Sentinel nodes of malignancies originating in the alimentary tract

Luminescent copper indium sulfide (CIS) quantum dots for bioimaging applications

Copper indium sulfide (CIS) quantum dots are ideal for bioimaging applications, by being characterized by high molar absorption coefficients throughout the entire visible spectrum, high photoluminescence quantum yield, high tolerance to the presence of lattice defects, emission tunability from the red to the near-infrared spectral region by changing their dimensions and composition, and long lifetimes (hundreds of nanoseconds) enabling time-gated detection to increase signal-to-noise ratio. The present review collects: (i) the most common procedures used to synthesize stable CIS QDs and the possible strategies to enhance their colloidal stability in aqueous environment, a property needed for bioimaging applications; (ii) their photophysical properties and parameters that affect the energy and brightness of their photoluminescence; (iii) toxicity and bioimaging applications of CIS QDs, including tumor targeting, time-gated detection and multimodal imaging, as well as theranostics. Future perspectives are analyzed in view of advantages and potential limitations of CIS QDs compared to most traditional QDs.

Intraoperative biophotonic imaging systems for image-guided interventions

Biophotonic imaging has revolutionized the operation room by providing surgeons intraoperative image-guidance to diagnose tumors more efficiently and to resect tumors with real-time image navigation. Among many medical imaging modalities, near-infrared (NIR) light is ideal for image-guided surgery because it penetrates relatively deeply into living tissue, while nuclear imaging provides quantitative and unlimited depth information. It is therefore ideal to develop an integrated imaging system by combining NIR fluorescence and gamma-positron imaging to provide surgeons with highly sensitive and quantitative detection of diseases, such as cancer, in real-time without changing the look of the surgical field. The focus of this review is to provide recent progress in intraoperative biophotonic imaging systems, NIR fluorescence imaging and intraoperative nuclear imaging devices, and their future perspectives for image-guided interventions.

Sentinel node biopsy during thoracolaparoscopic esophagectomy for advanced esophageal cancer

Background

Omitting extensive lymph node dissection could reduce esophagectomy morbidity in patients without lymph node metastases. Sentinel node biopsy may identify abdominal or thoracic lymph node metastases, thereby differentiating treatment. Feasibility of this approach was investigated in Western European esophageal cancer patients with advanced disease, without lymph node metastases at diagnostic work-up.

Methods

The sentinel node biopsy was performed in eight esophageal cancer patients with cT1-3N0 disease. One day pre-operatively, Tc-99m-labeled nanocolloid was endoscopically injected around the tumor. Lymphoscintigraphy was performed 1 and 3 h after injection. All patients underwent robotic thoracolaparoscopic esophagectomy with two-field lymph node dissection. Intraoperatively, sentinel nodes were detected by gamma probe. The resection specimen was analyzed for remaining activity by scintigraphy and gamma probe.

Results

Visualization rates of lymphoscintigraphy 1 and 3 h after tracer injection were 88 and 100 %, respectively. Intraoperative identification rate was 38 %. Postoperative identification was possible in all patients using the gamma probe to analyze the resection specimen. In 5/8 patients, lymph node metastases were found at histopathology, none of which was detected by the sentinel node biopsy. No adverse events related to the sentinel node biopsy were observed.

Conclusions

In our advanced esophageal cancer patients who underwent thoracolaparoscopic esophagectomy, the sentinel node biopsy did not predict lymph node status. Probably the real sentinel node could not be identified due to localization adjacent to the primary tumor or bypassing due to metastatic tumor involvement. Therefore, we consider the sentinel node biopsy not feasible in advanced esophageal cancer.

Elimination of scattered gamma rays from injection sites using upper offset energy windows in sentinel lymph node scintigraphy

OBJECTIVE

The identification of sentinel lymph nodes (SLNs) near injection sites is difficult because of scattered gamma rays. The purpose of this study was to investigate the optimal energy windows for elimination of scattered gamma rays in order to improve the detection of SLNs.

METHODS

The clinical study group consisted of 56 female patients with breast cancer. While the energy was centred at 140 keV with a 20% window for Tc-99m, this energy window was divided into five subwindows with every 4% in planar imaging. Regions of interest were placed on SLNs and the background, and contrast was calculated using a standard equation. The confidence levels of interpretations were evaluated using a five-grade scale.

RESULTS

The contrast provided by 145.6 keV±2% was the best, followed by 140 keV±2%, 151.2 keV±2%, 134.4 keV±2% and 128.8 keV±2% in that order. When 128.8 keV±2% and 134.4 keV±2% were eliminated from 140 keV±10% (145.6 keV±6%), the contrast of SLNs improved significantly. The confidence levels of interpretation and detection rate provided by the planar images with 140 keV±10% were 4.74±0.58 and 94.8%, respectively, and those provided by 145.6 keV±6% were 4.94±0.20 and 100%.

