The benefits and limitations of sentinel lymph node biopsy

A clinical feasibility study of a photoacoustic finder for sentinel lymph node biopsy in breast cancer patients: A prospective cross-sectional study

The sentinel lymph node (SLNb) is generally performed using radioisotopes, blue dyes, or both to improve false negative rate. However, ionizing radiation is involved in a gamma probe with radioisotopes and the blue dye detection relies on native visual inspection by an operator. To overcome these limitations, we developed the photoacoustic finder (PAF), a highly sensitive, non-radioactive detector that uses only blue dye and a photoacoustic signal to detect SLNs. A total of 121 patients with breast cancer were enrolled, and 375 lymph nodes were excised using conventional SLNb. The PAF was used to measure the signal from the excised lymph nodes. We compared the SLN detection rates of each method (gamma probe, visual inspection, and PAF) and conducted a non-inferiority test. The PAF detected 87 % of SLNs, comparable to the gamma probe (85 %) and superior to visual inspection (73 %). Non-inferiority tests confirmed PAF's performance was not inferior to visual inspection (p < 0.001) or the gamma probe (p < 0.015). Using the dual-modal method (gamma probe + visual inspection) as the gold standard, PAF showed a sensitivity of 0.81 and specificity of 0.63. This study demonstrates that PAF, using only blue dye, offers a non-inferior alternative to the standard dual-modal SLN detection method with radioactive materials, opening new avenues for radiation-free SLNb in the future.

Comparative Analysis of Nomogram and Machine Learning Models for Predicting Axillary Lymph Node Metastasis in Early-Stage Breast Cancer: A Study on Clinically and Ultrasound-Negative Axillary Cases Across Two Centers

OBJECTIVE

Early and accurate prediction of axillary lymph node metastasis (ALNM) is crucial in determining appropriate treatment strategies for patients with early-stage breast cancer. The aim of this study was to evaluate the efficacy of radiomic features extracted from ultrasound (US) images combined with machine learning (ML) methods in predicting ALNM to improve diagnostic accuracy and patient prognosis.

METHODS

In this retrospective study, data of 282 early-stage breast cancer patients from two centers were analyzed. We considered clinicopathological characteristics, conventional US features, contrast-enhanced ultrasound (CEUS) characteristics, and radiomics features. Radiomics features were extracted from US images, and using least absolute shrinkage and selection operator (LASSO) regression, 12 key features were selected to compute a Radiomics score (Rad-score). A nomogram was developed based on these features, alongside five ML models: Logistic Regression (LR), Naive Bayes (NB), Support Vector Machine (SVM), K-Nearest Neighbors (KNN), and Extreme Gradient Boosting (XGBoost). Model performance was evaluated using metrics such as the area under the curve (AUC), accuracy (ACC), sensitivity (SEN), specificity (SPE), negative predictive value (NPV), and positive predictive value (PPV).

RESULTS

Both the nomogram and ML models, including the Rad-score combined with histologic type, significantly predicted ALNM. Among all models, the XGBoost model showed the best performance with an AUC of 0.810 and an accuracy of 84.1% in the external test set, surpassing the nomogram and other ML models. SHapley Additive exPlanations (SHAP) analysis further provided insights into the influence of individual radiomics features on ALNM prediction.

CONCLUSIONS

While the nomogram provides a useful traditional statistical approach, integrating radiomics features with ML, particularly the XGBoost model enhanced by SHAP interpretability, offers superior predictive accuracy for ALNM in early-stage breast cancer patients.

Advances in molecular imaging and targeted therapeutics for lymph node metastasis in cancer: a comprehensive review

Lymph node metastasis is a critical indicator of cancer progression, profoundly affecting diagnosis, staging, and treatment decisions. This review article delves into the recent advancements in molecular imaging techniques for lymph nodes, which are pivotal for the early detection and staging of cancer. It provides detailed insights into how these techniques are used to visualize and quantify metastatic cancer cells, resident immune cells, and other molecular markers within lymph nodes. Furthermore, the review highlights the development of innovative, lymph node-targeted therapeutic strategies, which represent a significant shift towards more precise and effective cancer treatments. By examining cutting-edge research and emerging technologies, this review offers a comprehensive overview of the current and potential impact of lymph node-centric approaches on cancer diagnosis, staging, and therapy. Through its exploration of these topics, the review aims to illuminate the increasingly sophisticated landscape of cancer management strategies focused on lymph node assessment and intervention.

