Tumor Heterogeneity Assessed by 18F-FDG PET/CT Is Not Significantly Associated with Nodal Metastasis in Breast Cancer Patients

Abstract

Introduction: The purpose of this study was to evaluate the association of tumor heterogeneity as assessed by positron emission tomography/computed tomography (PET/CT) with pathological factors of breast cancer, and the prediction of nodal metastasis through tumor heterogeneity. Methods: From January 2013 to December 2013, 102 patients with invasive ductal carcinoma of the breast were enrolled into this study. [¹⁸F]Fluorodeoxyglucose PET/CT was performed before surgery. The metabolic tumor volume (MTV) of each lesion was calculated and a series of standardized uptake value (SUV) thresholds (e.g. 40%, 50%, 60%, 70%, and 80% of SUVmax) was obtained. A threshold-volume (dV/dT) curve was acquired by plotting thresholds to MTV values automatically calculated with these thresholds. Tumor heterogeneity was calculated from the slope of the threshold-volume curve and defined as heterogeneity factor (HF). Results: HF differed significantly according to T stage (p < 0.0001), N stage (p = 0.0131) and American Joint Committee on Cancer (AJCC) stage (p = 0.0006). Among the pathological parameters, dermal lymphatic involvement (p = 0.0039) showed the significant correlations with HF. Lymphovascular invasion (p = 0.0005) was the only independent factor for predicting nodal metastasis. Conclusions: Tumor heterogeneity measured by 18F-FDG PET/CT is significantly associated with dermal lymphatic involvement. However, PET might not be able to predict nodal metastasis in breast cancer.

Low-dose High-resolution 18F-FDG-PET/CT Using Time-of-flight and Point-spread Function Reconstructions: A Role in the Detection of Breast Carcinoma Axillary Lymph Node Metastases

“…Compared to other studies, our study achieved wellbalanced sensitivity and specificity, and the results of PSF and TOF techniques are virtually identical to those in the published populations (2)(3)5). The results of the evaluation of axillary lymph nodes are comparable to those of PET and magnetic resonance imaging (MRI) studies.…”

“…However, this is not a diagnostic imaging modality for the presence of metastatic lymph node involvement, but only a sign of the degree of lymphatic drainage. In contrast, 18 F-FDG-PET/CT is a method that directly evaluates metastatic infiltration (2,3,5) and is also relevant for prognosis of the disease (5,6). When evaluating axillary nodes, false-negative and false-positive findings may be obtained.…”

“…The standard procedure for assessing N-staging is sentinel node biopsy by radioguided excision and subsequent histopathological examination. The vast majority of ductal or lobular breast cancers, predominantly higher grade and triple-negative phenotypes, are known to accumulate 18 F-fluorodeoxyglucose ( 18 F-FDG) relatively well and therefore positron-emission tomography (PET)/CT can also be used to stage the disease (1)(2)(3). Although the use of 18 F-FDG-PET/CT has already been established for locally advanced tumors and restaging of the disease (1,2), its benefit has not been fully evaluated for the detection of axillary node involvement.…”

“…The vast majority of ductal or lobular breast cancers, predominantly higher grade and triple-negative phenotypes, are known to accumulate 18 F-fluorodeoxyglucose ( 18 F-FDG) relatively well and therefore positron-emission tomography (PET)/CT can also be used to stage the disease (1)(2)(3). Although the use of 18 F-FDG-PET/CT has already been established for locally advanced tumors and restaging of the disease (1,2), its benefit has not been fully evaluated for the detection of axillary node involvement. The decision to perform radical surgery or to plan neoadjuvant therapy primarily depends on the presence of axillary node involvement or the presence of occult distant metastases when the breast carcinoma is triplenegative, even when of size T1.…”

A risk‐based approach to identifying oligometastatic disease on imaging

“…Heterogeneity of morphological and functional imaging features is proving of interest in predicting metastatic risk. Although the data from 18 FDG PET remains controversial entropy measures from histogram analyses of MRI based tumour ADC can predict positive nodal status in rectal cancers and in gastric cancers, while in soft‐tissue sarcomas, first order statistics from ADC, which relate to signal variability and to entropy and dissimilarity, were higher in high grade tumours …”