Axillary lymph node staging in breast cancer by 2-fluoro-2-deoxy-D-glucose-positron emission tomography: clinical evaluation and alternative management

Utility of positron emission tomography for determination of axillary metastasis of breast cancer

Objectives

The involvement of axillary lymph nodes plays a key role in breast cancer staging. Positron emission tomography is a promising modality for detecting axillary lymph node metastasis. In addition, nomograms are used to predict the status of axillary lymph nodes. In this study, the role of positron emission tomography in determining axillary metastasis and its correlation with the nomogram was evaluated.

Material and Methods

The axillary maximum standard uptake value (SUVmax) values of the patients in the preoperative period, the features in the perioperative and postoperative specimen and Memorial Sloan Kettering Cancer Center nomogram data were evaluated.

Results

As axillary SUVmax detected by Positron emission tomography in the preoperative period increased, so did the likelihood of lymph node involvement. Axillary SUVmax value were compared with Memorial Sloan Kettering Cancer Center nomogram data but no correlation was found. Age, lymph node number, histopathology results, mass diameter, presence or absence of lymphovascular invasion and/or perineural invasion, tumor type, estrogen receptor status, Ki67 and Cerb-B2 statuses were not correlated. However, axillary SUVmax was inversely correlated with grade and progesterone receptor status.

Conclusion

Results from positron emission tomography of axillary lymph nodes in breasts cancer patients showed that SUVmax was only inversely related to cancer grade and progesterone receptor status while not correlating with other accepted parameters for tumor assessment. Thus there is insufficient reliability for the use of axillary SUVmax alone for accurate assessment of tumor characteristics at present.

Prediction of pathological response using 18F FDG PET/CT derived metabolic parameters in locally advanced breast cancer patients

AIM OF WORK

This study aims to assess the value of flurodeoxyglucose (FDG)-PET derived metabolic parameters for prediction of pathologic response in LABC postneoadjuvant therapy.

METHODS

Totally 47 patients with LABC underwent initial and postneoadjuvant therapy PET scans. ΔSUVmax%, ΔTLG% and ΔMTV% were calculated. Post-therapy histopathologic therapeutic response was assessed.

RESULTS

In total 91.5% of patients had invasive duct carcinoma and the remaining (8.5%) had invasive lobular carcinoma. Postneoadjuvant PET/CT was able to detect 91.7% of patients with pathologically proven complete response in primary tumor, 69% of those with Pathologic partial response and 88.3% of those with pathological no response (P value <0.001). However, 40 out of the 47 patients had regional nodal metastases. PET/CT was able to predict 57.1% of the patients with pathologically nonresponding nodal deposits and 93.9% of those revealed pathologic therapeutic effect (P value <0.001). Receiver operating characteristic curve (ROC) curve marked Δ1ry SUVmax of 26.25% (P value 0.003), Δ1ry TLG of 48.5% (P value 0.018). PET and pathological response correlated well with ΔSUVmax%, and Δ1ry TLG% correlated well with PET, pathologic response and expression of HER II receptors (P value <0.001, 0.003 and 0.037 respectively). ROC curve marked ΔLN SUVmax% of 80.15% (P value 0.012), ΔLN TLG% of 86.6% (P value 0.002), whereas for ΔLN MTV% cut off point of 55% (P value 0.003). ΔSUVmax%, ΔTLG % and ΔMTV% for regional nodal metastases, were significantly correlated with PET (P values <0.001, <0.001 and 0.003, respectively) and pathologic (P values 0.018, 0.001 and 0.002, respectively) response.

CONCLUSION

FDG-PET is a useful tool for monitoring the neoadjuvant therapeutic effect for primary and regional nodes in patients with LABC.

Circular RNAs Regulate Glucose Metabolism in Cancer Cells

Circular RNAs (circRNAs) were originally thought to result from RNA splicing errors. However, it has been shown that circRNAs can regulate cancer onset and progression in various ways. They can regulate cancer cell proliferation, differentiation, invasion, and metastasis. Moreover, they modulate glucose metabolism in cancer cells through different mechanisms such as directly regulating glycolytic enzymes and glucose transporter (GLUT) or indirectly regulating signal transduction pathways. In this review, we elucidate on the role of circRNAs in regulating glucose metabolism in cancer cells, which partly explains the pathogenesis of malignant tumors, and provides new therapeutic targets or new diagnostic and prognostic markers for human cancers.

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.

Comparison of [99mTc]3PRGD2 Imaging and [18F]FDG PET/CT in Breast Cancer and Expression of Integrin αvβ3 in Breast Cancer Vascular Endothelial Cells

PURPOSE

This study aimed to investigate the value of ^99mtechnetium-three polyethylene glycol spacers-arginine-glycine-aspartic acid ([^99mTc]3PRGD₂) imaging in diagnosis and staging of breast cancer compared with 2-deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]FDG) imaging, and to explore the expression of integrin α_vβ₃ in tumor vascular endothelial cells.

PROCEDURES

Forty-two women with suspected breast cancer underwent both [^99mTc]3PRGD₂ imaging and [¹⁸F]FDG imaging. Visual analysis was used to assess primary breast lesion, axillary lymph node, and distant metastasis. The tumor-blood (T/B) ratios from [^99mTc]3PRGD₂ imaging and the maximum standardized uptake value (SUVmax) from [¹⁸F]FDG imaging were analyzed for breast lesions. Integrin α_vβ₃ was analyzed through immunohistochemistry.

