Positron emission tomography in the staging and management of breast cancer

Development of a mechatronic guidance system for targeted ultrasound-guided biopsy under high-resolution positron emission mammography localization

PURPOSE

Image-guided needle biopsy of small, detectable lesions is crucial for early-stage diagnosis, treatment planning, and management of breast cancer. High-resolution positron emission mammography (PEM) is a dedicated functional imaging modality that can detect breast cancer independent of breast tissue density, but anatomical context and real-time needle visualization are not yet available to guide biopsy. We propose a mechatronic guidance system integrating an ultrasound (US)-guided core-needle biopsy (CNB) with high-resolution PEM localization to improve the spatial sampling of breast lesions. This paper presents the benchtop testing and phantom studies to evaluate the accuracy of the system and its constituent components for targeted PEM-US-guided biopsy under simulated high-resolution PEM localization.

METHODS

A mechatronic guidance system was developed to operate with the Radialis PEM system and a conventional US system. The system includes a user-operated guidance arm and end-effector biopsy device, integrating a US transducer and CNB gun, with its needle focused on a remote center of motion (RCM). Custom software modules were developed to track, display, and guide the end-effector biopsy device. Registration of the mechatronic guidance system to a simulated PEM detector plate was performed using a landmark-based method. Testing was performed with fiducials positioned in the peripheral and central regions of the simulated detector plate and registration error was quantified. Breast phantom experiments were performed under ideal detection and localization to evaluate for bias in the end-effector biopsy device. The accuracy of the complete mechatronic guidance system to perform targeted breast biopsy was assessed using breast phantoms with simulated lesions. Three-dimensional positioning error was quantified, and principal component analysis assessed for directional trends in 3D space within 95% prediction intervals. Targeted breast biopsies with test phantoms were performed and an overall in-plane needle targeting error was quantified.

RESULTS

The mean registration errors were 0.63 mm (N = 44) and 0.73 mm (N = 72) in the peripheral and central regions of the simulated PEM detector plate, respectively. A 3D 95% prediction ellipsoid shows an error volume <2.0 mm in diameter, centered on the mean registration error. Under ideal detection and localization, targets <1.0 mm in diameter can be sampled with 95% confidence. The complete mechatronic guidance system was able to successfully spatially sample simulated breast lesions, 4 mm and 6 mm in diameter and height (N = 20) in known 3D positions in the PEM image coordinate space. The 3D positioning error was 0.85 mm (N = 20) with 0.64 mm in-plane and 0.44 mm cross-plane component errors. Targeted breast biopsies resulted in a mean in-plane needle targeting error of 1.08 mm (N = 15) allowing for targets 1.32 mm in radius to be sampled with 95% confidence.

CONCLUSIONS

We demonstrated the utility of our mechatronic guidance system for targeted breast biopsy under high-resolution PEM localization. Breast phantom studies showed the ability to accurately guide, position, and target breast lesions with the accuracy to spatially sample targets <3.0 mm in diameter with 95% confidence. Future work will integrate the developed system with the Radialis PEM system toward combined PEM-US-guided breast biopsy.

Giant phyllodes tumors of the breast: imaging findings with clinicopathological correlation in 14 cases

PURPOSE

To describe imaging features in giant phyllodes tumors (GPTs) with radiology-pathologic correlations.

MATERIALS AND METHODS

Surgically confirmed 14 GPTs of the breast were retrospectively reviewed with ultrasound, mammograms, computed tomography, magnetic resonance imaging, and positron emission tomography.

RESULTS

The most GPTs showed circumscribed and lobulated masses with cystic necrosis. Five cases of core needle biopsy results were benign other than GPTs.

CONCLUSION

Radiology-pathologic correlation in GPTs is essential, due to differences of pathologic results (5/14 in our study) between core biopsy and surgical pathology.

Wide-field imaging of fluorescent deoxy-glucose in ex vivo malignant and normal breast tissue

Rapid in situ determination of surgical resection margins during breast cancer surgery would reduce patient time under anesthesia. We present preliminary data supporting the use of a fluorescent glucose analog (2-NBDG) as an optical contrast agent to differentiate freshly excised breast tissue containing cancerous cells from normal breast tissue. Multi-spectral images of 14 breast cancer specimens acquired before and after incubation with 2-NBDG demonstrated increased fluorescent signal in all of the malignant tissue due to increased 2-NBDG consumption. We demonstrate that 2-NBDG has potential as an optical contrast agent to differentiate cancerous from non-cancerous tissue.

