Background parenchymal enhancement and uptake as breast cancer imaging biomarkers: A state-of-the-art review

Within the past decade, background parenchymal enhancement (BPE) and background parenchymal uptake (BPU) have emerged as novel imaging-derived biomarkers in the diagnosis and treatment monitoring of breast cancer. Growing evidence supports the role of breast parenchyma vascularity and metabolic activity as probable risk factors for breast cancer development. Furthermore, in the presence of a newly-diagnosed breast cancer, added clinically-relevant data was surprisingly found in the respective imaging properties of the non-affected contralateral breast. Evaluation of the contralateral BPE and BPU have been found to be especially instrumental in predicting the prognosis of a patient with breast cancer and even anticipating their response to neoadjuvant chemotherapy. Simultaneously, further research has found a link between these two biomarkers, even though they represent different physical properties. The aim of this review is to provide an up to date summary of the current clinical applications of BPE and BPU as breast cancer imaging biomarkers with the hope that it propels their further usage in clinical practice.

Is 18F-FDG PET/CT Beneficial for Newly Diagnosed Breast Cancer Patients With Low Proportion of ER Expression?

OBJECTIVE

It is unclear whether the receptor status of breast malignancy or the proportion of receptors expression is useful in the interpretation of 18F-FDG PET/CT. This study's purpose was to analyze whether 18F-FDG PET/CT was valuable for helping newly diagnosed breast cancer patients find suspected or unsuspected metastasis lesions based on the proportion of receptors expression.

MATERIALS AND METHODS

Eighty newly diagnosed breast cancer patients were divided into six groups, containing N0 (no extraaxillary lymph node metastasis), N1 (extraaxillary lymph node metastasis), M0 (no distant metastasis), and M1 (distant metastasis) groups, C0 (no unsuspected metastasis), and C1 (unsuspected metastasis and treatment plan changed) detected by PET/CT. The main data, including the proportion of receptors ER (estrogen receptor), PR (progesterone receptor), and Her-2 (human epidermal growth factor receptor 2) status, were extracted. Simple correlation and logistic regression were preformed to analyze the association between them.

RESULTS

Patients in N1 group had lower proportion of ER (%) and PR (%) than that in N0 group (ER: 2 [0-80] vs. 80 [15-95]; PR: 1 [0-10] vs. 20 [0-45], p<0.001). Moreover, the proportions of ER and PR were negatively correlated with N1 (ER: [r= -0.339, p= 0.002], PR: [r= -0.247, p= 0.011]) by simple correlation. Also, patients in C1 group had lower proportion of ER (%) and PR (%) than those in C0 group (ER: 10 [0-85] vs. 80 [15-90], p=0.026; PR: 1 [0-10] vs. 20 [0-70], p=0.041), while the distribution of ER and PR between M1 and M0 group had no significant difference. After the adjustment of traditional factors, the negative correlation between the proportion of ER (OR=0.986, 95% CI of OR [0.972-0.999], p=0.016) and C1 was found by logistic regression, cutoff value was 25% (ER) calculated by ROC (Receiver Operating Characteristic) curve (AUC [Area Under Curve]= 0.647, p=0.024).

CONCLUSION

The proportion of ER in newly diagnosed breast cancer was negatively correlated with unsuspected metastasis detected by 18F-FDG PET/CT. 18F-FDG PET/CT might be recommended for newly diagnosed breast cancer patients with single lesions when the ER expression proportion is less than 25% to find unsuspected metastasis lesions and to modify treatment plan contrasted with conventional imaging and clinical examination.

Diagnostic Performance of FDG-PET/CT Scan as Compared to US-Guided FNA in Prediction of Axillary Lymph Node Involvement in Breast Cancer Patients

Purpose

The aim of this study was to evaluate the diagnostic ability of 2-deoxy-2-[fluorine-18]fluoro-d-glucose (¹⁸F-FDG) PET/non-contrast CT compared with those of ultrasound (US)-guided fine needle aspiration (FNA) for axillary lymph node (ALN) staging in breast cancer patients.