RESULTS

Forty-five breast lesions were found (malignant, n = 38; benign, n = 7). The sensitivity, specificity, and accuracy of [^99mTc]3PRGD₂ and [¹⁸F]FDG imaging in visual analysis for the breast lesion were 97.4, 87.5, and 95.6 % and 97.4, 71.4, and 93.3 %, respectively (P > 0.05). For semi-quantitative analysis, no significant difference of the area under the curves (AUC) was found in the imaging using the two radiopharmaceuticals (0.880 and 0.955; Z = 0.88, P > 0.05). The sensitivity, specificity, and accuracy for axillary lymph node metastasis with [^99mTc]3PRGD₂ and [¹⁸F]FDG were 78.05, 99.36, and 94.92 % and 85.37, 98.72, and 95.64 %, respectively (P > 0.05). Nine patients with distant metastases were all detected with the two radiopharmaceuticals. The expression of integrin α_vβ₃ was correlated with [^99mTc]3PRGD₂ uptake (r = 0.582, P = 0.001), which were significantly higher in the HER2-positive and stage III-IV patients (P < 0.05).

CONCLUSIONS

The prospective study demonstrated that [^99mTc]3PRGD₂ imaging seems to be valuable for diagnosis of breast cancer and its staging. It may be less sensitive for detecting small lymph node metastatic lesions when compared with [¹⁸F]FDG imaging. Integrin α_vβ₃ in tumor microvessels was associated with the breast cancer subtype and its staging.

Non-coding RNAs in the reprogramming of glucose metabolism in cancer

Proliferating cancer cells reprogram their metabolic circuitry to thrive in an environment deficient in nutrients and oxygen. Cancer cells exhibit a higher rate of glucose metabolism than normal somatic cells, which is achieved by switching from oxidative phosphorylation to aerobic glycolysis to meet the energy and metabolites demands of tumour progression. This phenomenon, which is known as the Warburg effect, has generated renewed interest in the process of glucose metabolism reprogramming in cancer cells. Several regulatory pathways along with glycolytic enzymes are responsible for the emergence of glycolytic dependence. Non-coding (nc)RNAs are a class of functional RNA molecules that are not translated into proteins but regulate target gene expression. NcRNAs have been shown to be involved in various biological processes, including glucose metabolism. In this review, we describe the regulatory role of ncRNAs-specifically, microRNAs and long ncRNAs-in the glycolytic switch and propose that ncRNA-based therapeutics can be used to inhibit the process of glucose metabolism reprogramming in cancer cells.

Automatic concentration and reformulation of PET tracers via microfluidic membrane distillation

Short-lived radiolabeled tracers for positron emission tomography (PET) must be rapidly synthesized, purified, and formulated into injectable solution just prior to imaging. Current radiosynthesizers are generally designed for clinical use, and the HPLC purification and SPE formulation processes often result in a final volume that is too large for preclinical and emerging in vitro applications. Conventional technologies and techniques for reducing this volume tend to be slow, resulting in radioactive decay of the product, and often require manual handling of the radioactive materials. We present a fully-automated microfluidic system based on sweeping gas membrane distillation to rapidly perform the concentration and formulation process. After detailed characterization of the system, we demonstrate fast and efficient concentration and formulation of several PET tracers, evaluate residual solvent content to establish the safety of the formulated tracers for injection, and show that the formulated tracer can be used for in vivo imaging.

Is sentinel lymph node biopsy a viable alternative to complete axillary dissection following neoadjuvant chemotherapy in women with node-positive breast cancer at diagnosis? An updated meta-analysis involving 3,398 patients

BACKGROUND

The use of sentinel lymph node biopsy (SLNB) following neoadjuvant chemotherapy (NAC) in patients presenting with clinically positive lymph nodes remains controversial.

METHODS

A computer-aided search of the literature regarding SLNB in clinically node-positive breast cancer treated with NAC was carried out to identify the false negative rate (FNR), sentinel lymph node identification rate (IR), and axillary pathological complete response (pCR).

RESULTS

Nineteen articles were used in the analysis yielding 3,398 patients. The pooled estimate of the FNR was 13% and that of the IR was 91%. The adjusted pCR rate was 47%. A trend toward significance was observed with only clinical stage N1 (cN1) disease whereby clinical stage N1 was associated with an increased pCR rate when compared to N2 or N3 disease (P = .06).

CONCLUSIONS

SLNB after NAC in biopsy-proven node-positive patients results in reasonably acceptable FNR and IR, making it a valid alternative management strategy to axillary dissection. More refined patient selection and optimal techniques can improve the FNR and IR in this patient population.