The Role of PET and PET/CT in the Surgical Management of Breast Cancer: A Review

The role of PET and PET/CT in the management of patients with breast cancer is in evolution. Recent investigations suggest dual time point imaging increases sensitivity of detection of smaller breast cancers even DCIS suggesting PET imaging may offer some value in patients where mammography is typically not particularly sensitive. PET/CT may have its greatest role in staging, especially for patients with locally advanced breast cancer and can even predict response to neoadjuvant therapy. PET/CT may be particularly useful in predicting the biology of higher risk triple-negative and HER-2/neupositive tumors. PET/CT will continue to play a major role in the management of patients with breast cancer.

Accuracy of clinical evaluation of locally advanced breast cancer in patients receiving neoadjuvant chemotherapy

BACKGROUND

Physical examination (PE), mammography (MG), breast magnetic resonance imaging (MRI), fluorodeoxyglucose positron emission tomography (PET), and pathologic evaluation are used to assess primary breast cancer. To the authors' knowledge, their accuracy has not been well studied in patients receiving neoadjuvant chemotherapy. Accuracies of each modality in tumor and lymph node assessment in patients with T3/T4 tumors receiving neoadjuvant chemotherapy were compared.

METHODS

Forty-five patients of a prospective clinical trial studying T3-T4M0 tumors were included. Patients received neoadjuvant chemotherapy: docetaxel/carboplatin with or without trastuzumab before and/or after surgery (depending on HER-2/neu status and randomization). Tumor measurements by PE, MG, and MRI and lymph node status by PE and PET were obtained before and after neoadjuvant chemotherapy. Concordance among different clinical measurements was assessed and compared with the tumor and lymph node staging by pathology. Spearman correlation (r) and root mean square error (RMSE) were used to measure the accuracy of measurements among all modalities and between modalities and pathologic tumor size.

RESULTS

Compared with the tumor size measured by PE, MRI was more accurate than MG at baseline (r=0.559, RMSE=35.4% vs r=0.046, RMSE=66.1%). After neoadjuvant chemotherapy, PE correlated better with pathology than MG or MRI (r=0.655, RMSE=88.6% vs r=0.146, RMSE=147.1% and r=0.364, RMSE=92.6%). Axillary lymph node assessment after neoadjuvant chemotherapy demonstrated high specificity but low sensitivity by PET and PE.

CONCLUSIONS

Findings suggested that MRI was a more accurate imaging study at baseline for T3/T4 tumor, and PE correlated best with pathology finding. PET and PE both correctly predicted positive axillary lymph nodes but not negative lymph nodes.

Positron emission tomography/computed tomography: the current technology and applications

Positron emission tomography (PET) and combined PET/CT provide powerful metabolic and anatomical information together in a single exam. This article reviews the fundamentals of PET physics, the state of the art and future directions in PET technology, and the current clinical applications of PET. The latter is quite diverse and includes oncology, cardiology, neurology, and infection and inflammation imaging, all with FDG as the tracer. Additionally, novel radiopharmeuticals are under development, many of which are target cellular processes that are more specific than glucose metabolism.

Multidisciplinary care for patients with breast cancer

The care of patients with breast cancer has become increasingly complex with advancements in diagnostic modalities, surgical approaches, and adjuvant treatments. A multidisciplinary approach to breast cancer care is essential to the successful integration of available therapies. This article addresses the key components of multidisciplinary breast cancer care, with a special emphasis on new and emerging approaches over the past 10 years in the fields of diagnostics, surgery, radiation, medical oncology, and plastic surgery.

Positron emission tomography-computed tomography in the detection of axillary lymph node metastasis in patients with early stage breast cancer

OBJECTIVE

The status of axillary lymph nodes (ALNs) is the most important prognostic factor in breast cancer. The purpose of this study was to evaluate the clinical usefulness of ALN involvement by means of positron emission tomography-computed tomography (PET-CT) compared with breast sonography and mammography in patients with early breast cancer.

METHODS

This study involved 108 breast cancer patients with non-palpable ALNs. All patients had PET-CT, breast sonography and mammography imaging before sentinel lymph node (SLN) biopsy. After SLN biopsy, all patients underwent complete ALN dissection. ALNs were evaluated by standard hematoxylin and eosin staining techniques. The findings of PET-CT, breast sonography and mammography imaging of 108 patients were compared with pathologic findings after surgery. Sensitivity, specificity and accuracy of individual diagnostic modalities were compared. Diagnostic accuracy was evaluated applying receiver operating characteristic (ROC) curve areas.