A TMVP1-modified near-infrared nanoprobe: molecular imaging for tumor metastasis in sentinel lymph node and targeted enhanced photothermal therapy

BACKGROUND

TMVP1 is a novel tumor targeting polypeptide screened by our laboratory with a core sequence of five amino acids LARGR. It specially binds to vascular endothelial growth factor receptor-3 (VEGFR-3), which is mainly expressed on neo-lymphatic vessels in sentinel lymph node (SLN) with tumor metastasis in adults. Here, we prepared a targeted nanoprobe using TMVP1-modified nanomaterials for tumor metastasis SLN imaging.

RESULTS

In this study, TMVP1-modified polymer nanomaterials were loaded with the near-infrared (NIR) fluorescent dye, indocyanine green (ICG), to prepare a molecular imaging TMVP1-ICG nanoparticles (NPs) to identify tumor metastasis in SLN at molecular level. TMVP1-ICG-NPs were successfully prepared using the nano-precipitation method. The particle diameter, morphology, drug encapsulation efficiency, UV absorption spectrum, cytotoxicity, safety, and pharmacokinetic properties were determined. The TMVP1-ICG-NPs had a diameter of approximately 130 nm and an ICG loading rate of 70%. In vitro cell experiments and in vivo mouse experiments confirmed that TMVP1-ICG-NPs have good targeting ability to tumors in situ and to SLN with tumor metastasis by binding to VEGFR-3. Effective photothermal therapy (PTT) with TMVP1-ICG-NPs was confirmed in vitro and in vivo. As expected, TMVP1-ICG-NPs improved ICG blood stability, targeted tumor metastasis to SLN, and enhanced PTT/photodynamic (PDT) therapy, without obvious cytotoxicity, making it a promising theranostic nanomedicine.

CONCLUSION

TMVP1-ICG-NPs identified SLN with tumor metastasis and were used to perform imaging-guided PTT, which makes it a promising strategy for providing real-time NIR fluorescence imaging and intraoperative PTT for patients with SLN metastasis.

Excitation coil for sentinel lymph node harvesting: design, digital twin and prototype

A recently developed prototype (Laparoscopic Differential Magnetometer, in short LapDiffMag) identifies magnetic tracer accumulated inside sentinel lymph nodes (SLNs) during clinical laparoscopic procedures. The LapDiffMag relies on excitation of superparamagnetic iron oxide nanoparticles (SPIONs) and subsequent laparoscopic detection based on a nonlinear detection principle. The prototype uses an excitation coil to generate a magnetic field needed to activate SPIONs. This study reports on the process of developing a new excitation coil by describing the design choices based upon clinical requirements, by modeling delivered magnetic field using digital twin, and by comparing the magnetic fields of modeled and manufactured prototype. Digital twin technology was used to produce relevant and reliable data to demonstrate the safety and effectiveness of the excitation coil. The magnetic field originating from manufactured prototype was validated at two different heights above the excitation coil and have shown a good concordance to the data generated by its digital twin. Clinical Relevance- Current standard-of-care for a variety of tumor types consists of minimally invasive radical resection of primary tumor and regional lymph nodes (LNs). The newly introduced excitation coil will (after full validation) enable minimally invasive harvesting of sentinel LNs by means of magnetic tracer detection.

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.

Performance of Molecular Lymphosonography for Detection and Quantification of Metastatic Involvement in Sentinel Lymph Nodes

OBJECTIVES

To assess the performance of molecular lymphosonography with dual-targeted microbubbles in detecting and quantifying the metastatic involvement in sentinel lymph nodes (SLNs) using a swine melanoma model.

METHODS

Targeted microbubbles were labeled with P-selectin and αV β3 -integrin antibodies. Control microbubbles were labeled with immunoglobulin G antibodies. First lymphosonography with Sonazoid (GE Healthcare, Oslo, Norway) was used to identify SLNs. Then dual-targeted and control microbubbles were injected intravenously to detect and quantify metastatic disease in the SLNs. Distant non-SLNs were imaged as benign controls. All evaluated lymph nodes (LNs) were surgically removed, and metastatic involvement was characterized by a histopathologic analysis. Two radiologists blinded to histopathologic results assessed the baseline B-mode images of LNs, and the results were compared to the histologic reference standard. The mean intensities of targeted and control microbubbles within the examined LNs were measured and compared to the LN histologic results.

