Defining the role of PET-CT in staging early breast cancer

PET Molecular Imaging in Breast Cancer: Current Applications and Future Perspectives

Positron emission tomography (PET) plays a crucial role in breast cancer management. This review addresses the role of PET imaging in breast cancer care. We focus primarily on the utility of 18F-fluorodeoxyglucose (FDG) PET in staging, recurrence detection, and treatment response evaluation. Furthermore, we delve into the growing interest in precision therapy and the development of novel radiopharmaceuticals targeting tumor biology. This includes discussing the potential of PET/MRI and artificial intelligence in breast cancer imaging, offering insights into improved diagnostic accuracy and personalized treatment approaches.

Synchronous Malignancies Identified by PET-CT Scan in Breast Cancer Patients

Breast cancer is a common malignancy and a common cause of cancer-related mortality in women. Pre-treatment workup of breast cancer does not routinely include positron emission tomography scans. We aimed to review cases of women with breast cancer and a synchronous second primary malignancy. We present three cases of women with non-metastatic cancer in whom a synchronous second primary malignancy was found. Synchronous, second primary malignancies which were identified included rectal cancer, gastrointestinal stromal tumor, and non-small cell lung cancer. All second primary malignancies were identified by a PET-CT scan. In conclusion, PET-CT may be used for detection of secondary primary malignancies in select breast cancer patients.

The Challenge of Staging Breast Cancer With PET/CT in the Era of COVID Vaccination

ABSTRACT

We report a case series of biopsy-proven reactive axillary lymph nodes, which were avid on FDG PET/CT in breast cancer patients post COVID-19 vaccination. With 4 cases presenting in a consecutive 10-day period, it became apparent that metabolically active axillary lymphadenopathy is an adverse effect of COVID-19 vaccines, currently being deployed worldwide. This may lead to patients undergoing unnecessary biopsy. We have started taking a COVID-19 vaccine status history before PET/CT. If enlarged/metabolically active axillary nodes are identified in the ipsilateral vaccinated arm, then axillary ultrasound at 4 weeks is suggested.

To Evaluate the Role of Positron Emission Tomography-Computerized Tomography in Initial Staging of Carcinoma Breast

BACKGROUND

Breast cancer is the most common cancer in urban and second common in rural Indian women. In India, in spite of the best treatment available being given to the patients they lose their lives because of paucity of diagnostic aids and lack of an organized breast cancer screening program. Early detection, accurate staging, and initiation of appropriate therapy are the key factors for improving the treatment outcome and prognosis of the disease for the patients. Traditional staging methods include clinical examination, blood tests, chest X-ray, ultrasound of the abdomen, and/or skeletal survey. As these tests lack sensitivity and specificity, these are being scaled down. The hybrid positron emission tomography-computerized tomography (PET-CT) is a unique tool in the field of imaging modalities that combines the effectiveness of PET and CT. This study was undertaken to assess the efficacy and accuracy of PET-CT as a single-session staging modality in the very initial stage itself and if it can replace the conventional means of staging.

METHODS

This was a cross-sectional study conducted in the Radiotherapy department at GGS Medical College and Hospital Faridkot from March 2014 to October 2015. 52 patients with newly diagnosed and histopathologically proven carcinoma breast were staged by conventional modalities (clinical examination, blood tests, X-ray chest, mammography, ultrasonography abdomen, skeletal survey) and by 18F-fluorodeoxyglucose (18F FDG) PET/CT. PET-CT images were used for the detection, localization, staging of tumors and detection, evaluation, and diagnosis of metastatic lesions, disease burden and organ function along with treatment planning and planning therapeutic procedures. Following the completion of initial study, the results of 18F FDG PET-CT staging in comparison with conventional staging method were assessed. Along with this, the accuracy, changes in staging of cases of carcinoma breast and cost-effectiveness of 18F-FDG PET-CT were also studied.

RESULTS

All the pathologic entities identified by conventional imaging were also perceived with 18F-FDG PET/CT. Therefore, we recommend the use of PET/CT as an important imaging modality for initial diagnosis of carcinoma breast.

Convolutional Neural Network of Multiparametric MRI Accurately Detects Axillary Lymph Node Metastasis in Breast Cancer Patients With Pre Neoadjuvant Chemotherapy

BACKGROUND

Accurate assessment of the axillary lymph nodes (aLNs) in breast cancer patients is essential for prognosis and treatment planning. Current radiological staging of nodal metastasis has poor accuracy. This study aimed to investigate the machine learning convolutional neural networks (CNNs) on multiparametric MRI to detect nodal metastasis with 18FDG-PET as ground truths.