RESULTS

The sensitivity, specificity and accuracy of PET-CT imaging were 48.5%, 84% and 73.2%, respectively. The sensitivity, specificity and accuracy of breast sonography were 51.5%, 89.3% and 77.8%, respectively. The sensitivity, specificity and accuracy of mammography were 33.3%, 96% and 76.9%, respectively. For involvement of ALNs, PET-CT imaging, breast sonography and mammography had areas under the ROC curve of 0.662, 0.704 and 0.647, respectively.

CONCLUSIONS

Compared with the combination of breast sonography and mammography, PET-CT was less sensitive and had less accuracy in detecting ALN metastasis. Consequently, PET-CT is not a reliable non-invasive modality for assessing ALN involvement that can replace ALN dissection or SLN biopsy before decisions are made on appropriate systemic interventions.

Preoperative Staging of Large Primary Breast Cancer With [18F]Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Compared With Conventional Imaging Procedures

Purpose

To evaluate the utility of positron emission tomography (PET) and [18F]fluorodeoxyglucose in the initial staging of large primary breast tumors.

Patients and Methods

This prospective study was approved by the ethics committee, and all patients gave their informed consent before enrollment. Sixty consecutive patients with large (> 3 cm) primary breast cancer diagnosed by clinical examination and breast magnetic resonance imaging (MRI) were entered onto the study. The mean age was 57 ± 13 years. Chest computed tomography (CT), liver ultrasonography, bone scan, and PET/CT were performed in all patients. All findings were histologically confirmed, and/or at least 1 year of follow-up was required. Correlation between parameters was calculated using Pearson's correlation coefficient. P < .05 was considered statistically significant.

Results

Primary tumor was identified by both PET/CT and MRI in all patients. Multifocal and/or multicentric tumors were found in 19 patients by MRI. Axillary lymph node metastases were found in 20 of 52 patients. Extra-axillary metastatic lymph nodes were also found in three patients. One patient showed an infiltrated lymph node in the contralateral axilla. The sensitivity and specificity for PET/CT to detect axillary lymph nodes metastases were 70% and 100%, respectively. PET/CT diagnosed all extra-axillary lymph nodes. The overall sensitivity and specificity of PET/CT in detecting distant metastases were 100% and 98%, respectively; whereas the sensitivity and specificity of conventional imaging were 60% and 83%, respectively. PET led to a change in the initial staging in 42% of patients.

Conclusion

PET/CT underestimates locoregional lymph node staging in large primary breast cancer patients. PET/CT is a valuable tool to discard unsuspected extra-axillary lymph nodes and distant metastases.

Advances in metabolic imaging for surgical oncology

This review focuses on several aspects of molecular imaging. First, current positron emission tomography (PET)/CT scanner technology and several novel imaging techniques that are being developed are briefly discussed. Next, current clinical indications for (18)F FDG PET and PET/CT that are relevant to the surgical oncologist are discussed. Finally, advances in molecular imaging that may herald the next generation of PET radiotracers beyond (18)F FDG are reviewed.

PET CT imaging in patients undergoing sentinel node biopsy for melanoma

AIMS

Sentinel lymph node biopsy (SLNB) has been adopted in the surgical treatment of melanoma to reduce morbidity and enhance staging. Positron emission tomography with computerised tomography (PET/CT) has been utilised in the staging of patients with malignancy though the role of this imaging modality in early stage melanoma is unclear. This study examined the preoperative value of PET/CT in patients undergoing SLNB for malignant melanoma.

METHODS

Patients presenting with primary melanoma without evidence of either locoregional or systemic metastasis were considered candidates for SLNB. Selected patients underwent preoperative PET/CT followed by definitive surgical therapy including SLNB with regional lymphadenectomy, where indicated.

RESULTS

During a 12-month period 83 patients were identified as having undergone SLNB for melanoma, of which 37 (45%) had preoperative PET/CT. Mean melanoma thickness 1.9 mm and 2.4 mm (PET/CT vs. no PET/CT, p>0.05). 13 (15.6%) patients were found to have lymphatic metastasis at SLNB; nine of these patients underwent PET/CT, only two of these scans were suggestive of lymphatic metastasis (positive predictive value 24%, negative predictive value 76%). PET/CT revealed no unheralded metastatic disease but did identify a second occult malignancy in 4 (10.8%) patients undergoing therapy for melanoma.