Postmastectomy radiation therapy after neoadjuvant chemotherapy: review and interpretation of available data

Postmastectomy radiotherapy (PMRT) has been shown to decrease locoregional recurrence and improve overall survival in patients with tumors greater than 5 cm or positive nodes. Because neoadjuvant chemotherapy (NAC) can cause significant downstaging, the indications for PMRT in the setting of NAC remain controversial and thus careful consideration of clinical stage at presentation, pathologic response to NAC, and other clinical characteristics, such as grade and biomarker status is required. The current review synthesizes both prospective and retrospective data to provide evidence for recommending PMRT after NAC for patients presenting with cT3-4 disease, cN2-3 disease, and residual nodal disease, as well as rationale for omitting PMRT in patients with cT1-2N0-1 disease who achieve a pathologic complete response. Other scenarios, including nodal complete response in the presence of other risk factors, are also explored. The topics of pre-NAC clinical staging and pathologic axillary nodal staging are reviewed, and radiation portal design is briefly discussed.

Sentinel node biopsy in breast cancer revisited

The axilla has long been a focus of clinicians' attention in the management of breast cancer. The approach to the axilla has undergone dramatic changes over the last century, from radical and extended radical excisions, through the introduction of sentinel node biopsy for node negative patients to the current situation where selective management of those with nodal involvement is being introduced. The introduction of lymphatic mapping and sentinel node biopsy in the 1990's has been key to the major changes that have occurred. In less than 20 years it has moved from a hypothesis to a situation where it is the default approach to almost all clinically node negative patients and is being considered in other situations where axillary clearance was previously considered standard. This article reviews the development and introduction of sentinel node biopsy, its current uncertainties and limitations, and possible future developments.

Different biological and prognostic breast cancer populations identified by FDG-PET in sentinel node-positive patients: results and clinical implications after eight-years follow-up

BACKGROUND

Sentinel node (SN) biopsy is the standard method to evaluate axillary node involvement in breast cancer (BC). Positron emission tomography with 2-(fluorine-18)-fluoro-2-deoxy-D-glucose (FDG-PET) provides a non-invasive tool to evaluate regional nodes in BC in a metabolic-dependent, biomolecular-related way. In 1999, we initiated a prospective non-randomized study to compare these two methods and to test the hypothesis that FDG-PET results reflect biomolecular characteristics of the primary tumor, thereby yielding valuable prognostic information.

PATIENTS AND METHODS

A total of 145 cT1N0 BC patients, aged 24-70 years, underwent FDG-PET and lymphoscintigraphy before surgery. SN biopsy was followed in all cases by complete axillary dissection. Pathologic evaluation in tissue sections for involvement of the SN and other non-SN nodes served as the basis of the comparison between FDG-PET imaging and SN biopsy.

RESULTS

FDG-PET and SN biopsy sensitivity was 72.6% and 88.7%, respectively, and negative predictive values were 80.5% and 92.2%, respectively. A subgroup of more aggressive tumors (ER-GIII, Her2+) was found mainly in the FDG-PET true-positive (FDG-PET+) patients, whereas LuminalA, Mib1 low-rate BCs were significantly undetected (p = 0.009) in FDG-PET false-negative (FDG-PET-) patients. Kaplan-Meier survival estimates after a median follow-up of more than 8 years showed significantly worse overall survival for FDG-PET+ patients in node-positive (N+) patients (p = 0.035) as compared to N+/FDG-PET- patients, which overlapped with survival curves of N- and FDG-PET+ or - patients.

CONCLUSIONS

Our findings suggest that FDG-PET results reflect intrinsic biologic features of primary BC tumors and have prognostic value with respect to nodal metastases. FDG-PET false negative cases appear to identify less aggressive indolent metastases. The possibility to identify a subgroup of N+ BC patients with an outcome comparable with N- BC patients could reduce the surgical and adjuvant therapeutic intervention.

Diagnostic performance of 18F-FDG PET/CT, ultrasonography and MRI. Detection of axillary lymph node metastasis in breast cancer patients

The aim of this study was to evaluate the diagnostic abilities of 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography(PET/CT) compared with those of ultrasonography and magnetic resonance imaging (MRI) for axillary lymph node staging in breast cancer patients.

PATIENTS, METHODS

Preoperative 18F-FDG PET/non-contrast CT, ultrasonography and MRI were performed in 215 women with breast cancer. Axillary lymph node dissection was performed in all patients and the diagnostic performance of each modality was evaluated using histopathologic assessments as the reference standard. ROC curves were compared to evaluate the diagnostic ability of several imaging modalities (i. e., ultrasonography, MRI and 18F-FDG PET/CT).

RESULTS

In total, 132 patients (61.4%) had axillary lymph node metastasis. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for the detection of axillary lymph node metastasis were 72.3%, 77.3%, 66.7%, 81.6%, 75.3% for ultrasonography, 67.5%, 78.0%, 65.9%, 79.2%, 74.0% for MRI, and 62.7%, 88.6%, 77.6%, 79.1%, 78.6% for 18F-FDG PET/CT, respectively. There was no significant difference in diagnostic ability among the imaging modalities (i.e., ultrasonography, MRI and 18F-FDG PET/CT). The diagnostic ability of 18F-FDG PET/CT was significantly improved by combination with MRI (p = 0.0002) or ultrasonography (p < 0.0001). The combination of 18F-FDG PET/CT with ultrasonography had a similar diagnostic ability to that of all three modalities combined (18F-FDG PET/CT+ultrasonography+MRI, p = 0.05).