MATERIALS AND METHODS

Data were obtained via a retrospective search. Inclusion criteria were patients with bilateral breast MRI and 18FDG-PETand/or CT scans obtained before neoadjuvant chemotherapy. In total, 238 aLNs were obtained from 56 breast cancer patients with 18FDG-PET and/or CT and breast MRI data. Radiologists scored each node based on all MRI as diseased and non-diseased nodes. Five models were built using T1-W MRI, T2-W MRI, DCE MRI, T1-W + T2-W MRI, and DCE + T2-W MRI model. Performance was evaluated using receiver operating curve (ROC) analysis, including area under the curve (AUC).

RESULTS

All CNN models yielded similar performance with an accuracy ranging from 86.08% to 88.50% and AUC ranging from 0.804 to 0.882. The CNN model using T1-W MRI performed better than that using T2-W MRI in detecting nodal metastasis. CNN model using combined T1- and T2-W MRI performed the best compared to all other models (accuracy = 88.50%, AUC = 0.882), but similar in AUC to the DCE + T2-W MRI model (accuracy = 88.02%, AUC = 0.880). All CNN models performed better than radiologists in detecting nodal metastasis (accuracy = 65.8%).

CONCLUSION

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PET/CT in breast cancer staging is useful for evaluation of axillary lymph node and distant metastases

INTRODUCTION

Breast cancer outcome is dependent on disease stage. The aim of the study was to assess the role of PET/CT in the evaluation of axillary lymph node and distant metastases in women with newly diagnosed primary breast cancer.

MATERIALS AND METHODS

We assessed, among patients with newly diagnosed primary breast cancer, associations of [¹⁸F] fluorodeoxyglucose (FDG) uptake (maximum standardized uptake value [SUV_max]) with clinical variables of the primary tumor, including regional nodal status and the presence of distant metastases.

RESULTS

Of 324 patients, 265 (81.8%) had focal uptake of FDG that corresponded with the cancerous lesion, and 21 (6.5%) had no FDG-avid findings. The remaining 38 patients had diffuse or nonspecific uptake of FDG. Among patients with a focal uptake of FDG (n = 265), the mean tumor size was 2.6 ± 1.9 (range 0.5-13.5), and the mean SUV_max was 5.3 ± 4.9 (range 1.2-25.0). In 83 patients (25.6%), PET/CT demonstrated additional suspected foci in the same breast. FDG-avid lymphadenopathy was observed in 156 patients (48.1%). Further assessment of lymph node involvement was available for 55/156 patients (axillary lymph node dissection [n = 21]; core needle biopsy [n = 34]) and confirmed axillary lymph node metastases in 47 (85.5%)). Thirteen patients (4.0%) had FDG-avid supraclavicular lymph nodes and six (1.9%) had FDG-avid internal mammary lymph nodes. Distant FDG-avid lesions were detected in 33 patients (10.2%).

CONCLUSION

PET/CT is a useful diagnostic tool for staging breast cancer patients, but its use should be limited to specific clinical situations; further evaluation is needed.

[89Zr]-Pertuzumab PET Imaging Reveals Paclitaxel Treatment Efficacy Is Positively Correlated with HER2 Expression in Human Breast Cancer Xenograft Mouse Models

Paclitaxel (PTX) treatment efficacy varies in breast cancer, yet the underlying mechanism for variable response remains unclear. This study evaluates whether human epidermal growth factor receptor 2 (HER2) expression level utilizing advanced molecular positron emission tomography (PET) imaging is correlated with PTX treatment efficacy in preclinical mouse models of HER2+ breast cancer. HER2 positive (BT474, MDA-MB-361), or HER2 negative (MDA-MB-231) breast cancer cells were subcutaneously injected into athymic nude mice and PTX (15 mg/kg) was administrated. In vivo HER2 expression was quantified through [89Zr]-pertuzumab PET/CT imaging. PTX treatment response was quantified by [18F]-fluorodeoxyglucose ([18F]-FDG) PET/CT imaging. Spearman's correlation, Kendall's tau, Kolmogorov-Smirnov test, and ANOVA were used for statistical analysis. [89Zr]-pertuzumab mean standard uptake values (SUVmean) of BT474 tumors were 4.9 ± 1.5, MDA-MB-361 tumors were 1.4 ± 0.2, and MDA-MB-231 (HER2-) tumors were 1.1 ± 0.4. [18F]-FDG SUVmean changes were negatively correlated with [89Zr]-pertuzumab SUVmean (r = -0.5887, p = 0.0030). The baseline [18F]-FDG SUVmean was negatively correlated with initial [89Zr]-pertuzumab SUVmean (r = -0.6852, p = 0.0002). This study shows PTX treatment efficacy is positively correlated with HER2 expression level in human breast cancer mouse models. Molecular imaging provides a non-invasive approach to quantify biological interactions, which will help in identifying chemotherapy responders and potentially enhance clinical decision-making.

