful in BC management, as supported by extensive evidence of its utility compared to other imaging modalities in several clinical scenarios.

Verteporfin Suppresses YAP-Induced Glycolysis in Breast Cancer Cells

OBJECTIVE

The inhibition of the Hippo pathway through targeting the Yes-associated protein (YAP) presents a novel and promising approach for treating tumors. However, the efficacy of YAP inhibitors in the context of breast cancer (BC) remains incompletely understood. Here, we aimed to investigate the involvement of YAP in BC's metabolic reprogramming and reveal the potential underlying mechanisms. To this end, we assessed the function of verteporfin (VP), a YAP-TEAD complex inhibitor, on the glycolytic activity of BC cells.

METHODS

We evaluated the expression of YAP by utilizing immunohistochemistry (IHC) in BC patients who have undergone 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) prior to biopsy/surgery. We employed RNA immunoprecipitation (RIP) and fluorescent in situ hybridization (FISH) assays to assess the interaction between YAP mRNA and human antigen R (HuR) in BC cells. The biological importance of YAP in the metabolism and malignancy of BC was evaluated in vitro. Finally, the effect of VP on glycolysis was determined by using 18F-FDG uptake, glucose consumption, and lactate production assays.

RESULTS

Our studies revealed that high expression of YAP was positively correlated with the maximum uptake value (SUVmax) determined by 18F-FDG PET/CT imaging in BC samples. Inhibition of YAP activity suppressed glycolysis in BC. The mechanism underlying this phenomenon could be the binding of YAP to HuR, which promotes glycolysis in BC cells. Treatment with VP effectively suppressed glycolysis induced by YAP overexpression in BC cells.

CONCLUSION

VP exhibited anti-glycolytic effect on BC cells, indicating its therapeutic value as an FDA-approved drug.

Utility of positron emission tomography for determination of axillary metastasis of breast cancer

Objectives

The involvement of axillary lymph nodes plays a key role in breast cancer staging. Positron emission tomography is a promising modality for detecting axillary lymph node metastasis. In addition, nomograms are used to predict the status of axillary lymph nodes. In this study, the role of positron emission tomography in determining axillary metastasis and its correlation with the nomogram was evaluated.

Material and Methods

The axillary maximum standard uptake value (SUVmax) values of the patients in the preoperative period, the features in the perioperative and postoperative specimen and Memorial Sloan Kettering Cancer Center nomogram data were evaluated.

Results

As axillary SUVmax detected by Positron emission tomography in the preoperative period increased, so did the likelihood of lymph node involvement. Axillary SUVmax value were compared with Memorial Sloan Kettering Cancer Center nomogram data but no correlation was found. Age, lymph node number, histopathology results, mass diameter, presence or absence of lymphovascular invasion and/or perineural invasion, tumor type, estrogen receptor status, Ki67 and Cerb-B2 statuses were not correlated. However, axillary SUVmax was inversely correlated with grade and progesterone receptor status.

Conclusion

Results from positron emission tomography of axillary lymph nodes in breasts cancer patients showed that SUVmax was only inversely related to cancer grade and progesterone receptor status while not correlating with other accepted parameters for tumor assessment. Thus there is insufficient reliability for the use of axillary SUVmax alone for accurate assessment of tumor characteristics at present.

The association between the amino acid transporter LAT1, tumor immunometabolic and proliferative features and menopausal status in breast cancer

L-type Amino Acid Transporter 1 (LAT1) facilitates the uptake of specific essential amino acids, and due to this quality, it has been correlated to worse patient outcomes in various cancer types. However, the relationship between LAT1 and various clinical factors, including menopausal status, in mediating LAT1's prognostic effects remains incompletely understood. This is particularly true in the unique subset of tumors that are both obesity-associated and responsive to immunotherapy, including breast cancer. To close this gap, we employed 6 sets of transcriptomic data using the Kaplan-Meier model in the Xena Functional Genomics Explorer, demonstrating that higher LAT1 expression diminishes breast cancer patients' survival probability. Additionally, we analyzed 3'-Deoxy-3'-18F-Fluorothymidine positron emission tomography-computed tomography (18F-FLT PET-CT) images found on The Cancer Imaging Archive (TCIA). After separating all patients based on menopausal status, we correlated the measured 18F-FLT uptake with various clinical parameters quantifying body composition, tumor proliferation, and immune cell infiltration. By analyzing a wealth of deidentified, open-access data, the current study investigates the impact of LAT1 expression on breast cancer prognosis, along with the menopausal status-dependent associations between tumor proliferation, immunometabolism, and systemic metabolism.

Metabolic Positron Emission Tomography in Breast Cancer

Metabolic PET, most commonly 18F-fluorodeoxyglucose (FDG) PET/computed tomography (CT), has had a major impact on the imaging of breast cancer and can have important clinical applications in appropriate patients. While limited for screening, FDG PET/CT outperforms conventional imaging in locally advanced breast cancer. FDG PET/CT is more sensitive than conventional imaging in assessing treatment response, accurately predicting complete response or nonresponse in early-stage cases. It also aids in determining disease extent and treatment response in the metastatic setting. Further research, including randomized controlled trials with FDG and other metabolic agents such as fluciclovine, is needed for optimal breast cancer imaging.

Role of Textural Analysis of Pretreatment 18F Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Response Prediction in Esophageal Carcinoma Patients

Introduction

Positron emission tomography/computed tomography (PET/CT) is routinely used for staging, response assessment, and surveillance in esophageal carcinoma patients. The aim of this study was to investigate whether textural features of pretreatment 18F-fluorodeoxyglucose (18F-FDG) PET/CT images can contribute to prognosis prediction in carcinoma oesophagus patients.

Materials and Methods

This is a retrospective study of 30 diagnosed carcinoma esophagus patients. These patients underwent pretreatment 18F-FDG PET/CT for staging. The images were processed in a commercially available textural analysis software. Region of interest was drawn over primary tumor with a 40% threshold and was processed further to derive 92 textural and radiomic parameters. These parameters were then compared between progression group and nonprogression group. The original dataset was subject separately to receiver operating curve analysis. Receiver operating characteristic (ROC) curves were used to identify the cutoff values for textural features with a P < 0.05 for statistical significance. Feature selection was done with principal component analysis. The selected features of each evaluator were subject to 4 machine-learning algorithms. The highest area under the curve (AUC) values was selected for 10 features.

Results

A retrospective study of 30 primary carcinoma esophagus patients was done. Patients were followed up after chemo-radiotherapy and they underwent follow-up PET/CT. On the basis of their response, patients were divided into progression group and nonprogression group. Among them, 15 patients showed disease progression and 15 patients were in the nonprogression group. Ten textural analysis parameters turned out to be significant in the prediction of disease progression. Cutoff values were calculated for these parameters according to the ROC curves, GLZLM_long zone emphasis (Gray Level Zone Length Matrix)_long zone emphasis (44.9), GLZLM_low gray level zone emphasis (0.006), GLZLM_short zone low gray level emphasis (0.0032), GLZLM_long zone low gray level emphasis (0.185), GLRLM_long run emphasis (Gray Level Run Length Matrix) (1.31), GLRLM_low gray level run emphasis (0.0058), GLRLM_short run low gray level emphasis (0.005496), GLRLM_long run low gray level emphasis (0.00727), NGLDM_Busyness (Neighborhood Gray Level Difference Matrix) (0.75), and gray level co-occurrence matrix_homogeneity (0.37). Feature selection by principal components analysis and feature classification by the K-nearest neighbor machine-learning model using independent training and test samples yielded the overall highest AUC.

Conclusions

Textural analysis parameters could provide prognostic information in carcinoma esophagus patients. Larger multicenter studies are needed for better clinical prognostication of these parameters.

18F-FDG PET-Derived Volume-Based Parameters to Predict Disease-Free Survival in Patients with Grade III Breast Cancer of Different Molecular Subtypes Candidates to Neoadjuvant Chemotherapy

We investigated whether baseline [¹⁸F] Fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET)-derived semiquantitative parameters could predict disease-free survival (DFS) in patients with grade III breast cancer (BC) of different molecular subtypes candidate to neoadjuvant chemotherapy (NAC). For each ¹⁸F-FDG-PET/CT scan, the following parameters were calculated in the primary tumor (SUVmax, SUVmean, MTV, TLG) and whole-body (WB_SUVmax, WB_MTV, and WB_TLG). Receiver operating characteristic (ROC) analysis was used to determine the capability to predict DFS and find the optimal threshold for each parameter. Ninety-five grade III breast cancer patients with different molecular types were retrieved from the databases of the University Hospital of Padua and the University Hospital of Ferrara (luminal A: 5; luminal B: 34; luminal B-HER2: 22; HER2-enriched: 7; triple-negative: 27). In luminal B patients, WB_MTV (AUC: 0.75; best cut-off: WB_MTV > 195.33; SS: 55.56%, SP: 100%; p = 0.002) and WB_TLG (AUC: 0.73; best cut-off: WB_TLG > 1066.21; SS: 55.56%, SP: 100%; p = 0.05) were the best predictors of DFS. In luminal B-HER2 patients, WB_SUVmax was the only predictor of DFS (AUC: 0.857; best cut-off: WB_SUVmax > 13.12; SS: 100%; SP: 71.43%; p < 0.001). No parameter significantly affected the prediction of DFS in patients with grade III triple-negative BC. Volume-based parameters, extracted from baseline ¹⁸F-FDG PET, seem promising in predicting recurrence in patients with grade III luminal B and luminal B- HER2 breast cancer undergoing NAC.

