Prospective multicenter study of axillary nodal staging by positron emission tomography in breast cancer: a report of the staging breast cancer with PET Study Group

The Impact of Hybrid PET-CT Scan on Overall Oncologic Management, with a Focus on Radiotherapy Planning: A Prospective, Blinded Study

Functional imaging using fluorodeoxyglucose positron-emission tomography (FDG-PET) has been increasing incorporated into radiotherapy planning in conjunction with computed tomography (CT). Hybrid FDG-PET/CT scanners allow these images to be obtained in very close temporal proximity without the need for repositioning patients, thereby minimizing imprecision when overlying these images. To prospectively examine the impact of hybrid PET/CT imaging on overall oncologic impact, with a focus on radiotherapy planning, we performed a prospective, blinded trial in 111 patients. Patients with lung cancer (n=38), head-and-neck squamous cell carcinoma (n=23), breast (n=8), cervix (n=15), esophageal (n=9), and lymphoma (n=18) underwent hybrid PET/CT imaging at the time of radiation therapy planning. A physician blinded to the PET dataset designed a treatment plan using all clinical information and the CT dataset. The treating physician subsequently designed a second treatment plan using the hybrid PET/CT dataset. The two treatment plans were compared to determine if a major alteration in overall oncologic management occured. In patients receiving potentially curative radiotherapy the concordance between CT-based and PET/CT-based GTVs was quantified using an index of conformality (CI). In 76/111 (68%) of patients, the PET/CT data resulted in a change in one or more of the following: GTV volume, regional/local extension, prescribed dose, or treatment modality selection. In 35 of these 76 cases (46%; 31.5% of the entire cohort) the change resulted in a major alteration in the oncologic management (dose, field design, or modality change). Thus, nearly a third of all cases had a major alteration in oncologic management as a result of the PET/CT data, and 29 of 105 patients (27.6%) who underwent potentially curative radiotherapy had major alterations in either dose or field design. Hybrid PET/CT imaging at the time of treatment planning may be highly informative and an economical manner in which to obtain PET imaging, with the dual goals of staging and treatment planning.

18F-FDG PET and PET/CT in the evaluation of cancer treatment response

Multimodality imaging, as represented by its greatest exponent, PET/CT, has a firm place in the evaluation of a patient presenting with cancer. With 18F-FDG, PET/CT is rapidly becoming the key investigative tool for the staging and assessment of cancer recurrence. In the last 5 y, PET/CT has also gained widespread acceptance as a key tool used to demonstrate early response to intervention and therapy. In this setting, a major clinical need is being addressed with 18F-FDG PET/CT, because of its inherent ability to demonstrate (before other markers of response) if disease modification has occurred. This review presents available evidence to this effect.

The predictive receiver operating characteristic curve for the joint assessment of the positive and negative predictive values

Binary test outcomes typically result from dichotomizing a continuous test variable, observable or latent. The effect of the threshold for test positivity on test sensitivity and specificity has been studied extensively in receiver operating characteristic (ROC) analysis. However, considerably less attention has been given to the study of the effect of the positivity threshold on the predictive value of a test. In this paper we present methods for the joint study of the positive (PPV) and negative predictive values (NPV) of diagnostic tests. We define the predictive receiver operating characteristic (PROC) curve that consists of all possible pairs of PPV and NPV as the threshold for test positivity varies. Unlike the simple trade-off between sensitivity and specificity exhibited in the ROC curve, the PROC curve displays what is often a complex interplay between PPV and NPV as the positivity threshold changes. We study the monotonicity and other geometric properties of the PROC curve and propose summary measures for the predictive performance of tests. We also formulate and discuss regression models for the estimation of the effects of covariates.

Utility of 18F-fluoro-deoxyglucose emission tomography/computed tomography fusion imaging (18F-FDG PET/CT) in combination with ultrasonography for axillary staging in primary breast cancer

Background

Accurate evaluation of axillary lymph node (ALN) involvement is mandatory before treatment of primary breast cancer. The aim of this study is to compare preoperative diagnostic accuracy between positron emission tomography/computed tomography with ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG PET/CT) and axillary ultrasonography (AUS) for detecting ALN metastasis in patients having operable breast cancer, and to assess the clinical management of axillary ¹⁸F-FDG PET/CT for therapeutic indication of sentinel node biopsy (SNB) and preoperative systemic chemotherapy (PSC).