Relationship Between FDG Uptake and the Platelet/lymphocyte Ratio in Patients With Breast Invasive Ductal Cancer

BACKGROUND/AIM

We investigated the relationship between F18-fluorodeoxyglucose (FDG) uptake and the platelet/lymphocyte ratio (PLR), as both represent inflammation.

PATIENTS AND METHODS

We retrospectively analyzed the cases of 143 consecutive invasive ductal carcinoma patients who had undergone preoperative FDG-PET and surgery. We divided the patients into groups based on their maximum standardized uptake value (SUVmax) values: low (<2.5) and high (≥2.5) and based on their PLRs: low (<130) and high (≥130). We determined the relationships between the SUVmax or PLR and clinicopathological features.

RESULTS

Seventy-three patients (51.0%) had a high SUVmax in their primary tumor. There were significant associations between SUVmax and the PLR. A multivariate analysis revealed that high PLR, but not NLR, was independent factor associated with a high SUVmax. Seventy-four patients (51.7%) had a high PLR; The factors significantly associated with high PLR were large tumor size, presence of node metastasis, presence of vascular invasion, high NLR, and high SUVmax.

CONCLUSION

In breast cancer patients, the PLR is independently associated with the SUVmax, but not with recurrent disease. In breast cancer patients with a high SUVmax and/or PLR, these values may reflect the tumor microenvironment.

PET-CT upstaging of unilateral operable breast cancer and its correlation with molecular subtypes

Context:

Prognosis and survival rates for breast cancer vary greatly depending on the cancer stage of the patient. Instead of a step-by-step approach using multiple investigations, we can get all the information about the metastatic load of the disease in PET-CT imaging by one single investigation. There is also a correlation between prognosis, FDG uptake, and molecular subtype of breast cancer (Luminal A, Luminal B, Human epidermal growth factor receptor 2 (HER2) positive and Triple-negative). Pre-treatment baseline PET-CT scan was done in 156 unilateral early and operable breast cancer patients from November 2017 to April 2019 in our prospective observational study.

Aims:

To evaluate the utility of PET-CT in staging and upstaging of early and operable breast cancer by detection of unsuspected lymph nodes and distant organ metastases.

To determine the prognostic association between SUVmax of the primary breast lesion in the upstaged cases and the molecular subtypes.

Results:

Thus, PET-CT can serve as one-stop imaging in unilateral operable early breast cancer patients for upstaging and prognostication based on the correlation of SUVmax with molecular subtypes of breast lesions in patients who will surely benefit from whole-body imaging.

Out of 156 patients, approximately 27 patients were upstaged after pre-treatment PET CT.

Six patients were upstaged to stage IIIC and 21 patients were upstaged to IV.

Regional nodes like internal mammary and supraclavicular nodes were detected in 7 patients and 5 patients, respectively, out of 156 patients.

Non-regional distant nodes and organ metastases were detected in 11 and 18 patients out of 156 patients.

Most common molecular subtype detected in the upstaged cases in our study was Luminal A (13 patients) followed by Triple negative (6), Luminal B (3) and HER2-neu-positive subtypes (1).

Conclusions:

FDG PET-CT is a substantial modality to provide information on regional, non regional lymph nodes and distant metastases in early operable breast cancer.

It helps in evaluating the whole body metastatic burden in a single sitting, therefore, reducing the need for multiple investigations.

SUVmax association of the index lesion with molecular subtype in the FDG PET scanning can serve as a prognostication factor in operable early breast cancer patients.

18F-fluorodeoxyglucose PET/computed tomography in locoregional staging and assessment of biological and clinical aggressiveness of breast cancer subtypes

OBJECTIVE

We aimed to evaluate the availability of fluorine-18-fluorodeoxyglucose (18F-FDG) PET/computed tomography (CT) in initial axillary lymph node (ALN) staging in breast cancer. The secondary objective is to evaluate the role of FDG PET/CT as a pretest in sentinel lymph node biopsy vs. axillary lymph node dissection when predicting disease aggressiveness.

METHODS

The study evaluated retrospectively 194 breast cancer patients who underwent preoperative 18F-FDG. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of FDG PET/CT for ALN metastases were confirmed with histopathology as the gold standard.

RESULTS

The value of the area under curve (AUC), sensitivity and specificity for ALN metastases were determined as 0.847, 78.8% and 92.6%, respectively. The cut-off value of the maximum standardized uptake value (SUVmax) for metastatic ALN detection was calculated as 1.79. PPV, NPV and the accuracy of 18F-FDG PET/CT were 0.933 (93.3%), 0.75 (75%) and 0.837 (83.7%), respectively. The SUVmax value of the primary lesion was significantly correlated with grade, estrogen receptor (ER) status, progesterone receptor (PR) status, SUVmax value of metastatic ALN, Her-2 status and Ki-67 level. Molecular subtypes revealed no statistically significant difference in terms of mean SUVmax value.