CONCLUSION

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

Stage-to-stage comparison of neoadjuvant chemotherapy versus adjuvant chemotherapy in pathological lymph node positive breast cancer patients

OBJECTIVE

The purpose of this study was to investigate the prognostic implications of post-neoadjuvant chemotherapy on the survival outcomes of breast cancer patients with persistent positive axillary lymph nodes by performing a stage-to-stage comparison between neoadjuvant chemotherapy and initial surgery.

METHODS

Retrospective analysis was performed on 813 breast cancer patients with positive axillary lymph node after surgery, who were treated between 2001 and 2006. Of these, 269 patients received neoadjuvant chemotherapy, and 544 patients were treated with surgery followed by adjuvant chemotherapy. The median follow-up time was 5.9 years.

RESULTS

The 5-year disease-free survival rates for patients in the neoadjuvant chemotherapy and adjuvant chemotherapy groups were 73 and 88%, respectively (P<0.001). The 5- and 9-year disease-free survival rates for ypStage II (82 and 76%) were significantly worse than those for pStage II (93 and 80%, P=0.002), and the rates for ypStage III (64 and 50%) were worse than those for pStage III (74 and 66%, P=0.04). The disease-free survival of ypStage II was similar to that of pStage III (P=0.16). Similar results were seen when comparing distant metastasis-free survival rates. Using multivariate analyses, grade, age, hormonal receptor status, final pathological stage and neoadjuvant chemotherapy itself were found to be independent negative prognostic factors for disease-free survival.

CONCLUSIONS

Stage-to-stage comparison of pathologically node-positive patients revealed that the survival outcome at each ypStage after neoadjuvant chemotherapy was worse than that for the comparable pStage. These data may help to formulate more accurate prognoses for patients with residual positive nodes after neoadjuvant chemotherapy.

Semiquantitative analysis of maximum standardized uptake values of regional lymph nodes in inflammatory breast cancer: is there a reliable threshold for differentiating benign from malignant?

RATIONALE AND OBJECTIVES

The aim of this study was to determine an optimum standardized uptake value (SUV) threshold for identifying regional nodal metastasis on 18F-fluorodeoxyglucose (FDG) positron emission tomographic (PET)/computed tomographic (CT) studies of patients with inflammatory breast cancer.

MATERIALS AND METHODS

A database search was performed of patients newly diagnosed with inflammatory breast cancer who underwent 18F-FDG PET/CT imaging at the time of diagnosis at a single institution between January 1, 2001, and September 30, 2009. Three radiologists blinded to the histopathology of the regional lymph nodes retrospectively analyzed all 18F-FDG PET/CT images by measuring the maximum SUV (SUVmax) in visually abnormal nodes. The accuracy of 18F-FDG PET/CT image interpretation was correlated with histopathology when available. Receiver-operating characteristic curve analysis was performed to assess the diagnostic performance of PET/CT imaging. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated using three different SUV cutoff values (2.0, 2.5, and 3.0).

RESULTS

A total of 888 regional nodal basins, including bilateral axillary, infraclavicular, internal mammary, and supraclavicular lymph nodes, were evaluated in 111 patients (mean age, 56 years). Of the 888 nodal basins, 625 (70%) were negative and 263 (30%) were positive for metastasis. Malignant lymph nodes had significantly higher SUVmax than benign lymph nodes (P < .0001). An SUVmax of 2.0 showed the highest overall sensitivity (89%) and specificity (99%) for the diagnosis of malignant disease.

CONCLUSIONS

SUVmax of regional lymph nodes on 18F-FDG PET/CT imaging may help differentiate benign and malignant lymph nodes in patients with inflammatory breast cancer. An SUV cutoff of 2 provided the best accuracy in identifying regional nodal metastasis in this patient population.

Prospective study of 2-[¹⁸F]fluorodeoxyglucose positron emission tomography in the assessment of regional nodal spread of disease in patients with breast cancer: an Ontario clinical oncology group study

PURPOSE

2-[(18)F]fluorodeoxyglucose (FDG) positron emission tomography (PET) is potentially useful in assessing lymph nodes and detecting distant metastases in women with primary breast cancer.

PATIENTS AND METHODS

Women diagnosed with operable breast cancer within 3 months underwent FDG-PET at one of five Ontario study centers followed by axillary lymph node assessment (ALNA) consisting of sentinel lymph node biopsy (SLNB) alone if sentinel lymph nodes (SLNs) were negative, SLNB with axillary lymph node dissection (ALND) if SLNB or PET was positive, or ALND alone if SLNs were not identified.

RESULTS

Between January 2005 and March 2007, 325 analyzable women entered this study. Sentinel nodes were found for 312 (96%) of 325 women and were positive for tumor in 90 (29%) of 312. ALND was positive in seven additional women. Using ALNA as the gold standard, sensitivity for PET was 23.7% (95% CI, 15.9% to 33.6%), specificity was 99.6% (95% CI, 97.2% to 99.9%), positive predictive value was 95.8% (95% CI, 76.9% to 99.8%), negative predictive value was 75.4% (95% CI, 70.1% to 80.1%), and prevalence was 29.8% (95% CI, 25.0% to 35.2%). Using logistic regression, tumor size was predictive for prevalence of tumor in the axilla and for PET sensitivity. PET scan was suspicious for distant metastases in 13 patients; three (0.9%) were confirmed as metastatic disease and 10 (3.0%) were false positive.

