18F-FDG PET of locally invasive breast cancer and association of estrogen receptor status with standardized uptake value: microarray and immunohistochemical analysis

Correlation between Histopathological Prognostic Tumor Characteristics and [18F]FDG Uptake in Corresponding Metastases in Newly Diagnosed Metastatic Breast Cancer

BACKGROUND

In metastatic breast cancer (MBC), [18F]fluorodeoxyglucose positron emission tomography/computed tomography ([18F]FDG-PET/CT) can be used for staging. We evaluated the correlation between BC histopathological characteristics and [18F]FDG uptake in corresponding metastases.

PATIENTS AND METHODS

Patients with non-rapidly progressive MBC of all subtypes prospectively underwent a baseline histological metastasis biopsy and [18F]FDG-PET. Biopsies were assessed for estrogen, progesterone, and human epidermal growth factor receptor 2 (ER, PR, HER2); Ki-67; and histological subtype. [18F]FDG uptake was expressed as maximum standardized uptake value (SUVmax) and results were expressed as geometric means.

RESULTS

Of 200 patients, 188 had evaluable metastasis biopsies, and 182 of these contained tumor. HER2 positivity and Ki-67 ≥ 20% were correlated with higher [18F]FDG uptake (estimated geometric mean SUVmax 10.0 and 8.8, respectively; p = 0.0064 and p = 0.014). [18F]FDG uptake was lowest in ER-positive/HER2-negative BC and highest in HER2-positive BC (geometric mean SUVmax 6.8 and 10.0, respectively; p = 0.0058). Although [18F]FDG uptake was lower in invasive lobular carcinoma (n = 31) than invasive carcinoma NST (n = 146) (estimated geometric mean SUVmax 5.8 versus 7.8; p = 0.014), the metastasis detection rate was similar.

CONCLUSIONS

[18F]FDG-PET is a powerful tool to detect metastases, including invasive lobular carcinoma. Although BC histopathological characteristics are related to [18F]FDG uptake, [18F]FDG-PET and biopsy remain complementary in MBC staging (NCT01957332).

Increased tumor glycolysis is associated with decreased immune infiltration across human solid tumors

Response to immunotherapy across multiple cancer types is approximately 25%, with some tumor types showing increased response rates compared to others (i.e. response rates in melanoma and non-small cell lung cancer (NSCLC) are typically 30-60%). Patients whose tumors are resistant to immunotherapy often lack high levels of pre-existing inflammation in the tumor microenvironment. Increased tumor glycolysis, acting through glucose deprivation and lactic acid accumulation, has been shown to have pleiotropic immune suppressive effects using in-vitro and in-vivo models of disease. To determine whether the immune suppressive effect of tumor glycolysis is observed across human solid tumors, we analyzed glycolytic and immune gene expression patterns in multiple solid malignancies. We found that increased expression of a glycolytic signature was associated with decreased immune infiltration and a more aggressive disease across multiple tumor types. Radiologic and pathologic analysis of untreated estrogen receptor (ER)-negative breast cancers corroborated these observations, and demonstrated that protein expression of glycolytic enzymes correlates positively with glucose uptake and negatively with infiltration of CD3⁺ and CD8⁺ lymphocytes. This study reveals an inverse relationship between tumor glycolysis and immune infiltration in a large cohort of multiple solid tumor types.

18F-Alfatide II for the evaluation of axillary lymph nodes in breast cancer patients: comparison with 18F-FDG

PURPOSE

¹⁸F-Alfatide II has been translated into clinical use and been proven to have good performance in identifying breast cancer. In this study, we investigated ¹⁸F-Alfatide II for evaluation of axillary lymph nodes (ALN) in breast cancer patients and compared the performance with ¹⁸F-FDG.

METHODS

A total of 44 female patients with clinically suspected breast cancer were enrolled and underwent ¹⁸F-Alfatide II and ¹⁸F-FDG PET/CT within a week. Tracer uptakes in ALN were evaluated by visual analysis, semi-quantitative analysis with maximum standardized uptake value (SUV_max), mean standardized uptake value (SUV_mean), and SUV_max ratio of target/non-target (T/NT).

RESULTS

Among 44 patients, 37 patients were pathologically diagnosed with breast cancer with metastatic (17 cases) or non-metastatic (20 cases) ALN. The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of visual analysis were 70.6%, 90%, 81.1%, 85.7%, and 78.3% for ¹⁸F-Alfatide II, 64.7%, 90%, 78.4%, 84.6%, and 75% for ¹⁸F-FDG, respectively. By combining ¹⁸F-Alfatide II and ¹⁸F-FDG, the sensitivity significantly increased to 82.4%, the specificity was 85%, the accuracy increased to 83.8%, the PPV was 82.4%, and the NPV significantly increased to 85.0%. Three cases of luminal B subtype were false negative for both ¹⁸F-Alfatide II and ¹⁸F-FDG. The other 2 false negative cases of ¹⁸F-Alfatide II were triple-negative subtype and 3 false negative cases of ¹⁸F-FDG were luminal B subtype too. The AUCs of three semi-quantitative parameters (SUV_max, SUV_mean, T/NT) for ¹⁸F-Alfatide II were between 0.8 and 0.9, whereas those for ¹⁸F-FDG were more than 0.9. ¹⁸F-Alfatide II T/NT had the highest Youden index (76.5%), specificity (100%), accuracy (89.2%), and PPV (100%) among these semi-quantitative parameters. ¹⁸F-Alfatide II uptake as well as ¹⁸F-FDG uptake in metastatic axillary lymph nodes (MALN) was significantly higher than that in benign axillary lymph nodes (BALN). Both ¹⁸F-Alfatide II and ¹⁸F-FDG did not show difference in primary tumor uptake irrespective of ALN status.

CONCLUSION

¹⁸F-Alfatide II can be used in breast cancer patients to detect metastatic ALN, however, like ¹⁸F-FDG, with high specificity but relatively low sensitivity. The combination of ¹⁸F-Alfatide II and ¹⁸F-FDG can significantly improve sensitivity and NPV. ¹⁸F-Alfatide II T/NT may serve as the most important semi-quantitative parameter to evaluate ALN.

Relationships of 18F-FDG uptake by primary tumors with prognostic factors and molecular subtype in ductal breast cancer

OBJECTIVES

In this study, we aimed to investigate the correlation between SUVmax of primary tumor and prognostic factors/molecular subtype in ductal breast cancer patients.

MATERIALS AND METHODS

We retrospectively reviewed 150 female patients with pathologically proven invasive ductal breast cancer from January 2015 to October 2019 who underwent ¹⁸F-FDG PET/CT for initial staging. Histopathological prognostic features of the primary tumor (histological grade, hormone receptor status, Ki-67 index, vb.) were obtained from the tru-cut biopsy report. In ¹⁸F-FDG PET/CT studies, the maximum standardized uptake value (SUVmax) of the primary breast tumor was calculated and compared with the presence of axillary lymphadenopathy and/or distant metastases, histopathological prognostic factors and molecular subtype.

RESULTS

The high SUVmax of primary breast tumors is significantly correlated with the clinicopathological factors: high tumor size, high histologic grade, high Ki-67 index, axillary lymph node positivity and distant metastasis. SUVmax value was significantly higher in patients with basal subtype than patients with Luminal A subtype (8,14 ± 3,71 and 4,64 ± 2,45, p = 0,002). Correlation analysis revealed a low correlation between Ki-67 index and SUVmax (r = 0,276, p = 0,001) and moderate correlation between tumor size and SUVmax (r = 0,470, p = 0,001). In multivariate linear regression analysis, Ki-67 index and tumor size had a statistically significant effect on SUVmax values. As these parameters increase, it is seen that it increases SUVmax values (p = 0,004, Std Beta: 0,228, 95% CI:0,010-0,055 and p = 0,001, Std Beta:0,374, 95% CI:0,55-0,136, respectively).