Prognostic significance of pretreatment 18F-fluorodeoxyglucose positron emission tomography/computed tomography in patients with T2N1 hormone receptor-positive, ERBB2-negative breast cancer who underwent adjuvant chemotherapy

PURPOSE

To determine whether tumor uptake of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) is associated with invasive disease-free survival (IDFS) in patients with hormone receptor (HR)-positive ERBB2-negative early-stage breast cancer treated with adjuvant chemotherapy.

METHODS

This is a single-center cohort study of women with breast cancer who underwent surgery between 2008 and 2015 at Asan Medical Center, Seoul, Korea. Patients were enrolled if they were diagnosed with HR-positive ERBB2-negative breast cancer with histology of invasive ductal carcinoma, had an American Joint Committee on Cancer pathologic tumor stage of T2N1 with 1-3 positive axillary nodes, underwent preoperative ¹⁸F-FDG positron emission tomography/computed tomography (PET/CT), and underwent breast cancer surgery followed by anthracycline- or taxane-based adjuvant chemotherapy. The primary outcome measure was IDFS. The maximum standardized uptake value (SUVmax) was dichotomized using a predefined cut-off of 4.14.

RESULTS

A total of 129 patients were included. The median follow-up period for IDFS in those without recurrence was 82 months (interquartile range, 65-106). Multivariable Cox analysis showed that SUVmax was independently associated with IDFS [adjusted hazard ratio 2.49; 95% confidence interval (CI), 1.06-5.84]. Ten-year IDFS estimates via the Kaplan-Meier method were 0.60 (95% CI, 0.42-0.74) and 0.82 (95% CI, 0.65-0.91) for high and low SUVmax groups, respectively. The overall association between SUVmax and IDFS appeared to be consistent across subgroups divided according to age, progesterone receptor status, histologic grade, or presence of lymphovascular invasion.

CONCLUSION

High SUVmax on preoperative ¹⁸F-FDG PET/CT was independently associated with reduced long-term IDFS in T2N1 HR-positive ERBB2-negative breast cancer patients who underwent adjuvant chemotherapy.

18F-FDG PET/CT radiomics signature and clinical parameters predict progression-free survival in breast cancer patients: A preliminary study

Introduction

This study aimed to investigate the feasibility of predicting progression-free survival (PFS) in breast cancer patients using pretreatment 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) radiomics signature and clinical parameters.

Methods

Breast cancer patients who underwent 18F-FDG PET/CT imaging before treatment from January 2012 to December 2020 were eligible for study inclusion. Eighty-seven patients were randomly divided into training (n = 61) and internal test sets (n = 26) and an additional 25 patients were used as the external validation set. Clinical parameters, including age, tumor size, molecularsubtype, clinical TNM stage, and laboratory findings were collected. Radiomics features were extracted from preoperative PET/CT images. Least absolute shrinkage and selection operators were applied to shrink feature size and build a predictive radiomics signature. Univariate and multivariate Cox proportional hazards models and Kaplan-Meier analysis were used to assess the association of rad-score and clinical parameter with PFS. Nomograms were constructed to visualize survival prediction. C-index and calibration curve were used to evaluate nomogram performance.

Results

Eleven radiomics features were selected to generate rad-score. The clinical model comprised three parameters: clinical M stage, CA125, and pathological N stage. Rad-score and clinical-model were significantly associated with PFS in the training set (P&lt; 0.01) but not the test set. The integrated clinical-radiomics (ICR) model was significantly associated with PFS in both the training and test sets (P&lt; 0.01). The ICR model nomogram had a significantly higher C-index than the clinical model and rad-score in the training and test sets. The C-index of the ICR model in the external validation set was 0.754 (95% confidence interval, 0.726–0.812). PFS significantly differed between the low- and high-risk groups stratified by the nomogram (P = 0.009). The calibration curve indicated the ICR model provided the greatest clinical benefit.

Conclusion

The ICR model, which combined clinical parameters and preoperative 18F-FDG PET/CT imaging, was able to independently predict PFS in breast cancer patients and was superior to the clinical model alone and rad-score alone.

α- and β-Genotyping of Thalassemia Patients Based on a Multimodal Liver MRI Radiomics Model: A Preliminary Study in Two Centers

BACKGROUND

So far, there is no non-invasive method that can popularize the genetic testing of thalassemia (TM) patients on a large scale. The purpose of the study was to investigate the value of predicting the α- and β- genotypes of TM patients based on a liver MRI radiomics model.

METHODS

Radiomics features of liver MRI image data and clinical data of 175 TM patients were extracted using Analysis Kinetics (AK) software. The radiomics model with optimal predictive performance was combined with the clinical model to construct a joint model. The predictive performance of the model was evaluated in terms of AUC, accuracy, sensitivity, and specificity.

RESULTS

The T2 model showed the best predictive performance: the AUC, accuracy, sensitivity, and specificity of the validation group were 0.88, 0.865, 0.875, and 0.833, respectively. The joint model constructed from T2 image features and clinical features showed higher predictive performance: the AUC, accuracy, sensitivity, and specificity of the validation group were 0.91, 0.846, 0.9, and 0.667, respectively.

CONCLUSION

The liver MRI radiomics model is feasible and reliable for predicting α- and β-genotypes in TM patients.

Progress and current utility of radiomics in PET/CT study of non-metastatic breast cancer: A systematic review

AIM

To synthesize the current evidence of the usefulness of radiomics in PET/CT image analysis in local and locally advanced breast cancer. Also, to evaluate the methodological quality of the radiomic studies published.

METHODS

Systematic review of articles in different databases until 2021 using the terms "PET", "radiomics", "texture", "breast". Only articles with human data and that included a PET image were included. Studies with simulated data and with less than 20 patients were excluded. Were extracted sample size, radiotracer used, imaging technique, and radiomics characteristics from each article. The methodological quality of the studies was determined using the QUADAS-2 tool.

RESULTS

18 articles were selected. The retrospective design was the most used. The most studied radiomic characteristic was SUVmax. Several radiomic parameters were correlated with tumor characterization, and tumor heterogeneity proved useful for predicting disease course and response to treatment. Most articles showed a high risk of bias, mainly from the patient selection.

CONCLUSIONS

A high probability of bias was observed in most of the published articles. Radiomics is a developing field and more studies are needed to demonstrate its usefulness in routine clinical practice. The QUADAS-2 tool allows critical assessment of the methodological quality of the available evidence. Despite its limitations, radiomics is shown to be an instrument that can help to achieve personalized oncologic management of breast cancer.

Prognostic impact of 18F-FDG PET/CT in pathologic stage II invasive ductal carcinoma of the breast: re-illuminating the value of PET/CT in intermediate-risk breast cancer

BACKGROUND

The aim of this study is to investigate the impact of ¹⁸F-FDG PET/CT on prognosis of stage II invasive ductal carcinoma (IDC) of the breast primarily treated with surgery.

METHODS

The clinical records of 297 consecutive IDC with preoperative PET/CT and pathologically staged II in surgery from 2013 to 2017 were retrospectively reviewed. The maximum standardized uptake value (SUVmax), peak standardized uptake value (SUVpeak), tumor-to-liver ratio (TLR), and metabolic tumor volume (MTV) were measured. Association of clinicopathologic factors (age, T stage, N stage, AJCC pathologic stage of IIA or IIB, pathologic prognostic stage, grade, hormonal receptor status, HER2 status, Ki-67, and adjuvant therapy) and PET parameters with DFS was assessed using the Cox proportional hazards model.

RESULTS

There were 35 recurrences and 10 deaths at a median follow-up of 49 months (range 0.8 ~ 87.3). All PET parameters were significantly associated with DFS in univariate analysis but in multivariate analysis, SUVpeak was the only factor significantly associated with DFS (hazard ratio 2.58, 95% confidence interval 1.29-5.15, P = 0.007). In cohorts with higher values of SUVpeak or TLR, patients who received adjuvant chemotherapy had significantly superior DFS.