Patients and Methods

Preoperative ¹⁸F-FDG PET/non-contrast CT was performed in 268 women with breast cancer, as well as ALN dissection or sentinel lymph node (SLN) biopsy. One hundred sixty-four patients underwent US-guided FNA in combination with ¹⁸F-FDG PET/CT. The diagnostic performance of each modality was evaluated using histopathologic assessments as the reference standard. The receiver operating characteristic (ROC) curves were compared to evaluate the diagnostic ability of several imaging modalities.

Results

Axillary ¹⁸F-FDG uptake was positive in 180 patients, and 125 patients had axillary metastases according to the final pathology obtained by ALN dissection and/or SLN dissection. Of the patients with positive ¹⁸F-FDG uptake in the axilla, 21% had false-positive results, whereas 79% were truly positive. Eighty-eight patients had negative ¹⁸F-FDG uptake in the axilla, among which 25% were false-negative. ¹⁸F-FDG-PET/CT had a sensitivity of 86.59% and a specificity of 63.46% in the assessment of ALN metastasis; on the other hand, US-guided FNA had a sensitivity of 91.67% and a specificity of 87.50%. The mean primary cancer size (p = 0.04) and tumor grade (p = 0.04) in combination were the only factors associated with the accuracy of ¹⁸F-FDG PET/CT for detecting metastatic ALNs.

Conclusion

The diagnostic performance of ¹⁸F-FDG PET/CT for the detection of axillary node metastasis in breast cancer patients was not significantly different from that of US-guided FNA. Combining ¹⁸F-FDG PET/CT with US-guided FNA or SLN biopsy could improve the diagnostic performance compared to ¹⁸F-FDG PET/CT alone.

Simultaneous FAPI PET/MRI Targeting the Fibroblast-Activation Protein for Breast Cancer

Background Integrated PET/MRI is a promising modality for breast assessment. The most frequently used tracer, fluorine 18 (¹⁸F) fluorodeoxyglucose (FDG), is applied for whole-body staging in advanced breast cancer but has limited accuracy in evaluating primary breast lesions. The fibroblast-activation protein (FAP) is abundantly expressed in invasive breast cancer. FAP-directed PET tracers have recently become available, but results in primary breast tumors remain lacking. Purpose To evaluate the use of FAP inhibitor (FAPI) breast PET/MRI in assessing breast lesions and of FAPI whole-body scanning for lymph node (LN) and distant staging using the ligand gallium 68 (⁶⁸Ga)-FAPI-46. Materials and Methods In women with histologically confirmed invasive breast cancer, all primary ⁶⁸Ga-FAPI-46 breast and whole-body PET/MRI and PET/CT examinations conducted at the authors' center between October 2019 and December 2020 were retrospectively analyzed. MRI lesion characteristics and standardized uptake values (SUVs) were quantified with dedicated software. Mann-Whitney U tests were used to compare tumor SUVs across different tumor types. The Pearson correlation coefficient was calculated between SUV and measures of MRI morphologic characteristics. Results Nineteen women (mean age, 49 years ± 9 [standard deviation]) were evaluated-18 to complement initial staging and one for restaging after therapy for distant metastases. Strong tracer accumulation was observed in all 18 untreated primary breast malignancies (mean maximum SUV [SUV_max] = 13.9 [range, 7.9-29.9]; median lesion diameter = 26 mm [range, 9-155 mm]), resulting in clear tumor delineation across different gradings, receptors, and histologic types. All preoperatively verified LN metastases in 13 women showed strong tracer accumulation (mean SUV_max= 12.2 [range, 3.3-22.4]; mean diameter = 21 mm [range, 14-35 mm]). Tracer uptake established or supported extra-axillary LN involvement in seven women and affected therapy decisions in three women. Conclusion This retrospective analysis indicates use of ⁶⁸Ga fibroblast-activation protein inhibitor tracers for breast cancer diagnosis and staging. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Mankoff and Sellmyer in this issue.

Benefits and harms of implementing [18F]FDG-PET/CT for diagnosing recurrent breast cancer: a prospective clinical study

Background

[¹⁸F]-fluorodeoxyglucose-positron emission tomography/computed tomography ([¹⁸F]FDG-PET/CT) has been implemented sporadically in hospital settings as the standard of care examination for recurrent breast cancer. We aimed to explore the clinical impact of implementing [¹⁸F]FDG-PET/CT for patients with clinically suspected recurrent breast cancer and validate the diagnostic accuracy.