CONCLUSION

FDG-PET is not sufficiently sensitive to detect positive axillary lymph nodes, nor is it sufficiently specific to appropriately identify distant metastases. However, the very high positive predictive value (96%) suggests that PET when positive is indicative of disease in axillary nodes, which may influence surgical care.

High rate of solitary sentinel node metastases identification by fluorescence-guided lymphatic imaging in breast cancer

BACKGROUND

The lymph node status was shown to be an important prognostic factor for breast cancer, but controversial issues remain. There has been increased focus on optimizing the visualization of lymph nodes for an accurate and selective approach to axillary lymph nodes. Fluorescence-guided lymphatic imaging is a potential candidate for further research on remaining controversies.

METHODS

Forty-seven patients were subject to injection of indocyanine green for navigation to the SLN based on fluorescent dye retention detection. In two groups, patients either received intended axillary lymph node dissection (ALND) and sentinel lymph node biopsy (SLNB) for superstaging or isolated SLNB for minimal-invasive staging. The prospective study was designed to evaluate the technical feasibility with focus on solitary positive SLN.

RESULTS

Visualization of lymphatic vessels with bright fluorescence of the SLN was feasible in 46 of 47 patients. Eighteen of 19 nodal positive patients were correctly identified with a sensitivity of 94.7% in all patients after ALND. After immunohistochemistry, in 19 of 25 overall nodal positive patients (76%) the SLN was the only positive lymph node.

CONCLUSION

Fluorescence-guided imaging using fluorescence retention detection allows transcutaneous navigation with a high rate of solitary positive SLN identification as an alternative technique for further research.

[Non-invasive imaging modalities for preoperative axillary lymph node staging in patients with breast cancer]

In the last decade sentinel lymph node biopsy has become a well-established method for axillary lymph node staging in patients with breast cancer. Using preoperative imaging modalities it can be tested whether patients are suitable for sentinel node biopsy or if they should directly undergo an axillary dissection. The imaging modalities used must be mainly characterized by a high positive predictive value (PPV). For this question B-mode ultrasound is the best evaluated method and provides clear morphological signs for a high PPV (>90%) but the sensitivity barely exceeds 50%. It has not yet been proven whether other modalities such as duplex sonography, magnetic resonance imaging, computed tomography (CT) or scintigraphy might achieve a higher sensitivity while still maintaining a high PPV. There is only some evidence that positron emission tomography (PET) might achieve a higher sensitivity. This should be confirmed by further studies because PET or PET/CT will play an increasing role for an initial whole body staging in patients with breast cancer in the near future.

Positron emission tomography (PET) for assessment of axillary lymph node status in early breast cancer: A systematic review and meta-analysis

PURPOSE

Sentinel lymph node biopsy (SLNB) and axillary lymph node dissection (ALND) are used to assess axillary nodal status in breast cancer, but are invasive procedures associated with morbidity, including lymphoedema. This systematic review evaluates the diagnostic accuracy of positron emission tomography (PET), with or without computed tomography (CT), for assessment of axillary nodes in early breast cancer.

METHODS

Eleven databases including MEDLINE, EMBASE and the Cochrane Library, plus research registers and conference proceedings, were searched in April 2009. Study quality was assessed using the QUality Assessment of Diagnostic Accuracy Studies (QUADAS) checklist. Sensitivity and specificity were meta-analysed using a bivariate random effects approach.

RESULTS

Across 26 studies evaluating PET or PET/CT (n = 2591 patients), mean sensitivity was 63% (95% CI: 52-74%; range 20-100%) and mean specificity 94% (95% CI: 91-96%; range 75-100%). Across 7 studies of PET/CT (n = 862), mean sensitivity was 56% (95% CI: 44-67%) and mean specificity 96% (90-99%). Across 19 studies of PET-only (n = 1729), mean sensitivity was 66% (50-79%) and mean specificity 93% (89-96%). Mean sensitivity was 11% (5-22%) for micrometastases (≤2 mm; five studies; n = 63), and 57% (47-66%) for macrometastases (>2 mm; four studies; n = 111).

CONCLUSIONS

PET had lower sensitivity and specificity than SLNB. Therefore, replacing SLNB with PET would avoid the adverse effects of SLNB, but lead to more false negative patients at risk of recurrence and more false positive patients undergoing unnecessary ALND. The present evidence does not support the routine use of PET or PET-CT for the assessment of the clinically negative axilla.

Positron emission tomography for benign and malignant disease

Functional imaging using radiolabeled probes that specifically bind and accumulate in target tissues has improved the sensitivity and specificity of conventional imaging. Fluorodeoxyglucose (FDG)-positron emission tomography (PET) has shown improved diagnostic accuracy in differentiating benign from malignant lesions in the setting of solitary pulmonary nodules. FDG-PET has become useful in preoperative staging of patients with lung cancer, and is being tested with many other malignancies for its ability to change patient management. This article provides an overview of the current status of FDG-PET and presents the challenges of moving toward routine use.