CONCLUSIONS

The results of this study do not support the use of PET/CT in patients undergoing SLNB for melanoma. SLNB appears to be a more sensitive staging modality in the detection of lymphatic metastasis; however PET/CT may have a future role as a screening tool for malignancy.

Breast MRI and18F FDG PET/CT in the management of breast cancer

GOALS

18F FDG PET/CT is used for diagnosis, staging and establishing the response to therapy in various malignancies, including breast cancer (BC). Dedicated breast MRI (BMRI) is gaining a role in the management of BC patients (pts), demonstrating high sensitivity and specificity for detection of small lesions. We were therefore prompted to review our experience with PET and BMRI in BC.

METHODS

This is a retrospective study of 21 women with BC, 30-76 years old, who had BMRI and whole-body FDG PET/CT at our institution from Jun 2002 to May 2005. A total of 6 patients (group A) had BMRI and PET/CT in the preoperative period and 15 patients (group B) had BMRI and PET/CT after surgery. Reinterpretation of the imaging studies for accuracy and data analysis from medical records were performed.

RESULTS

For group A, BMRI identified breast lesions in 4 patients, while PET/CT was able to identify breast lesions in 5 patients. All these were proven to be malignancy on pathology examination. In group B, BMRI detected recurrent breast lesions in 8 patients, with 88.9% sensitivity and 83.3% specificity. In the same patient population, PET/CT was 33.3% sensitive and 91.7% specific. As a whole body examination, PET/CT revealed metastatic disease in 6 patients (100% sensitive and 90% specific). Overall, sensitivities and specificities for breast disease detection were 85.7% and 85.7% for BMRI, and 75% and 92.3% for 18F FDG PET/ CT.

CONCLUSIONS

As expected, BMRI is more sensitive than PET/CT in the detection of breast lesions. However, PET/CT as a whole-body examination changed the management of disease by detection of distant lesions in 6 of the 21 patients. Our study suggests that 18F FDG PET/CT and BMRI should be considered as complimentary imaging tools in the pre- and postoperative work-up of patients diagnosed with breast cancer.

A new predictive and prognostic marker (ATP bioluminescence and positron emission tomography) in vivo and in vitro for delivering adjuvant treatment plan to invasive breast tumor patients

The cell proliferation rate has been used to assess the biological aggressiveness and the metastatic potential of breast carcinoma. Different methods (flow cytometric S phase and proliferation associated antigens) have been used to assess the rate of proliferation previously. In this preliminary study, the cell proliferation rate of normal (N=45), benign (N=29) and invasive breast tumor tissue (N=70) has been quantified in vitro by ATP bioluminescence assay. Next, individual prognostic factor (tumor grades, lymph node involvement, estrogen and progesterone receptor and HER-2 status) has been correlated with the level of metabolic rate (ATP). The results showed that invasive tumor had the highest level of ATP bioluminescence compared with that of benign tumor (mean difference=1.97) and the normal breast tissue (mean difference=2.75). In addition, ATP level positively correlated with the number of axillary lymph node involvement (r(spearman)=0.433, P=0.021). These findings suggested that the measurement of ATP level may serve as a mean for the detection of cell proliferation and hence a surrogate marker for disease prognosis.

Breast imaging. Preoperative breast cancer staging: comparison of USPIO-enhanced MR imaging and 18F-fluorodeoxyglucose (FDC) positron emission tomography (PET) imaging for axillary lymph node staging--initial findings

