Tumor marker-guided PET in breast cancer patients-a recipe for a perfect wedding: a systematic literature review and meta-analysis

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

INTRODUCTION

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Comparing the diagnostic efficacy of [18F]FDG PET/CT and [18F]FDG PET/MRI for detecting bone metastases in breast cancer: a meta-analysis

BACKGROUND

This meta-analysis aimed to evaluate the comparative diagnostic efficacy of [18F]FDG PET/CT and [18F] FDG PET/MRI in detecting bone metastases in breast cancer patients.

METHODS

An extensive search was conducted in the PubMed, Embase, Web of Science, and Cochrane Library databases to identify available publications up to February 2023. Studies were included if they evaluated the diagnostic efficacy of [18F]FDG PET/CT and [18F]FDG PET/MRI in patients with breast cancer bone metastases. Sensitivity and specificity were assessed using the DerSimonian and Laird method, followed by transformation via the Freeman-Tukey double inverse sine transformation.

RESULTS

16 articles (including 4 head-to-head comparison articles) involving 1,261 patients were included in the meta-analysis. The overall sensitivity of [18F]FDG PET/CT in patient-based analysis, lesion-based analysis, and head-to-head comparison were 0.73, 0.89, and 0.87, respectively, while the overall sensitivity of [18F]FDG PET/MRI were 0.99, 0.99, and 0.99. The results indicated that [18F]FDG PET/MRI appears to a higher sensitivity in comparison to [18F]FDG PET/CT(all P < 0.05). In contrast, the overall specificity of [18F]FDG PET/CT in patient-based analysis, lesion-based analysis, and head-to-head comparison were 1.00, 0.99, and 1.00, respectively, while the overall specificity of [18F]FDG PET/MRI were 1.00, 0.99, and 0.98. These results suggested that [18F]FDG PET/CT has a similar level of specificity compared to [18F]FDG PET/MRI.

CONCLUSIONS

Our meta-analysis indicates that [18F]FDG PET/MRI demonstrates superior sensitivity and similar specificity to [18F]FDG PET/CT in detecting bone metastases in breast cancer patients. Further prospective research is required to confirm these findings and assess the clinical application of these techniques.

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

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

State of the Art in 2022 PET/CT in Breast Cancer: A Review

Molecular imaging with positron emission tomography is a powerful and well-established tool in breast cancer management. In this review, we aim to address the current place of the main PET radiopharmaceuticals in breast cancer care and offer perspectives on potential future radiopharmaceutical and technological advancements. A special focus is given to the following: the role of ¹⁸F-fluorodeoxyglucose positron emission tomography in the clinical management of breast cancer patients, especially during staging; detection of recurrence and evaluation of treatment response; the role of 16α-¹⁸Ffluoro-17β-oestradiol positron emission tomography in oestrogen receptors positive breast cancer; the promising radiopharmaceuticals, such as ⁸⁹Zr-trastuzumab and ⁶⁸Ga- or ¹⁸F-labeled fibroblast activation protein inhibitor; and the application of artificial intelligence.

FDG-PET/CT for Primary Staging and Detection of Recurrence of Breast Cancer

Breast cancer is the most frequent cancer diagnosed in women worldwide. Accurate baseline staging is necessary to plan optimal breast cancer management. Early detection and staging of recurrence are also essential for optimal therapeutic management. Hybrid FDG-PET/CT imaging offers high sensitivity in detecting extra axillary lymph nodes and distant metastases. Although FDG-PET/CT has some limitations for low proliferative tumors, low-grade tumors and for well-differentiated luminal breast cancer, PET/CT is useful for the initial staging of breast cancer, regardless of tumor phenotype (luminal, triple negative, or HER2+) and of tumor grade. Although FDG-PET/CT performs better for invasive ductal carcinoma (invasive carcinoma of no specific subtype), it is also helpful for staging invasive lobular carcinomas. At initial staging, FDG-PET/CT becomes very useful for staging from clinical stage IIB (T2N1 or T3N0). FDG-PET/CT could be useful in patients with clinical stage IIA (T1N1 or T2N0), but there is not enough strong evidence to recommend routine use in this subgroup. For clinical stage I (T1N0) patients, FDG-PET/CT offers no added value. In patients with recurrent breast cancer, FDG-PET/CT is more effective than conventional imaging in detecting locoregional or distant recurrence, whether suspected by clinical examination, conventional imaging, or elevation of a tumor marker (CA 15.3 or CEA). PET/CT is effective even in the presence of normal tumor markers. PET/CT is also a powerful imaging modality for performing a whole-body workup of a known recurrence and for determining whether or not the recurrence is isolated.