Methods

Women with suspected distant recurrent breast cancer were prospectively enrolled in the study between September 2017 and August 2019. [¹⁸F]FDG-PET/CT was performed, and the appearance of incidental benign and malignant findings was registered. Additional examinations, complications, and the final diagnosis were registered to reflect the clinical consequence of such findings. The diagnostic accuracy of [¹⁸F]FDG-PET/CT as a stand-alone examination was analyzed. Biopsy and follow-up were used as a reference standard.

Results

[¹⁸F]FDG-PET/CT reported breast cancer metastases in 72 of 225 women (32.0%), and metastases were verified by biopsy in 52 (52/225, 23.1%). Prior probability and posterior probability of a positive test for suspected metastatic cancer and incidental malignancies were 27%/85% and 4%/20%, respectively. Suspected malignant incidental findings were reported in 46 patients (46/225, 20.4%), leading to further examinations and final detection of nine synchronous cancers (9/225, 4.0%). These cancers originated from the lung, thyroid, skin, pancreas, peritoneum, breast, kidney, one was malignant melanoma, and one was hematological cancer. False-positive incidental malignant findings were examined in 37/225 patients (16.4%), mainly in the colon (n = 12) and thyroid gland (n = 12). Ten incidental findings suspicious for benign disease were suggested by [¹⁸F]FDG-PET/CT, and further examinations resulted in the detection of three benign conditions requiring treatment. Sensitivity, specificity, and AUC-ROC for diagnosing distant metastases were 1.00 (0.93–1.0), 0.88 (0.82–0.92), and 0.98 (95% CI 0.97–0.99), respectively.

Conclusion

[¹⁸F]FDG-PET/CT provided a high posterior probability of positive test, and a negative test was able to rule out distant metastases in women with clinically suspected recurrent breast cancer. One-fifth of patients examined for incidental findings detected on [¹⁸F]FDG-PET/CT were diagnosed with clinically relevant conditions. Further examinations of false-positive incidental findings in one of six women should be weighed against the high accuracy for diagnosing metastatic breast cancer.

Trial registration Clinical.Trials.gov. NCT03358589. Registered 30 November 2017—Retrospectively registered, http://www.ClinicalTrials.gov

Supplementary Information

The online version contains supplementary material available at 10.1186/s13550-021-00833-3.

Clinical Impact of FDG-PET/CT Compared with CE-CT in Response Monitoring of Metastatic Breast Cancer

Simple Summary

The method of treatment evaluation in patients with chronic breast cancer may affect clinical decision making and treatment protocols. In this study, we compared the two imaging modalities for the evaluation of treatment responses in 65 patients with spread breast cancer. We included 34 patients who underwent contrast-enhanced computed tomography (CE-CT) and 31 patients who underwent positron emission tomography/computed tomography (FDG-PET/CT). Then, we compared the response categories and clinical effects within the two modalities during a follow-up period of an average of 17.3 months. Our results showed that CE-CT modality reported more scans as stable disease, while FDG-PET/CT modality reported regressive metastatic disease more often. This means that FDG-PET/CT responds more precisely with respect to the changes in patients’ clinical condition, while CE-CT tends to report stable disease in most of the scans. Therefore, FDG-PET/CT may be a more suitable imaging modality than CE-CT for the evaluation of treatment in patients with metastatic breast cancer.

Abstract

We compared response categories and impacts on treatment decisions for metastatic breast cancer (MBC) patients that are response-monitored with contrast-enhanced computed-tomography (CE-CT) or fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT). A comparative diagnostic study was performed on MBC patients undergoing response monitoring by CE-CT (n = 34) or FDG-PET/CT (n = 31) at the Odense University Hospital (Denmark). The responses were assessed visually and allocated into categories of complete response (CR/CMR), partial response (PR/PMR), stable disease (SD/SMD), and progressive disease (PD/PMD). Response categories, clinical impact, and positive predictive values (PPV) were compared for follow-up scans. A total of 286 CE-CT and 189 FDG-PET/CT response monitoring scans were performed. Response categories were distributed into CR (3.8%), PR (8.4%), SD (70.6%), PD (15%), and others (2.1%) by CE-CT and into CMR (22.2%), PMR (23.8%), SMD (31.2%), PMD (18.5%), and others (4.4%) by FDG-PET/CT, revealing a significant difference between the groups (P < 0.001). PD and PMD caused changes of treatment in 79.1% and 60%, respectively (P = 0.083). PPV for CE-CT and FDG-PET/CT was 0.85 (95% CI: 0.72–0.97) and 0.70 (95% CI: 0.53–0.87), respectively (P = 0.17). FDG-PET/CT indicated regression of disease more frequently than CE-CT, while CE-CT indicated stable disease more often. FDG-PET/CT seems to be more sensitive than CE-CT for monitoring response in metastatic breast cancer.