CONCLUSION

Metabolic parameters derived from preoperative PET/CT was significantly associated with recurrence in stage II IDC primarily treated with surgery. PET/CT can be a powerful prognostic tool in conjunction with novel staging systems and current biomarkers for patients undergoing contemporary therapy. Our results urge to reconsider the currently underestimated value of PET/CT confined to diagnostic aspect and to newly recognize its prognostic impact in these intermediate-risk breast cancer.

PET/CT-based radiomics analysis may help to predict neoadjuvant chemotherapy outcomes in breast cancer

BACKGROUND

The aim of this study was to evaluate the clinical usefulness of radiomics signature-derived 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography-computed tomography (PET-CT) for the early prediction of neoadjuvant chemotherapy (NAC) outcomes in patients with (BC).

METHODS

A total of 124 patients with BC who underwent pretreatment PET-CT scanning and received NAC between December 2016 and August 2019 were studied. The dataset was randomly assigned in a 7:3 ratio to either the training or validation cohort. Primary tumor segmentation was performed, and radiomics signatures were extracted from each PET-derived volume of interest (VOI) and CT-derived VOI. Radiomics signatures associated with pathological treatment response were selected from within a training cohort (n = 85), which were then applied to generate different classifiers to predict the probability of pathological complete response (pCR). Different models were then independently tested in the validation cohort (n = 39) regarding their accuracy, sensitivity, specificity, and area under the curve (AUC).

RESULTS

Thirty-five patients (28.2%) had pCR to NAC. Twelve features consisting of five PET-derived signatures, four CT-derived signatures, and three clinicopathological variables were candidates for the model's development. The random forest (RF), k-nearest neighbors (KNN), and decision tree (DT) classifiers were established, which could be utilized to predict pCR to NAC with AUC ranging from 0.819 to 0.849 in the validation cohort.

CONCLUSIONS

The PET/CT-based radiomics analysis might provide efficient predictors of pCR in patients with BC, which could potentially be applied in clinical practice for individualized treatment strategy formulation.

PET-Derived Radiomics and Artificial Intelligence in Breast Cancer: A Systematic Review

Breast cancer (BC) is a heterogeneous malignancy that still represents the second cause of cancer-related death among women worldwide. Due to the heterogeneity of BC, the correct identification of valuable biomarkers able to predict tumor biology and the best treatment approaches are still far from clear. Although molecular imaging with positron emission tomography/computed tomography (PET/CT) has improved the characterization of BC, these methods are not free from drawbacks. In recent years, radiomics and artificial intelligence (AI) have been playing an important role in the detection of several features normally unseen by the human eye in medical images. The present review provides a summary of the current status of radiomics and AI in different clinical settings of BC. A systematic search of PubMed, Web of Science and Scopus was conducted, including all articles published in English that explored radiomics and AI analyses of PET/CT images in BC. Several studies have demonstrated the potential role of such new features for the staging and prognosis as well as the assessment of biological characteristics. Radiomics and AI features appear to be promising in different clinical settings of BC, although larger prospective trials are needed to confirm and to standardize this evidence.

Prognostic Value of Neutrophil-to-Lymphocyte Ratio and Early Standardized Uptake Value Reduction in Patients With Breast Cancer Receiving Neoadjuvant Chemotherapy

PURPOSE

We investigated the treatment response and prognosis using the neutrophil-to-lymphocyte ratio (NLR) and standardized uptake value (SUV) of ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) in neoadjuvant settings.

METHODS

Baseline NLR and maximum SUV (SUV_max) were retrospectively analyzed in 273 females with breast cancer who received neoadjuvant chemotherapy followed by surgery. Of these, 101 patients underwent ¹⁸F-FDG PET after 3-4 neoadjuvant chemotherapy cycles, which allowed the measurement of ΔSUV_max, an early reduction in SUV_max. NLR and early SUV_max reduction (ΔSUV_max) were classified as low and high, respectively, relative to the median values.

RESULTS

The mean NLR was lower, and the mean ΔSUV_max was higher in patients with pathologic complete response (pCR) than in those with residual tumors. The ΔSUV_max was an independent variable associated with pCR. Furthermore, the high NLR group had poor recurrence-free survival (RFS) and overall survival. Among patients with ΔSUV_max data, high NLR (adjusted hazard ratio, 2.82; 95% confidence intervals [CI], 1.26-6.28; P = 0.016) and low ΔSUV_max (adjusted hazard ratio, 2.39; 95% CI, 1.07-5.34; P = 0.037) were independent prognostic factors for poor RFS. The categorization of the patients into four groups according to the combination of NLR and ΔSUV_max showed that patients with high NLR and low ΔSUV_max had significantly poorer RFS.

CONCLUSION

Baseline NLR and ΔSUV_max were significantly associated with the prognosis of patients with breast cancer who received neoadjuvant chemotherapy. These results suggest that metabolic non-responders with defective immune systems have worse survival outcomes.

Radiomic and Volumetric Measurements as Clinical Trial Endpoints—A Comprehensive Review

Simple Summary

The extraction of quantitative data from standard-of-care imaging modalities offers opportunities to improve the relevance and salience of imaging biomarkers used in drug development. This review aims to identify the challenges and opportunities for discovering new imaging-based biomarkers based on radiomic and volumetric assessment in the single-site solid tumor sites: breast cancer, rectal cancer, lung cancer and glioblastoma. Developing approaches to harmonize three essential areas: segmentation, validation and data sharing may expedite regulatory approval and adoption of novel cancer imaging biomarkers.

Abstract

Clinical trials for oncology drug development have long relied on surrogate outcome biomarkers that assess changes in tumor burden to accelerate drug registration (i.e., Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST v1.1) criteria). Drug-induced reduction in tumor size represents an imperfect surrogate marker for drug activity and yet a radiologically determined objective response rate is a widely used endpoint for Phase 2 trials. With the addition of therapies targeting complex biological systems such as immune system and DNA damage repair pathways, incorporation of integrative response and outcome biomarkers may add more predictive value. We performed a review of the relevant literature in four representative tumor types (breast cancer, rectal cancer, lung cancer and glioblastoma) to assess the preparedness of volumetric and radiomics metrics as clinical trial endpoints. We identified three key areas—segmentation, validation and data sharing strategies—where concerted efforts are required to enable progress of volumetric- and radiomics-based clinical trial endpoints for wider clinical implementation.

Correlation of 18-fluorodeoxyglucose uptake values on PET-CT scan with histological prognostic markers in breast cancer

BACKGROUND

Positron emission tomography-computed tomography (PET-CT) scan utilizes 18-fluorodeoxyglucose (18-FDG), based on the principle of higher glycolytic activity and reduced glucose-6-phosphatase levels in cancer cells. This imaging modality is usually advised in the metastatic evaluation of stage III breast cancer patients. The correlation of maximum standard uptake values of primary lesion with different pathological and molecular markers has not been studied extensively.

METHODS

Retrospective analysis of the data was performed from our prospectively maintained breast cancer database. All the patients who had undergone 18-FDG PET-CT scan at initial evaluation for staging between June 2017 and April 2020 were included in the study. One-way ANOVA test or Student's t-test as appropriate was performed to assess the difference of means in maximum standard uptake values (SUVmax) of the primary lesion and axillary nodes with clinical stage, histological grade, molecular subtype. Bonferroni post hoc test was also applied.

RESULTS

Out of 388 patients in the breast cancer database, 45 patients met inclusion criteria. There was a significant correlation of molecular subtype (p = 0.029) with SUVmax of the primary lesion. Higher primary SUVmax was associated with higher T stage (p = 0.01) and higher histological grade (p = 0.06). In each molecular subtype, there was an increase in mean SUVmax of the primary lesion with increasing histological grade and vice versa.

CONCLUSIONS

SUVmax of the primary lesion in breast cancer patients reflects tumor biology. Higher SUVmax can predict patients with triple-negative breast cancers and higher grades in primary tumors. However, further large-scale validatory studies are essential.

Radiomics in Oncological PET Imaging: A Systematic Review-Part 1, Supradiaphragmatic Cancers

Radiomics is an upcoming field in nuclear oncology, both promising and technically challenging. To summarize the already undertaken work on supradiaphragmatic neoplasia and assess its quality, we performed a literature search in the PubMed database up to 18 February 2022. Inclusion criteria were: studies based on human data; at least one specified tumor type; supradiaphragmatic malignancy; performing radiomics on PET imaging. Exclusion criteria were: studies only based on phantom or animal data; technical articles without a clinically oriented question; fewer than 30 patients in the training cohort. A review database containing PMID, year of publication, cancer type, and quality criteria (number of patients, retrospective or prospective nature, independent validation cohort) was constructed. A total of 220 studies met the inclusion criteria. Among them, 119 (54.1%) studies included more than 100 patients, 21 studies (9.5%) were based on prospectively acquired data, and 91 (41.4%) used an independent validation set. Most studies focused on prognostic and treatment response objectives. Because the textural parameters and methods employed are very different from one article to another, it is complicated to aggregate and compare articles. New contributions and radiomics guidelines tend to help improving quality of the reported studies over the years.