Impact on the long-term prognosis of FDG PET/CT in luminal-A and luminal-B breast cancer

PURPOSE

The aim of the present study was to explore the prognostic role of 2- deoxy-2-[18F]fluoro-D-glucose PET (FDG PET)/CT in recurrent luminal A and luminal B breast cancer.

MATERIALS AND METHODS

From two institutional databases, we retrospectively retrieved data about breast cancer patients undergoing FDG PET/CT between 2011 and 2018 for the assessment of recurrency. Molecular subtypes of breast cancer were defined based on the expression of estrogen, progesterone, human epidermal growth factor receptor 2 (HER2)-b receptors and proliferation index. Overall survival (OS, intended as the time from PET/CT and the time of death) was registered for each patient, by checking the medical charts. Parametric and survival analyses were computed.

RESULTS

Data of 179 patients were retrieved. Sixty-three patients had luminal A, 88 luminal B and 28 luminal B/He breast cancer. At the time of PET/CT scan, cancer antigen (CA) 15.3 levels was within the normal range in 119 patients, whereas it was increased in 60 patients. FDG PET/CT results were suggestive for disease recurrence in 114 (63.7%) patients. The median time lapse from the FDG PET/CT scan to the last clinical follow-up visit was 51 months (1-192 months). Patients with evidence of a PET/CT scan suggestive for disease recurrence showed a significantly shorter OS (P < 0.001) compared to patients with no PET/CT evidence of recurrence, in each subset of luminal breast cancer. Moreover, PET/CT was able to stratify the prognosis of patients independently from the level of tumor marker.

CONCLUSION

These data suggest that FDG PET/CT may be an attractive prognostic tool in recurrent breast cancer. Our study supports its prognostic role both in luminal A and B-type molecular subtypes, regardless of the CA 15.3 levels.

Examining the evolving utility of 18FDG-PET/CT in breast cancer recurrence

Many studies have demonstrated the utility of ¹⁸fluorodeoxyglucose-positron emission tomography/computed tomography (¹⁸FDG-PET/CT) scan in evaluating breast cancer recurrence in subsets of patients based on age, histological subtype and cancer stage to guide response to conventional chemoradiation guidelines during treatment of metastatic breast cancer disease. This literature review focuses on the breakthrough of ¹⁸FDG-PET/CT imaging within the paradigm of breast cancer oncology centered toward improving risk stratification and prognostication of disease relapse based on cancer molecular phenotypes, tumor markers, early metabolic activity and response to neoadjuvant chemotherapy (NAC). The authors consider the rapid shift toward biomarker based molecular tracers to quantify treatment response and pathologic complete response with more recent imaging modalities such as dedicated breast positron emission tomography (dbPET), and the advantages afforded by this multisystem approach.

CA 15.3 measurements for separating FDG PET/CT positive from negative findings in breast carcinoma recurrence

In breast cancer CA 15.3 is considered the tumour marker of choice. CA 15.3 is directly related to the disease extent and to hormone status (estrogen receptor ER+/ ER-, progesterone receptor PR+/PR-). This study was designed to assess the impact of disease extent, hormone receptor and HER2-status, and circulating blood volume on the area-under the ROC-curve of CA 15.3 to separate FDG PET positive from negative findings. Patients, methods: We retrospectively evaluated 379 FDG PET/CT examinations performed in 80 patients with breast cancer. Blood volumes were derived using the formulas by Nadler and multiplied by their corresponding CA 15.3 measurement. Results: ROC-curve analysis revealed an AUC of 0.695 (p = 0.0001) for CA 15.3 to separate FDG PET positive from negative findings. AUC measurements to separate normal scan find-ings from loco-regional disease and meta- static disease were 0.527 (p = 0.587) and 0.732 (p = 0.0001), respectively. AUC measurements for CA 15.3 to separate positive from negative FDG PET findings, in ER+ and ER- patients, were respectively 0.772 (p = 0.0001) and 0.596 (p = 0.143). AUC measurements for CA 15.3 to separate positive from negative FDG PET findings, in PR+ and PR- patients, were respectively 0.675 (p = 0.0001) and 0.694 (p = 0.0001). In HER2-positive and -negative patients, the AUC measurements were respectively 0.594 (p = 0.178) and 0.701 (p = 0.0001) to separate positive from negative FDG PET findings. Conclusion: The AUC for CA 15.3 measurements to separate FDG PET positive from negative findings in breast cancer patients with suspected recurrence proved to be directly related to the extent of the recurrent disease and hormone receptor status and inversely related to HER2-status. Correcting CA 15.3 measurements for blood volumes did not impact the AUC.