RESULTS

Thirty-five SLNs and 34 non-SLNs from 13 Sinclair swine were included in this study. Twenty-one SLNs (62%) were malignant, whereas 100% of non-SLNs were benign. The sensitivity of B-mode imaging for metastatic LN diagnosis for both readers was relatively high (90% and 71%), but the specificity was very poor (50% and 58%). The sensitivity and specificity of molecular lymphosonography for metastatic LN detection were 91% and 67%, respectively. The mean intensities from dual-targeted microbubbles correlated well with the degree of metastatic LN involvement (r = 0.6; P < 0.001).

CONCLUSIONS

Molecular lymphosonography can increase the specificity of metastatic LN detection and provide a measure to quantify the degree of metastatic involvement.

Predictive value of primary tumor parameters using 18F-FDG PET/CT for occult lymph node metastasis in breast cancer with clinically negative axillary lymph node

OBJECTIVE

This study aimed to demonstrate the clinical significance of total lesion glycolysis (TLG) of primary breast cancer using ¹⁸F-FDG PET/CT to predict axillary lymph node (ALN) metastasis in invasive ductal breast cancer (IDC) with a clinically negative axillary lymph node (cN-ALN).

METHODS

135 patients, newly diagnosed with IDC with _CN-ALN between July 2016 and October 2017, were retrospectively enrolled. We estimated primary tumor PET/CT parameters including the maximum standard uptake value (SUV_max), metabolic tumor volume (MTV), and TLG, as well as clinicopathologic findings. All patients received breast surgery followed by pathologic axillary lymph node examination.

RESULTS

Of the 135 patients, 31 (23.0%) were diagnosed with pathologically proven metastatic ALN. In univariate analysis, SUV_max, MTV, and TLG of the primary breast tumor were correlated with metastatic ALN along with tumor size, lymphovascular invasion, CD34, and D2-40. On multivariate analysis, TLG (> 5.74, p = 0.009) had independent significance for predicting ALN metastasis in IDC with cN-ALN.

CONCLUSION

We demonstrated that TLG of primary tumors can be useful in predicting pathologic ALN metastasis in IDC patients with cN-ALN.

Microphthalmia transcription factor in malignant melanoma predicts occult sentinel lymph node metastases and survival

Microphthalmia transcription factor (Mitf) is involved in melanocyte development and differentiation. We previously reported that Mitf expression, as detected by immunohistochemical analysis, is an independent prognostic marker in patients with intermediate-thickness melanoma. However, the clinical significance of Mitf expression in melanoma is not well delineated. In this prospective study, we attempted to demonstrate the correlation between Mitf expression in primary melanoma and the sentinel lymph node status and prognosis. We prospectively examined primary cutaneous melanomas from 94 patients undergoing nodal staging by sentinel lymph node biopsy. We quantified the percentage of tumor cells whose nuclei stained with the Mitf antibody visually. Survival curves were generated using the Kaplan-Meier method. The correlation between Mitf expression and nodal status was evaluated using the Mann-Whitney U-test. Here we demonstrate that Mitf expression is directly correlated with both disease-free survival (DFS) and overall survival (OS) over a median follow-up of 28.5 months. The mean DFS and OS in the eight patients whose melanomas did not stain positive for Mitf were 15.75±3.36 months (median, 12 months) and 38.17±5.18 months (median, 29 months), respectively. These results are significantly lower than those for patients who showed evidence of Mitf expression, in whom the mean DFS and OS were 66.1±4.03 months (median, not reached, P=0.0001) and 66.75±38.17 months (median, not reached, P=0.0001), respectively. The mean DFS and OS with greater than 25% (67 patients) of the melanoma cells staining positive for Mitf expression were 78.37±2.78 and 82.38±1.6 months, respectively, compared with 26.37±3.2 months (P=0.0001) and 44.53±4.5 months (P=0.0001), respectively, with up to 25% (27 patients) of cells stained positive for Mitf expression. In addition, there was a significant relationship between Mitf expression and nodal status, as evaluated by sentinel node biopsy. For example, none of the melanomas with greater than 50% Mitf expression had a positive sentinel node biopsy. Our study shows that expression of the molecular marker Mitf in primary cutaneous melanomas is a useful tool in assessing lymph node status. Mitf immunostaining in the primary tumor serves as a reliable predictor of occult lymph node metastases, as well as a favorable prognosticator of DFS and OS in melanoma patients.