CONCLUSION

High values of AUC, sensitivity, specificity, NPV and PPV encourage utilization of PET/CT for locoregional staging of nonmetastatic breast carcinoma. The significant correlation between the primary tumor SUVmax value and grade, ER status, PR status and Ki-67 level increases the prognostic predictive value of the preoperative PET/CT.

Early metabolic response of breast cancer to neoadjuvant endocrine therapy: comparison to morphological and pathological response

Background

Neoadjuvant endocrine therapy (NET) has shown efficacy in terms of clinical response and surgical outcome in postmenopausal patients with estrogen receptor-positive / HER2-negative breast cancer (ER+/HER2- BC) but monitoring of tumor response is challenging. The aim of the present study was to investigate the value of an early metabolic response compared to morphological and pathological responses in this population.

Methods

This was an ancillary study of CARMINA 02, a phase II clinical trial evaluating side-by-side the efficacy of 4 to 6 months of anastrozole or fulvestrant. Positron Emission Tomography/Computed Tomography using 2-deoxy-2-[¹⁸F]fluoro-D-glucose (FDG-PET/CT) scans were performed at baseline (M0), early after 1 month of treatment (M1) and pre-operatively in 11 patients (74.2 yo ± 3.6). Patients were classified as early “metabolic responders” (mR) when the decrease of SUVmax was higher than 40%, and “metabolic non-responders” (mNR) otherwise. Early metabolic response was compared to morphological response (palpation, US and MRI), variation of Ki-67 index, pathological response according to the Sataloff classification and also to Preoperative Endocrine Prognostic Index (PEPI) score. It was also correlated with overall survival (OS) and recurrence-free survival (RFS).

Results

Tumor size measured on US and on MRI was smaller in mR than mNR, with the highest statistically significant difference at M1 (p = 0.01 and 7.1 × 10^− 5, respectively). No statistically significant difference in the variation of tumor size between M0 and M1 assessed on US or MRI was observed between mR and mNR. mR had a better clinical response: no progressive disease in mR vs 2 in mNR and 2 partial response in mR vs 1 partial response in mNR. One patient with a pre-operative complete metabolic response had the best pathological response. Pathological response did not show any statistically significant difference between mR and mNR. mR had better OS and RFS (Kaplan-Meier p = 0.08 and 0.06, respectively). All cancer-related events occurred in mNR: 3 patients died, 2 of them from progressive disease.

Conclusions

FDG-PET/CT imaging could become a “surrogate marker” to monitor tumor response, especially as NET is a valuable treatment option in postmenopausal women with ER+/HER2- BC.

The Evolving Role of FDG-PET/CT in the Diagnosis, Staging, and Treatment of Breast Cancer

The applications of 2-deoxy-2-[¹⁸F]fluoro-D-glucose positron emission tomography/X-ray computed tomography (PET/CT) in the management of patients with breast cancer have been extensively studied. According to these studies, PET/CT is not routinely performed for the diagnosis of primary breast cancer, although PET/CT in specific subtypes of breast cancer correlates with histopathologic features of the primary tumor. PET/CT can detect metastases to mediastinal, axial, and internal mammary nodes, but it cannot replace the sentinel node biopsy. In detection of distant metastases, this imaging tool may have a better accuracy in detecting lytic bone metastases compared to bone scintigraphy. Thus, PET/CT is recommended when advanced-stage disease is suspected, and conventional modalities are inconclusive. Also, PET/CT has a high sensitivity and specificity to detect loco-regional recurrence and is recommended in asymptomatic patients with rising tumor markers. Numerous studies support the future role of PET/CT in prediction of response to neoadjuvant chemotherapy (NAC). PET/CT has a higher diagnostic value for prognostic risk stratification in comparison with conventional modalities. With the continuing research on the treatment planning and evaluation of patients with breast cancer, the role of PET/CT can be further extended.

Influence of age on radiomic features in 18F-FDG PET in normal breast tissue and in breast cancer tumors

Background

To help interpret measurements in breast tissue and breast tumors from ¹⁸F-FDG PET scans, we studied the influence of age in measurements of PET parameters in normal breast tissue and in a breast cancer (BC) population.

Results

522 women were included: 331 pts without history of BC (B-VOI) and 191 patients with BC (T-VOI). In B-VOI, there were significant differences between all age groups for Standardized Uptake Values (SUVs) and for 12 textural indices (TI) whereas histogram-based indices (HBI) did not vary between age groups. SUV values decreased over time whereas Homogeneity increased. We had a total of 210 T-VOI and no significant differences were found according to the histological type between 190 ductal carcinoma and 18 lobular carcinoma. Conversely, according to BC subtype most differences in PET parameters between age groups were found in Triple-Negative tumors (52) for 9 TI. On post-hoc Hochberg, most differences were found between the <45 year old (PRE) group and POST groups in NBT and in Triple-Negative tumors.