PET/CT Variants and Pitfalls in Breast Cancers

There are a number of normal variants and pitfalls which are important to consider when evaluating F-18 Fluorodeoxyglucose (FDG) with Positron Emission Tomography (PET) in breast cancer patients. Although FDG-PET is not indicated for the initial diagnosis of breast cancer, focally increased glucose metabolism within breast tissue represents a high likelihood for a neoplastic process and requires further evaluation. Focally increased glucose metabolism is not unique to breast cancer. Other malignancies such as lymphoma, metastases from solid tumors as well as inflammatory changes also may demonstrate increased glucose metabolism either within the breast or at other sites throughout the body. Importantly, benign breast disease may also exhibit increased glucose metabolism, limiting the specificity of FDG-PET. Breast cancer has a wide range of metabolic activity attributed to tumor heterogeneity and breast cancer subtype. Intracellular signaling pathways regulating tumor glucose utilization contribute to these pitfalls of PET/CT in breast cancer. The evaluation of axillary lymph nodes by FDG-PET is less accurate than sentinel lymph node procedure, however is very accurate in identifying level II and III axillary lymph node metastases or retropectoral metastases. It is important to note that non-malignant inflammation in lymph nodes are often detected by modern PET/CT technology. Therefore, particular consideration should be given to recent vaccinations, particularly to COVID-19, which can commonly result in increased metabolic activity of axillary nodes. Whole body FDG-PET for staging of breast cancer requires specific attention to physiologic variants of FDG distribution and a careful comparison with co-registered anatomical imaging. The most important pitfalls are related to inflammatory changes including sarcoidosis, sarcoid like reactions, and other granulomatous diseases as well as secondary neoplastic processes.

FDG-PET/CT for Response Monitoring in Metastatic Breast Cancer: The Feasibility and Benefits of Applying PERCIST

Background: We aimed to examine the feasibility and potential benefit of applying PET Response Criteria in Solid Tumors (PERCIST) for response monitoring in metastatic breast cancer (MBC). Further, we introduced the nadir scan as a reference. Methods: Response monitoring FDG-PET/CT scans in 37 women with MBC were retrospectively screened for PERCIST standardization and measurability criteria. One-lesion PERCIST based on changes in SULpeak measurements of the hottest metastatic lesion was used for response categorization. The baseline (PERCIST_baseline) and the nadir scan (PERCIST_nadir) were used as references for PERCIST analyses. Results: Metastatic lesions were measurable according to PERCIST in 35 of 37 (94.7%) patients. PERCIST was applied in 150 follow-up scans, with progression more frequently reported by PERCIST_nadir (36%) than PERCIST_baseline (29.3%; p = 0.020). Reasons for progression were (a) more than 30% increase in SUL_peak of the hottest lesion (n = 7, 15.9%), (b) detection of new metastatic lesions (n = 28, 63.6%), or both (a) and (b) (n = 9, 20.5%). Conclusions: PERCIST, with the introduction of PERCIST_nadir, allows a graphical interpretation of disease fluctuation that may be beneficial in clinical decision-making regarding potential earlier termination of non-effective toxic treatment. PERCIST seems feasible for response monitoring in MBC but prospective studies are needed to come this closer.

Expanded criteria for pretreatment staging CT in breast cancer

Background

There is wide variation in the approach to staging for distant metastatic disease in breast cancer. This study sought to identify factors predictive of distant metastatic disease at presentation to enable appropriate selection of patients for pretreatment CT.