CONCLUSION

Because lower energy windows contain many scattered gamma rays, upper offset energy windows, which exclude lower energy windows, improve the image contrast of SLNs near injection sites.

Sentinel lymph node in oesophageal cancer-a systematic review and meta-analysis

BACKGROUND

Sentinel lymph nodes (SLNs) have been used to predict regional lymph node metastasis in patients with melanoma and breast cancer. However, the validity of the SLN hypothesis is still controversial for oesophageal cancer. We performed this meta-analysis to evaluate the feasibility and accuracy of radio-guided SLN mapping for oesophageal cancer.

METHODS

A systematic search was conducted using MEDLINE, PubMed, EMBASE, Current Contents Connect, Cochrane library, Google scholar, Science Direct, and Web of Science. Original data was abstracted from each study and used to calculate a pooled event rates and 95% confidence interval (95% CI).

RESULTS

The search identified 23 relevant articles. The overall detection rate was 0.93 (95% CI: 0.894-0.950), sensitivity 0.87 (95% CI: 0.811-0.908), negative predictive value 0.77 (95% CI: 0.568-0.890) and the accuracy was 0.88 (95% CI: 0.817-0.921). In the adenocarcinoma cohort, detection rate was 0.98 (95% CI: 0.923-0.992), sensitivity 0.84 (95% CI: 0.743-0.911) and the accuracy was 0.87(95% CI: 0.796-0.913). In the squamous cell carcinoma group, detection rate was 0.89 (95% CI: 00.792-0.943), sensitivity 0.91 (95% CI: 0.754-0.972) and the accuracy was 0.84 (95% CI: 0.732-0.914).

CONCLUSIONS

It is possible to identify and obtain a SLN before neoadjuvant therapy in oesophageal cancer. However, further work is needed to optimize radiocolloid type, refine the technique and develop a quick and accurate way to determine SLN status intraoperatively. This technique has to be further evaluated before it can be applied widely.

Tumor differentiation as related to sentinel lymph node status in gastric cancer

AIM: To investigate the influence of tumor grade on sentinel lymph node (SLN) status in patients with gastric cancer (GC).

METHODS: We retrospectively studied 71 patients with GC who underwent SLN mapping during gastric surgery to evaluate the relationship between SLN status and tumor grade.

RESULTS: Poorly differentiated tumors were detected in 50/71 patients, while the other 21 patients had moderately differentiated tumors. SLNs were identified in 58/71 patients (82%). In 41 of the 58 patients that were found to have stained nodes (70.7%), the tumor was of the poorly differentiated type (group I), while in the remaining patients with stained nodes 17/58 (29.3%), the tumor was of the moderately differentiated type (group II). Positive SLNs were found in 22/41 patients in group I (53.7%) and in 7/17 patients in group II (41.2%) (P = 0.325). The rate of positivity for the SLNs in the two groups (53.7% vs 41.2%) was not statistically significant (P = 0.514).

CONCLUSION: Most of our patients were found to have poorly differentiated adenocarcinoma of the stomach and there was no correlation between tumor grade and SLN involvement.

Optimization of coded aperture radioscintigraphy for sentinel lymph node mapping

PURPOSE

Radioscintigraphic imaging during sentinel lymph node (SLN) mapping could potentially improve localization; however, parallel-hole collimators have certain limitations. In this study, we explored the use of coded aperture (CA) collimators.

PROCEDURES

Equations were derived for the six major dependent variables of CA collimators (i.e., masks) as a function of the ten major independent variables, and an optimized mask was fabricated. After validation, dual-modality CA and near-infrared (NIR) fluorescence SLN mapping were performed in pigs.

RESULTS

Mask optimization required the judicious balance of competing dependent variables, resulting in sensitivity of 0.35%, XY resolution of 2.0 mm, and Z resolution of 4.2 mm at an 11.5-cm field of view. The findings in pigs suggested that NIR fluorescence imaging and CA radioscintigraphy could be complementary, but present difficult technical challenges.

CONCLUSIONS

This study lays the foundation for using CA collimation for SLN mapping, and also exposes several problems that require further investigation.

Sentinel lymph node biopsy in esophageal cancer: should it be standard of care?

INTRODUCTION

Sentinel node mapping is established in some superficial cancers but remains controversial in harder-to-access solid tumors. There are an increasing number of recent studies suggesting that isolated tumor cells have prognostic significance in predicting poor survival, in breast cancer, esophageal cancer, and others. It is for this reason that we have persevered with the sentinel lymph node concept in our esophagectomy cancer patients, and we report our results since 2008.