Association between tumor 18F-fluorodeoxyglucose metabolism and survival in women with estrogen receptor-positive, HER2-negative breast cancer

We examined whether ¹⁸F-fluorodeoxyglucose metabolism is associated with distant relapse-free survival (DRFS) and overall survival (OS) in women with estrogen receptor (ER)-positive, HER2-negative breast cancer. This was a cohort study examining the risk factors for survival that had occurred at the start of the study. A cohort from Asan Medical Center, Korea, recruited between November 2007 and December 2014, was included. Patients received anthracycline-based neoadjuvant chemotherapy. The maximum standardized uptake value (SUV) of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) was measured. The analysis included 466 women. The median (interquartile range) follow-up period without distant metastasis or death was 6.2 (5.3-7.6) years. Multivariable analysis of hazard ratio (95% confidence interval [CI]) showed that the middle and high tertiles of SUV were prognostic for DRFS (2.93, 95% CI 1.62-5.30; P < 0.001) and OS (4.87, 95% CI 1.94-12.26; P < 0.001). The 8-year DRFS rates were 90.7% (95% CI 85.5-96.1%) for those in the low tertile of maximum SUV vs. 73.7% (95% CI 68.0-79.8%) for those in the middle and high tertiles of maximum SUV. ¹⁸F-fluorodeoxyglucose PET/CT may assess the risk of distant metastasis and death in ER-positive, HER2-negative patients.

FDG PET/CT to Predict Recurrence of Early Breast Invasive Ductal Carcinoma

This study investigated the prognostic value of FDG PET/CT radiomic features for predicting recurrence in patients with early breast invasive ductal carcinoma (IDC). The medical records of consecutive patients who were newly diagnosed with primary breast IDC after curative surgery were reviewed. Patients who received any neoadjuvant treatment before surgery were not included. FDG PET/CT radiomic features, such as a maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), total lesion glycolysis (TLG), skewness, kurtosis, entropy, and uniformity, were measured for the primary breast tumor using LIFEx software to evaluate recurrence-free survival (RFS). A total of 124 patients with early breast IDC were evaluated. Eleven patients had a recurrence (8.9%). Univariate survival analysis identified large tumor size (>2 cm, p = 0.045), high Ki-67 expression (≥30%, p = 0.017), high AJCC prognostic stage (≥II, p = 0.044), high SUVmax (≥5.0, p = 0.002), high MTV (≥3.25 mL, p = 0.044), high TLG (≥10.5, p = 0.004), and high entropy (≥3.15, p = 0.003) as significant predictors of poor RFS. After multivariate survival analysis, only high MTV (p = 0.045) was an independent prognostic predictor. Evaluation of the MTV of the primary tumor by FDG PET/CT in patients with early breast IDC provides useful prognostic information regarding recurrence.

Differences in sensitivity to neoadjuvant chemotherapy among invasive lobular and ductal carcinoma of the breast and implications on surgery-A systematic review and meta-analysis

Meta-analysis of >87,000 patients demonstrates that patients with invasive lobular carcinoma of the breast are far less likely to achieve pCR of the breast or axilla compared to their ductal counterparts, receive less BCS and more frequently return positive margins.

BACKGROUND

Neoadjuvant chemotherapy (NACT) facilitates tumour downstaging, increases breast conserving surgery (BCS) and assesses tumour chemosensitivity. Despite clinicopathological differences in Invasive Ductal Carcinoma (IDC) and Invasive Lobular Carcinoma (ILC), decision making surrounding the use NACT does not take account of histological differences.

AIM

To determine the impact NACT on pathological complete response (pCR), breast conserving surgery (BCS), margin status and axillary pCR in ILC and IDC.

METHODS

A systematic review was performed in accordance with the PRISMA guidelines. Studies reporting outcomes among ILC and IDCs following NACT were identified. Dichotomous variables were pooled as odds ratios (ORs) with 95% confidence intervals_(CI) using the Mantel-Haenszel method. P-values <0.05 were statistically significant.

RESULTS

40 studies including 87,303 (7596 ILC [8.7%]and 79,708 IDC [91.3%]) patients were available for analysis. Mean age at diagnosis was 54.9 vs. 50.9 years for ILC and IDC, respectively. IDCs were significantly more likely to achieve pCR (22.1% v 7.4%, OR: 3.03 [95% CI 2.5-3.68] p < 0.00001), axillary pCR (23.6% vs. 13.4%, OR: 2.01 [95% CI 1.77-2.28] p < 0.00001) and receive BCS (45.7% vs. 33.3%, OR 2.14 [95% CI 1.87-2.45] p < 0.00001) versus ILCs. ILCs were significantly more likely to have positive margins at the time of surgery (36% vs 13.5%, OR 4.84 [95% CI 2.88-8.15] p < 0.00001).

CONCLUSION

This is the largest study comparing the impact of NACT among ILC and IDC with respect to pCR and BCS. ILC has different outcomes to IDC following NACT and incorporate it into treatment decisions and future clinical guidelines.

Prognostic Value of Metabolic, Volumetric and Textural Parameters of Baseline [18F]FDG PET/CT in Early Triple-Negative Breast Cancer

Simple Summary

The aim of this study was to evaluate PET/CT parameters to determine different prognostic groups in TNBC, in order to select patients with a high risk of relapse, for whom therapeutic escalation can be considered. We have demonstrated that the MTV, TLG and entropy of the primary breast lesion could be of interest to predict the prognostic outcome of TNBC patients.

Abstract

(1) Background: triple-negative breast cancer (TNBC) remains a clinical and therapeutic challenge primarily affecting young women with poor prognosis. TNBC is currently treated as a single entity but presents a very diverse profile in terms of prognosis and response to treatment. Positron emission tomography/computed tomography (PET/CT) with ¹⁸F-fluorodeoxyglucose ([¹⁸F]FDG) is gaining importance for the staging of breast cancers. TNBCs often show high [¹⁸F]FDG uptake and some studies have suggested a prognostic value for metabolic and volumetric parameters, but no study to our knowledge has examined textural features in TNBC. The objective of this study was to evaluate the association between metabolic, volumetric and textural parameters measured at the initial [¹⁸F]FDG PET/CT and disease-free survival (DFS) and overall survival (OS) in patients with nonmetastatic TBNC. (2) Methods: all consecutive nonmetastatic TNBC patients who underwent a [¹⁸F]FDG PET/CT examination upon diagnosis between 2012 and 2018 were retrospectively included. The metabolic and volumetric parameters (SUV_max, SUV_mean, SUV_peak, MTV, and TLG) and the textural features (entropy, homogeneity, SRE, LRE, LGZE, and HGZE) of the primary tumor were collected. (3) Results: 111 patients were enrolled (median follow-up: 53.6 months). In the univariate analysis, high TLG, MTV and entropy values of the primary tumor were associated with lower DFS (p = 0.008, p = 0.006 and p = 0.025, respectively) and lower OS (p = 0.002, p = 0.001 and p = 0.046, respectively). The discriminating thresholds for two-year DFS were calculated as 7.5 for MTV, 55.8 for TLG and 2.6 for entropy. The discriminating thresholds for two-year OS were calculated as 9.3 for MTV, 57.4 for TLG and 2.67 for entropy. In the multivariate analysis, lymph node involvement in PET/CT was associated with lower DFS (p = 0.036), and the high MTV of the primary tumor was correlated with lower OS (p = 0.014). (4) Conclusions: textural features associated with metabolic and volumetric parameters of baseline [¹⁸F]FDG PET/CT have a prognostic value for identifying high-relapse-risk groups in early TNBC patients.

The prognostic role of baseline 18F-FDG PET/CT SUVmax and SUVmax change in patients with node-positive breast cancer receiving neoadjuvant chemotherapy

OBJECTIVE

This study aimed to determine the prognostic role of baseline maximum standardized uptake value (SUVmax) obtained by pretreatment PET/CT and the change in SUVmax (ΔSUVmax [%]) in patients with axillary lymph node-positive breast cancer receiving neoadjuvant chemotherapy (NAC).

METHODS

One hundred and eighty patients with baseline SUVmax and 121 patients with SUVmax measurement after treatment were evaluated in the study. The baseline SUVmax value of the breast (SUVmax_BI) and axilla (SUVmax_AI) and the change in the SUVmax of the breast (ΔSUVmax_B) and axilla (ΔSUVmax_A) were measured. The optimal cut-off value of SUVmax and ΔSUVmax were determined by ROC curve analysis. Disease-free survival (DFS) and overall survival (OS) were calculated using Kaplan-Meier curves.