Methods

Data were collected retrospectively for all patients with newly diagnosed breast cancer (screening and symptomatic) over 3 years (2014–2017). Detailed demographic, pathological, biological, and management data were recorded at presentation, and outcome data were recorded after follow-up. Binomial logistic regression was used to identify variables independently associated with distant metastatic disease at presentation.

Results

A total of 1377 patients with newly diagnosed breast cancer were identified, of whom 1025 had complete data; 323 staging CT examinations were performed. Distant metastases were identified at presentation in 47 (4.6 per cent). Some 30 of 47 patients with metastatic disease met established criteria for staging (T4, recurrence, symptoms of possible distant metastases), leaving 17 patients with metastatic disease potentially missed by use of these criteria alone. Multivariable analysis showed that tumour size at least 3 cm combined with sonographically abnormal axillary lymph nodes predicted a high probability of distant metastatic disease at presentation (positive predictive value 18.8 per cent, odds ratio 4.83, P < 0.001). Addition of this criterion increased the positive CT rate to 17.1 per cent.

Conclusion

Selective pretreatment CT staging can be further optimized with the addition of tumour size at least 3 cm with abnormal axillary nodes to established staging criteria.

Evaluation of an Automatic Classification Algorithm Using Convolutional Neural Networks in Oncological Positron Emission Tomography

Introduction: Our aim was to evaluate the performance in clinical research and in clinical routine of a research prototype, called positron emission tomography (PET) Assisted Reporting System (PARS) (Siemens Healthineers) and based on a convolutional neural network (CNN), which is designed to detect suspected cancer sites in fluorine-18 fluorodeoxyglucose (¹⁸F-FDG) PET/computed tomography (CT).

Method: We retrospectively studied two cohorts of patients. The first cohort consisted of research-based patients who underwent PET scans as part of the initial workup for diffuse large B-cell lymphoma (DLBCL). The second cohort consisted of patients who underwent PET scans as part of the evaluation of miscellaneous cancers in clinical routine. In both cohorts, we assessed the correlation between manually and automatically segmented total metabolic tumor volumes (TMTVs), and the overlap between both segmentations (Dice score). For the research cohort, we also compared the prognostic value for progression-free survival (PFS) and overall survival (OS) of manually and automatically obtained TMTVs.

Results: For the first cohort (research cohort), data from 119 patients were retrospectively analyzed. The median Dice score between automatic and manual segmentations was 0.65. The intraclass correlation coefficient between automatically and manually obtained TMTVs was 0.68. Both TMTV results were predictive of PFS (hazard ratio: 2.1 and 3.3 for automatically based and manually based TMTVs, respectively) and OS (hazard ratio: 2.4 and 3.1 for automatically based and manually based TMTVs, respectively). For the second cohort (routine cohort), data from 430 patients were retrospectively analyzed. The median Dice score between automatic and manual segmentations was 0.48. The intraclass correlation coefficient between automatically and manually obtained TMTVs was 0.61.

Conclusion: The TMTVs determined for the research cohort remain predictive of total and PFS for DLBCL. However, the segmentations and TMTVs determined automatically by the algorithm need to be verified and, sometimes, corrected to be similar to the manual segmentation.

Bilateral Silicone Granulomas Mimicking Breast Cancer Recurrence on 18F-FDG PET/CT

ABSTRACT

We report the case of a 45-year-old woman with a history of right breast reconstruction with silicone implant for breast cancer. An 18F-FDG PET/CT performed several years later revealed the presence of 18F-FDG-avid nodules at the periphery of the silicone implant, in the right internal mammary chain, and in the contralateral breast. Needle core biopsies were positive for bilateral silicone granulomas, without any sign of malignancy. This case displays intense 18F-FDG uptake in silicone granulomas affecting the contralateral breast after implant reconstruction.

Measuring Glucose Uptake in Primary Invasive Breast Cancer Using Simultaneous Time-of-Flight Breast PET/MRI: A Method Comparison Study with Prone PET/CT

Purpose

To compare the measurement of glucose uptake in primary invasive breast cancer using simultaneous, time-of-flight breast PET/MRI with prone time-of-flight PET/CT.