Methods

One hundred eighty-three patients with primary operable breast cancer were recruited. All patients underwent ¹⁸F-FDG PET/CT and AUS followed by SNB and/or ALN dissection (ALND). Using ¹⁸F-FDG PET/CT, we studied both a visual assessment of ¹⁸F-FDG uptake and standardized uptake value (SUV) for axillary staging.

Results

In a visual assessment of ¹⁸F-FDG PET/CT, the diagnostic accuracy of ALN metastasis was 83% with 58% in sensitivity and 95% in specificity, and when cut-off point of SUV was set at 1.8, sensitivity, specificity, and accuracy were 36, 100, and 79%, respectively. On the other hand, the diagnostic accuracy of AUS was 85% with 54% in sensitivity and 99% in specificity. By the combination of ¹⁸F-FDG PET/CT and AUS to the axilla, the sensitivity, specificity, and accuracy were 64, 94, and 85%, respectively. If either ¹⁸F-FDG PET uptake or AUS was positive in allixa, the probability of axillary metastasis was high; 50% (6 of 12) in ¹⁸F-FDG PET uptake only, 80% (4 of 5) in AUS positive only, and 100% (28 of 28) in dual positive. By the combination of AUS and ¹⁸F-FDG PET/CT, candidates of SNB were more appropriately selected. The axillary ¹⁸F-FDG uptake was correlated with the maximum size and nuclear grade of metastatic foci (p = 0.006 and p = 0.03).

Conclusion

The diagnostic accuracy of ¹⁸F-FDG PET/CT was shown to be nearly equal to ultrasound, and considering their limited sensitivities, the high radiation exposure by ¹⁸F-FDG PET/CT and also costs of the examination, it is likely that AUS will be more cost-effective in detecting massive axillary tumor burden. However, when we cannot judge the axillary staging using AUS alone, metabolic approach of ¹⁸F-FDG PET/CT for axillary staging would enable us a much more confident diagnosis.

Evolving role of imaging modalities in inflammatory breast cancer

Imaging plays several key roles in the diagnosis and assessment of inflammatory breast cancer (IBC). These include characterization of the known tumor, delineation of locoregional disease in the ipsilateral and contralateral breast and regional lymph node basins, diagnosis of distant metastases, and evaluation of treatment response. We review the role of conventional imaging modalities, including mammography and sonography. We also discuss the potential of using evolving imaging modalities such as magnetic resonance imaging (MRI), positron emission tomography with computed tomography (PET/CT), and more advanced or emerging imaging techniques in the assessment of IBC.

FDG PET, PET/CT, and breast cancer imaging

Currently, the clinical role of positron emission tomography (PET) and PET/computed tomography (CT) in patients with breast cancer is to provide additional information in select scenarios in which results of conventional imaging are indeterminate or of limited utility. There is currently no clinical role for fluorodeoxyglucose (FDG) PET in detection of breast cancer or evaluation of axillary lymph nodes, but these are areas of active research. FDG PET is complementary to conventional staging procedures and should not be a replacement for either bone scintigraphy or diagnostic CT. FDG PET and PET/CT have been shown to be particularly useful in the restaging of breast cancer, in evaluation of response to therapy, and as a problem-solving method when results of conventional imaging are equivocal. In these situations, FDG PET often demonstrates locoregional or unsuspected distant disease that affects management. PET has demonstrated a particular capability for evaluation of chemotherapy response in both patients with locally advanced breast carcinoma and those with metastatic disease.

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.