Conclusion

We found significant SUVs and TI differences as a function of age in normal breast tissue and in BC radiomic phenotype with Triple-Negative tumors being the most affected. Our findings suggest that age should be taken into account as a co-covariable in radiomic models.

Methods

Patients were classified in 3 age groups: <45 yo (PRE), ≥45 and <55 yo (PERI) and ≥55 and <85 yo (POST) and we compared PET parameters using Anova test with post-hoc Bonferroni/Hochberg analyses: SUV (max, mean and peak), HBI and TI in both breasts and in breast tumor regions.

Preoperative [18]fluorodeoxyglucose-positron emission tomography/computed tomography in early stage breast cancer: Rates of distant metastases

AIM

To investigate rates of distant metastases (DM) detected with [18]fluorodeoxyglucose-positron emission tomography/computed tomography (18FDG-PET/CT) in early stage invasive breast cancer.

METHODS

We searched the English language literature databases of PubMed, EMBASE, ISI Web of Knowledge, Web of Science and Google Scholar, for publications on DM detected in patients who had 18FDG-PET/CT scans as part of the staging for early stages of breast cancer (stage I and II), prior to or immediately following surgery. Reports published between 2011 and 2017 were considered. The systematic review was conducted according to the PRISMA guidelines.

RESULTS

Among the 18 total studies included in the analysis, the risk of DM ranged from 0% to 8.3% and 0% to 12.9% for stage I and II invasive breast cancer, respectively. Among the patients with clinical stage II, the rate of occult metastases diagnosed by 18FDG-PET/CT was 7.2% (range, 0%-19.6%) for stage IIA and 15.8% (range, 0%-40.8%) for stage IIB. In young patients (< 40-year-old), 18FDG-PET/CT demonstrated a higher prevalence of DM at the time of diagnosis for those with aggressive histology (i.e., triple-negative receptors and poorly differentiated grade).

CONCLUSION

Young patients with poorly differentiated tumors and stage IIB triple-negative breast cancer may benefit from 18FDG-PET/CT at initial staging to detect occult DM prior to surgery.

PET Probe-Guided Surgery in Patients with Breast Cancer: Proposal for a Methodological Approach

BACKGROUND

Although it is valuable for detecting distant metastases, identifying recurrence, and evaluating responses to chemotherapy, the role of ¹⁸F-fluorodeoxyglucose positron-emission tomography/computed tomography (¹⁸F-FDG PET/CT) in assessing locoregional nodal status for initial staging of breast cancer has not yet been well-defined in clinical practice. In the current report, we describe a new PET probe-based clinical approach, with evaluation of the technical performance of a handheld high-energy gamma probe for intraoperative localization of breast carcinomas, and evaluation of lymph node metastases during radio-guided oncological surgery.

PATIENTS AND METHODS

Three patients underwent a PET/CT scan immediately prior to surgery following the standard clinical protocol. Intraoperatively, tumors were localized and resected with the assistance of a hand-held gamma probe. PET-guided assessment of the presence or absence of regional nodal spread of malignancy was compared with the reference standard of histopathological examination.

RESULTS

In all three cases, perioperative ¹⁸F-FDG PET/CT imaging and intraoperative gamma probe detection verified complete resection of the hypermetabolic lesions and demonstrated no additional suspicious occult disease.

CONCLUSION

This innovative approach demonstrates great promise for providing real-time access to metabolic and morphological tumor information that may lead to an optimal disease-tailored approach. In carefully selected indications, a PET probe can be a useful adjunct in surgical practice, but further trials with a larger number of patients need to be performed to verify these findings.

Patterns of Care and Clinical Outcomes of HER2-positive Metastatic Breast Cancer Patients With Newly Diagnosed Stage IV or Recurrent Disease Undergoing First-line Trastuzumab-based Therapy: A Multicenter Retrospective Cohort Study

BACKGROUND

The aim of the study was to compare the patterns of care and clinical outcomes of HER2-positive metastatic breast cancer (MBC) patients with de novo or recurrent disease who underwent first-line trastuzumab-based therapy.

PATIENTS AND METHODS

This was a multicenter retrospective cohort study including consecutive patients with HER2-positive MBC who received first-line trastuzumab-based therapy. Analyses on treatment response and effectiveness were conducted according to type of metastatic presentation (ie, de novo vs. recurrent disease). Exploratory analyses were used to evaluate whether the use of surgery of the primary tumor in the de novo cohort influenced patients' survival.