CONCLUSION

High SUVmax value is associated with factors suggesting poor prognosis. Pretreatment ¹⁸F-FDG PET/CT can be used as a tool to predict prognosis in breast cancer.

Prognostic value of metabolic signature on 18F-FDG uptake in breast cancer patients after radiotherapy

Radiotherapy (RT) is a major modality of postoperative treatment in breast cancer. The maximal standardized value (SUVmax) is ¹⁸FDG-PET/CT derived parameter that reported to be a valuable prognostic factor in cancer patients. Herein, we aimed to identify a prognostic gene signature associated with glucose uptake for breast cancer patients after RT by leveraging the mRNA expression profiling on public datasets. The glucose uptake signature was constructed using the single sample gene set enrichment analysis (ssGSEA) algorithm and evaluated in GSE21217 where SUVmax value was measured by PET-CT directly. The prognostic value was validated in three post-RT breast cancer cohorts (GSE103744, NKI, and FUSCC databases). The patients were stratified into glucose uptake signature score-high and low groups. Patients with a higher score had worse survival than those with a lower score. Mechanistically, the glucose uptake signature was calculated in each cell type of a single-cell RNA-seq database from five breast cancer patients. Glucose uptake signature score was significantly elevated in the malignant epithelial cells compared with normal ones. The immunosuppression markers including PDCD1, TIGIT, LAG3, and HAVCR2 were significantly upregulated in the T cells bearing a high glucose uptake signature score. Collectively, our results demonstrated the potential prognostic value of a glucose uptake signature in the post-RT breast cancer patients.

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.

Radiomics Signatures Based on Multiparametric MRI for the Preoperative Prediction of the HER2 Status of Patients with Breast Cancer

OBJECTIVES

The aim of our study was to preoperatively predict the human epidermal growth factor receptor 2 (HER2) status of patients with breast cancer using radiomics signatures based on single-parametric and multiparametric magnetic resonance imaging (MRI).

METHODS

Three hundred six patients with invasive ductal carcinoma of no special type (IDC-NST) were retrospectively enrolled. Quantitative imaging features were extracted from fat-suppressed T2-weighted and dynamic contrast-enhanced T1 weighted (DCE-T1) preoperative MRI. Then, three radiomics signatures based on fat-suppressed T2-weighted images, DCE-T1 images and their combination were developed using a support vector machine (SVM) to predict the HER2-positive vs HER2-negative status of patients with breast cancer. The area under the curve (AUC), accuracy, sensitivity, and specificity were calculated to assess the predictive performances of the signatures.

RESULTS

Twenty-eight quantitative radiomics features, namely, 14 texture features, 4 first-order features, 9 wavelet features, and 1 shape feature, were used to construct radiomics signatures. The performance of the radiomics signatures for distinguishing HER2-positive from HER2-negative breast cancer based on fat-suppressed T2-weighted images, DCE-T1 images, and their combination had an AUC of 0.74 (95% confidence interval [CI], 0.700 to 0.770), 0.71 (0.673 to 0.738), and 0.86 (0.832 to 0.882) in the primary cohort and 0.70 (0.666 to 0.744), 0.68 (0.650 to 0.726), and 0.81 (0.776 to 0.837) in the validation cohort, respectively.

CONCLUSION

Radiomics signatures based on multiparametric MRI represent a potential and efficient alternative tool to evaluate the HER2 status in patients with breast cancer.

Clustering subtypes of breast cancer by combining immunohistochemistry profiles and metabolism characteristics measured using FDG PET/CT

BACKGROUND

The aim of this study was to investigate the effect of combining immunohistochemical profiles and metabolic information to characterize breast cancer subtypes.

METHODS

This retrospective study included 289 breast tumors from 284 patients who underwent preoperative 18 F-fluorodeoxyglucose (FDG) positron emission tomography/ computed tomography (PET/CT). Molecular subtypes of breast cancer were classified as Hormonal, HER2, Dual (a combination of both Hormonal and HER2 features), and triple-negative (TN). Histopathologic findings and immunohistochemical results for Ki-67, EGFR, CK 5/6, and p53 were also analyzed. The maximum standardized uptake value (SUV) measured from FDG PET/CT was used to evaluate tumoral glucose metabolism.

RESULTS

Overall, 182, 24, 47, and 36 tumors were classified as Hormonal, HER2, Dual, and TN subtypes, respectively. Molecular profiles of tumor aggressiveness and the tumor SUV revealed a gradual increase from the Hormonal to the TN type. The tumor SUV was significantly correlated with tumor size, expression levels of p53, Ki-67, and EGFR, and nuclear grade (all p < 0.001). In contrast, the tumor SUV was negatively correlated with the expression of estrogen receptors (r = - 0.234, p < 0.001) and progesterone receptors (r = - 0.220, p < 0.001). Multiple linear regression analysis revealed that histopathologic markers explained tumor glucose metabolism (adjusted R-squared value 0.238, p < 0.001). Tumor metabolism can thus help define breast cancer subtypes with aggressive/adverse prognostic features.

CONCLUSIONS

Metabolic activity measured using FDG PET/CT was significantly correlated with the molecular alteration profiles of breast cancer assessed using immunohistochemical analysis. Combining molecular markers and metabolic information may aid in the recognition and understanding of tumor aggressiveness in breast cancer and be helpful as a prognostic marker.

Relationship between Prognostic Stage in Breast Cancer and Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography

This retrospective study examined the relationship between the standardized uptake value max (SUVmax) of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) and the prognostic stage of breast cancer. We examined 358 breast cancers in 334 patients who underwent ¹⁸F-FDG PET/CT for initial staging between January 2016 and December 2019. We extracted data including SUVmax of ¹⁸F-FDG PET and pathological biomarkers, including estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), and nuclear grade. Anatomical and prognostic stages were determined per the American Joint Committee on Cancer (eighth edition). We examined whether there were statistical differences in SUVmax between each prognostic stage. The mean SUVmax values for clinical prognostic stages were as follow: stage 0, 2.2 ± 1.4; stage IA, 2.6 ± 2.1; stage IB, 4.2 ± 3.5; stage IIA, 5.2 ± 2.8; stage IIB, 7.7 ± 6.7; and stage III + IV, 7.0 ± 4.5. The SUVmax values for pathological prognostic stages were as follows: stage 0, 2.2 ± 1.4; stage IA, 2.8 ± 2.2; stage IB, 5.4 ± 3.6; stage IIA, 6.3 ± 3.1; stage IIB, 9.2 ± 7.5, and stage III + IV, 6.2 ± 5.2. There were significant differences in mean SUVmax between clinical prognostic stage 0 and ≥II (p < 0.001) and I and ≥II (p < 0.001). There were also significant differences in mean SUVmax between pathological prognostic stage 0 and ≥II (p < 0.001) and I and ≥II (p < 0.001). In conclusion, mean SUVmax increased with all stages up to prognostic stage IIB, and there were significant differences between several stages. The SUVmax of ¹⁸F-FDG PET/CT may contribute to prognostic stage stratification, particularly in early cases of breast cancers.

Relationships of 18F-FDG uptake by primary tumors with prognostic factors and molecular subtype in ductal breast cancer

OBJECTIVES

In this study, we aimed to investigate the correlation between SUVmax of primary tumor and prognostic factors/molecular subtype in ductal breast cancer patients.

MATERIALS AND METHODS

We retrospectively reviewed 150 female patients with pathologically proven invasive ductal breast cancer from January 2015 to October 2019 who underwent 18F-FDG PET/CT for initial staging. Histopathological prognostic features of the primary tumor (histological grade, hormone receptor status, Ki-67 index, vb.) were obtained from the tru-cut biopsy report. In 18F-FDG PET/CT studies, the maximum standardized uptake value (SUVmax) of the primary breast tumor was calculated and compared with the presence of axillary lymphadenopathy and/or distant metastases, histopathological prognostic factors and molecular subtype.