Materials and Methods

In this prospective study, women with biopsy-proven invasive breast cancer undergoing preoperative breast MRI from 2016 to 2018 were eligible. Participants who had fasted underwent prone PET/CT of the breasts approximately 60 minutes after injection of 370 MBq (10 mCi) fluorine 18 fluorodeoxyglucose (18F-FDG) followed by prone PET/MRI using standard clinical breast MRI sequences performed simultaneously with PET acquisition. Volumes of interest were drawn for tumors and contralateral normal breast fibroglandular tissue to calculate standardized uptake values (SUVs). Spearman correlation, Wilcoxon signed ranked test, Mann-Whitney test, and Bland-Altman analyses were performed.

Results

Twenty-three women (mean age, 50 years; range, 33-70 years) were included. Correlation between tumor uptake values measured with PET/MRI and PET/CT was strong (r s = 0.95-0.98). No difference existed between modalities for tumor maximum SUV (SUVmax) normalized to normal breast tissue SUVmean (normSUVmax) (P = .58). The least amount of measurement bias was observed with normSUVmax, +3.86% (95% limits of agreement: -28.92, +36.64).

Conclusion

These results demonstrate measurement agreement between PET/CT, the current reference standard for tumor glucose uptake quantification, and simultaneous time-of-flight breast 18F-FDG PET/MRI.Keywords: Breast, Comparative Studies, PET/CT, PET/MR Supplemental material is available for this article. © RSNA, 2021See also the commentary by Mankoff and Surti in this issue.

Prospective evaluation of whole-body MRI and 18F-FDG PET/MRI in N and M staging of primary breast cancer patients

OBJECTIVES

To evaluate and compare the diagnostic potential of whole-body MRI and whole-body 18F-FDG PET/MRI for N and M staging in newly diagnosed, histopathologically proven breast cancer.

MATERIAL AND METHODS

A total of 104 patients (age 53.4 ± 12.5) with newly diagnosed, histopathologically proven breast cancer were enrolled in this study prospectively. All patients underwent a whole-body 18F-FDG PET/MRI. MRI and 18F-FDG PET/MRI datasets were evaluated separately regarding lesion count, lesion localization, and lesion characterization (malignant/benign) as well as the diagnostic confidence (5-point ordinal scale, 1-5). The N and M stages were assessed according to the eighth edition of the American Joint Committee on Cancer staging manual in MRI datasets alone and in 18F-FDG PET/MRI datasets, respectively. In the majority of lesions histopathology served as the reference standard. The remaining lesions were followed-up by imaging and clinical examination. Separately for nodal-positive and nodal-negative women, a McNemar chi2 test was performed to compare sensitivity and specificity of the N and M stages between 18F-FDG PET/MRI and MRI. Differences in diagnostic confidence scores were assessed by Wilcoxon signed rank test.

RESULTS

MRI determined the N stage correctly in 78 of 104 (75%) patients with a sensitivity of 62.3% (95% CI: 0.48-0.75), a specificity of 88.2% (95% CI: 0.76-0.96), a PPV (positive predictive value) of 84.6% % (95% CI: 69.5-0.94), and a NPV (negative predictive value) of 69.2% (95% CI: 0.57-0.8). Corresponding results for 18F-FDG PET/MRI were 87/104 (83.7%), 75.5% (95% CI: 0.62-0.86), 92.2% (0.81-0.98), 90% (0.78-0.97), and 78.3% (0.66-0.88), showing a significantly better sensitivity of 18F-FDG PET/MRI determining malignant lymph nodes (p = 0.008). The M stage was identified correctly in MRI and 18F-FDG PET/MRI in 100 of 104 patients (96.2%). Both modalities correctly staged all 7 patients with distant metastases, leading to false-positive findings in 4 patients in each modality (3.8%). In a lesion-based analysis, 18F-FDG PET/MRI showed a significantly better performance in correctly determining malignant lesions (85.8% vs. 67.1%, difference 18.7% (95% CI: 0.13-0.26), p < 0.0001) and offered a superior diagnostic confidence compared with MRI alone (4.1 ± 0.7 vs. 3.4 ± 0.7, p < 0.0001).

CONCLUSION

18F-FDG PET/MRI has a better diagnostic accuracy for N staging in primary breast cancer patients and provides a significantly higher diagnostic confidence in lesion characterization than MRI alone. But both modalities bear the risk to overestimate the M stage.