18F-FDG PET/CT imaging in oncology

Accurate diagnosis and staging are essential for the optimal management of cancer patients. Positron emission tomography with 2-deoxy-2-[fluorine-18]fluoro-D-glucose integrated with computed tomography (18F-FDG PET/CT) has emerged as a powerful imaging tool for the detection of various cancers. The combined acquisition of PET and CT has synergistic advantages over PET or CT alone and minimizes their individual limitations. It is a valuable tool for staging and restaging of some tumors and has an important role in the detection of recurrence in asymptomatic patients with rising tumor marker levels and patients with negative or equivocal findings on conventional imaging techniques. It also allows for monitoring response to therapy and permitting timely modification of therapeutic regimens. In about 27% of the patients, the course of management is changed. This review provides guidance for oncologists/radiotherapists and clinical and surgical specialists on the use of 18F-FDG PET/CT in oncology.

Locoregional recurrence of breast cancer in patients treated with breast conservation surgery and radiotherapy following neoadjuvant chemotherapy

PURPOSE

Breast conservation surgery (BCS) and radiotherapy (RT) following neoadjuvant chemotherapy (NCT) have been linked with high locoregional recurrence (LRR) rates and ipsilateral breast tumor recurrence (IBTR) rates. The purpose of this study was to analyze clinical outcomes in patients who exhibited LRR and IBTR after being treated by BCS and RT following NCT.

METHODS AND MATERIALS

In total, 251 breast cancer patients treated with BCS and RT following NCT between 2001 and 2006 were included. All patients had been shown to be clinically node-positive. Clinical stage at diagnosis (2003 AJCC) was II in 68% of patients and III in 32% of patients. Of those, 50%, 35%, and 15% of patients received anthracycline-based, taxane-based, and combined anthracycline-taxane NCT, respectively. All patients received RT.

RESULTS

During follow-up (median, 55 months), 26 (10%) patients had LRR, 19 of these patients had IBTR. Five-year actuarial rates of IBTR-free and LRR-free survival were 91% and 89%, respectively. In multivariate analyses, lack of hormone suppression therapy was found to increase both LRR and IBTR rates. Hazard ratios were 7.99 (p<0.0001) and 4.22 (p=0.004), respectively. Additionally, pathology stage N2 to N3 increased LRR rate (hazard ratio, 4.22; p=0.004), and clinical AJCC stage III IBTR rate (hazard ratio, 9.05; p=0.034). Achievement of pathological complete response and presence of multifocal tumors did not affect LRR or IBTR.

CONCLUSIONS

In patients with locally advanced disease, who were clinically node-positive at presentation, BCS after NCT resulted in acceptably low rates of IBTR and LRR. Mastectomy should be considered as an option in patients who present with clinical stage III tumors or who are not treated with adjuvant hormone suppression therapy, because they exhibit high IBTR rates after NCT and BCS.

The value of dual-time-point 18F-FDG PET/CT for identifying axillary lymph node metastasis in breast cancer patients

OBJECTIVE

The sensitivity of 18-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET) for detecting axillary lymph node (ALN) metastases in breast cancer is reported to be low. Several studies have shown, however, that dual-time-point (18)F-FDG PET imaging provides improved accuracy in the diagnosis of certain primary tumours when compared with single-scan imaging. The purpose of this study was to assess whether the use of dual-time-point (18)F-FDG PET/CT scans could improve the diagnostic accuracy of ALN metastasis in breast cancer.

METHOD

The study included 171 breast cancer patients who underwent pre-operative (18)F-FDG PET/CT scans at 2 time-points, the first at 1 h after radiotracer injection and the second 3 h after injection. Where (18)F-FDG uptake was in the ALN perceptibly increased, the maximum standardised uptake values for both time-points (SUVmax1 and SUVmax2) and the retention index (RI) were calculated. Correlation between the PET/CT results and post-operative histological results was assessed.

RESULTS

The performance of 1 h and 3 h PET/CT scans was equal, with sensitivity 60.3% and specificity 84.7%, in detecting ALN metastasis. Out of 171 patients, 60 had ALNs with increased (18)F-FDG uptake on 1 h or 3 h images. There was no significant difference in RI between the metastatic ALN-positive group and the node-negative group. The area under the receiver operating characteristic (ROC) curve for SUVmax1 was 0.90 (p<0.001) and 0.87 for SUVmax2 (p<0.001).

CONCLUSION

Dual time-point imaging did not improve the overall performance of (18)F-FDG PET/CT in detecting ALN metastasis in breast cancer patients.

The use of FDG-PET in assessing axillary lymph node status in breast cancer: a systematic review and meta-analysis of the literature

Axillary lymph node status is the most powerful prognostic indicator in patients with breast cancer. FDG-PET has been suggested as a non-invasive method of staging the axilla. The aim of this study was to review and aggregate all studies that measured the performance of FDG-PET in patients with breast cancer, using surgically obtained axillary histology as a reference, in a meta-analysis. A systematic review of the literature was performed and data extracted from all eligible studies. These were then analysed using meta-analysis software and summary receiver operating characteristic (SROC) curves were plotted for the aggregate data. The data was then tested to determine which parameters impacted on the sensitivity and specificity of the studies. Sensitivities ranging from 20 to 100% and specificities ranging from 65 to 100% have been reported. An aggregated ROC analysis found an area under the curve of 0.95 (95% CI 0.91-0.97) and a Q* value of 0.89 (95% CI 0.85-0.92) in a total of 25 studies involving 2,460 patients. The AUC and Q* values indicated little difference between the compared study characteristics. The performance of the technique currently remains below, which is required to replace assessment of axillary node status by surgical biopsy and histological assessment. However, sensitivity and specificity are high and FDG-PET may have a role to play under particular circumstances. Moreover, the additional benefit of an assessment of distal metastatic spread provided by FDG-PET requires further investigation.