Ultrasound-guided photoacoustic imaging for the selective detection of EGFR-expressing breast cancer and lymph node metastases

We assessed the use of ultrasound (US)-guided photoacoustic imaging (PAI) and anti-EGFR antibody-conjugated gold nanorods (anti-EGFR-GNs) to non-invasively detect EGFR-expressing primary tumor masses and regional lymph node (LN) metastases in breast tumor mice generated by injecting MCF-7 (EGFR-negative) or MDA-MB-231 (EGFR-positive) human breast cells using a preclinical Vevo 2100 LAZR Imaging system. Anti-EGFR-GNs provided a significant enhancement in the PA signal in MDA-MB-231 tumor and the axillary LN metastases relative to MCF-7 tumor and non-LN metastases. We demonstrated that US-guided PAI using anti-EGFR-GNs is highly sensitive for the selective visualization of EGFR-expressing breast primary tumors as well as LN micrometastases.

Hybrid surgical guidance based on the integration of radionuclear and optical technologies

With the evolution of imaging technologies and tracers, the applications for nuclear molecular imaging are growing rapidly. For example, nuclear medicine is increasingly being used to guide surgical resections in complex anatomical locations. Here, a future workflow is envisioned that uses a combination of pre-operative diagnostics, navigation and intraoperative guidance. Radioguidance can provide means for pre-operative and intraoperative identification of "hot" lesions, forming the basis of a virtual data set that can be used for navigation. Luminescence guidance has shown great potential in the intraoperative setting by providing optical feedback, in some cases even in real time. Both of these techniques have distinct drawbacks, which include inaccuracy in areas that contain a background signal (radioactivity) or a limited degree of signal penetration (luminescence). We, and others, have reasoned that hybrid/multimodal approaches that integrate the use of these complementary modalities may help overcome their individual weaknesses. Ultimately, this will lead to advancement of the field of interventional molecular imaging/image-guided surgery. In this review, an overview of clinically applied hybrid surgical guidance technologies is given, whereby the focus is placed on tracers and hardware.

Accurate sequential detection of primary tumor and metastatic lymphatics using a temperature-induced phase transition nanoparticulate system

Primary tumor and tumor-associated metastatic lymphatics have emerged as new targets for anticancer therapy, given that these are difficult to treat using traditional chemotherapy. In this study, docetaxel-loaded Pluronic nanoparticles with Flamma™ (FPR-675, fluorescence molecular imaging dye; DTX/FPR-675 Pluronic NPs) were prepared using a temperature-induced phase transition for accurate detection of metastatic lymphatics. Significant accumulation was seen at the primary tumor and in metastatic lymph nodes within a short time. Particle size, maximum drug loading capacity, and drug encapsulation efficiency of the docetaxel-loaded Pluronic NPs were approximately 10.34±4.28 nm, 3.84 wt%, and 94±2.67 wt%, respectively. Lymphatic tracking after local and systemic delivery showed that DTX/FPR-675 Pluronic NPs were more potent in tumor-bearing mice than in normal mice, and excised mouse lymphatics showed stronger near-infrared fluorescence intensity on the tumor-bearing side than on the non-tumor-bearing side at 60 minutes post-injection. In vivo cytotoxicity and efficacy data for the NPs demonstrated that the systemically administered NPs caused little tissue damage and had minimal side effects in terms of slow renal excretion and prolonged circulation in tumor-bearing mice, and rapid renal excretion in non-tumor-bearing mice using an in vivo real-time near-infrared fluorescence imaging system. These results clearly indicate that docetaxel-loaded Pluronic NPs could provide a strategy to achieve effective cancer therapy by simultaneous delivery to primary tumors, tumor lymphatics, and tumor-associated metastatic lymphatics.

Breast cancer characteristics-comparison of preoperative and postoperative values

Breast cancer characteristics obtained at the time of diagnosis are important for setting the basic strategy of the treatment. Reliability of preoperative investigation differs for various features of the disease. The aim of this study was to ascertain the agreements and differences between preoperative and postoperative values. This retrospective study analyzed the results of 617 women with primary surgery of the breast and axilla. Cohen's kappa coefficient has been employed to measure the degree of agreement between preoperative and postoperative values. Substantial or "almost perfect" agreement has been documented for the histological type of the tumors, their histopathological grade, proliferation index Ki67, as well as for estrogen, progesterone, and HER-2/neu receptors. Substantial differences exist between preoperative and postoperative diagnoses of invasiveness of the tumor, determination of the size of the tumors, and the number of tumor foci. Preoperative imaging and clinical examination of lymph nodes exhibited unacceptably high false negative rates. Heterogeneity of breast cancer cell population, methodology of histology examinations, and insufficient imaging of lymph nodes are the major limitations precluding satisfactory accuracy of preoperative diagnosis. Preoperatively diagnosed in situ carcinomas, as well as multifocal lesions, were the most often sources of diagnostic failures.