RESULTS

The high SUVmax of primary breast tumors is significantly correlated with the clinicopathological factors: high tumor size, high histologic grade, high Ki-67 index, axillary lymph node positivity and distant metastasis. SUVmax value was significantly higher in patients with basal subtype than patients with Luminal A subtype (8.14±3.71 and 4.64±2.45, p=0.002). Correlation analysis revealed a low correlation between Ki-67 index and SUVmax (r=0.276, p=0.001) and moderate correlation between tumor size and SUVmax (r=0.470, p=0.001). In multivariate linear regression analysis, Ki-67 index and tumor size had a statistically significant effect on SUVmax values. As these parameters increase, it is seen that it increases SUVmax values (p=0.004, Std Beta: 0.228, 95% CI: 0.010-0.055 and p=0.001, Std Beta: 0.374, 95% CI: 0.55-0.136, respectively).

CONCLUSION

High SUVmax value is associated with prognotic factors suggesting poor prognosis. Pretreatment 18F-FDG PET/CT can be used as a tool to predict prognosis in breast cancer.

Radiogenomics Based on PET Imaging

Radiogenomics or imaging genomics is a novel omics strategy of associating imaging data with genetic information, which has the potential to advance personalized medicine. Imaging features extracted from PET or PET/CT enable assessment of in vivo functional and physiological activity and provide comprehensive tumor information non-invasively. However, PET features are considered secondary to features on conventional imaging, and there has not yet been a review of the radiogenomic approach using PET features. This review article summarizes the current state of PET-based radiogenomic research for cancer, which discusses some of its limitations and directions for future study.

A review on immunohistochemical and histopathologic validation in PET-CT findings with consideration to microRNAs

Purpose

This review provides an overview of some of the most recent clinical trials which investigated various types of cancer and other diseases, through the use of PET-CT imaging, highlighting the use of immunohistochemical stains or conventional histopathology for the validation or contradiction of their hypothesis. Furthermore, we investigate a potential new direction of research by analyzing the upcoming role of microRNAs in disease confirmation.

Methods

An extensive search of MEDLINE/PubMed and SCOPUS electronic databases was made, using the MeSH terms "positron emission tomography computed tomography" and "immunohistochemistry" as well as "SUV" and "immunohistochemistry", restricting the search by clinical trials and time period. Further searches were made for articles regarding Ki-67 and microRNAs in correlation with metabolic PET-CT uptake.

Results

Out of all 389 initial search results, 27 original articles were found relevant to the topic. Their contents were synthesized and discussed regarding the matter at hand. No relevant clinical trials involving microRNAs were found.

Conclusions

Immunohistochemical and histopathologic results remain widely used and indispensable in modern research, concerning PET-CT validation. Possible candidates for diagnosis confirmation, in future research, may reside in the further development of microRNAs.

Mitochondrial RNA Expression and Single Nucleotide Variants in Association with Clinical Parameters in Primary Breast Cancers

The human mitochondrial DNA (mtDNA) encodes 37 genes, including thirteen proteins essential for the respiratory chain, and RNAs functioning in the mitochondrial translation apparatus. The total number of mtDNA molecules per cell (mtDNA content) is variable between tissue types and also between tumors and their normal counterparts. For breast cancer, tumors tend to be depleted in their mtDNA content compared to adjacent normal mammary tissue. Various studies have shown that primary breast tumors harbor somatic mtDNA variants. A decrease in mtDNA content or the presence of somatic variants could indicate a reduced mitochondrial function within breast cancer. In this explorative study we aimed to further understand genomic changes and expression of the mitochondrial genome within breast cancer, by analyzing RNA sequencing data of primary breast tumor specimens of 344 cases. We demonstrate that somatic variants detected at the mtRNA level are representative for somatic variants in the mtDNA. Also, the number of somatic variants within the mitochondrial transcriptome is not associated with mutational processes impacting the nuclear genome, but is positively associated with age at diagnosis. Finally, we observe that mitochondrial expression is related to ER status. We conclude that there is a large heterogeneity in somatic mutations of the mitochondrial genome within primary breast tumors, and differences in mitochondrial expression among breast cancer subtypes. The exact impact on metabolic differences and clinical relevance deserves further study.

18F-FDG PET/CT for Systemic Staging of Newly Diagnosed Breast Cancer in Men

¹⁸F-FDG PET/CT has demonstrated substantial value in systemic staging of newly diagnosed breast cancer in women. However, it is not known whether breast cancer in male patients benefits similarly. This study assesses ¹⁸F-FDG PET/CT systemic staging in patients with newly diagnosed male breast cancer and determines detection rates for unsuspected distant metastases stratified by pre-PET/CT stage. Methods: In this Institutional Review Board-approved retrospective study, our Health Care Information System was screened for stage I-III male patients with breast cancer who underwent ¹⁸F-FDG PET/CT before systemic or radiation therapy from 2004 to 2017. Initial stage was determined by mammography, ultrasound, or surgery. ¹⁸F-FDG PET/CT was evaluated to identify unsuspected extraaxillary regional nodal and distant metastases, and a post-PET/CT stage was determined. Rates of upstaging to stage IV were determined for each initial stage. Results: During the 14-y period, 10,124 unique patients underwent ¹⁸F-FDG PET/CT for breast cancer at our institution. Of these, 106 patients were men, and 39 of these patients were imaged at initial staging and met the inclusion criteria. Median age was 62 y (range, 31-90 y), most had ductal carcinoma (95%), and most were estrogen receptor-positive (97%). In 7 of 39 patients (18%), ¹⁸F-FDG PET/CT identified previously unsuspected distant metastases, which increased patient stage to IV. This included 3 of 19 (16%) initial stage IIB patients and 4 of 12 (33%) initial stage III patients. ¹⁸F-FDG PET/CT also detected an unsuspected synchronous lymphoma in 1 patient. Conclusion: ¹⁸F-FDG PET/CT revealed previously unsuspected distant metastases in 16% of male patients with pre-PET/CT stage IIB breast cancer and 33% of those with stage III breast cancer. These rates are comparable to previously published upstaging rates in female patients. ¹⁸F-FDG PET/CT demonstrates value for systemic staging of male patients with breast cancer and should be considered for use in newly diagnosed patients, particularly those with stage IIB and III disease.

Non-invasive tumor genotyping using radiogenomic biomarkers, a systematic review and oncology-wide pathway analysis

With targeted treatments playing an increasing role in oncology, the need arises for fast non-invasive genotyping in clinical practice. Radiogenomics is a rapidly evolving field of research aimed at identifying imaging biomarkers useful for non-invasive genotyping. Radiogenomic genotyping has the advantage that it can capture tumor heterogeneity, can be performed repeatedly for treatment monitoring, and can be performed in malignancies for which biopsy is not available. In this systematic review of 187 included articles, we compiled a database of radiogenomic associations and unraveled networks of imaging groups and gene pathways oncology-wide. Results indicated that ill-defined tumor margins and tumor heterogeneity can potentially be used as imaging biomarkers for 1p/19q codeletion in glioma, relevant for prognosis and disease profiling. In non-small cell lung cancer, FDG-PET uptake and CT-ground-glass-opacity features were associated with treatment-informing traits including EGFR-mutations and ALK-rearrangements. Oncology-wide gene pathway analysis revealed an association between contrast enhancement (imaging) and the targetable VEGF-signalling pathway. Although the need of independent validation remains a concern, radiogenomic biomarkers showed potential for prognosis prediction and targeted treatment selection. Quantitative imaging enhanced the potential of multiparametric radiogenomic models. A wealth of data has been compiled for guiding future research towards robust non-invasive genomic profiling.