Feasibility of FDG PET/CT to monitor the response of axillary lymph node metastases to neoadjuvant chemotherapy in breast cancer patients

PURPOSE

The aim of this study was to assess the accuracy of (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT to visualize lymph node metastases before the start of neoadjuvant chemotherapy and to determine how often the visualization is sufficiently prominent to allow monitoring of the axillary response.

METHODS

Thirty-eight patients with invasive breast cancer of >3 cm and/or lymph node metastasis underwent FDG PET/CT before neoadjuvant chemotherapy. The results of the FDG PET/CT were compared with those from ultrasonography with fine-needle aspiration (FNA) cytology or sentinel node biopsy. Patients suitable for response monitoring of the axilla were defined as having either a maximum standardized uptake value (SUV(max)) >or= 2.5 or a tumour to background ratio >or=5 in the most intense lymph node.

RESULTS

The sensitivity and specificity of FDG PET/CT in detecting axillary involvement were 97 and 100%, respectively. No difference existed between the SUV(max) of the primary tumour and that from the related most intense lymph node metastasis. Moreover, the mean tumour to background ratio was 90% higher in the lymph nodes compared to the primary tumour (p = 0.006). Ninety-three per cent of the patients had sufficient uptake in the lymph nodes to qualify for subsequent response monitoring of the axilla. A considerable distinction in metabolic activity was observed between the different subtypes of breast cancer. The mean SUV(max) in lymph node metastases of oestrogen receptor (ER)-positive, triple-negative and human epidermal growth factor receptor 2 (HER2)-positive tumours was 6.6, 11.6 and 6.6, respectively.

CONCLUSION

The high accuracy in visualizing lymph node metastases and the sufficiently high SUV(max) and tumour to background ratio at baseline suggest that it is feasible to monitor the axillary response with FDG PET/CT, especially in triple-negative tumours.

The Role of Lymphatic Mapping and Sentinel Lymph Node Biopsy in the Staging of Breast Cancer

The widespread application of sentinel lymph node biopsy in the evaluation of patients with breast cancer has allowed for the more limited, selective treatment of regional lymph nodes and decreased the number of complete regional dissections performed in patients without nodal metastases. Surgical excision and pathologic evaluation of nodes for metastases allow for reliable staging and prediction of additional lymph node metastases. Sentinel lymph node biopsy also enables a meticulous histologic evaluation of multiple sections augmented by immunohistochemical staining. The current role of sentinel lymph node biopsy in the staging of breast cancer and ongoing controversies relating to the procedure are discussed.

[The role of preoperative investigation with 18-FDG-PET/CT in primary operable breast cancer]

INTRODUCTION

The widespread use of PET/CT has a potential to change oncological diagnosis fundamentally. In our study we intended to clarify if preoperative PET/CT was able to assess axillary lymph node status, and the potential of these to modify preliminary treatment plans based on conventional diagnostic methods.

PATIENTS AND METHODS

We carried out 18-FDG PET/CT before elective surgery in 52 primary operable breast cancer patients between February 2008 and February 2009 at the DEOEC Clinical Department of Surgery. Total body imaging was performed in all cases; scans were evaluated by two specialists first visually, then semi-quantitatively based on body mass-corrected lesion suvmax values. The assessments were compared with axillary ultrasound and final histological diagnosis.

RESULTS

Two patients were excluded from the study due to failure to report for further treatment. Based on the results obtained from the remaining 50 patients, PET/CT showed a sensitivity of 80%, a specificity of 100%, positive and negative predictive values of 100% and 84.6% respectively for detecting axillary lymph node metastases. The same figures for axillary ultrasound, in respective order, were 30%, 81.8%, 60% and 56.2%. Prompted by the PET/CT results, we modified 9 patients' (18%) preliminary, conventional diagnosis-based treatment schemes.

CONCLUSIONS

In case of a positive axillary PET/CT, it is unnecessary to perform SNB--axillary block dissection is called for with no further deliberation. Preoperative PET/CT can facilitate patient selection as regards possible benefit from neoadjuvant therapy. Preoperative PET/CT has a potential to modify the original management plan in about 15 to 20%. In case of a negative PET/CT scan, further studies are necessary to be able to spare the axilla from surgical intervention with confidence.

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.

Integrated contrast-enhanced diagnostic whole-body PET/CT as a first-line restaging modality in patients with suspected metastatic recurrence of breast cancer

OBJECTIVE(S)

Only few information exist about the diagnostic accuracy of PET/CT for restaging patients with metastatic recurrence of breast carcinoma. Therefore, our study hypothesis was to perform diagnostic contrast enhanced CT (ce-CT) and FDG-PET in a one-step investigation, to prove sensitivity of each modality and to determine whether diagnostic PET/CT adds information over PET or contrast enhanced CT alone for restaging of patients with suspected recurrence of breast cancer.