RESULTS

From January 2000 to December 2013, 416 patients were included in the study, 113 (27.2%) presented with de novo MBC and 303 (72.8%) with recurrent disease. Compared with patients in the recurrence cohort, those in the de novo cohort had worse baseline characteristics, received more aggressive first-line treatments, and showed better survival, with an adjusted hazard ratio (HR) for progression-free survival (PFS) of 0.65 (95% confidence interval [CI], 0.43-0.97; P = .035) and for overall survival (OS) of 0.53 (95% CI, 0.30-0.95; P = .034). In the de novo cohort, the 54 patients (47.8%) who underwent surgery of the primary tumor had significantly better PFS (adjusted HR, 0.44; 95% CI, 0.26-0.72; P = .001) and OS (adjusted HR, 0.49; 95% CI, 0.26-0.93; P = .029) than those who did not undergo surgery.

CONCLUSION

Patients with de novo HER2-positive MBC showed significantly better survival outcomes than those with recurrent disease. In this population, surgery of the primary breast tumor was associated with better outcomes.

Application of positron emission tomography (PET/CT) in diagnosis of breast cancer. Part I. Diagnosis of breast cancer prior to treatment

Positron emission tomography with computed tomography (PET/CT) is gaining popularity as a method for overall staging assessment of breast cancer. Currently, it is not a part of the routine workup before the beginning of treatment, because of insufficient sensitivity for the detection of small tumors (due to its limited spatial resolution), the heterogeneity of radiotracer uptake by the primary tumor, and unsatisfactory sensitivity in detection of lymph node metastases (particularly when they are small). Nevertheless, it should be considered when there is a high risk of metastases, because then initial PET/CT examination allows for accurate staging and may change the treatment algorithm in up to almost 50% of stage III patients, due to detection of distant and lymph node metastases throughout the whole body. Despite the discussed limitations of PET/CT, there is ongoing research concerning the recommendations for the examination prior to treatment. For a particular group of patients with high risk of metastases, PET/CT may be expected to become a part of the routine workup as the most appropriate staging method.

(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.

Assessment of multifocality and axillary nodal involvement in early-stage breast cancer patients using 18F-FDG PET/CT compared to contrast-enhanced and diffusion-weighted magnetic resonance imaging and sentinel node biopsy

BACKGROUND

Non-invasive evaluation of the extent of axillary nodal involvement in early-stage breast cancer (ESBC) patients and accurate assessment of multifocality are both challenging. Few reports have explored whether 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) might be more useful than other diagnostic methods in these contexts.

PURPOSE

To prospectively evaluate the diagnostic utility of FDG PET/CT, contrast-enhanced, and diffusion-weighted magnetic resonance imaging (DCE-MRI and DWI), and sentinel lymph node biopsy (SNB), in detection of axillary metastatic lymph nodes in ESBC patients; and to explore the utilities of FDG PET/CT and DCE-MRI for identification of multifocality.

MATERIAL AND METHODS

Twenty-four female patients (mean age, 47 ± 9.9 years; range, 24-68 years) with ESBC underwent whole-body FDG PET/CT and breast MRI prior to operation. SNB and axillary lymph node dissection (ALND) were performed on all patients, as was mastectomy or wide local tumor excision. Histopathological findings served as the gold standard when evaluating either multifocality or axillary nodal involvement.

RESULTS

The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy, of PET/CT and DCE-MRI, used to detect multifocality, were as follows: 67% versus 78%, 100% versus 53%, 100% versus 50%, 83% versus 80%, and 88% versus 63%. SNB afforded the highest sensitivity (93%) in terms of detection of axillary metastasis. The sensitivity, NPV, and accuracy of PET/CT were 67%, 62%, and 75% respectively, thus higher than the equivalent values of either DCE-MRI or DWI.

CONCLUSION

For assessment of multifocality in ESBC patients, highly specific results of PET/CT should be taken into account along with DCE-MRI findings. For evaluation of axillary nodal involvement, PET/CT has higher sensitivity, NPV, and accuracy values than DCE-MRI and DWI and may guide a surgical decision to proceed or not to SNB or ALND.

Prone Versus Supine Breast FDG-PET/CT for Assessing Locoregional Disease Distribution in Locally Advanced Breast Cancer

RATIONALE AND OBJECTIVES

Prone (18)F fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) may have advantages for breast imaging because of improved separation of deep anatomic structures. There are limited data on whether prone and supine FDG-PET/CT provide similar information regarding breast and axillary disease in the setting of locally advanced breast cancer (LABC). The purpose of this study was to compare the information on locoregional disease distribution provided by prone versus supine FDG-PET in newly diagnosed LABC.

MATERIALS AND METHODS

In an Institutional Review Board-approved prospective trial, 24 patients with newly diagnosed LABC underwent both supine and prone FDG-PET/CT at the same scanning session. Three readers performed an independent review of all scans and categorized the locoregional disease distribution as breast only (BO)-unifocal, BO-multifocal, BO-multicentric, or breast + axillary involvement. For breast + axillary disease, the readers also assessed the number of involved axillary lymph nodes. Interobserver discrepancies were resolved at a consensus reading session.