Tumor characteristics and metabolic quantification in carcinoma breast: An institutional experience

BACKGROUND

In India, carcinoma breast is the most common cancer among urban women population and second most common cancer after carcinoma cervix in rural areas. One in 22 women in India develops carcinoma of the breast in their lifetime. Fluorine-18-fluoro-2-deoxy-D-glucose (18F-FDG) uptake in breast cancer usually indicates the degree of tumor metabolism and hence can predict its behavior and prognosis. On the other hand, the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER-2) or neu state of breast cancer is a biomarker that provides important prognostic information in addition to predicting response to therapy.

AIMS

The main objective of this study is to assess whether a correlation exists between 18F-FDG uptake in untreated cases of breast cancer, their receptor status (ER, PR, and HER-2 or neu), tumor histology, and tumor size.

SUBJECTS AND METHODS

Sixty consecutive female patients, with biopsy-proven primary breast cancer, were enrolled in this prospective study for whom 18F-FDG positron emission tomography-computed tomography scan was done in the Department of Nuclear Medicine. Results obtained were analyzed using appropriate statistical tests (t-test and Pearson Chi-square tests), and interpretation was made with 95% confidence level.

RESULTS

In our series, a positive correlation between tumor size, high tumor grade, and standardized uptake value (SUV) was found. Tumors with positive receptor status for estrogen, progesterone, and HER-2/neu receptors had statistically insignificant lower maximum SUV (SUVmax) values than their negative counterparts. Triple-negative breast tumors (ER-, PR-, and no overexpression of HER-2/neu) are currently a subject of major interest because of their aggressiveness, poor prognosis, and lack of targeted therapy. Based on receptor status when the SUVmaxof the group with triple-negative receptor status (ER-/PR-/HER-2/neu-) was compared to rest of the patient group, it was seen that patients with negative receptor status had significantly higher mean SUVmaxvalues.

CONCLUSIONS

We have inferred that in patients with breast cancer, various biological parameters such as tumor size, grade, histology, and hormonal receptor status have different impact on tumor metabolic activity.

Strong association of epidermal growth factor receptor status with breast cancer FDG uptake

PURPOSE

Imaging tumor FDG uptake could complement breast cancer biomarkers of risk and treatment response. Although breast cancer FDG uptake is reputedly influenced by major biomarker states, the role of epidermal growth factor receptor (EGFR) expression remains largely unexplored.

METHODS

This is a retrospective study that included 499 patients with primary breast cancer at initial presentation. Tumor FDG uptake was measured on pretreatment PET/CT as maximum standardized uptake value (SUVmax), and biomarkers were assessed by immunohistochemistry of tumor tissue. Regression analysis was performed for predictors of high tumor FDG uptake (SUVmax ≥ 8.6).

RESULTS

SUVmax was higher in ER- (36.5%; 11.2 ± 6.0 vs. 8.3 ± 5.3), PR- (42.3%; 10.9 ± 6.0 vs. 8.2 ± 5.2), and triple-negative tumors (19.8%; 12.0 ± 6.9 vs. 8.7 ± 5.2; all p < 0.0001). EGFR expression (28.5%) was more frequent in ER-, PR-, triple-negative, cytokeratin 5/6 (CK5/6) + and mutant P53 (mP53) + tumors (all p < 0.0001). EGFR+ was associated with higher SUVmax among all tumors (11.9 ± 6.0 vs. 8.3 ± 5.3), ER- tumors (p < 0.0001), PR- and + tumors (p < 0.0001 and 0.027), hormone receptor- and + tumors (p < 0.0001 and 0.004), human epidermal growth factor receptor 2 (HER2)- and + tumors (p < 0.0001 and 0.006), non-triple negative tumors (p < 0.0001), CK5/6- and + tumors (p = 0.021 and <0.0001), and mP53- and + tumors (p < 0.0001 and 0.008). Tumors had high FDG uptake in 73.2% of EGFR+ and 40.6% of EGFR- tumors. On regression analysis, significant multivariate predictors of high tumor FDG uptake were large size, EGFR+ and CK5/6+ for the entire subjects, and EGFR+ and CK5/6+ for ER- and hormone receptor negative subgroups. High FDG uptake was able to sub-stratify EGFR+ tumors that were more likely to be ER- and CK5/6+, and EGFR- tumors more likely to be mP53 +.

CONCLUSIONS

Primary breast tumor FDG uptake is strongly influenced by EGFR status beyond that by other major biomarkers including hormone receptor and HER2 status, and EGFR expression is a strong independent predictor of high breast tumor FDG uptake.

Metabolic PET Imaging in Oncology

OBJECTIVE

In this article, we provide a general overview of how cancer cells subvert critical metabolic pathways to support their growth and unchecked division. Furthermore, we outline how molecular imaging can diagnostically exploit the resulting differences between cancer and normal cells.

CONCLUSION

Molecular PET can provide valuable information about the metabolic dysregulation in cancer.

Radiogenomic Analysis of Oncological Data: A Technical Survey

In the last few years, biomedical research has been boosted by the technological development of analytical instrumentation generating a large volume of data. Such information has increased in complexity from basic (i.e., blood samples) to extensive sets encompassing many aspects of a subject phenotype, and now rapidly extending into genetic and, more recently, radiomic information. Radiogenomics integrates both aspects, investigating the relationship between imaging features and gene expression. From a methodological point of view, radiogenomics takes advantage of non-conventional data analysis techniques that reveal meaningful information for decision-support in cancer diagnosis and treatment. This survey is aimed to review the state-of-the-art techniques employed in radiomics and genomics with special focus on analysis methods based on molecular and multimodal probes. The impact of single and combined techniques will be discussed in light of their suitability in correlation and predictive studies of specific oncologic diseases.

Molecular imaging using PET and SPECT for identification of breast cancer subtypes

Breast cancer is a major disease with high morbidity and mortality in women. As a highly heterogeneous tumor, it contains different molecular subtypes: luminal A, luminal B, human epidermal growth factor 2-positive, and triple-negative subtypes. As each subtype has unique features, it may not be universal to the optimal treatment and expected response for individual patients. Therefore, it is critical to identify different breast cancer subtypes. Targeting subcellular levels, molecular imaging, especially PET and single photon emission computed tomography, has become a promising means to identify breast cancer subtypes and monitor treatment. Different biological processes between various subtypes, including changes correlated with receptor expression, cell proliferation, or glucose metabolism, have the potential for imaging with PET and single photon emission computed tomography radiopharmaceuticals. Receptor imaging, with radiopharmaceuticals targeting estrogen receptor, progesterone receptor, or human epidermal growth factor 2, is available to distinguish receptor-positive tumors from receptor-negative ones. Cell proliferation imaging with fluorine-18 fluorothymidine PET aids identification of luminal A and B subtypes on the basis of the correlation with the immunohistochemical biomarker Ki-67. Glucose metabolism imaging with fluorine-18 fluorodeoxyglucose PET may have potential to discriminate triple-negative subtypes from others. With increasing numbers of novel radiopharmaceuticals, noninvasive molecular imaging will be applied widely for the identification of different subtypes and provide more in-vivo information on individualized management of breast cancer patients.

Do 18F-FDG PET/CT findings have a relationship with histopathological and immunohistochemical factors of breast cancer in men?

PURPOSE

We aimed to investigate the relationship between histopathological and immunohistochemical features of male breast cancer (MBC) and comprehensive fluorine-18-fluorodeoxyglucose (F-FDG) PET/computed tomography (CT) parameters.

METHODS

Fifteen male patients with newly diagnosed breast cancer who underwent F-FDG PET/CT were included in the study. Maximum and average standardized uptake value (SUVmax and SUVavg), metabolic total volume, and total lesion glycolysis (TLG) were compared with the histopathological and immunohistochemical findings of patients. In addition, metabolic tumor-node-metastases (TNM) staging was performed following the determination of metastatic axillary lymph nodes and tumor size by F-FDG PET/CT and verified by histopathological evaluation.