METHODS

Thirty-one of 32 consecutive patients underwent resection for invasive esophageal cancer along with sentinel lymph node retrieval (resection rate, 97%). Peritumoral injection of (99m)Tc antimony colloid was performed by upper endoscopy prior to the operation. A two-surgeon synchronous approach via a right thoracotomy and laparotomy was performed with a conservative lymphadenectomy. Sentinel lymph nodes were identified with a gamma probe both in and ex vivo, and sent off separately for three serial sections and immunohistochemistry with AE1/AE3.

RESULTS

The median patient age was 63.4 years (range, 45-75 years). Most patients (81%) had an adenocarcinoma, and 61% had received neoadjuvant therapy. At least one sentinel lymph node (median, 3) was identified in 29 of 31 patients (success rate, 94%). Sentinel nodes were present in more than one nodal station in 16 patients (55%). One false negative case led to a sensitivity of 90%. In 28 of 29 patients, the sentinel lymph node accurately predicted findings in non-sentinel nodes (accuracy, 96%).

CONCLUSIONS

Sentinel lymph node biopsy is both feasible and accurate in esophageal resections with conservative lymphadenectomy. It allows targeted serial sectioning and immunohistochemical studies of those nodes and should become standard of care in patients undergoing esophagectomy for esophageal cancer.

Tracer-cocktail injections for combined pre- and intraoperative multimodal imaging of lymph nodes in a spontaneous mouse prostate tumor model

To improve surgical guidance toward prostate draining lymph nodes, we investigate the potential of intraoperative fluorescence imaging and combined pre- and intraoperative multimodality imaging approaches. Transgenic adenocarcinoma mouse prostate mice with spontaneous prostate tumors are injected intratumorally with: 1. a cocktail of patent blue (Pb) and indocyanine green (ICG); 2. a cocktail of albumin radiocolloids (99mTc-NanoColl), Pb, and ICG; or 3. a cocktail of radiolabeled albumin (99mTc-Vasculosis), Pb, and ICG. The distribution of these imaging agents over the lymph nodes (LNs) are studied at different time points after injection. We find that at 60-min postinjection, ICG significantly improves the detection of the LNs compared to Pb, 53 versus 7%, respectively. Moreover, a cocktail of ICG and 99mTc-NanoColl improves the fluorescent detection rate to 86%, equalling that of the clinically applied 99mTc-NanoColl. A similar overlap is observed in our initial clinical pilot data. Fluorescent detection of the LNs using a ICG with 99mTc-Vasculosis gives similar results as "free" ICG (58%; 60 min). A 99mTc-NanoColl, Pb, and cocktail ICG enriches the standard 99mTc-NanoColl approach by adding optical detection of the sentinel lymph nodes. Furthermore, this approach improves fluorescent-based guidance and enables both accurate surgical planning and intraoperative detection, based on a single injection.

(Non-targeted) radioactive/fluorescent nanoparticles and their potential in combined pre- and intraoperative imaging during sentinel lymph node resection

One clinical precedent for the use of nanosized imaging agents is the localization of the tumor draining sentinel lymph nodes. In this application, radiocolloids such as (99m)Tc-NanoColl are currently used to plan the surgical procedure and to provide acoustic guidance during the intervention. Additional injections of dyes are common to provide optical surgical guidance. Bimodal imaging agents, which are both radioactive and fluorescent, have the potential to be used for both surgical planning and intraoperative fluorescence guidance towards the sentinel lymph nodes. This review provides an overview of the radioactive, fluorescent, and size properties of (non-targeted) bimodal nanoparticles, and their (potential) value in sentinel lymph node detection.

Feasibility study of sentinel lymph node biopsy in esophageal cancer with conservative lymphadenectomy

INTRODUCTION

Lymphoscintigraphy and sentinel node mapping is established in breast cancer and melanoma but not in esophageal cancer, even though many centers have shown that occult tumor deposits in lymph nodes influence prognosis. We report our initial experience with lymphoscintigraphy and sentinel lymph node biopsy in patients undergoing resection for esophageal cancer.

METHODS

Sixteen of 17 consecutive patients underwent resection for invasive esophageal cancer along with sentinel lymph node retrieval (resection rate, 94%). Peritumoral injection of (99m)Tc antimony colloid was performed by upper endoscopy prior to the operation. A two-surgeon synchronous approach via right thoracotomy and laparotomy was performed with conservative lymphadenectomy. Sentinel lymph nodes were identified using a gamma probe both in vivo and ex vivo. Sentinel lymph nodes were sent off separately for serial sections and immunohistochemistry.

RESULTS

Median patient age was 60.4 years (range, 45-75 years). Fifteen were male, and thirteen had adenocarcinoma. At least one sentinel lymph node (median, 2) was identified in 14 of 16 patients (success rate, 88%). Sentinel nodes were present in more than one nodal station in five patients (31%). In all 14 patients, the sentinel lymph node accurately predicted findings in non-sentinel nodes (accuracy, 100%). Three patients with positive sentinel lymph nodes had metastases identified in non-sentinel nodes (sensitivity, 100%).