FDG-PET/CT in high-risk primary breast cancer-a prospective study of stage migration and clinical impact

PURPOSE

To investigate the clinical impact of FDG-PET/CT for staging and treatment planning in high-risk primary breast cancer.

METHODS

Women with high-risk primary breast cancer were enrolled between September 2017 and August 2019 at Odense University Hospital, Denmark. Conventional mammography with/without MRI was performed before staging by FDG-PET/CT. We studied the accuracy of FDG-PET/CT for the detection of distant metastases, the effect on the change of treatment, and the prevalence of incidental findings. Biopsy and follow-up were used as a reference standard for the accuracy analysis.

RESULTS

Of 103 women, 24 (23%) were diagnosed with distant metastases by FDG-PET/CT. Among these, breast surgery was omitted in 18 and could have been spared in six. Another sixteen (16%) patients were upstaged to more advanced loco-regional disease, leading to more extensive radiotherapy. Sensitivity and specificity for diagnosing distant metastases were 1.00 (95% confidence interval: 0.86-1.00) and 0.95 (0.88-0.99), respectively. Twenty-nine incidental findings were detected in 24 women (23%), leading to further examinations in 22 and diagnosis of eight (8/22, 36%) synchronous diseases: cancer (n = 4), thyroiditis (n = 2), aorta aneurysm (n = 1), and meningioma (n = 1).

CONCLUSIONS

FDG-PET/CT had a substantial impact on staging and change of treatment in women with high-risk primary breast cancer, and further examination of incidental findings was considered clinically relevant. Our findings suggest that FDG-PET/CT should be considered for primary staging in high-risk primary breast cancer to improve treatment planning.

From palliative to curative intent: PET/CT findings in the light of breast cancer intrinsic subgroup

PURPOSE

Among breast cancer subgroups, Luminal A is the subgroup with the best prognosis. We report the case of a young woman presenting with a localized luminal A breast cancer with a suspicious liver lesion on initial positron emission tomography (PET)/computed tomography (CT) scan staging.

CASE DESCRIPTION

A 31-year-old woman presented with localized breast cancer accessible to curative treatment. However, PET/CT staging revealed an increase of focal activity in the liver, suspicious of a secondary malignant localization, changing the care towards palliative intent. Discrepancy between breast cancer luminal A subtype and the liver lesion led to further investigations (contrast ultrasound, magnetic resonance imaging, and biopsy), excluding a malignant process, and were in favor of toxic hepatitis, probably secondary to herbal tea consumption.

CONCLUSIONS

Questioning PET/CT findings in light of the cancer subtype enabled us to rectify the diagnosis and allow this patient to be treated with curative intent.

FDG-PET/CT for Response Monitoring in Metastatic Breast Cancer: Today, Tomorrow, and Beyond

While current international guidelines include imaging of the target lesion for response monitoring in metastatic breast cancer, they do not provide specific recommendations for choice of imaging modality or response criteria. This is important as clinical decisions may vary depending on which imaging modality is used for monitoring metastatic breast cancer. FDG-PET/CT has shown high accuracy in diagnosing metastatic breast cancer, and the Positron Emission Tomography Response Criteria in Solid Tumors (PERCIST) have shown higher predictive values than the CT-based Response Evaluation Criteria in Solid Tumors (RECIST) for prediction of progression-free survival. No studies have yet addressed the clinical impact of using different imaging modalities or response evaluation criteria for longitudinal response monitoring in metastatic breast cancer. We present a case study of a patient with metastatic breast cancer who was monitored first with conventional CT and then with FDG-PET/CT. We retrospectively applied PERCIST to evaluate the longitudinal response to treatment. We used the one-lesion PERCIST model measuring SULpeak in the hottest metastatic lesion on consecutive scans. This model provides a continuous variable that allows graphical illustration of disease fluctuation along with response categories. The one-lesion PERCIST approach seems able to reflect molecular changes and has the potential to support clinical decision-making. Prospective clinical studies addressing the clinical impact of PERCIST in metastatic breast cancer are needed to establish evidence-based recommendations for response monitoring in this disease.