RESULTS

There were no significant differences between all groups classified on the basis of histopathological and immunohistochemical parameters for SUVmax, SUVavg, TLG, and metabolic total volume. The only difference was found in patients with distant metastases and stage IV. SUVmax, SUVavg, and TLG were higher in patients with distant metastases compared with patients without distant metastases (P: 0.005, 0.011, and 0.042, respectively). Strong correlations were found between metabolic TNM staging and histopathological TNM staging (for T stage; r: 0.590, P: 0.021, N stage; r: 0.694, P: 0.002, TNM stage; r: 0.835, P: 0.002). In addition, no differences were found with any metabolic F-FDG PET/CT parameters in survival.

CONCLUSION

Although no correlation was found between metabolic parameters and groups categorized on the basis of histopathological or immunohistochemical features, F-FDG PET/CT is a reliable imaging modality to determine tumor size, axillary lymph node involvement, and metabolic TNM staging of MBC. In addition, none of those metabolic F-FDG PET/CT parameters predicted survival in MBC.

Spectrum of the Breast Lesions With Increased 18F-FDG Uptake on PET/CT

Interpretation of ¹⁸F-FDG PET/CT studies in breast is challenging owing to nonspecific FDG uptake in various benign and malignant conditions. Benign conditions include breast changes in pregnancy and lactation, gynecomastia, mastitis, fat necrosis, fibroadenoma, intraductal papilloma, and atypical ductal hyperplasia. Among malignancies, invasive ductal carcinoma and invasive lobular carcinoma are common histological types of breast carcinoma. Rarely, other unusual histological types of breast carcinomas (eg, intraductal papillary carcinoma, invasive micropapillary carcinoma, medullary carcinoma, mucinous carcinoma, and metaplastic carcinoma), lymphoma, and metastasis can be the causes. Knowledge of a wide spectrum of hypermetabolic breast lesions on FDG PET/CT is essential in accurate reading of FDG PET/CT. The purpose of this atlas article is to demonstrate features of various breast lesions encountered at our institution, both benign and malignant, which can result in hypermetabolism on FDG PET/CT imaging.

Evaluation of the association between HIF-1α and HER-2 expression, hormone receptor status, Ki-67 expression, histology and tumor FDG uptake in breast cancer

The present study aimed to examine hypoxia-inducible factor (HIF)-1α expression and its association with glucose uptake in invasive breast cancer. In addition, connections between glucose uptake and several other prognostic parameters of breast cancer were studied. Between August 2013 and April 2015, 92 patients with biopsy-diagnosed breast cancer were subjected to ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography. The primary tumor and nodal maximum standardized uptake values (SUVmax) were recorded, and HIF-1α expression and clinical parameters, including tumor mass, estrogen receptor (ER) and progesterone receptor (PgR) levels, human epidermal growth factor receptor-2 (HER-2), Ki-67 index, grade and histology, were analyzed. SUVmax was compared with clinicopathological parameters and HIF-1α expression. The median SUVmax values of the ER-negative and PgR-negative tumors were significantly increased compared with ER and PgR-positive tumors, respectively (P=0.004 and P=0.008). SUVmax differed significantly between the T2 and T3 tumors and the T1 tumors. The median SUVmax levels were higher in the Ki-67 expression >10% group than the Ki-67 index <10% group (P=0.001). Although the median SUVmax values in HER-2-positive and -negative tumors were similar, triple-negative tumors demonstrated significantly higher values (P=0.04). With regard to tumor grade, the median SUVmax was greater in the high-grade tumors compared with the low-grade tumors. SUVmax did not exhibit a significant correlation with HIF-1α expression; however, HIF-1α expression was associated with tumor size and PgR expression. HIF-1α expression increased with a larger tumor size (r=0.27; P=0.008) and decreased PgR expression (r=−0.26; P=0.0002). The axillary nodal SUVmax of the N1 tumors was significantly lower than the N2 and N3 tumors (P<0.0001). In the multivariate analysis, tumor size, Ki-67 expression and ER Allred score were independent factors that impacted SUVmax. The results of the present study indicated strong associations between tumor size, tumor grade, Ki-67 expression, triple-negativity, downregulated hormone receptor expression and SUVmax values. Conversely, there was no association observed between glucose uptake and levels of HIF-1α. Based on these results, it is suggested that the lack of assiocation between hypoxia and glucose uptake indicates phenotypic independence.

Factors Associated with (18)F-Fluorodeoxyglucose Uptake in T1 and T2 Invasive Ductal Carcinoma of the Breast

PURPOSE

The objective of this study was to investigate the relationship between diversity of (18)F-fluorodeoxyglucose ((18)F-FDG) uptake of primary tumor in positron emission tomography (PET) and various clinicopathologic factors in breast cancer of same pathologic T1, T2 stage.

METHODS

A total of 258 patients with invasive ductal breast cancer were enrolled in this study. All patients underwent (18)F-FDG PET-CT before surgery. Patients were divided into two groups according to tumor size based on the pathologic T stage, and maximum standardized uptake value (SUVmax) of 2.5, respectively.

RESULTS

On the univariate analysis, estrogen receptor (ER), tumor size, lymphovascular invasion, p53, pathologic N status (pN) and Nottingham tumor grade (NG) were associated with high SUVmax in T1 and T2 breast cancer. On the multivariate logistic regression, tumor size and NG remained significant variables dividing high and low SUVmax. In the T1 group, ER, p53 and NG were significantly associated with high SUVmax on the univariate analysis. In this group, p53 and NG remained significant variables for dividing high and low SUVmax on the multivariate logistic regression. In the T2 group, only NG was associated with high SUVmax on the univariate analysis.

CONCLUSIONS

NG showed an association with (18)F-FDG uptake in both T1 and T2 breast cancer independently; however, p53 in T1 breast cancer.

Correlation of Molecular Subtypes of Invasive Ductal Carcinoma of Breast with Glucose Metabolism in FDG PET/CT: Based on the Recommendations of the St. Gallen Consensus Meeting 2013

PURPOSE

This study aimed to investigate the relationship between the SUVmax of primary breast cancer lesions and the molecular subtypes based on the recommendations of the St. Gallen consensus meeting 2013.

METHODS

Clinical records of patients who underwent F-18 FDG PET/CT for initial staging of invasive ductal carcinoma (IDC) of the breast were reviewed. A total of 183 patients were included. SUVmax was correlated with the molecular subtypes defined by the St. Gallen Consensus Meeting 2013, i.e., luminal A-like (LA), luminal B-like HER2 negative (LBHER2-), luminal B-like HER2 positive (LBHER2+), HER2 positive (HER2+), and triple negative (TN), and with the clinicohistopathologic characteristics.

RESULTS

The molecular subtype was LA in 38 patients, LBHER2- in 72, LBHER2+ in 21, HER2+ in 30, and TN in 22. The mean SUVmax in the LA, LBHER2-, LBHER2+, HER2+, and TN groups were 4.5 ± 2.3, 7.2 ± 4.9, 7.2 ± 4.3, 10.2 ± 5.5, and 8.8 ± 7.1, respectively. Although SUVmax differed significantly among these subtypes (p < 0.001), the values showed a wide overlap. Optimal cut-off SUVmax to differentiate LA from LBHER2-, LBHER2+, HER2+ and TN were 5.9, 5.8, 7.5, and 10.2 respectively, with area under curve (AUC) of 0.648, 0.709, 0.833, and 0.697 respectively. The cut-off value of 5.9 yielded the highest accuracy for differentiation between the LA and non-LA subtypes, with sensitivity, specificity, and AUC of 79.4 %, 57.9 %, and 0.704 respectively.

CONCLUSION

The SUVmax showed a significant correlation with the molecular subtype. Although SUVmax measurements could be used along with immunohistochemical analysis for differentiating between molecular subtypes, its application to individual patients may be limited due to the wide overlaps in SUVmax.