RESULTS

ΔSUVmax_B, pCR_B, pCR_A, and pCR parameters were found to be associated with relapse (P < .001, P = .033, P = .016, and P = .013, respectively). ΔSUVmax_B and SUVmax_AI were associated with mortality (P = .001 and P = .006, respectively). Multiple Cox regression analyses revealed that ΔSUVmax_B value was an independent prognostic factor for relapse and mortality (P = .013 and P = .010, respectively).

CONCLUSION

The results showed that ΔSUVmax_B was an independent prognostic factor for relapse and mortality in patients with axillary lymph node-positive breast cancer who received NAC.

Comparison of Ultrasound Features With Maximum Standardized Uptake Value Assessed by 18F-Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography for Prognosis of Estrogen Receptor+/Human Epithelial Growth Factor Receptor 2- Breast Cancer

ABSTRACT

estrogen receptor (ER)+/human epithelial growth factor receptor 2 (HER2)- breast cancers have less aggressive traits and a favorable prognosis when treated early. Prediction of prognosis for treatment outcome or survival in ER+/HER2- cancer is important. Ultrasound (US) is an effective and easy technique for breast cancer diagnosis and tumor characterization. Positron emission tomography/computed tomography (PET/CT) is widely used for diagnosis, staging, and therapeutic response in cancer evaluation, and a high maximum standardized uptake value (SUVmax) is associated with poor prognosis. The study aim was to compare the prognostic value of US features with that of the SUVmax assessed by PET/CT in ER+/HER- breast cancer patients. We retrospectively identified breast cancer patients in our institutional database who had undergone preoperative US and PET/CT, and 96 patients with invasive ductal carcinoma and ductal carcinoma in situ were included in this study. The US features of mass shape, margin, echo pattern, orientation, posterior features, boundary, and calcification in the mass were analyzed. We then analyzed the US features to look for correlations with SUVmax and associations with margins, boundaries, posterior features, histological grade, and ki-67 expression. High SUVmax was correlated with irregular shape, not-circumscribed margin, posterior acoustic enhancement, echogenic halo, and calcification in the mass (P < 0.05, all). Posterior acoustic enhancement was correlated with high ki-67 expression. Many US features of ER+/HER- breast cancer showed associations with SUVmax. Some US features of ER+/HER- breast cancer were useful for predicting prognosis.

Diagnostic Performance of [18F]FDG PET in Staging Grade 1-2, Estrogen Receptor Positive Breast Cancer

Positron emission tomography using [¹⁸F]fluorodeoxyglucose (FDG PET) potentially underperforms for staging of patients with grade 1–2 estrogen receptor positive (ER+) breast cancer. The aim of this study was to retrospectively investigate the diagnostic accuracy of FDG PET in this patient population. Suspect tumor lesions detected on conventional imaging and FDG PET were confirmed with pathology or follow up. PET-positive lesions were (semi)quantified with standardized uptake values (SUV) and these were correlated with various pathological features, including the histological subtype. Pre-operative imaging detected 155 pathologically verified lesions (in 74 patients). A total of 115/155 (74.2%) lesions identified on FDG PET were classified as true positive, i.e., malignant (in 67 patients) and 17/155 (10.8%) lesions as false positive, i.e., benign (in 9 patients); 7/155 (4.5%) as false negative (in 7 patients) and 16/155 (10.3%) as true negative (in 14 patients). FDG PET incorrectly staged 16/70 (22.9%) patients. The FDG uptake correlated with histological subtype, showing higher uptake in ductal carcinoma, compared to lobular carcinoma (p < 0.05). Conclusion: Within this study, FDG PET inadequately staged 22.9% of grade 1–2, ER + BC cases. Incorrect staging can lead to inappropriate treatment choices, potentially affecting survival and quality of life. Prospective studies investigating novel radiotracers are urgently needed.

Feasibility of prognosis assessment for cancer of unknown primary origin using texture analysis of 18F-fluorodeoxyglucose PET/computed tomography images of largest metastatic lymph node

OBJECTIVE

Cancers of unknown primary origin cannot be staged using images, making the prognosis difficult. We attempted to predict prognosis of patients with unknown primary origin using tumour heterogeneity recently introduced in F-fluorodeoxyglucose (F-FDG) PET/computed tomography (CT).

METHODS

Overall, 30 patients with unknown primary origin who underwent whole-body F-FDG PET/CT scans were retrospectively enrolled for texture analysis. The volume of interest was placed in the largest metastatic lymph nodes and conventional parameters and grey-level co-occurrence matrix (GLCM) were calculated. Statistical analysis of image-based variables was performed using Cox regression analyses. Patients were stratified into two groups based on cutoff values of GLCMentropy obtained using receiver operating characteristics (ROCs). Patients were analyzed, and overall survival (OS) was compared using Kaplan-Meier analysis.

RESULTS

Univariate Cox regression analysis showed significant differences in prognosis for parenchymal organ metastasis (P < 0.01), GLCM homogeneity (P = 0.01), GLCMcontrast (P < 0.01), GLCMentropy (P < 0.01) and GLCMdissimilarity (P < 0.01). Multivariate Cox regression analysis showed a significant difference in reduced prognosis for GLCMentropy positive (P < 0.01). Stratification was performed based on the GLCMentropy cutoff value, determined using ROCs analysis, with smaller groups showing better OS.

CONCLUSIONS

Despite previous difficulties in predicting prognosis in patients with unknown primary origin, F-FDG PET/CT texture features may enable stratification of prognosis. This could be useful for appropriate patient selection and management and help identify a subset of patients with favourable outcomes. These novel findings may be helpful for prognostication and improving patient care.

Prognostic value of SUVmax in breast cancer and comparative analyses of molecular subtypes: A systematic review and meta-analysis

BACKGROUND

To assess the prognostic capability of the maximum standardized uptake values (SUVmax) measured in the primary tumor and axillary lymph nodes (ALNs) by pretreatment fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography and analyze outcomes according to the molecular breast cancer subtypes.

METHODS

The databases were systematically searched using keywords for breast cancer, positron emission tomography/computed tomography, and SUVmax; the extracted studies reported at least 1 form of survival data, event-free survival (EFS) and overall survival. Comparative analyses of the pooled hazard ratios (HRs) for EFS and overall survival were performed to assess their correlations with SUVmax. The pooled HR was estimated using random-effects model according to the results of heterogeneity.

RESULTS

Thirteen eligible studies comprising 3040 patients with breast cancer were included. The pooled HRs of high SUVmax in the primary tumor and ALN were 3.01 (95% CI 1.83-4.97, P < .00001; I2 = 82%) and 3.72 (95% CI 1.15-12.01; I2 = 92%; P = .03), respectively. Patients with higher SUVmax demonstrated a poorer survival prognosis. Furthermore, comparative analyses according to the molecular subtypes demonstrated that the SUVmax in the primary tumor or ALN can be a predictive parameter in patients with the luminal subtype disease. Subtype analysis results indicated a significant association of the luminal group, with a HR of 2.65 (95% CI 1.31-5.37; I2 = 27%; P = .007).

CONCLUSIONS

SUVmax from pretreatment is a significant prognostic factor for EFS in patients with breast cancer. Despite several limitations, correlation with molecular subtype (luminal type) was demonstrated. Further large-scale studies are required to investigate the precise prognostic capability of SUVmax.

The prognostic role of baseline 18F-FDG PET/CT SUVmax and SUVmax change in patients with node-positive breast cancer receiving neoadjuvant chemotherapy

OBJECTIVE

This study aimed to determine the prognostic role of baseline maximum standardized uptake value (SUVmax) obtained by pretreatment PET/CT and the change in SUVmax (ΔSUVmax [%]) in patients with axillary lymph node-positive breast cancer receiving neoadjuvant chemotherapy (NAC).

METHODS

One hundred and eighty patients with baseline SUVmax and 121 patients with SUVmax measurement after treatment were evaluated in the study. The baseline SUVmax value of the breast (SUVmaxBI) and axilla (SUVmaxAI) and the change in the SUVmax of the breast (ΔSUVmaxB) and axilla (ΔSUVmaxA) were measured. The optimal cut-off value of SUVmax and ΔSUVmax were determined by ROC curve analysis. Disease-free survival (DFS) and overall survival (OS) were calculated using Kaplan-Meier curves.