RESULTS

Two scanning sessions were excluded because the prone scan had omitted part of the axilla from the field of view. In the remaining 22 patients, the consensus categorization of anatomic disease distribution was concordant between prone and supine scanning in 21 patients (linear kappa 0.91, 95% confidence interval [0.79-1]). In the 16 patients with breast + axillary disease, equal numbers of involved lymph nodes were identified on prone and supine scanning in 12 patients, whereas in the remaining four patients, prone scanning resulted in a higher number of visualized lymph nodes.

CONCLUSIONS

Prone and supine FDG-PET/CT provided statistically identical information on locoregional disease distribution in LABC. However, prone scanning may perform better than supine for assessing the number of involved lymph nodes. Prone FDG-PET/CT may be useful in future clinical and research efforts, including hybrid PET-magnetic resonance imaging (MRI) applications.

Effectiveness of Breast MRI and (18)F-FDG PET/CT for the Preoperative Staging of Invasive Lobular Carcinoma versus Ductal Carcinoma

Purpose

We evaluated the utility of magnetic resonance imaging (MRI) and ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) for the preoperative staging of invasive lobular carcinoma (ILC) of the breast and compared the results with those of invasive ductal carcinoma (IDC).

Methods

The study included pathologically proven 32 ILCs and 73 IDCs. We compared clinical and histopathological characteristics and the diagnostic performances of MRI and ¹⁸F-FDG PET/CT for the primary mass, additional ipsilateral and/or contralateral lesion(s), and axillary lymph node metastasis between the ILC and IDC groups.

Results

Primary ILCs were greater in size, but demonstrated lower maximum standardized uptake values than IDCs. All primary masses were detected on MRI. The detection rate for ILCs (75.0%) was lower than that for IDCs (83.6%) on ¹⁸F-FDG PET/CT, but the difference was not significant. For additional ipsilateral lesion(s), the sensitivities and specificities of MRI were 87.5% and 58.3% for ILC and 100.0% and 66.7% for IDC, respectively; whereas the sensitivities and specificities of ¹⁸F-FDG PET/CT were 0% and 91.7% for ILC and 37.5% and 94.7% for IDC, respectively. The sensitivity of ¹⁸F-FDG PET/CT for ipsilateral lesion(s) was significantly lower in the ILC group than the IDC group. The sensitivity for ipsilateral lesion(s) was significantly higher with MRI; however, specificity was higher with ¹⁸F-FDG PET/CT in both tumor groups. There was no significant difference in the diagnostic performance for additional contralateral lesion(s) or axillary lymph node metastasis on MRI or ¹⁸F-FDG PET/CT for ILC versus IDC.

Conclusion

The MRI and ¹⁸F-FDG PET/CT detection rates for the primary cancer do not differ between the ILC and IDC groups. Although ¹⁸F-FDG PET/CT demonstrates lower sensitivity for primary and additional ipsilateral lesions, it shows higher specificity for additional ipsilateral lesions, and could play a complementary role in the staging of ILC as well as IDC.

Increase in Distant Stage Breast Cancer Incidence Rates in US Women Aged 25-49 Years, 2000-2011: The Stage Migration Hypothesis

Background. Unexplained increases have been reported in incidence rates for breast cancer diagnosed at distant stage in younger U.S. women, using data from the Surveillance, Epidemiology and End Results (SEER) Program. Methods. This report focused on recent SEER trends (2000–2011) in age-standardized incidence rates of invasive breast cancer at ages 25–39 and 40–49 years and the hypothesis that stage migration may have resulted from advances in detecting distant metastases at diagnosis. Results. Increases in the rates for distant stage were roughly equal to decreases in the rates for the most advanced stage subgroups within regional stage; this was evident for estrogen receptor (ER) negative cancers, associated with poorer prognosis, but not for ER positive cancers. The 3-year relative survival rate increased over time for distant stage (especially in the ER positive subgroup) and regional stage but not for localized stage; these trends do not contradict the stage-migration hypothesis. Conclusions. Findings provide some support for stage migration as one explanation for the recent increase in incidence of distant stage breast cancer, but additional studies are needed using other databases.

Retrospective analysis of 18F-FDG PET/CT for staging asymptomatic breast cancer patients younger than 40 years

National Comprehensive Cancer Network guidelines consider (18)F-FDG PET/CT for only clinical stage III breast cancer patients. However, there is debate whether TNM staging should be the only factor in considering if PET/CT is warranted. Patient age may be an additional consideration, because young breast cancer patients often have more aggressive tumors with potential for earlier metastases. This study assessed PET/CT for staging of asymptomatic breast cancer patients younger than 40 y.