Ductal carcinoma in situ and ductal carcinoma in situ with microinvasion: correlation of FDG uptake with histological and biological prognostic factors

BACKGROUND

Several studies investigated the correlation between the intensity of fluorodeoxyglucose (FDG) uptake and some histological and biological characteristics in breast cancer. Ductal carcinoma in situ (DCIS) is generally thought to be a precursor lesion of invasive breast cancer. The aim of this study was to assess the correlation between FDG uptake values on positron emission tomography/computed tomography (PET/CT) with histological and biological prognostic factors in DCIS and ductal carcinoma in situ with microinvasion (DCIS-Mi).

MATERIALS AND METHODS

PET/CT images for initial staging of confirmed DCIS and DCIS-Mi patients, taken between July 2004 and December 2009, were reviewed retrospectively. Maximum standardized uptake values (SUVmax) and tumor background count density ratio on PET/CT were compared with tumor characteristics. Histological and biological prognostic factors included tumor size, nuclear grade, Van Nuys Prognostic Index, estrogen receptor, progesterone receptor, HER2, and Ki-67 index.

RESULTS

In total, 87 lesions from 83 patients (all females; mean age 51 ± 9 years) were studied. The Van Nuys Prognostic Index group was 1 in 25 lesions, 2 in 36, and 3 in 26. On statistical analysis, significant differences in SUVmax and tumor background count density ratio were seen between the Van Nuys Prognostic Index groups and according to tumor size and HER2. The correlation between SUVmax and Ki-67 was significant. However, the correlation between tumor background count density ratio and Ki-67 was not statistically significant.

CONCLUSION

In DCIS and DCIS-Mi cases, significant correlations were found between increased FDG uptake and several histological and biological factors for poor prognosis (tumor size, Van Nuys Prognostic Index, and HER2).

Prognostic value of FDG PET/CT-based metabolic tumor volumes in metastatic triple negative breast cancer patients

FDG PET/CT-based measures of tumor burden show promise to predict survival in patients with metastatic breast cancer, but the patient populations studied so far are heterogeneous. The reports may have been confounded by the markedly different prognosis of the various subtypes of breast cancer. The purpose of this study is to evaluate the correlation between tumor burden on FDG PET/CT and overall survival (OS) in patients within a defined population: metastatic triple negative breast cancer (MTNBC). FDG PET/CT scans of 47 consecutive MTNBC patients (54±12 years-old) with no other known malignancies were analyzed. A total 393 lesions were identified, and maximum standardized uptake value (SUVmax), mean SUV, metabolic tumor volume (MTV), total lesion number (TLN) and total lesion glycolysis (TLG), were measured and correlated with patient survival by Mantel-Cox tests and Cox regression analysis. At a median follow-up time of 12.4 months, 41 patients died with a median OS of 12.1 months. Patients with MTV less than 51.5 ml lived nearly three times longer (22 vs 7.1 months) than those with a higher MTV (χ(2)=21.3, P<0.0001). In a multivariate Cox regression analysis only TLN and MTV were significantly correlated with survival. Those with an MTV burden in the 75(th) percentile versus the 25(th) percentile had a hazard ratio of 6.94 (p=0.001). In patients with MTNBC, MTV appears to be a strong prognostic factor. If validated in prospective studies, MTV may be a valuable tool for risk stratification of MTNBC patients in clinical trials and to guide patient management.

Initial Results of a Prospective Clinical Trial of 18F-Fluciclovine PET/CT in Newly Diagnosed Invasive Ductal and Invasive Lobular Breast Cancers

(18)F-labeled 1-amino-3-fluorocyclobutane-1-carboxylic acid ((18)F-fluciclovine) is a leucine analog PET/CT radiotracer that depicts amino acid transport into cells. Amino acid transport proteins have been shown to be upregulated in breast malignancies by microarray and immunohistochemical analysis, so we hypothesized that (18)F-fluciclovine may provide a novel method of visualizing breast cancer and now report a prospective clinical trial of (18)F-fluciclovine PET/CT in newly diagnosed advanced local invasive ductal carcinoma (IDC) and invasive lobular carcinoma (ILC).

METHODS

Twenty-seven women with a new diagnosis of locally advanced IDC (n = 19) or ILC (n = 8) underwent PET/CT of the chest after intravenous administration of 370 MBq of (18)F-fluciclovine. The SUVmax, SUVmean, metabolic tumor volume, and total lesion avidity were obtained for the primary breast tumor, axillary lymph nodes, and extraaxillary lymph nodes. Sites of previously unsuspected malignancy were recorded and confirmed by pathology. Results of (18)F-fluciclovine PET/CT were compared with those of (18)F-FDG PET/CT, when available, using the concordance correlation coefficient.

RESULTS

All locally advanced breast cancers were (18)F-fluciclovine-avid. Of 21 patients with pathologically proven axillary nodal metastases, (18)F-fluciclovine-avid axillary nodes were seen in 20. (18)F-fluciclovine detected pathologically proven extraaxillary nodal metastases in 3 patients, including 2 previously unsuspected internal mammary nodes. Fourteen patients underwent (18)F-FDG PET/CT for comparison with (18)F-fluciclovine. Concordance for metabolic tumor volume between (18)F-fluciclovine and (18)F-FDG was strong (concordance correlation coefficient, 0.89; 95% confidence interval, 0.73-0.96), but concordance for SUVmax was weak (concordance correlation coefficient, 0.04; 95% confidence interval, -0.16-0.24). In patients with both modalities available (n = 14), primary ILCs (n = 4) demonstrated (18)F-fluciclovine avidity (median SUVmax, 6.1; range, 4.5-10.9) greater than (18)F-FDG avidity (median SUVmax, 3.7; range, 1.8-6.0). Primary IDCs (n = 10) had a lower (18)F-fluciclovine avidity (median SUVmax, 6.8; range, 3.6-9.9) than (18)F-FDG avidity (median SUVmax, 10; range, 3.3-43.5).

CONCLUSION

(18)F-fluciclovine PET/CT demonstrates potential for imaging of both IDC and ILC, including the detection of unsuspected extraaxillary nodal metastases. The low concordance for SUVmax between (18)F-fluciclovine and (18)F-FDG suggests that these tracers measure different biologic phenomena within the tumor. The apparently higher uptake of (18)F-fluciclovine in ILC requires confirmation in a larger cohort.

Imaging genomics in cancer research: limitations and promises

Recently, radiogenomics or imaging genomics has emerged as a novel high-throughput method of associating imaging features with genomic data. Radiogenomics has the potential to provide comprehensive intratumour, intertumour and peritumour information non-invasively. This review article summarizes the current state of radiogenomic research in tumour characterization, discusses some of its limitations and promises and projects its future directions. Semi-radiogenomic studies that relate specific gene expressions to imaging features will also be briefly reviewed.

Preoperative 18F-FDG PET/CT predicts disease-free survival in patients with primary invasive ductal breast cancer

BACKGROUND

Previous studies have correlated the maximum standardized uptake value (SUVmax) of breast cancer lesions with histological and biological characteristics such as tumor size, histologic grade, or hormonal receptor expression status. However, controversy remains concerning the prognostic value of SUVmax in breast cancer.

PURPOSE

To determine if the SUVmax of a tumor on 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) is associated with disease-free survival in patients with primary invasive ductal breast cancer.

MATERIAL AND METHODS

The institutional review board of our hospital approved this retrospective study. From 2009 to 2011, 508 women (mean age, 53.6 years; age range, 26-85 years) with newly diagnosed invasive ductal breast cancer who had undergone preoperative 18F-FDG PET/CT followed by surgery were identified. Clinicopathological variables and FDG uptake quantified by SUVmax were analyzed. The Cox proportional hazards model was used to evaluate the association between SUVmax and disease-free survival after controlling for clinicopathological parameters.