RESULTS

ΔSUVmaxB, pCRB, pCRA, and pCR parameters were found to be associated with relapse (p < 0.001, p = 0.033, p = 0.016, and p = 0.013, respectively). ΔSUVmaxB and SUVmaxAI were associated with mortality (p = 0.001 and p = 0.006, respectively). Multiple Cox regression analyses revealed that ΔSUVmaxB value was an independent prognostic factor for relapse and mortality (p = 0.013 and p = 0.010, respectively).

CONCLUSION

The results showed that ΔSUVmaxB was an independent prognostic factor for relapse and mortality in patients with axillary lymph node-positive breast cancer who received NAC.

Radiomics: A Primer for Breast Radiologists

Radiomics has a long-standing history in breast imaging with computer-aided detection (CAD) for screening mammography developed in the late 20th century. Although conventional CAD had widespread adoption, the clinical benefits for experienced breast radiologists were debatable due to high false-positive marks and subsequent increased recall rates. The dramatic growth in recent years of artificial intelligence-based analysis, including machine learning and deep learning, has provided numerous opportunities for improved modern radiomics work in breast imaging. There has been extensive radiomics work in mammography, digital breast tomosynthesis, MRI, ultrasound, PET-CT, and combined multimodality imaging. Specific radiomics outcomes of interest have been diverse, including CAD, prediction of response to neoadjuvant therapy, lesion classification, and survival, among other outcomes. Additionally, the radiogenomics subfield that correlates radiomics features with genetics has been very proliferative, in parallel with the clinical validation of breast cancer molecular subtypes and gene expression assays. Despite the promise of radiomics, there are important challenges related to image normalization, limited large unbiased data sets, and lack of external validation. Much of the radiomics work to date has been exploratory using single-institution retrospective series for analysis, but several promising lines of investigation have made the leap to clinical practice with commercially available products. As a result, breast radiologists will increasingly be incorporating radiomics-based tools into their daily practice in the near future. Therefore, breast radiologists must have a broad understanding of the scope, applications, and limitations of radiomics work.

Prognostic value of metabolic tumor volume and total lesion glycolysis in breast cancer: a meta-analysis

OBJECTIVES

PET using F-fluorodeoxyglucose (FDG) has proven to be valuable in staging and monitoring of treatment response in breast cancer. We aimed to assess the prognostic value of metabolic tumor volume (MTV) and total lesion glycolysis (TLG) in patients with breast cancer.

METHODS

A systematic search of MEDLINE and EMBASE was performed using the keywords of breast cancer, PET, and volume. Inclusion criteria were F-FDG PET used as an initial imaging tool; studies limited to patients with breast cancer who had not undergone any treatment before PET scans; and studies reporting survival data. Event-free survival (EFS) and overall survival (OS) were considered markers of outcome.

RESULTS

Nine studies comprising 975 patients were included in this study. The pooled hazard ratio (HR) for adverse events was 33.73 (P < 0.00001; I = 0%) with MTV from primary tumor and 2.89 (P < 0.00001; I = 45%) with TLG from primary tumor, meaning that primary tumors with high volumetric parameters were associated with progression or recurrence. However, the combined HRs for EFS of MTV, and TLG, and those for OS of MTV from whole-body tumor were NS. The pooled HR for OS of TLG from whole-body tumor was 2.95 (P = 0.18; I = 71%).

CONCLUSION

Volumetric parameters from F-FDG PET are significant prognostic factors for outcome in patients with breast cancer. Patients with a high MTV or TLG from primary tumor have a higher risk of adverse events. Patients with a high TLG from whole-body tumor have a higher risk of deaths.

Integration of Multitargeted Polymer-Based Contrast Agents with Photoacoustic Computed Tomography: An Imaging Technique to Visualize Breast Cancer Intratumor Heterogeneity

One of the primary challenges in breast cancer diagnosis and treatment is intratumor heterogeneity (ITH), i.e., the coexistence of different genetically and epigenetically distinct malignant cells within the same tumor. Thus, the identification of ITH is critical for designing better treatments and hence to increase patient survival rates. Herein, we report a noninvasive hybrid imaging technology that integrates multitargeted and multiplexed patchy polymeric photoacoustic contrast agents (MTMPPPCAs) with single-impulse panoramic photoacoustic computed tomography (SIP-PACT). The target specificity ability of MTMPPPCAs to distinguish estrogen and progesterone receptor-positive breast tumors was demonstrated through both fluorescence and photoacoustic measurements and validated by tissue pathology analysis. This work provides the proof-of-concept of the MTMPPPCAs/SIP-PACT system to identify ITH in nonmetastatic tumors, with both high molecular specificity and real-time detection capability.

A Systematic Review of PET Textural Analysis and Radiomics in Cancer

Background: Although many works have supported the utility of PET radiomics, several authors have raised concerns over the robustness and replicability of the results. This study aimed to perform a systematic review on the topic of PET radiomics and the used methodologies. Methods: PubMed was searched up to 15 October 2020. Original research articles based on human data specifying at least one tumor type and PET image were included, excluding those that apply only first-order statistics and those including fewer than 20 patients. Each publication, cancer type, objective and several methodological parameters (number of patients and features, validation approach, among other things) were extracted. Results: A total of 290 studies were included. Lung (28%) and head and neck (24%) were the most studied cancers. The most common objective was prognosis/treatment response (46%), followed by diagnosis/staging (21%), tumor characterization (18%) and technical evaluations (15%). The average number of patients included was 114 (median = 71; range 20–1419), and the average number of high-order features calculated per study was 31 (median = 26, range 1–286). Conclusions: PET radiomics is a promising field, but the number of patients in most publications is insufficient, and very few papers perform in-depth validations. The role of standardization initiatives will be crucial in the upcoming years.

Harmonized pretreatment quantitative volume-based FDG-PET/CT parameters for prognosis of stage I-III breast cancer: Multicenter study

OBJECTIVES

This study investigated harmonized pretreatment volume-based quantitative FDG-PET/CT parameters in breast cancer patients for prognostic value.

RESULTS

During a median overall follow-up period of 5.3 years, 91 patients had recurrence and 40 died. Multivariate analysis of ER-positive/HER2-negative patients showed high maximum standardized uptake value (SUVmax) (p = 0.018), high total lesion glycolysis (TLG) (p = 0.010), and clinical N-classification (p = 0.0027) as independent negative predictors of RFS, while high maximum SUVmax (p = 0.037), advanced clinical T-classification (p = 0.030), and advanced TNM stage (p = 0.0067) were independent negative predictors of OS. For recurrence and death in HER2-positive patients, high total TLG (p = 0.037, p = 0.0048, respectively) and advanced TNM stage (p = 0.048, p = 0.046, respectively) were independent prediction factors. In the triple-negative group, independent factors related to recurrence and death were high maximum SUVmax (p = 0.0014, p = 0.0003, respectively) and advanced TNM stage (p < 0.0001, p < 0.0001, respectively).

MATERIALS AND METHODS

Records of 546 stage I-III invasive breast cancer patients, including 344 estrogen receptor (ER)-positive/human epidermal growth factor receptor 2 (HER2)-negative, 110 HER2-positive, and 92 triple-negative cases, treated at four institutions were reviewed retrospectively. Harmonized primary tumor and nodal maximum SUVmax, metabolic tumor volume (MTV), and TLG indicated in pretreatment FDG-PET/CT results were analyzed. Evaluations of relationships of clinicopathological factors, volume-based quantitative parameters, recurrence-free survival (RFS), and overall survival (OS) for each subtype were performed with a Cox proportional hazards model and log-rank test.

CONCLUSIONS

The results indicated that potential surrogate markers for prognosis in patients with the three main subtypes of operable breast cancer include harmonized pretreatment quantitative volume-based FDG-PET/CT parameters, particularly whole-lesion SUVmax and TLG.

Hormonal Receptor Immunochemistry Heterogeneity and 18F-FDG Metabolic Heterogeneity: Preliminary Results of Their Relationship and Prognostic Value in Luminal Non-Metastatic Breast Cancers

Introduction

We aimed to investigate whether ¹⁸F-FDG PET metabolic heterogeneity reflects the heterogeneity of estrogen receptor (ER) and progesterone receptor (PR) expressions within luminal non-metastatic breast tumors and if it could help in identifying patients with worst event-free survival (EFS).

Materials and methods

On 38 PET high-resolution breast bed positions, a single physician drew volumes of interest encompassing the breast tumors to extract SUV_max, histogram parameters and textural features. High-resolution immunochemistry (IHC) scans were analyzed to extract Haralick parameters and descriptors of the distribution shape. Correlation between IHC and PET parameters were explored using Spearman tests. Variables of interest to predict the EFS status at 8 years (EFS-8y) were sought by means of a random forest classification. EFS-8y analyses were then performed using univariable Kaplan-Meier analyses and Cox regression analysis. When appropriate, Mann-Whitney tests and Spearman correlations were used to explore the relationship between clinical data and tumoral PET heterogeneity variables.