METHODS

Fifty-two patients with suspected recurrence of breast cancer were included in our study. All of them were free of metastasis after the first line therapy. Indications for restaging were: Elevated tumor markers n=32, clinical deterioration n=16 and/or suspicious findings on other imaging studies n=48. Integrated PET/CT was performed using contrast-enhanced diagnostic CT for attenuation correction.

RESULTS

PET was correct in 44/52 patients (85%), ce-CT in 38/52 patients (73%) and PET/CT in 50/52 patients (96%). Sensitivity and specificity of lesion detection of PET, CT and PET/CT were 84%, 66% and 93%, and 100%, 92%, and 100%, respectively.

DISCUSSION

PET/CT can improve staging and alter therapeutic options in patients suspected to have breast cancer recurrence and distant metastatic disease, primarily by demonstrating local or distant nodal involvement occult at other imaging studies. The added value of FDG-PET/CT over other diagnostic modalities is mainly expressed by the fact that a noninvasive whole-body evaluation is possible in a single examination.

Regulation of the Warburg effect in early-passage breast cancer cells

Malignancy in cancer is associated with aerobic glycolysis (Warburg effect) evidenced by increased trapping of [(18)F]deoxyglucose (FdG) in patients imaged by positron emission tomography (PET). [(18)F]deoxyglucose uptake correlates with glucose transporter (GLUT-1) expression, which can be regulated by hypoxia-inducible factor 1 alpha (HIF-1alpha). We have previously reported in established breast lines that HIF-1alpha levels in the presence of oxygen leads to the Warburg effect. However, glycolysis and GLUT-1 can also be induced independent of HIF-1alpha by other factors, such as c-Myc and phosphorylated Akt (pAkt). This study investigates HIF-1alpha, c-Myc, pAkt, and aerobic glycolysis in low-passage breast cancer cells under the assumption that these represent the in vivo condition better than established lines. Similar to in vivo FdG-PET or primary breast cancers, rates of glycolysis were diverse, being higher in cells expressing both c-Myc and HIF-1alpha and lower in cell lines low or negative in both transcription factors. No correlations were observed between glycolytic rates and pAkt levels. Two of 12 cell lines formed xenografts in mice. Both were positive for HIF-1alpha and phosphorylated c-Myc, and only one was positive for pAkt. Glycolysis was affected by pharmacological regulation of c-Myc and HIF-1alpha. These findings suggest that c-Myc and/or HIF-1alpha activities are both involved in the regulation of glycolysis in breast cancers.

Breast cancer axillary lymph node metastasis detection by a high-resolution dedicated breast camera: a comparative study with SPECT and pinhole SPECT

We evaluated the usefulness of (99m)Tc-tetrofosmin planar scintigraphy acquired with a high-resolution (HR) dedicated breast camera in comparison with conventional single-photon emission computed tomography (SPECT) and pinhole-SPECT (P-SPECT) in breast cancer (BC) axillary lymph node metastasis detection in a consecutive series of 76 BC patients, 28 of whom had axillary lymph node metastases, including 9 positive at clinical examination. HR planar scintigraphy was true positive in only 7 patients with >3 palpable metastases (sensitivity: 25%), while SPECT was true positive in 23 of 28 cases (sensitivity: 82.1%) and P-SPECT in 25 of 28 (sensitivity: 89.3%). SPECT was false negative in 5 patients with nonpalpable <or= 3 nodes, including 2 with one micrometastatic node, while P-SPECT was false negative in the latter 2 cases, and in another of the cases, false negative at SPECT with one macrometastatic node. Neither planar nor SPECT had false-positive findings (specificity: 100%), while P-SPECT had two (specificity: 95.8%). P-SPECT presented the best resolution in showing the metastatic nodes and was the only procedure able to define the number of involved nodes, thus delivering important prognostic information. HR planar scintigraphy appears an ineffective diagnostic tool in BC axillary lymph node metastasis detection, only succeeding in identifying palpable and >3 metastatic nodes. SPECT should be preferred, significantly improving the sensitivity of planar scintigraphy, especially when using a pinhole collimator.

Is there a role for positron emission tomography in breast cancer staging?

Positron emission tomography (PET) with fluorine-18 fluorodeoxyglucose (FDG) is a radiotracer imaging method that is used in the care of patients with cancer. We conducted a nonsystematic review of the literature regarding the applicability of this technique in patients with breast cancer, encompassing the impact of FDG-PET on surgical management, including axillary node staging and sentinel lymph node biopsy; the use of FDG-PET in the evaluation of the primary tumor; the role of FDG-PET in the evaluation of distant metastases both at diagnosis and in the investigation of suspected recurrence; and the ability of FDG-PET to predict treatment response. FDG-PET is not sufficiently sensitive to replace histologic surgical staging of the axilla. Although FDG avidity of the primary tumor has been shown to be an unfavorable indicator, there is insufficient information to recommend its routine use for this indication. FDG-PET is more sensitive than conventional imaging in the detection of metastatic or recurrent disease, but the impact of increased sensitivity on patient care and outcome has not been demonstrated. The data regarding prediction of treatment response are insufficient to reach any conclusion. There are a number of prospective, adequately powered clinical trials currently in progress that should provide more definitive answers regarding the role, if any, of this technique in the management of patients with breast cancer.