Standardized Uptake Values for Breast Carcinomas Assessed by Fluorodeoxyglucose-Positron Emission Tomography Correlate with Prognostic Factors

Several studies have revealed the diagnostic value of fluorodeoxyglucose-positron emission tomography for breast carcinomas. However, breast carcinomas display considerable variation in 18F-labeled 2-fluoro-2-deoxy-D-glucose uptake, and few papers have reported the clinical utility of the standardized uptake values (SUV). The purpose of this study is to investigate the relationship between SUV assessed by positron emission tomography (PET) and the clinicopathological characteristics of breast carcinoma. We reviewed 52 breast carcinomas of 45 patients presented at our department between January 2004 and July 2005. We compared the histopathological findings of the breast carcinomas with the preoperative SUV. Of the 52 breast carcinomas, 49 (94%) were detected by preoperative PET. A positive correlation was found between the SUV and tumor size ( P < 0.01), histological grade ( P < 0.01), the expression of the estrogen receptor ( P < 0.001), progesterone receptor ( P < 0.01), and p53 ( P < 0.01). The number of metastatic axillary lymph nodes (r = 0.73; P < 0.0001) and the MIB-1 labeling rates (r = 0.5; P < 0.01) correlated with the SUV of the breast carcinomas. No relationship existed between the SUV and the following: histological tumor types ( P = 0.07), human epidermal growth factor receptor-2 status ( P = 0.10), and the presence of metastatic lymph nodes ( P = 0.10). The SUV of the breast carcinomas correlate with several histopathological and immunohistochemical prognostic factors. We can obtain information on the degree of malignancy of the carcinoma and prognostic factors by preoperative PET examination.

PET/CT in oncology: for which tumours is it the reference standard?

Positron emission tomography (PET)/computed tomography (CT) has a growing role in the imaging of many cancers. As our experience has grown over the past number of years so has our understanding for which cancers it is particularly useful. The value of PET/CT at each stage of the cancer journey is different for each cancer. This review attempts to tease out the role of PET/CT in the common cancers with particular emphasis on where it is the imaging investigation of choice.

Preoperative Identification of the Sentinel Lymph Node in Breast Cancer

BACKGROUND

Preoperative diagnosis of sentinel lymph node (SLN) metastasis would justify a single axillary operation. We hypothesized that ultrasound-guided core needle biopsy (USGCNB) of a morphologically normal or abnormal lymph node in the anatomic position of the SLN would accomplish this goal.

METHODS

A total of 179 clinically N0 breast cancer patients underwent high-resolution lower axillary ultrasound (US) evaluation with core needle biopsy and microclip placement of a node when feasible. SLN biopsy was performed in 131 patients and the node X-rayed when appropriate. The node was removed surgically, and the one identified and analyzed preoperatively was compared with it clinically, radiologically and/or pathologically.

RESULTS

A node was seen on US in 145 (81%) of 179 patients, and a core needle biopsy was performed in 121 patients. A total of 3.5 +/- 1.38 (mean +/- SD) core samples were obtained per node. Of those node biopsy samples, 55 (45.5%) had metastases. Metastasis size was 14.9 +/- 10.1 mm. Metastases were found in 9 (13.6%) of 66 patients in whom the needle core was negative; in these falsely negative biopsy samples, the node metastases were 8.73 +/- 6.24 mm (P = .120). Eight (33.3%) of 24 nodes that did not undergo biopsy had metastases. Seven (20.6%) of 34 of those not seen on US had SLN metastases. In 47 (78.3%) of 60 patients, the node that underwent core needle biopsy was the SLN found by the surgeon during surgery (P < .001).

CONCLUSIONS

Preoperative identification, core needle biopsy, and documentation of metastasis in the first SLN in breast cancer was achieved by focused lower ipsilateral axillary US. Knowledge of the lymph node status might change the patient's planned surgery.