Results

For ER expression, correlations were mainly observed with ¹⁸F-FDG histogram parameters, whereas for PR expression correlations were mainly observed with gray-level co-occurrence matrix (GLCM) parameters. The strongest correlations were observed between skewness__ER and uniformity__HISTO (ρ = −0.386, p = 0.017) and correlation__PR and entropy__GLCM (ρ = 0.540, p = 0.001), respectively. The median follow-up was 6.5 years and the 8y-EFS was 71.0%. Random forest classification found age, clinical stage, SUV_max, skewness__ER, kurtosis__ER, entropy__HISTO, and uniformity__HISTO to be variables of importance to predict the 8y-EFS. Univariable Kaplan-Meier survival analyses showed that skewness__ER was a predictor of 8y-EFS (66.7 ± 27.2 versus 19.1 ± 15.2, p = 0.018 with a cut-off value set to 0.163) whereas other IHC and PET parameters were not. On multivariable analysis including age, clinical stage and skewness__ER, none of the parameters were independent predictors. Indeed, skewness__ER was significantly higher in youngest patients (ρ = −0.351, p = 0.031) and in clinical stage III tumors (p = 0.023).

Conclusion

A heterogeneous distribution of ER within the tumor in IHC appeared as an EFS-8y prognosticator in luminal non-metastatic breast cancers. Interestingly, it appeared to be correlated with PET histogram parameters which could therefore become potential non-invasive prognosticator tools, provided these results are confirmed by further larger and prospective studies.

Semi-automatic evaluation of baseline whole-body tumor burden as an imaging biomarker of 68Ga-PSMA-11 PET/CT in newly diagnosed prostate cancer

OBJECTIVES

The prognostic value of baseline tumor burden of prostate cancer was rarely studied. We aimed to evaluate the whole-body tumor burden of ⁶⁸Ga- prostate specific membrane antigen-HBED-CC (⁶⁸Ga-PSMA-11) PET/CT in newly diagnosed prostate cancer semi-automatically, and explore its preliminary application in predicting prognosis.

METHODS

Similar to metabolic tumor volume (MTV) and total lesion glycolysis (TLG) of ¹⁸F-FDG PET/CT, ⁶⁸Ga-PSMA-11 PET/CT tumor burden parameters including whole-body PSMA tumor volume (wbPSMA-TV) and whole-body total lesions PSMA uptake (wbTL-PSMA) were acquired semi-automatically. The intra-observer and inter-observer reliability was analyzed. The relationship between tumor burden and prostate-specific antigen (PSA) value or Gleason score was investigated. The preliminary application of tumor burden in predicting progression-free survival (PFS) was explored.

RESULTS

Fifty-nine newly diagnosed prostate cancer patients were retrospectively analyzed. Semi-automatic quantification of whole-body tumor burden had excellent intra-observer and inter-observer consistency [all intra-class correlation coefficient (ICC) > 0.990]. wbPSMA-TV and wbTL-PSMA were 32.6 (range 1.0-3968.2) cm³ and 161.9 (range 6.0-24971.7), respectively. wbPSMA-TV and wbTL-PSMA correlated with PSA (r = 0.858, p < 0.001; r = 0.879, p < 0.001) and Gleason score (r = 0.793, p < 0.001; r = 0.805, p < 0.001) significantly. In univariate analysis, wbPSMA-TV, wbTL-PSMA, SUV_max, SUV_peak, SUV_mean, PSMA-TV, TL-PSMA of primary tumor, fPSA and Gleason score were independent significant predictors of PFS (all p < 0.05). Moreover, in multivariate analysis, wbTL-PSMA [hazard ratio (HR): 1.001, p = 0.014] and Gleason score (HR: 5.124, p = 0.031) can significantly predict progression-free prognosis.

CONCLUSIONS

As imaging biomarkers, wbPSMA-TV and wbTL-PSMA correlated with clinical characteristics significantly. High wbTL-PSMA or Gleason score was associated with shorter PFS of newly diagnosed prostate cancer independently.

Is FDG-PET texture analysis related to intratumor biological heterogeneity in lung cancer?

OBJECTIVES

We aimed at investigating the origin of the correlations between tumor volume and ¹⁸F-FDG-PET texture indices in lung cancer.

METHODS

Eighty-five consecutive patients with newly diagnosed non-small cell lung cancer (NSCLC) underwent a ¹⁸F-FDG-PET/CT scan before treatment. Seven phantom spheres uniformly filled with ¹⁸F-FDG, and covering a range of activities and volumes similar to that found in lung tumors, were also scanned. Established texture indices were computed for lung tumors and homogeneous spheres. The dependence between textural indices and volume in homogeneous spheres was modeled and then used to predict texture indices in lung tumors. Correlation analyses were carried out between predicted and texture features measured in lung tumors. Cox proportional hazards regression was used to investigate the associations between overall survival and volume-adjusted textural features.

RESULTS

All textural features showed strong, non-linear correlations with volume, both in tumors and homogeneous spheres. Correlations between predicted versus measured texture features were very high for contrast (r² = 0.91), dissimilarity (r² = 0.90), ZP (r² = 0.90), GLNN (r² = 0.86), and homogeneity (r² = 0.82); high for entropy (r² = 0.50) and HILAE (r² = 0.53); and low for energy (r² = 0.30). Cox regressions showed that among volume-adjusted features, only HILAE was associated with overall survival (b = - 0.35, p = 0.008).

CONCLUSION

We have shown that texture indices previously found to be correlated with a number of clinically relevant outcomes might not provide independent information apart from that driven by their correlation with tumor volume, suggesting that these metrics might not be suitable as intratumor heterogeneity markers.

KEY POINTS

• Associations between texture FDG-PET indices and overall survival have been widely reported in lung cancer, with tumor volume also being associated with overall survival, and therefore, it is still unclear whether the predictive power of textural indices is simply driven by this correlation. • Our results demonstrated strong non-linear correlations between textural indices and volume, showing an analogous behavior for lung tumors from patients and homogeneous spheres inserted in phantoms. • Our findings showed that texture FDG-PET indices might not provide independent information apart from that driven by their correlation with tumor volume.

Long-term outcomes in patients with PET-predicted poor-responsive HER2-positive breast cancer treated with neoadjuvant bevacizumab added to trastuzumab and docetaxel: 5-year follow-up of the randomised Avataxher study

BACKGROUND

The open-label, randomised Phase 2 AVATAXHER study (NCT01142778) demonstrated that early PET assessment identified HER2-positive breast cancer patients who responded poorly to neoadjuvant docetaxel plus trastuzumab. Adding neoadjuvant bevacizumab for PET-predicted poor-responders improved pathological complete response (pCR) rates (43.8% vs 24.0%). We investigated long-term study outcomes.

METHODS

Patients were treated in three groups. All patients initially received two cycles of standard neoadjuvant therapy with [¹⁸F]-FDG PET conducted before each cycle. Those with ≥70% change in the maximum standardised uptake value (∆SUVmax) received four further cycles of standard neoadjuvant therapy (PET responders). PET-predicted poor-responders (∆SUVmax <70%) were randomised (2:1) to neoadjuvant therapy with (Group A) or without (Group B) bevacizumab for cycles 3-6. All patients received one further cycle of trastuzumab before surgery plus adjuvant trastuzumab (11 cycles).

FINDINGS

142 patients were randomized and treated (PET responders, n = 69; Group A, n = 48; Group B, n = 25). 5-year disease-free survival rates were 90.5% (95% CI: 80.0-95.6%) in PET responders, 90.2% (95% CI: 75.9-96.2%) in Group A, and 76.0% (95% CI: 54.2-88.4%) in Group B. However, no difference was observed between randomised arms in a sensitivity analysis. During adjuvant therapy, the incidence of Grade ≥3 (Group A: 25.6%; Group B 12.5%) and serious adverse events (Group A: 18.6%; Group B 12.5%) was higher in Group A vs Group B, but with no apparent effect on cardiac events.

INTERPRETATION

In patients with HER2-positive breast cancer, an intervention based on early PET assessment and improvement of pCR does not modify disease-free survival.

FUNDING

Roche France.

Alternative volumetric PET pjmirometers for evaluation of breast cancer cases with 18F-FDG PET/CT imaging: Metabolic tumour volume and total lesion glycolysis

INTRODUCTION

We aimed to investigate the prognostic and clinical values of two volumetric PET pjmirometers used in conjunction with SUV_max at different thresholds in invasive ductal carcinoma (IDC).

METHODS

A total of 139 metastatic IDC BC who underwent 18F-FDG PET/CT imaging were included to study. MTV and TLG (40%, 50%, 60% and 70%) used in conjunction with primary tumour SUV_max . Nodal involvement, distant metastasis, ER, PR, Ki-67 expression and survival data evaluated by comparing FDG PET pjmirometers.