Magnetic resonance (MR) imaging after ultra-small super paramagnetic iron oxide (USPIO) injection and 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) for preoperative axillary lymph node staging in patients with breast cancer were evaluated using histopathologic findings as the reference standard. USPIO-enhanced MR and FDG-PET were performed in ten patients with breast cancer who were scheduled for surgery and axillary node resection. T2-weighted fast spin echo, T1-weighted three-dimensional (3D) gradient echo, T2*-weighted gradient echo and gadolinium-enhanced T1-weighted 3D gradient echo with spectral fat saturation were evaluated. MR imaging before USPIO infusion was not performed. The results were correlated with FDG-PET (acquired with dedicated PET camera, visual analysis) and histological findings. The histopathologic axillary staging was negative for nodal malignancy in five patients and positive in the remaining five patients. There was one false positive finding for USPIO-enhanced MR and one false negative finding for FDG-PET. A sensitivity (true positive rate) of 100%, specificity (true negative rate) of 80%, positive predictive value of 80%, and negative predictive value of 100% were achieved for USPIO-enhanced MR and of 80%, 100%, 100%, 80% for FDG-PET, respectively. The most useful sequences in the detection of invaded lymph nodes were in the decreasing order: gadolinium-enhanced T1-weighted 3D gradient echo with fat saturation, T2*-weighted 2D gradient echo, T1-weighted 3D gradient echo and T2-weighted 2D spin echo. In our study, USPIO-enhanced T1 gradient echo after gadolinium injection and fat saturation emerged as a very useful sequence in the staging of lymph nodes. The combination of USPIO-enhanced MR and FDG-PET achieved 100% sensitivity, specificity, PPV and NPV. If these results are confirmed, the combination of USPIO MR with FDG-PET has the potential to identify the patient candidates for axillary dissection versus sentinel node lymphadenectomy.

Ductal Carcinomain-situ of the breast detected by [F-18] fluorodeoxyglucose positron emission tomography

A 48-year-old Japanese woman underwent [F-18] fluorodeoxyglucose positron emission tomography (FDG-PET) as part of her medical examination. A small hot spot was detected in her right breast. Quadrantectomy with sentinel lymph node (SN) biopsy using an endoscope was performed, and ductal carcinoma in-situ of the breast was diagnosed. The tumor size was 0.9 cm in its greatest diameter, and there were no cancer cells detected in the SN on frozen hematoxylin-eosin staining and cytokeratin immunohistochemical staining. We reported this rare case of ductal carcinoma in-situ detected by FDG-PET as past of a medical checkup.

Neoadjuvant chemotherapy in breast cancer: early response prediction with quantitative MR imaging and spectroscopy

A prospective study was undertaken in women undergoing neoadjuvant chemotherapy for locally advanced breast cancer in order to determine the ability of quantitative magnetic resonance imaging (MRI) and proton spectroscopy (MRS) to predict ultimate tumour response (percentage decrease in volume) or to detect early response. Magnetic resonance imaging and MRS were carried out before treatment and after the second of six treatment cycles. Pharmacokinetic parameters were derived from T₁-weighted dynamic contrast-enhanced MRI, water apparent diffusion coefficient (ADC) was measured, and tissue water : fat peak area ratios and water T₂ were measured using unsuppressed one-dimensional proton spectroscopic imaging (30 and 135 ms echo times). Pharmacokinetic parameters and ADC did not detect early response; however, early changes in water : fat ratios and water T₂ (after cycle two) demonstrated substantial prognostic efficacy. Larger decreases in water T₂ accurately predicted final volume response in 69% of cases (11/16) while maintaining 100% specificity and positive predictive value. Small/absent decreases in water : fat ratios accurately predicted final volume non-response in 50% of cases (3/6) while maintaining 100% sensitivity and negative predictive value. This level of accuracy might permit clinical application where early, accurate prediction of non-response would permit an early change to second-line treatment, thus sparing patients unnecessary toxicity, psychological morbidity and delay of initiation of effective treatment.

Pilot clinical trial of 18F-fluorodeoxyglucose positron-emission mammography in the surgical management of breast cancer

BACKGROUND

High-resolution positron-emission mammography (PEM) is a new device, which allows the imaging of breast tissue. A prospective study was performed to assess the accuracy of PEM in newly diagnosed breast cancer patients.

METHODS

In a prospective multicenter study, 44 women with confirmed breast cancers were imaged with a high-resolution PEM scanner (Naviscan PET Systems, Rockville, MD) with 18F-fluorodeoxyglucose. The images were blindly evaluated and were compared with final pathology.

RESULTS

The majority of the index lesions were seen on PEM (89%, 39/44). PEM detected 4 of 5 incidental breast cancers, 3 of which were not seen by any other imaging modalities. Of 19 patients undergoing breast-conserving surgery, PEM correctly predicted 6 of 8 (75%) patients with positive margins and 100% (11/11) with negative margins.

CONCLUSION

The current PEM device shows promise in detecting breast malignancies and may assist in the planning of adequate partial mastectomy procedures to better ensure negative margins.