A randomized phase-III trial of docetaxel/capecitabine versus doxorubicin/cyclophosphamide as primary chemotherapy for patients with stage II/III breast cancer

We aimed to determine the efficacies of a non-anthracycline-containing regimen, docetaxel/capecitabine (TX), in comparison with an anthracycline-containing regimen, doxorubicin/cyclophosphamide (AC), as primary chemotherapy for node-positive early stage breast cancer. In this phase-III single center randomized study, we randomized 209 women with axillary node positive, stage II/III breast cancer to receive four cycles of either TX or AC followed by surgery and cross-over to the other treatment as an adjuvant therapy. The primary endpoint was tumor pathologic complete response (pCR). Clinical response rates, toxicity profiles, disease free survival (DFS), and overall survival were secondary objectives. In total, 204 patients had clinical and radiological evaluation of response, and underwent surgery. Compared with AC, TX increased pCR in primary tumors (21% vs. 10%, respectively, P = 0.024) and clinical response (84% vs. 65%, P = 0.003). TX was associated with less nausea and vomiting, but more stomatitis, diarrhea, myalgia, and skin/nail changes than AC. With a median follow-up of 37 months, there was no significant difference in DFS by treatment groups (P = 0.932). Fewer patients developed recurrence who achieved pCR in lymph node (LN) (P = 0.025; hazard ratio, 0.189; 95% CI, 0.044-0.815) in the multivariate analysis. TX showed superior efficacies to AC with increased pathologic and clinical complete response rates. Although these findings did not translate into a gain in DFS, the patients who achieved pCR in LN developed significantly less recurrence.

FDG-PET/CT in restaging of patients with recurrent breast cancer: possible impact on staging and therapy

We aimed to compare the value of combined positron emission tomography (PET)/CT, PET+CT (viewed side by side), CT alone and PET alone concerning the rTNM stage and influence on therapy in patients with recurrent breast cancer. 44 patients with suspicion of recurrent breast cancer underwent whole-body [18F]-2-fluoro-2-deoxy-d-glucose (FDG)-PET/CT. Images of combined PET/CT, PET+CT, PET alone and CT alone were evaluated by four blinded reader teams. Diagnostic accuracies and influence on therapy were compared. Histology and a mean clinical follow up of 456 days served as the standard of reference. Differences between the staging procedures were tested for statistical significance by McNemar's test. Overall TNM tumour stage was correctly determined in 40/44 patients with PET/CT, in 38/44 with PET+CT, in 36/44 with PET alone and in 36/44 patients with CT alone. No statistically significant difference was detected between all tested imaging modalities. PET/CT changed the therapy in two patients compared with PET+CT, in four patients compared with PET alone and in five patients compared with CT alone. Combined PET/CT appeared to be more accurate in assessing the rTNM and showed a moderate impact on therapy over PET and CT. Minor improvements were noted when compared with PET+CT. Experienced readers might therefore be able to provide accurate staging results for further therapy from separately acquired studies.

F-18 Fluorodeoxyglucose-Positron Emission Tomography Imaging for Primary Breast Cancer and Loco-Regional Staging

Breast cancer is the most common female malignancy in Western countries. The limitations of mammography, ultrasound and MRI do not allow reliable identification of primary breast cancer at early stages. Functional breast imaging with positron emission tomography (PET) and F-18 fluorodeoxyglucose (FDG) enables the visualization of increased glucose metabolism of breast cancer. However, despite the successful identification of primary breast cancer, FDG-PET provides a low sensitivity to detect small tumors. Therefore, FDG-PET does not allow screening of asymptomatic women and cannot be used to exclude breast cancer in patients with suspicious breast masses or abnormal mammography. FDG-PET is a powerful tool for staging of breast cancer patients, but does not detect micrometastases and small tumor infiltrated lymph nodes. Nevertheless, in patients with locally advanced breast cancer, PET accurately determines the extent of disease, particularly the loco-regional lymph node status. Advances in technology, for example the development of dedicated breast imaging devices such as positron emission mammography, hold promise to improve the detection of primary tumors in the future.

Impact of PET/CT in Comparison With Same Day Contrast Enhanced CT in Breast Cancer Management

PURPOSE

To evaluate the impact of F-18 fluorodeoxyglucose (FDG) positron emission tomography with fused computerized tomography (PET/CT) in comparison with same day contrast enhanced CT (CE-CT) in breast cancer management.

METHOD

Seventy studies in 49 breast cancer patients, 17 for initial and 53 for restaging disease were included. All patients underwent PET/CT for diagnostic purposes followed by CE-CT scans of selected body regions. PET/CT was started approximately 90 minutes following IV injection of 10-15 mCi of F-18 FDG on a GE Discovery PET/CT system. Oral contrast was given before F-18 FDG injection. The CE-CT was performed according to departmental protocol.