The prognostic value of lymph node cross-sectional cancer area in node-positive breast cancer: a comparison with N stage and lymph node ratio

The number of positive axillary lymph nodes (LNs) is the only node-related factor for prognostic evaluation of breast cancer recognized by AJCC (TNM staging). However, N staging may not completely reflect LN tumor involvement due to the erroneous count of LNs in the presence of matted LNs and different tumor volume in LNs. Additionally, the positive/total LN ratio (LNR) has been shown to outperform N staging in survival prediction. In our study, to better quantify the tumor involvement of axillary LNs, we measured the cross-sectional cancer area (CSCA) of the positive LNs in 292 breast cancer patients diagnosed between 1998 and 2000 in our institution and compared its prognostic value to that of number of positive LNs (metLN)/N stage and LNR. Statistical analyses of these three LN-related factors were performed by Kaplan-Meier method and multivariate Cox's regression model. Patients were divided into three groups based on the different LN CSCA (<50, 50–500, and >500 mm²), or LNR (<0.1, 0.1–0.65, and >0.65), or N stage (N1–N3). Multivariate analysis demonstrated LNR was the most significant LN-related survival predictor with hazard ratio (HR) 25.0 (P = 0.001), compared to the metLN (HR 0.09, P = 0.052) and CSCA (HR 2.24, P = 0.323).

Multimodal sentinel lymph node mapping with single-photon emission computed tomography (SPECT)/computed tomography (CT) and photoacoustic tomography

The identification of cancer cells in the lymph nodes surrounding a tumor is important in establishing a prognosis. Optical detection techniques such as fluorescence and photoacoustic tomography (PAT) have been reported in preclinical studies for noninvasive sentinel lymph node (SLN) mapping. A method for validation of these techniques is needed for clinical trials. We report the use of a multimodal optical-radionuclear contrast agent as a validation tool for PAT in a preclinical model. Methylene blue (MB) was radiolabeled with (125)I for multimodal SLN mapping and used in conjunction with MB to assess the feasibility of multimodal SLN mapping in a rat model by PAT and single-photon emission computed tomography (SPECT). MB provided sufficient contrast for identifying SLNs noninvasively with a PAT system adapted from a clinical ultrasound imaging system. The signal location was corroborated by SPECT using (125)I labeled MB. The translation of PAT into the clinic can be facilitated by a direct comparison with established imaging methods using a clinically relevant dual SPECT and photoacoustic imaging agent. The new high-resolution PAT is a promising technology for the sensitive and accurate SLN detection in cancer patients.

In vivo quantitative evaluation of the transport kinetics of gold nanocages in a lymphatic system by noninvasive photoacoustic tomography

Sentinel lymph node (SLN) biopsy has emerged as a preferred method for axillary lymph node staging of breast cancer, and imaging the SLN in three-dimensional space is a prerequisite for the biopsy. Conventional SLN mapping techniques based on the injection of an organic dye or a suspension of radioactive colloids suffer from invasive surgical operation for visual detection of the dye or hazardous radioactive components and low spatial resolution of Geiger counters in detecting the radioactive colloids. This work systematically investigates the use of gold nanocages (AuNCs) as a novel class of optical tracers for noninvasive SLN imaging by photoacoustic (PA) tomography in a rat model. The transport of AuNCs in a lymphatic system and uptake by the SLN were evaluated by PA tomography on the axillary region of a rat. Quantification of AuNCs accumulated in the lymph node was achieved by correlating the data from PA imaging with the results from inductively coupled plasma mass spectrometry. Several parameters were systematically evaluated and optimized, including the concentration, size, and surface charge of the AuNCs. These results are critical to the further development of this AuNC-based PA tomography system for noninvasive SLN imaging, providing valuable information for metastatic cancer staging.

Adoption of surgical innovations: factors influencing use of sentinel lymph node biopsy for breast cancer

PURPOSE

Sentinel lymph node biopsy (SLNB) has been unevenly adopted into practice in Canada. In this qualitative study, the authors explored individual, institutional, and policy factors that may have influenced SLNB adoption. This information will guide interventions to improve SLNB implementation.

METHODS

Qualitative methodology was used to examine factors influencing SLNB adoption. Grounded theory guided data collection and analysis. Semistructured interviews were based on Roger's diffusion of innovation theory. Purposive and snowball sampling was used to identify participants. Semistructured telephone interviews were conducted with urban, rural, academic, and community health care providers and administrators to ensure all perspectives and motivations were explored. Two individuals independently analyzed data and achieved consensus on emerging themes and their relationship.