RESULTS

Mean ± SD SUV_max of lesions (n = 139) was 13.97 ± 9.21. Primary tumour 18F-FDG uptake associated increased tumour diameter (>2 cm), high Ki-67 (>15%) and distant organ metastasis (DOM) (P = 0.015, 0.005 and 0.016, respectively). There was significant association between molecular subtypes and SUV_max (P = 0.002). High MTV associated with tumour diameter (MTV 40-70%), axillary lymph node (ALN) diameter (MTV 40-70%), and distant nodal metastasis (DNM) (MTV 50-70%). High TLG associated with tumour diameter (TLG 40-70%), high Ki-67 (TLG 40-70%), ALN metastasis (TLG 40%), ALN diameter (TLG 40-70%) and DNM (TLG 40-70%). Median survival found shorter in DOM patients (P = 0.030, Log Rank = 0.110).

CONCLUSION

We think evaluation of MTV and TLG at different thresholds in addition to SUV_max would enhance diagnostic and prognostic value of 18F-FDG PET/CT, and thus contribute to disease management.

The correlation of 18F-FDG PET/CT metabolic parameters, clinicopathological factors, and prognosis in breast cancer

PURPOSE

To study the imaging parameters of ¹⁸F-fluorodeoxy glucose (¹⁸F-FDG) in breast cancer on positron emission tomography/computed tomography (PET/CT)-the correlation of clinical pathological factors and prognosis among the maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of lesions for patients.

METHODS

From January 2012 to December 2014, a total of 125 female patients were treated in our hospital for the first time and were diagnosed as breast cancer by histopathology. They were selected as the research subjects. All of them had complete ¹⁸F-FDG PET/CT examination data before surgery, the postoperative clinicopathological information, and follow-up data. They were divided into the event group (38 cases) and the event-free group (87 cases) according to whether local recurrence or distant metastasis occurred after the follow-up, with the follow-up time 4-60 months. The correlation on ¹⁸F-FDG PET/CT metabolic parameters of breast cancer with clinicopathological factors and prognosis was retrospectively evaluated.

RESULTS

The primary lesions of 125 cases with breast cancers all had higher ¹⁸F-FDG uptake, and the SUVmax, MTV, and TLG of the primary tumors in the event group were significantly higher than those in the event-free group (t = 2.645, 2.782, 15.263, p = 0.011, 0.008, 0.000), p < 0.05; SUVmax, MTV, and TLG of primary breast cancer have no correlation with age and tumor site of patient (p > 0.05); there were statistically significant differences in the SUVmax, MTV, and TLG of primary tumor in the comparison of different tumor size, T stage, N stage, and histological grades (p < 0.05); all of SUVmax, MTV, and TLG in the estrogen receptor (ER) and/or progesterone receptor (PR) positive groups were lower than those in the negative group, with statistically significant difference (p < 0.05); the SUVmax, MTV, and TLG of human epidermal growth factor receptor 2 (HER2) positive group, proliferating cell nuclear antigen (Ki-67) high expression group were higher than those in the negative group and low expression group, with statistically significant difference (p < 0.05). There were 38 recurrence and metastasis cases within 125 cases with breast cancer in 5 years after operation, with the total recurrence and metastasis rate as 30.40% (38/125). The event-free survival rate in the SUVmax ≥ 8.64 group was significantly lower than that in the SUVmax < 8.64 group (p < 0.01).

CONCLUSIONS

The metabolic parameters of ¹⁸F-FDG PET/CT in breast cancer can reflect the biological behavior of the tumor indirectly; therefore, it was studied on the related correlation to provide the guidance of clinical individualized comprehensive treatment and prognostic judgment.

[18F]FDG uptake of bone marrow on PET/CT for predicting distant recurrence in breast cancer patients after surgical resection

Background

The objective of this study was to investigate the prognostic value of 2-Deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]FDG) uptake of bone marrow (BM) and metabolic parameters of primary tumor on positron emission tomography/computed tomography (PET/CT) for predicting distant recurrence in patients with breast cancer.

Methods

Pretreatment [¹⁸F]FDG PET/CT images of 345 breast cancer patients were retrospectively evaluated. Maximum standardized uptake value, metabolic tumor volume, and total lesion glycolysis (TLG) of primary breast cancer and bone marrow-to-liver uptake ratio (BLR) on PET/CT were measured. A Cox proportional hazard regression model was used to evaluate the prognostic potential of parameters for predicting recurrence-free survival (RFS) and distant RFS. For Kaplan-Meier analysis, the specific cutoff values pf BLR and TLG were determined by the maximal chi-square method.

Results

The median follow-up duration of the enrolled patients was 48.7 months, and during follow-up, 36 patients (10.4%) experienced the cancer recurrence. BLR was significantly correlated with T stage, serum inflammatory markers, and recurrence pattern (p < 0.05). Patients with high BLR and TLG showed worse RFS and distant RFS than those with low BLR and TLG. On multivariate analysis, BLR was significantly associated with both RFS and distant RFS after adjusting for T stage, estrogen receptor status, and TLG (p = 0.001 for both). Only 0.5% of patients with TLG < 9.64 g and BLR < 0.91 experienced distant recurrence. However, patients with TLG ≥ 9.64 g and BLR ≥ 0.91 had a distant recurrence rate of 40.7%.

Conclusions

BLR on pretreatment [¹⁸F]FDG PET/CT were significant predictors for RFS and distant RFS in patients with breast cancer. By combining [¹⁸F]FDG uptake of BM and volumetric PET/CT index of breast cancer, the risk of distant recurrence could be stratified.

PET/CT radiomics in breast cancer: Mind the step

The aim of the present review was to assess the current status of positron emission tomography/computed tomography (PET/CT) radiomics research in breast cancer, and in particular to analyze the strengths and weaknesses of the published papers in order to identify challenges and suggest possible solutions and future research directions. Various combinations of the terms "breast", "radiomic", "PET", "radiomics", "texture", and "textural" were used for the literature search, extended until 8 July 2019, within the PubMed/MEDLINE database. Twenty-six articles fulfilling the inclusion/exclusion criteria were retrieved in full text and analyzed. The studies had technical and clinical objectives, including diagnosis, biological characterization (correlation with histology, molecular subtypes and IHC marker expression), prediction of response to neoadjuvant chemotherapy, staging, and outcome prediction. We reviewed and discussed the selected investigations following the radiomics workflow steps related to the clinical, technical, analysis, and reporting issues. Most of the current evidence on the clinical role of PET/CT radiomics in breast cancer is at the feasibility level. Harmonized methods in image acquisition, post-processing and features calculation, predictive models and classifiers trained and validated on sufficiently representative datasets, adherence to consensus guidelines, and transparent reporting will give validity and generalizability to the results.

Global heterogeneity assessed with 18F-FDG PET/CT. Relation with biological variables and prognosis in locally advanced breast cancer

AIM

To analyze the relationship between measurements of global heterogeneity, obtained from ¹⁸F-FDG PET/CT, with biological variables, and their predictive and prognostic role in patients with locally advanced breast cancer (LABC).

MATERIAL AND METHODS

68 patients from a multicenter and prospective study, with LABC and a baseline ¹⁸F-FDG PET/CT were included. Immunohistochemical profile [estrogen receptors (ER) and progesterone receptors (PR), expression of the HER-2 oncogene, Ki-67 proliferation index and tumor histological grade], response to neoadjuvant chemotherapy (NC), overall survival (OS) and disease-free survival (DFS) were obtained as clinical variables. Three-dimensional segmentation of the lesions, providing SUV, volumetric [metabolic tumor volume (MTV) and total lesion glycolysis (TLG)] and global heterogeneity variables [coefficient of variation (COV) and SUVmean/SUVmax ratio], as well as sphericity was performed. The correlation between the results obtained with the immunohistochemical profile, the response to NC and survival was also analyzed.

RESULTS

Of the patients included, 62 received NC. Only 18 responded. 13 patients relapsed and 11 died during follow-up. ER negative tumors had a lower COV (p=0.018) as well as those with high Ki-67 (p=0.001) and high risk phenotype (p=0.033) compared to the rest. No PET variable showed association with the response to NC nor OS. There was an inverse relationship between sphericity with DFS (p=0.041), so, for every tenth that sphericity increases, the risk of recurrence decreases by 37%.

CONCLUSIONS

Breast tumors in our LABC dataset behaved as homogeneous and spherical lesions. Larger volumes were associated with a lower sphericity. Global heterogeneity variables and sphericity do not seem to have a predictive role in response to NC nor in OS. More spherical tumors with less variation in gray intensity between voxels showed a lower risk of recurrence.