RESULTS

Out of a total of 257 lesions, 210 were concordant between PET/CT and CE-CT. There were 47 discordant lesions, which were verified by either biopsy (35) or follow-up (12 PET positive CE-CT negative lesions). PET/CT correctly identified 25 true positive (TP). CE-CT identified 2 TP lesions missed by PET/CT which were false negatives (FNs): one liver metastasis with necrosis, which was nonavid to FDG uptake because of necrosis and a second one missed on abdominal metastatic node, which did not change staging or treatment. PET/CT incorrectly identified 2 false positive lesions while CE-CT incorrectly identified 18 false positive. TP recurrence of the disease was found by PET/CT in 44% (15/34 pts), whereas 56% (19/34 pts) were free of disease. The CE-CT described progression of the disease in 1 true negative PET/CT study and no progression in 2 TP PET/CT studies. The sensitivity, specificity, accuracy, positive productive value, and negative productive value for PET/CT were 97.8%, 93.5%, 97.3%, 99.1%, 85% and for CE-CT were 87.6%, 42%, 82.1%, 91.6%, 31.7%.

CONCLUSION

In this study, PET/CT played a more important role than CE-CT scans alone and provided an impact on the management of breast cancer patients.

Predictors of axillary lymph node metastasis in breast cancer: a systematic review

AIMS

To review the established and emerging techniques in axillary lymph node prediction and explore their potential impact on clinical practice. To reliably identify patients in whom axillary lymph node surgery, including SLNB, can be safely omitted.

METHODS

Searches of PubMed were made using the search terms "axilla" (or "axillary"), "lymph", "node" and "predictor" (or "prediction"). Articles from abstracts and reports from meetings were included only when they related directly to previously published work.

FINDINGS

There are numerous studies in which the predictive utility of biomarkers as determinants of axillary lymph node status have been investigated. Few of these have specifically addressed the attributes of the primary tumour which could offer much potential for the prediction of tumour metastasis to the axillary lymph nodes.

CONCLUSIONS

Currently, no single marker is sufficiently accurate to obviate the need for formal axillary staging using SLNB or axillary clearance.

Feasibility and accuracy of sentinel lymph node biopsy after preoperative chemotherapy in breast cancer patients with documented axillary metastases

BACKGROUND

The feasibility and accuracy of sentinel lymph node (SLN) biopsy in patients with breast cancer after preoperative chemotherapy has been demonstrated in a number of large, single-institution studies. However, a relative contraindication to SLN biopsy after preoperative chemotherapy is the presence of axillary metastases at initial diagnosis. The objective of this study was to determine the feasibility and accuracy of SLN biopsy after preoperative chemotherapy in patients with documented axillary metastases at presentation.

METHODS

Between 1994 and 2002, 69 patients who had axillary metastases identified by ultrasound-guided, fine-needle aspiration underwent SLN biopsy after treatment on prospective, preoperative chemotherapy protocols. All but 8 patients underwent axillary lymph node dissection (ALND). Those 8 patients either declined additional surgery or were offered enrollment in other institutional protocols.

RESULTS

The median patient age was 49 years, and the median primary tumor size was 4 cm. The SLN identification rate was 92.8%. Thirty-one of 64 patients (48.4%) had successfully mapped, positive SLNs. Sixty-one patients underwent ALND, including 5 patients who did not have an SLN identified. In the 56 patients in whom a SLN was identified and an ALND was performed, 10 patients had a false-negative SLN (25%).

CONCLUSIONS

SLN biopsy was feasible after preoperative chemotherapy, even in patients who initially presented with cytologically proven, lymph node-positive disease. However, the false-negative rate of SLN biopsy in this group of patients was much higher than that observed in clinically lymph node-negative patients. Based on the current results, the status of the SLN cannot be used as a reliable indicator of the presence or absence of residual disease in the axilla in this patient population.