RESULTS

A total of 43 interviews were completed with 21 surgeons, 5 pathologists, 7 nuclear medicine physicians, and 10 administrators. Generated themes included awareness of SLNB with the exception of some administrators, acknowledged advantage of SLNB, SLNB compatibility with beliefs regarding axillary staging, acknowledgment that SLNB was a complex innovation to adopt, extensive trialing of SLNB prior to adoption, observable benefits with SLNB, acknowledgment that hospital-level administrative support enabled adoption, desire for a provincial policy supporting SLNB to assist in hospital-level adoption, requirement of a local high-volume breast surgery champion who communicated extensively with team to facilitate local adoption, and need for credentialing of SLNB to ensure quality.

CONCLUSIONS

SLNB is a complex innovation to adopt. Successful adoption was assisted by a high-volume breast cancer surgical champion, interprofessional communication, and administrative support.

Noninvasive photoacoustic and fluorescence sentinel lymph node identification using dye-loaded perfluorocarbon nanoparticles

The contrast mechanisms used for photoacoustic tomography (PAT) and fluorescence imaging differ in subtle, but significant, ways. The design of contrast agents for each or both modalities requires an understanding of the spectral characteristics as well as intra- and intermolecular interactions that occur during formulation. We found that fluorescence quenching that occurs in the formulation of near-infrared (NIR) fluorescent dyes in nanoparticles results in enhanced contrast for PAT. The ability of the new PAT method to utilize strongly absorbing chromophores for signal generation allowed us to convert a highly fluorescent dye into an exceptionally high PA contrast material. Spectroscopic characterization of the developed NIR dye-loaded perfluorocarbon-based nanoparticles for combined fluorescence and PA imaging revealed distinct dye-dependent photophysical behavior. We demonstrate that the enhanced contrast allows detection of regional lymph nodes of rats in vivo with time-domain optical and photoacoustic imaging methods. The results further show that the use of fluorescence lifetime imaging, which is less dependent on fluorescence intensity, provides a strategic approach to bridge the disparate contrast reporting mechanisms of fluorescence and PA imaging methods.

PET/CT and breast cancer

This paper summarises the current status of PET/CT in relation to breast cancer.

(18)F-FDG PET/CT with Contrast Enhancement for Evaluation of Axillary Lymph Node Involvement in T1 Breast Cancer

BACKGROUND

(18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography ((PET) safely predicts axillary status in patients with breast cancer, but is not sufficiently accurate in early breast cancer patients. This study analyzed the value of (18)F-FDG PET/computed tomography (CT) with contrast enhancement in detecting axillary lymph node involvement in T1 breast cancer patients.

METHODS

Contrast-enhanced (18)F-FDG PET/CT was performed within 20 days of surgery in 143 breast cancer patients with tumors ≤2 cm in size. The patients underwent either axillary lymph node dissection (ALND) or sentinel lymph node biopsy (SLNB), and histopathology reports were used to provide the definitive diagnosis against which the contrast-enhanced (18)F-FDG PET/CT study results were compared.

RESULTS

The sensitivity, specificity, and negative and positive predictive values of contrast-enhanced (18)F-FDG PET/CT in detecting axillary involvement were 70.0%, 92.2%, 88.8%, and 77.8%, respectively, in the entire series of 143 patients, with eight false-positive and 12 false negative results. The false-negative results were associated with the number of metastatic lymph nodes and the rate of FDG uptake.

CONCLUSION

Contrast-enhanced (18)F-FDG PET/CT cannot replace histologic staging using SLNB in patients with breast cancer, but (18)F-FDG PET/CT increases the sensitivity for predicting axillary node metastasis, and allows for a selective approach to either ALND or SLNB, even in patients with T1 breast cancer.

A further survey of surgical management of the axilla in UK breast cancer patients

INTRODUCTION

The aims of this study were to investigate the practice of axillary lymph node management within different units throughout the UK, and to assess changes in practice since our previous survey in 2004.

SUBJECTS AND METHODS

A structured questionnaire was sent to 350 members of the British Association of Surgical Oncology.