METHODS

In this Institutional Review Board-approved retrospective study, our hospital information system was screened for breast cancer patients younger than 40 y who underwent staging PET/CT before any treatment. Patients with symptoms or conventional imaging findings suggestive of distant metastases or with prior malignancy were excluded. Initial stage was based on physical examination, mammography, ultrasound, and breast MR imaging. PET/CT was then evaluated to identify unsuspected extraaxillary regional nodal and distant metastases.

RESULTS

One hundred thirty-four patients with initial breast cancer stage I to IIIC met inclusion criteria. PET/CT findings led to upstaging to stage III or IV in 28 patients (21%). Unsuspected extraaxillary regional nodes were found in 15 of 134 patients (11%) and distant metastases in 20 of 134 (15%), with 7 of 134 (5%) demonstrating both. PET/CT revealed stage IV disease in 1 of 20 (5%) patients with initial clinical stage I, 2 of 44 (5%) stage IIA, 8 of 47 (17%) stage IIB, 4 of 13 (31%) stage IIIA, 4 of 8 (50%) stage IIIB, and 1 of 2 (50%) stage IIIC. All 20 patients upstaged to stage IV were histologically confirmed. Four synchronous thyroid and 1 rectal malignancies were identified.

CONCLUSION

PET/CT revealed distant metastases in 17% of asymptomatic stage IIB breast cancer patients younger than 40 y. Although guidelines of the National Comprehensive Cancer Network recommend against systemic staging in patients with stage II disease, our data suggest that PET/CT might be valuable in younger patients with stage IIB and III disease. Use of PET/CT in younger patients has the potential to reduce the morbidity and cost of unnecessary therapies in young breast cancer patients.

Follow-up tests to detect recurrent disease: patient's reassurance or medical need?

It is widely believed by both doctors and patients that regular follow-up with imaging is important for patients who have been treated for early breast cancer. In reality, current evidence does not support this. Randomised trials have shown no benefit for intensive versus routine follow-up and studies have also shown that follow-up by a general practitioner or nurse specialist is likely to be as effective as by a breast cancer specialist. Specifically there is no evidence that specialised imaging including PET/CT is of any benefit. Newer approaches including the assessment of circulating tumour cells and/or circulating tumour DNA may eventually prove advantageous, but currently must be considered experimental. In summary, current evidence suggests that there is no basis for intensive follow-up beyond standard regular clinical assessment and annual mammography following treatment of early breast cancer. There may be better models for follow-up than the traditional resource-intensive hospital outpatient visit, including nurse-led open access follow-up. Monitoring for long-term sequelae of treatment is becoming as important as the detection of recurrence in an era where long-term survival is increasingly common.

Additional value of F-18 FDG PET/CT for initial staging in breast cancer with clinically negative axillary nodes

The aim of this study was to evaluate the clinical impact of the preoperative ¹⁸F-FDG PET/CT in the initial workup of breast cancer with clinically negative axillary nodes. Whether the status of the clinical axillary nodal involvement can be considered a parameter for making a decision to omit the preoperative ¹⁸F-FDG PET/CT in the situation reported herein was also determined. A total of 178 patients who had newly diagnosed breast cancer and for whom the conventional diagnostic modalities showed no sign of axillary node metastasis were retrospectively enrolled in this study. All the patients underwent preoperative ¹⁸F-FDG PET/CT. The images and histologic results that were obtained were analyzed. ¹⁸F-FDG PET/CT detected primary lesions in 156 of the 178 patients, with an overall sensitivity of 87.6 %, and false negative results were obtained for 22 patients (12.4 %). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of ¹⁸F-FDG PET/CT in the detection of axillary nodes were 20.8, 86.9, 37.0, 74.8, and 69.1 %, respectively. Extra-axillary node metastasis was identified in two patients (1.1 %) who had internal mammary nodes. There was no distant metastasis, but coexisting primary tumor was detected in five patients (2.8 %). In total, the therapeutic plan was changed based on ¹⁸F-FDG PET/CT in seven (3.9 %) of the 178 patients, but considering only the cases confined to breast cancer, the change occurred in only two patients (1.1 %). ¹⁸F-FDG PET/CT almost did not affect the initial staging and treatment plan in breast cancer with clinically negative axillary node. If the axillary node is clinically negative in the preoperative workup of breast cancer, then ¹⁸F-FDG PET/CT can be omitted.

Role of positron emission tomography/computed tomography in breast cancer

Although positron emission tomography (PET) imaging may not be used in the diagnosis of breast cancer, the use of PET/computed tomography is imperative in all aspects of breast cancer staging, treatment, and follow-up. PET will continue to be relevant in personalized medicine because accurate tumor status will be even more critical during and after the transition from a generic metabolic agent to receptor imaging. Positron emission mammography is an imaging proposition that may have benefits in lower doses, but its use is limited without new radiopharmaceuticals.