Comparative diagnostic accuracy of 18F-FDG PET/CT for breast cancer recurrence

In the last decades, in addition to conventional imaging techniques and magnetic resonance imaging (MRI), ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) has been shown to be relevant in the detection and management of breast cancer recurrence in doubtful cases in selected groups of patients. While there are no conclusive data indicating that imaging tests, including FDG PET/CT, produce a survival benefit in asymptomatic patients, FDG PET/CT can be useful for identifying the site of relapse when traditional imaging methods are equivocal or conflicting and for identifying or confirming isolated loco-regional relapse or isolated metastatic lesions. The present narrative review deals with the potential role of FDG PET in these clinical settings by comparing its accuracy and impact with conventional imaging modalities such as CT, ultrasound, bone scan, ¹⁸F-sodium fluoride PET/CT (¹⁸F-NaF PET/CT) as well as MRI. Patient-focused perspectives in terms of patients' satisfaction and acceptability are also discussed.

¹⁸F-FDG PET/CT for Staging and Restaging of Breast Cancer

Many studies have pointed out the role of (18)F-FDG PET/CT (or (18)F-FDG PET) in patients with clinical stage III or II breast cancer. (18)F-FDG PET/CT might advantageously replace other staging procedures, such as bone scanning and possibly contrast-enhanced CT of the thorax or abdomen-pelvis. We discuss the findings, locoregional or distant, that can be expected in different categories of breast cancer and their impact on prognosis and management. We also discuss the role of (18)F-FDG PET/CT in restaging and how (18)F-FDG PET/CT compares with conventional techniques in restaging for patients with suspected disease recurrence. We conclude with some recommendations for clinical practice and future research.

[18F]Fluorodeoxyglucose (FDG)-Positron Emission Tomography (PET)/Computed Tomography (CT) in Suspected Recurrent Breast Cancer: A Prospective Comparative Study of Dual-Time-Point FDG-PET/CT, Contrast-Enhanced CT, and Bone Scintigraphy

PURPOSE

To prospectively investigate the diagnostic accuracy of [(18)F]fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) with dual-time-point imaging, contrast-enhanced CT (ceCT), and bone scintigraphy (BS) in patients with suspected breast cancer recurrence.

PATIENTS AND METHODS

One hundred women with suspected recurrence of breast cancer underwent 1-hour and 3-hour FDG-PET/CT, ceCT, and BS within approximately 10 days. The study was powered to estimate the precision of the individual imaging tests. Images were visually interpreted using a four-point assessment scale, and readers were blinded to other test results. The reference standard was biopsy along with treatment decisions and clinical follow-up (median, 17 months).

RESULTS

FDG-PET/CT resulted in no false negatives and fewer false positives than the other imaging techniques. Accuracy of results were similar for 1-hour and 3-hour FDG-PET/CT. For distant recurrence, the area under the receiver operating curve was 0.99 (95% CI, 0.97 to 1) for FDG-PET/CT, 0.84 (95% CI, 0.73 to 0.94) for ceCT, and 0.86 (95% CI, 0.77 to 0.94) for the combined ceCT+BS. Of 100 patients, 22 (22%) were verified with distant recurrence, and 18 of these had bone involvement. Nineteen patients (19%) had local recurrence only. In exploratory analyses, diagnostic accuracy of FDG-PET/CT was better than ceCT alone or ceCT combined with BS in diagnosing distant, bone, and local recurrence, shown by a greater area under the receiver operating curve and higher sensitivity, specificity, and superior likelihood ratios.

CONCLUSION

FDG-PET/CT was accurate in diagnosing recurrence in breast cancer patients. It allowed for distant recurrence to be correctly ruled out and resulted in only a small number of false-positive cases. Exploratory findings suggest that FDG-PET/CT has greater accuracy than conventional imaging technologies in this patient group.

CA15-3 is a useful serum tumor marker for diagnostic integration of hybrid positron emission tomography with integrated computed tomography during follow-up of breast cancer patients

BACKGROUND

The aim of this study was to evaluate the value of CA15-3 for the diagnostic integration of molecular imaging findings performed with hybrid positron emission tomography and computed tomography (PETCT) technology.