RESULTS

There were 177 replies from respondents who managed more than 100 patients a year with breast cancer. Of these: 12 did not perform axillary ultrasound at all in their centre; 17 (10%) employed axillary node clearance (ANC) on all patients; 122 (69%) performed sentinel node biopsy (SNB) with dual localisation; and 111 respondents had attended the New Start Course. Radioisotope was most frequently injected 2 h or more before operation. Just 13 surgeons were convinced of the value of dissecting internal mammary nodes visualised on a scan. Reasons for not using dual localisation included lack of nuclear medicine facilities, no local ARSAC licence holder, no probe, and no funding. Sixty-six surgeons stated that, if they had an ARSAC licence and could inject the radioactivity in theatre, this would be a major improvement. In addition, 83 (47%) did not perform SLNB in patients receiving neo-adjuvant chemotherapy.

CONCLUSIONS

Despite significant changes since 2004, substantial variation remains in management of the axilla. A number of surgeons are practicing outwith current guidelines.

Current status of sentinel lymph-node biopsy in patients with breast cancer

Axillary node status is the most important prognostic indicator for patients with invasive breast cancer. Sentinel lymph-node biopsy (SLNB) is widely accepted and the preferred procedure for identifying lymph-node metastasis. SLNB allows focused excision and pathological examination of the most likely axillary lymph nodes to receive tumor metastases while avoiding morbidities associated with complete axillary nodal dissection. Since its introduction in the early 1990s, the process of SLNB has undergone continual modification and refinement; however, the procedure varies between institutions and controversies remain. In this review, we examine the technical issues that influence the success of lymph node mapping, discuss the controversies, and summarize the indications and contraindications for axillary node mapping and biopsy in clinical practice.

Sentinel Lymph Node Biopsy in Breast Cancer

The axillary lymph node status is the most reliable prognostic indicator of recurrence and overall survival in patients with breast cancer. The current standard surgical procedure for the management of invasive breast cancer is the complete removal of the cancer with total axillary clearance. However, recently, selective sentinel lymph node mapping and biopsy is gaining acceptance as a useful and accurate staging procedure, as it is minimally invasive. The sentinel lymph node is the first node into which a primary cancer drains, and is thus the first node to be involved by metastases. Patients whose sentinel nodes are negative for breast cancer metastases, can be spared a more extensive axillary lymph node dissection, with reduction in the postoperative morbidity. Sentinel node mapping is usually performed by intradermal or peritumoral injection of a combination of blue dye and radiotracer. Sentinel node examination is sometimes done intraoperatively, by imprint cytology and frozen sections, for an immediate assessment, to plan the extent of surgery at a single sitting. Permanent sections of the sentinel node are studied by serial sectioning, and immunohistochemistry for cytokeratin is done to detect micrometastases which are frequently missed on hematoxylin and eosin (H&E)-stained sections. The various aspects of sentinel node examination, and its role to decide further management in patients with ductal carcinoma-in-situ, and in other clinical settings, are discussed in this review.

Diagnostic value of full-dose FDG PET/CT for axillary lymph node staging in breast cancer patients

PURPOSE

The aims of this study were (1) to evaluate FDG PET/CT and CT for the detection of axillary lymph node metastases in breast cancer (BC) patients and (2) to evaluate FDG PET/CT as a pre-test for the triage to sentinel lymph node biopsy (SLNB) versus axillary lymph node dissection (ALND).

METHODS

The sensitivity, specificity, positive and negative predictive value (PPV, NPV), and accuracy of FDG PET/CT and CT for axillary lymph node metastases were determined in 61 patients (gold standard: histopathology). According to the equation "NPV = specificity (1-prevalence) / [specificity (1-prevalence) + (1-sensitivity) prevalence]" FDG PET/CT was evaluated as a triage tool for SLNB versus ALND.

RESULTS

The sensitivity, specificity, PPV, NPV and accuracy of FDG PET/CT was 58, 92, 82, 77 and 79% and of CT 46, 89, 72, 71 and 72%, respectively. Patients with an up to approximately 60% risk for axillary lymph node metastases appear to be candidates for SLNB provided that the axilla is unremarkable on FDG PET/CT.

CONCLUSION

FDG PET/CT cannot replace invasive approaches for axillary staging but may extend the indication for SLNB.

Inference for constrained estimation of tumor size distributions

SUMMARY

In order to develop better treatment and screening programs for cancer prevention programs, it is important to be able to understand the natural history of the disease and what factors affect its progression. We focus on a particular framework first outlined by Kimmel and Flehinger (1991, Biometrics, 47, 987-1004) and in particular one of their limiting scenarios for analysis. Using an equivalence with a binary regression model, we characterize the nonparametric maximum likelihood estimation procedure for estimation of the tumor size distribution function and give associated asymptotic results. Extensions to semiparametric models and missing data are also described. Application to data from two cancer studies is used to illustrate the finite-sample behavior of the procedure.