RESULTS

There were 21 recurrences at a median follow-up of 46 months. The mean SUVmax of the primary tumor was significantly higher in patients with a recurrence than those who remained disease-free (9.5 ± 3.5 vs. 6.6 ± 4.2, P < 0.001). A receiver operating characteristic curve indicated that a SUVmax of 5.95 was the optimal cut-off value to predict disease-free survival. Multivariate analysis identified a high SUVmax (≥5.95) and high T stage as independent significant variables associated with worse disease-free survival.

CONCLUSION

A high primary tumor SUVmax on 18F-FDG PET/CT was an independent factor associated with worse disease-free survival in patients with primary invasive ductal breast cancer.

Src Inhibition Blocks c-Myc Translation and Glucose Metabolism to Prevent the Development of Breast Cancer

Preventing breast cancer will require the development of targeted strategies that can effectively block disease progression. Tamoxifen and aromatase inhibitors are effective in addressing estrogen receptor-positive (ER(+)) breast cancer development, but estrogen receptor-negative (ER(-)) breast cancer remains an unmet challenge due to gaps in pathobiologic understanding. In this study, we used reverse-phase protein array to identify activation of Src kinase as an early signaling alteration in premalignant breast lesions of women who did not respond to tamoxifen, a widely used ER antagonist for hormonal therapy of breast cancer. Src kinase blockade with the small-molecule inhibitor saracatinib prevented the disorganized three-dimensional growth of ER(-) mammary epithelial cells in vitro and delayed the development of premalignant lesions and tumors in vivo in mouse models developing HER2(+) and ER(-) mammary tumors, extending tumor-free and overall survival. Mechanistic investigations revealed that Src blockade reduced glucose metabolism as a result of an inhibition in ERK1/2-MNK1-eIF4E-mediated cap-dependent translation of c-Myc and transcription of the glucose transporter GLUT1, thereby limiting energy available for cell growth. Taken together, our results provide a sound rationale to target Src pathways in premalignant breast lesions to limit the development of breast cancers.

(18)F-FDG/PET May Help to Identify a Subgroup of Patients with T1-T2 Breast Cancer and 1-3 Positive Lymph Nodes Who Are at a High Risk of Recurrence after Mastectomy

Purpose

The purpose of this study is to assess the utility of positron emission tomography (PET) for predicting recurrence among patients with T1-T2/N1 breast cancer who were treated with mastectomy.

Materials and Methods

Of 712 consecutive patients with T1-T2/N1 breast cancer treated during 2003-2012, 109 had undergone preoperative ¹⁸F-fluorodeoxyglucose/PET and were included. Metabolic (maximum standardized uptake value [SUV_max]), volumetric (metabolic tumor volume [MTV]), and combined (total lesion glycolysis [TLG]) indices were measured. The resulting values were analyzed and compared with clinical outcome.

Results

At the median follow-up of 46.7 months, the 3-year relapse-free survival (RFS) rate was 95.2%. SUV_max (area under curve, 0.824) was more useful than MTV or TLG as a means of identifying patients at high risk for any recurrence. In multivariate analysis, SUV_max remained an independent risk factor for RFS (p=0.006). Using the method of Contal and O’Quigley, a SUV_max threshold of 5.36 showed the best predictive performance. The PET-based high-risk group (≥ 5.36 in either breast or nodes) had more T1c-T2, high-grade, hormone-receptor negative, and invasive ductal carcinoma tumors than the low-risk group (< 5.36 in both breast and nodes). The prognosis was much worse when high SUV_max (≥ 5.36) was detected in nodes (p < 0.001). In the no-radiotherapy cohort, the PET-based high-risk group had increased risk of locoregional recurrence when compared to the low-risk group (p=0.037).

Conclusion

High SUV_max on preoperative PET showed association with elevated risk of locoregional recurrence and any recurrence. Pre-treatment PET may improve assessments of recurrence risk and clarify indications for post-mastectomy radiotherapy in this subset of patients.

Stratifying triple-negative breast cancer prognosis using 18F-FDG-PET/CT imaging

This study aims to stratify prognosis of triple-negative breast cancer (TNBC) patients using pre-treatment 18F-FDG-PET/CT, alone and with correlation to immunohistochemistry biomarkers. 200 consecutive TNBC breast cancer patients treated between 2008 and 2012 were retrieved. Among the full cohort, 79 patients had pre-treatment 18F-FDG-PET/CT scans. Immunostaining status of basal biomarkers (EGFR, CK5/6) and other clinicopathological variables were obtained. Three PET image features were evaluated: maximum uptake values (SUVmax), mean uptake (SUVmean), and metabolic volume (SUVvol) defined by SUV > 2.5. All variables were analyzed versus disease-free survival (DFS) using univariate and multivariate Cox analysis, Kaplan-Meier curves, and log-rank tests. The optimal cutoff points of variables were estimated using time-dependent survival receiver operating characteristic (ROC) analysis. All PET features significantly correlated with proliferation marker Ki-67 (all p < 0.010). SUVmax stratified the prognosis of TNBC patients with optimal cutoff derived by ROC analysis (≤3.5 vs. >3.5, AUC = 0.654, p = 0.006). SUVmax and EGFR were significant prognostic factors in univariate and multivariate Cox analyses. To integrate prognosis of biological and imaging markers, patients were first stratified by EGFR into low (≤15 %) and high (>15 %) risk groups. Further, SUVmax was used as a variable to stratify the two EGFR groups. In the high EGFR group, patients with high FDG uptake (SUVmax > 3.5) had worse survival outcome (median DFS = 7.6 months) than those patients with low FDG uptake (SUVmax ≤ 3.5, median DFS = 11.6 months). In the low EGFR group, high SUVmax also indicated worse survival outcome (17.2 months) than low SUVmax (22.8 months). The risk stratification with integrative EGFR and PET was statistically significant with log-rank p ≪ 0.001. Pre-treatment 18F-FDG-PET/CT imaging has significant prognostic value for predicting survival outcome of TNBC patients. Integrated with basal-biomarker EGFR, PET imaging can further stratify patient risks in the pre-treatment stage and help select appropriate treatment strategies for individual patients.

Correlation of the value of 18F-FDG uptake, described by SUVmax, SUVavg, metabolic tumour volume and total lesion glycolysis, to clinicopathological prognostic factors and biological subtypes in breast cancer

OBJECTIVE

The aim of this study was to observe the relationships between different metabolic parameters and clinicopathological features (CPFs) or immunohistochemically defined biological subtypes (IHC-BS) in breast cancer.

MATERIALS AND METHODS

Eighty-two women (83 lesions, tumour size>15 mm) underwent PET/computed tomography imaging after a core biopsy. Maximum and average standardized uptake values (SUVmax, SUVavg), metabolic tumour volume (MTV) and total lesion glycolysis (TLG) in the primary tumour were calculated and compared with CPFs and IHC-BS. Tumours with oestrogen receptor (ER) positivity were separately investigated in relation to their progesterone receptor (PR) status.

RESULTS

Significant correlation was found between all metabolic parameters and high nuclear grade or ER status or IHC-BS. All parameters were higher in PR(-) and triple-negative cases than in PR(+) and non-triple-negative tumours, and the correlation was significant for most of the metabolic parameters (except for SUVavg in the case of PR status and MTV in the case of triple negativity). Significant correlation was found only for SUVmax regarding the human epidermal growth factor receptor 2 (HER2) status. There was moderate correlation between the Ki67 expression and the SUVmax or SUVavg. All metabolic parameters were higher in ER(+)/PR(-)/HER2(-) lesions compared with ER(+)/PR(+)/HER2(-) cancers. However, ER(+)/PR(-)/HER2(+) tumours had lower SUVmax and SUVavg compared with ER(+)/PR(+)/HER2(+) lesions.

CONCLUSION

Our study confirms that the fluorine-18 fluorodeoxyglucose uptake in primary tumour is associated with distinct CPFs or IHC-BS in breast cancer. SUVmax may reflect tumour metabolism more reliably compared with SUVavg, MTV or total lesion glycolysis. Our preliminary results suggest different biological properties in ER(+) tumours with different PR statuses.