The evolution of the conservative approach to breast cancer

The profound revolution that surgical treatment of breast cancer has undergone during the past 30 years has led to the progressive reduction of the extent of surgery, with less mutilation. As a consequence, quality of life has improved and women are now more motivated to follow screening programs for early diagnosis of the disease. Since conservative surgery is as effective as radical surgery, research is now focused on reducing radiotherapy. Overall, survival after breast cancer is not affected by reducing the extent of surgery, which, together with less invasive diagnostic procedures, has a good effect on patients' quality of life. For this reason in our Institute we are now evaluating the feasibility of a reduction of the radiation field and the sensibility and sensitivity of new diagnostic approaches for axillary staging.

PET/CT: form and function

Functional imaging with positron emission tomography (PET) is playing an increasingly important role in the diagnosis and staging of malignant disease, image-guided therapy planning, and treatment monitoring. PET with the labeled glucose analogue fluorine 18 fluorodeoxyglucose (FDG) is a relatively recent addition to the medical technology for imaging of cancer, and FDG PET complements the more conventional anatomic imaging modalities of computed tomography (CT) and magnetic resonance imaging. CT is complementary in the sense that it provides accurate localization of organs and lesions, while PET maps both normal and abnormal tissue function. When combined, the two modalities can help both identify and localize functional abnormalities. Attempts to align CT and PET data sets with fusion software are generally successful in the brain; other areas of the body is more challenging, owing to the increased number of degrees of freedom between the two data sets. These challenges have recently been addressed by the introduction of the combined PET/CT scanner, a hardware-oriented approach to image fusion. With such a device, accurately registered anatomic and functional images can be acquired for each patient in a single scanning session. Currently, over 800 combined PET/CT scanners are installed in medical institutions worldwide, many of them for the diagnosis and staging of malignant disease and increasingly for monitoring of the response to therapy. This review will describe some of the most recent technologic developments in PET/CT instrumentation and the clinical indications for which combined PET/CT has been shown to be more useful than PET and CT performed separately.

Breast conservation: Current results and future perspectives at the European Institute of Oncology

In the recent 10 years breast cancer treatments' scenario is radically changed. Extraordinary new surgical approaches give more and more conservative solutions both for the breast and especially for the axilla avoiding dissection in more than 80% of early cases. Instrumental early diagnosis and clinical prediction are now able to identify very initial cases often in premalignant stage. Technology arrived in the operating theatre for the intraoperative radiotherapy treatments giving to the patients the better quality of life with the help also of the plastic surgeons. There are still near horizons to reach: modern neo-adjuvant and adjuvant treatments are going quickly from the laboratory to patient's bed.

A comparative study on the value of FDG-PET and sentinel node biopsy to identify occult axillary metastases

BACKGROUND

Sentinel node biopsy (SNB) has become a standard treatment in staging axillary lymph nodes in early breast cancer. SNB, however, is an invasive procedure and is time-consuming when the sentinel node is analysed intra-operatively. Breast cancer is frequently characterised by increased 2-fluoro-2-deoxy-D-glucose uptake and many studies have shown encouraging results in detecting axillary lymph node metastases. The aim of this study was to compare SNB and -positron emission tomography (-PET) imaging, to assess their values in detecting occult axillary metastases.

PATIENTS AND METHODS

In all, 236 patients with breast cancer and clinically negative axilla were enrolled in the study. 18-FDG-PET was carried out before surgery, using a positron emission tomography (PET)/computed tomography scanner. In all patients, SNB was carried out after identification through lymphoscintigraphy. Patients underwent axillary lymph nodes dissection (ALND) in cases of positive FDG-PET or positive SNB. The results of PET scan were compared with histopathology of SNB and ALND.

RESULTS

In all, 103 out of the 236 patients (44%) had metastases in axillary nodes. Sensitivity of FDG-PET scan for detection of axillary lymph node metastases in this series was low (37%); however, specificity and positive predictive values were acceptable (96% and 88%, respectively).

CONCLUSIONS

The high specificity of PET imaging indicates that patients who have a PET-positive axilla should have an ALND rather than an SNB for axillary staging. In contrast, FDG-PET showed poor sensitivity in the detection of axillary metastases, confirming the need for SNB in cases where PET is negative in the axilla.