METHODS

We retrospectively selected 45 patients with a median age of 60 years (range 39-85 years) and a previous history of breast cancer (BC) who had already been treated with surgery and other treatments. Three measurements of CA15-3 were collected within 1 year before PETCT examination, at 6-9 months 3-6 months and 0-3 months before PETCT. The prolonged clinical outcome or imaging follow-up was used to define disease relapse. An increase in tumor marker value was compared with PETCT findings and disease relapse. Sensitivity and specificity for both tests were calculated with respect to clinical outcome.

RESULTS

Disease relapse was detected in 16 out of 45 BC patients. CA15-3 and PETCT showed 75% sensitivity with a specificity percentage of 76% for CA15-3 and 79% for PETCT. Serum CA15-3 expression levels were significantly higher in BC patients with multiple metastatic sites with hepatic involvement. Analysis of serial CA15-3 serum levels showed an increase in CA15-3 3-6 months before PETCT could identify BC patients at risk for relapse (AUC = 0.81). Moreover, patients receiving anti-hormonal or chemotherapy medications with negative PETCT and positive CA15-3 relapsed after a median time of 158 days compared to patients who were negative for both tests and who were free from disease for at least 1 year.

CONCLUSIONS

Our results showed that serial increases in CA15-3 can be used to predict positive PETCT results in BC patients during follow-up. Increased levels of CA15-3 may be considered an early warning sign in patients needing accurate molecular imaging investigations, as they are at higher risk of recurrence. In cases of elevated levels, multiple lesions or liver involvement may exist. Also, patients receiving chemotherapeutic or anti-hormonal treatment who have negative PETCT scans and increased CA15-3 serum levels should be considered at risk for relapse, because the CA15-3-linked biochemical signal of the presence of a tumor can predict positive metabolic imaging.

The utility of 18 F-FDG PET/CT for suspected recurrent breast cancer: impact and prognostic stratification

Background

The incremental value of ¹⁸FDG PET/CT in patients with breast cancer (BC) compared to conventional imaging (CI) in clinical practice is unclear. The aim of this study was to evaluate the management impact and prognostic value of ¹⁸ F-FDG PET/CT in this setting.

Methods

Sixty-three patients who were referred to our institution for suspicion of BC relapse were retrospectively enrolled. All patients had been evaluated with CI and underwent PET/CT. At a median follow-up of 61 months, serial clinical, imaging and pathologic results were obtained to validate diagnostic findings. Overall Survival (OS) was estimated using Kaplan Meier methods and analyzed using the Cox proportional hazards regression models.

Results

Forty-two patients had a confirmed relapse with 37 (88%) positive on CI and 40 (95%) positive on PET/CT. When compared with CI, PET/CT had a higher negative predictive value (86% versus 54%) and positive predictive value (95% versus 70%). The management impact of PET/CT was high (change of treatment modality or intent) in 30 patients (48%) and medium (change in radiation treatment volume or dose fractionation) in 6 patients (9%). Thirty-nine patients (62%) died during follow-up. The PET/CT result was a highly significant predictor of OS (Hazard Ratio [95% Confidence Interval] =4.7 [2.0-10.9] for PET positive versus PET negative for a systemic recurrence; p = 0.0003). In a Cox multivariate analysis including other prognosis factors, PET/CT findings predicted survival (p = 0.005). In contrast, restaging by CI was not significant predictor of survival.

Conclusion

Our study support the value of ¹⁸ F-FDG PET/CT in providing incremental information that influence patient management and refine prognostic stratification in the setting of suspected recurrent breast cancer.

Usefulness of traditional serum biomarkers for management of breast cancer patients

The measurement of serum tumor markers levels in breast cancer (BC) patients is an economic and noninvasive diagnostic assay frequently requested by clinical oncologists to get information about the presence or absence of disease as well as its evolution. Despite their wide use in clinical practice, there is still an intense debate between scientific organizations about the real usefulness for patient monitoring during followup as well as response to therapy evaluation in case of advanced BC. In this review, we want to highlight the current recommendations published by scientific organizations about the use of “established” BC serum markers (CEA, TPA, TPS, CIFRA-21, CA15-3, and s-HER2) in clinical oncology practice. Moreover, we will focus on recent papers evidencing the usefulness of tumor markers levels measurement as a guide for the prescription and diagnostic integration of molecular imaging exams such as those performed by hybrid 18-fluorofeoxyglucose-positron emission tomography with integrated computed tomography. This technology is nowadays able to detect early cancer lesions undetectable by conventional morphological imaging investigation and most likely responsible for increasing of serum tumor markers levels.