Journal Club: Diagnostic value of (18)F-FDG PET/CT and MRI in predicting the clinicopathologic subtypes of invasive breast cancer

OBJECTIVE

The purpose of this study was to assess the diagnostic value of (18)F-FDG PET/CT and MRI in predicting the clinicopathologic subtypes of breast cancer.

MATERIALS AND METHODS

The cases of 89 patients with mass-type invasive breast cancer who underwent FDG PET/CT and MRI before therapy were retrospectively analyzed. Eight imaging variables-maximum standardized uptake value (SUVmax), apparent diffusion coefficient, size, shape, margin, intratumoral enhancement, dynamic kinetics, and high intratumoral signal intensity on T2-weighted images-were compared with results for the pathologic markers Ki-67 antibody, estrogen receptor (ER), progesterone receptor (PR), and ERBB2 (formerly HER2 or HER2/neu). The diagnostic performance of the imaging variables for sub-typing was evaluated, and the predictors of the subtypes were elucidated.

RESULTS

Higher SUVmax was significantly associated with a high Ki-67 index (p < 0.0001), ER-negative status (p = 0.0001), and PR-negative status (p = 0.047). Significant correlation was also found between size and ER status (p = 0.002) and between shape and PR status (p = 0.044). The AUC exceeded 0.7 only in identification of the luminal A sub-type by application of cutoff values for SUVmax (AUC, 0.751). When smaller tumors were excluded, AUC increased (AUC, 0.803 for tumors > 16 mm). Multivariate analysis showed that SUVmax was the sole independent predictor of luminal A subtype (odds ratio per SD, 0.291; p < 0.0001). SUVmax was significantly lower for luminal A (4.4 ± 2.2) than non-luminal A (8.1 ± 4.4; p < 0.0001) tumors. A cutoff value of 5.4 yielded 79% sensitivity and 68% specificity for prediction that a tumor was the luminal A subtype.

CONCLUSION

FDG PET/CT findings may contribute to differentiation of the luminal A and non-luminal A subtypes of invasive breast cancer.

[18F]-fluorodeoxyglucose positron emission tomography can contribute to discriminate patients with poor prognosis in hormone receptor-positive breast cancer

BACKGROUND

Patients with hormone receptor-positive breast cancer typically show favorable survival. However, identifying individuals at high risk of recurrence among these patients is a crucial issue. We tested the hypothesis that [18F]-fluorodeoxyglucose positron emission tomography (FDG-PET) scans can help predict prognosis in patients with hormone receptor-positive breast cancer.

METHODS

Between April 2004 and December 2008, 305 patients with hormone receptor-positive breast cancer who underwent FGD-PET were enrolled. Patients with luminal B subtype were identified by positivity for human epidermal growth factor receptor-2 (HER2) or high Ki67 (≥14%) according to criteria recently recommended by the St. Gallen panelists. The cut-off value of SUVmax was defined using the time-dependent receiver operator characteristic curve for recurrence-free survival (RFS).

RESULTS

At a median follow up of 6.23 years, continuous SUVmax was a significant prognostic factor with a hazard ratio (HR) of 1.21 (p = 0.021). The cut-off value of SUVmax was defined as 4. Patients with luminal B subtype (n = 82) or high SUVmax (n = 107) showed a reduced RFS (p = 0.031 and 0.002, respectively). In multivariate analysis for RFS, SUVmax carried independent prognostic significance (p = 0.012) whereas classification with immunohistochemical markers did not (p = 0.274). The Harell c-index was 0.729. High SUVmax was significantly associated with larger tumor size, positive nodes, HER2 positivity, high Ki67 (≥14%), high tumor grade, and luminal B subtype.

CONCLUSIONS

Among patients with hormone receptor-positive breast cancer, FDG-PET can help discriminate patients at high risk of tumor relapse.

¹⁸F-FDG-PET/CT in staging, restaging, and treatment response assessment of male breast cancer

PURPOSE

Male breast cancer (BC) is a rare disease, with patterns different from those found in women. Most tumors are detected at more advanced stages than in women. The aim of this study was to analyze the performance of [18F]fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG-PET/CT) in staging, restaging, and therapy response assessment.

METHODS

We performed a systematic analysis in the database of Saint-Louis Hospital to identify male patients with BC referred for PET/CT. (18)F-FDG-PET/CT findings considered suspicious for malignancy were compared to biopsy results, further work-up and/or patient follow-up of at least 6 months. Performances of (18)F-FDG-PET/CT were compared to that of conventional imaging (CI) using the McNemar test. The impact of PET/CT on management was evaluated.

RESULTS

During 6 consecutive years, among 12,692 (18)F-FDG-PET/CT oncology studies, 30 were performed in 15 men with BC: 7 examinations for initial staging, 11 for restaging, and 12 for response assessment. Tumors profile was ER+ and one had HER2 overexpression. PET/CT sensitivity, specificity, positive predictive value, negative predictive value and accuracy to detect distant metastases were 100%, 67%, 86%, 100% and 89%, respectively. PET/CT was more informative than CI in 40% of studies (p=0.03; 95% confidence interval: 3.26 - 40%). Findings from (18)F-FDG-PET/CT led to modification in the planned treatment in 13/30 cases (43%).

CONCLUSION

Although all the tumors were ER+, primary lesions and metastases were diagnosed with high sensitivity. (18)F-FDG-PET/CT seems to be a powerful imaging method to perform staging, restaging and treatment response assessment in male patients with BC.

Imaging features of HER2 overexpression in breast cancer: a systematic review and meta-analysis

Breast cancer imaging phenotype is diverse and may relate to molecular alterations driving cancer behavior. We systematically reviewed and meta-analyzed relations between breast cancer imaging features and human epidermal growth factor receptor type 2 (HER2) overexpression as a marker of breast cancer aggressiveness. MEDLINE and EMBASE were searched for mammography, breast ultrasound, magnetic resonance imaging (MRI), and/or [(18)F]fluorodeoxyglucose positron emission tomography studies through February 2013. Of 68 imaging features that could be pooled (85 articles, 23,255 cancers; random-effects meta-analysis), 11 significantly related to HER2 overexpression. Results based on five or more studies and robustness in subgroup analyses were as follows: the presence of microcalcifications on mammography [pooled odds ratio (pOR), 3.14; 95% confidence interval (CI), 2.46-4.00] or ultrasound (mass-associated pOR, 2.95; 95% CI, 2.34-3.71), branching or fine linear microcalcifications (pOR, 2.11; 95% CI, 1.07-4.14) or extremely dense breasts on mammography (pOR, 1.37; 95% CI, 1.07-1.76), and washout (pOR, 1.57; 95% CI, 1.11-2.21) or fast initial kinetics (pOR, 2.60; 95% CI, 1.43-4.73) on MRI all increased the chance of HER2 overexpression. Maximum [(18)F]fluorodeoxyglucose standardized uptake value (SUVmax) was higher upon HER2 overexpression (pooled mean difference, +0.76; 95% CI, 0.10-1.42). These results show that several imaging features relate to HER2 overexpression, lending credibility to the hypothesis that imaging phenotype reflects cancer behavior. This implies prognostic relevance, which is especially relevant as imaging is readily available during diagnostic work-up.

Understanding the tumor microenvironment and radioresistance by combining functional imaging with global gene expression

The objective of this review is to present an argument for performing joint analyses between functional imaging with global gene expression studies. The reason for making this link is that tumor microenvironmental influences on functional imaging can be uncovered. Such knowledge can lead to (1) more informed decisions regarding how to use functional imaging to guide therapy and (2) discovery of new therapeutic targets. As such, this approach could lead to identification of patients who need aggressive treatment tailored toward the phenotype of their tumor vs those who could be spared treatment that carries risk for more normal tissue complications. Only a handful of papers have been published on this topic thus far, but all show substantial promise.