Recent developments in the systemic therapy of advanced gastroesophageal malignancies

Cancers of the upper gastrointestinal tract are a common cause of worldwide morbidity and mortality. The prognosis for patients with these cancers remains poor and only a minority of patients are cured. Systemic therapy has been used to treat patients with advanced disease but outcomes have not improved dramatically in the past few decades. Newer, more effective agents are desperately needed, and agents such as the taxanes (docetaxel and paclitaxel), irinotecan, oxaliplatin and capecitabine have recently shown some promise. In addition, molecularly targeted, non-cytotoxic therapies are being evaluated with the hope of improving the available therapeutic options. This article reviews the current clinical data regarding systemic therapy for patients with advanced upper gastrointestinal malignancies.

In vitro and in vivo Evaluation of 111In-labeled E. coli Heat-Stable Enterotoxin Analogs for Specific Targeting of Human Breast Cancers

Research into the interaction between the E. coli heat-stable enterotoxin (STh) and the guanylin receptor guanylate cyclase C (GC-C) has generated >100 synthetic analogs of the peptide, several of which have been investigated as imaging or therapeutic agents for colorectal cancers. The evidence presented here suggests that in addition to STh binding to GC-C expressing cell lines derived from human colon, STh also specifically binds to an as yet unidentified receptor expressed in high densities on the surface of cell lines derived from human breast cancers. In vitro whole-cell crosslinking studies using 125I-labeled F19-STh(1-19) demonstrate that the putative STh binding protein migrates as an approximately 120-125 kDa species by SDS-PAGE, significantly smaller than the glycosylated GC-C molecule found in the T84 human colon cancer cell line. RT-PCR using total RNA isolated from breast and colon cancer cell lines indicates that GC-C transcripts are undetectable in human breast cancer cell lines and abundant in human colon cancer cell lines. In vitro competitive binding studies using STh analogs and the estrogen receptor positive (ER+) T-47D cell line demonstrated IC50 values between 2.6 and 8.5 nM. Similar studies on the estrogen receptor negative (ER-) cell line MDA-MB-231 showed IC50's between 5.6 and 9.9 nM. Saturation binding analysis revealed receptor expression to fall between 40,000 and 120,000 sites per cell in these cell lines, receptor abundances equal to or greater than the abundance of GC-C in colorectal cancer cell lines. STh binding to these cells, although of similar affinity to STh binding to GC-C, is distinguishable from it on the basis of its ligand specificity. The characteristics of STh analogs as radiopharmaceutical agents were tested in an in vivo model utilizing T-47D human breast cancer cell xenografts in SCID mice. Clearance of STh analogs was rapid, primarily via renal excretion into the urine, with >85% ID excreted into the urine at 1 h p.i. Tumor uptake at 1 h p.i. in T-47D tumor cell xenografts was 0.67+/-0.23% ID/g, and was significantly decreased (p<0.05) upon co-administration of 4 mg/kg unlabeled STh. These results suggest that STh may find application for the imaging and treatment of breast cancer.

Fluorodeoxyglucose positron emission tomography with sentinel lymph node biopsy for evaluation of axillary involvement in breast cancer

Background

This study analysed the value of [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) in detecting axillary lymph node involvement in women with breast cancer.

Methods

In the first 150 women in this prospective study, axillary lymph node dissection (ALND) was performed regardless of the PET results. In a second group (125 women) FDG-PET was complemented with sentinel lymph node biopsy (SLNB) only in those who did not have pathological axillary uptake.

Results

The sensitivity and specificity of FDG-PET in detecting axillary involvement was 84·5 and 98·5 per cent respectively in the whole series of 275 patients, with two false-positive and 22 false-negative results. False-negative results were associated with some intrinsic tumour characteristics. In 21 women, PET revealed pathological uptake, suggesting involvement of the internal mammary lymph node chain. Whole-body PET identified a second synchronous tumour in five asymptomatic patients and haematogenous metastases in two patients.

Conclusion

The high positive predictive value of PET (98·4 per cent) suggests that FDG uptake in the axilla could be an indication for full ALND without previous SLNB.