Micrometastases in cervical lymph nodes from patients with squamous carcinoma of the head and neck: should they be actively sought? Maybe

Techniques are now being developed, which allow ever smaller metastatic deposits in regional lymph nodes to be detected; the question is, should they be sought, or does their presence convey no additional information for treatment of head and neck carcinoma patients at this time? Preliminary findings have suggested that the presence of micrometastases may carry with it some prognostic information, and as a consequence, the search for micrometastases would, for the foreseeable future, appear to be a fertile ground for investigation. To bring some uniformity to this project, it is suggested that these definitions be adopted: a micrometastasis measures greater than 0.2 mm but less than 2.0 mm in diameter, and smaller deposits should be designated as isolated tumor cells, which, in turn, are subdivided into those isolated tumor cells detected by light microscopy, immunohistochemistry, or molecular methods. At this juncture, the import of such micrometastases remains in the realm of the clinical investigator--it remains an open question whether the identification of micrometastases (however they may ultimately come to be defined) will prove to have an impact on the care of head and neck cancer patients.

Management of breast cancer in pregnancy

The concurrent diagnosis of breast cancer and pregnancy remains a challenging clinical situation. Ethical concerns regarding maternal and fetal well-being and potential risks and harms of treatment influence the clinical decision process. Ethical considerations of treatment initiation have emphasized the role of autonomy for the patient and the concept of beneficence and non-maleficence for patient and fetus. Limited prospective data are available to assist the physician and patient in making an informed decision. Recent data on diagnosis, evaluation, and management of pregnant patients with breast cancer have informed the development of international recommendations and guidelines for management of breast cancer during pregnancy. This article reviews the epidemiology, clinical presentation, diagnosis, therapy, and outcomes of breast cancer occurring concomitantly with pregnancy.

Contraindications of sentinel lymph node biopsy: are there any really?

BACKGROUND

One of the most exciting and talked about new surgical techniques in breast cancer surgery is the sentinel lymph node biopsy. It is an alternative procedure to standard axillary lymph node dissection, which makes possible less invasive surgery and side effects for patients with early breast cancer that wouldn't benefit further from axillary lymph node clearance. Sentinel lymph node biopsy helps to accurately evaluate the status of the axilla and the extent of disease, but also determines appropriate adjuvant treatment and long-term follow-up. However, like all surgical procedures, the sentinel lymph node biopsy is not appropriate for each and every patient.

METHODS

In this article we review the absolute and relative contraindications of the procedure in respect to clinically positive axilla, neoadjuvant therapy, tumor size, multicentric and multifocal disease, in situ carcinoma, pregnancy, age, body-mass index, allergies to dye and/or radio colloid and prior breast and/or axillary surgery.

RESULTS

Certain conditions involving host factors and tumor biologic characteristics may have a negative impact on the success rate and accuracy of the procedure. The overall fraction of patients unsuitable or with multiple risk factors that may compromise the success of the sentinel lymph node biopsy, is very small. Nevertheless, these patients need to be successfully identified, appropriately advised and cautioned, and so do the surgeons that perform the procedure.

CONCLUSION

When performed by an experienced multi-disciplinary team, the SLNB is a highly effective and accurate alternative to standard level I and II axillary clearance in the vast majority of patients with early breast cancer.

Sentinel Lymph Node Biopsy During Pregnancy: Initial Clinical Experience

The diagnosis of breast cancer or melanoma in a pregnant patient presents some unique and difficult challenges for both patients and providers. Lymphatic mapping and sentinel lymph node (SLN) biopsy has become an attractive alternative to elective lymphadenectomy procedures for patients with breast cancer and melanoma. However, there is no data on the safety or utility of sentinel node mapping in pregnant patients. Therefore, we reviewed our experience with mapping in gravid patients. Academic institutions throughout North Carolina were asked to contribute cases of mapping performed during pregnancy. A total of nine women underwent sentinel node mapping during pregnancy. All nine were Caucasian with an average age of 32. SLN were found in all cases and mapping procedures were for breast cancer (three), and melanoma (six). There were no adverse reactions to the SLN procedures and one patient developed a seroma at a biopsy site. All went on to have term deliveries without known adverse effects. This limited experience shows that SLN mapping procedures are feasible in pregnant patients. However, this is not a general endorsement of such procedures in pregnant patients. We suggest that potential risks of vital dye or radioactive tracers be clearly explained to the parents when the mother is a candidate for a mapping procedure, and be balanced against the risk of delaying therapy or omitting nodal staging.