CONCLUSIONS

Sentinel lymph node biopsy is feasible in esophageal resection with conservative lymphadenectomy, and initial results suggest it is accurate in predicting overall nodal status. Further study is needed to assess impact on patient management and prognosis.

Sentinel lymph node mapping with type-II quantum dots

Sentinel lymph node (SLN) mapping is an important cancer surgery during which the first lymph node draining the site of a tumor is identified, resected, and analyzed for the presence or absence of malignant cells. Fluorescent semiconductor nanocrystals (quantum dots [QDs]) of the appropriate size, charge, and emission wavelength permit this surgery to be performed rapidly, with high sensitivity and under complete image guidance. We describe the materials and methods necessary for the production and characterization of type-II near-infrared fluorescent QDs, which have been optimized for SLN mapping. They contain a CdTe core, CdSe shell, and a highly anionic, oligomeric phosphine organic coating. We also describe how to utilize such QDs in animal model systems of SLN mapping.

Detection of metastatic disease with sentinel lymph node dissection in colorectal carcinoma patients

BACKGROUND

In curative colorectal cancer surgery, radical lymph node dissection is essential for staging and decision-making for adjuvant treatment.

PURPOSE

The aims of the study were to analyse to what extent sentinel lymph node dissection (SLND) in colorectal cancer could upstage N0 patients and how lymphatic mapping could demonstrate micrometastatic disease.

PATIENTS AND METHODS

In a prospective study, patients were selected by CT scanning, avoiding bulky disease and distant metastasis. When standard staining (HE) was negative, micrometastases were searched for by immunohistochemistry (cytokeratin 11, CEA and Ca19-9 antibodies). Micrometastatic lymph nodes were classified N+(i).

RESULTS

Detection of sentinel lymph nodes was successful in 48 out of 52 colorectal cancer patients. Among the 44 M0 patients, 22 were N0 (i-) and 22 were N+ (13 with standard HE procedure, three were N+ (macrometastasis) with the SN as the only positive node and six patients had 1-4 micrometastatic SN (N+(i)). An overall potential upstaging of 9/44 could be considered after SLND. With a mean follow-up of 48 months survival, analysis showed that disease-specific survival of the group of six N+(i) patients was intermediate between the group of 22 N0 (i-) patients and the group of 16 N+ patients.

CONCLUSION

SLND may improve the detection of metastasis in conventionally bivalved nodes. Further studies could assess if micrometastatic disease detected in SN could be integrated into the risk factors for stage II patients in order to consider adjuvant chemotherapy.

Radioguided occult lesion localisation in breast cancer using an intraoperative portable gamma camera: first results

PURPOSE

The role of the radioguided occult lesion localisation (ROLL) technique in breast cancer has been increasing in recent years. One of the important drawbacks of such a technique is radiotracer spillage within the mammary gland that makes the precise lesion resection difficult, and this requires the use of a hook-wire collocation to reach the lesion. The possibility of obtaining an intraoperative image of the specimen could help to confirm whether the lesion is correctly removed. Some types of portable gamma cameras have been designed, but up to now, intraoperative use has been confined to surgery of parathyroid adenomas and sentinel lymph node location. The aim of the study was to value the usefulness of an intraoperative gamma camera to assess the resection of non-palpable breast lesions.

MATERIALS AND METHODS

The study involved 42 women diagnosed with non-palpable early breast cancer. Lymphoscintigraphy was performed on the day before surgery by injection of (99m)Tc-labelled nanocolloid. During surgery a gamma probe was used to guide the surgeon, and afterwards images of the surgical bed and the tumoral specimen were acquired by means of a portable gamma camera, fitted with a pinhole collimator. A (99m)Tc pointer was used to draw an outline image around the specimen.

RESULTS

On lymphoscintigraphy, radiotracer was concentrated in 31 cases. During surgery, all lesions were removed. In the images acquired by the portable gamma camera, the lesion was centred inside the surgical specimen in 23 of 42 cases, non-centred in 15 and in contact in 4 cases. Congruence of 60% was found between the intraoperative images and the histopathological results. The posterior margin was the most frequently involved. The whole acquisition time for the tumoral specimen with its margins was 5 min at most.

CONCLUSION

The use of portable gamma cameras in theatre is in an early phase. The short period of time required during the surgical procedure will allow the surgical team to improve this technique until it can replace hand-held probes. The intraoperative acquisition of such images can predict the involvement of surgical margins, avoiding future surgical procedures.

Stereoscopic scintigraphic imaging of breast cancer sentinel lymph nodes

BACKGROUND

Lymphoscintigraphy is used preoperatively to identify sentinel lymph nodes (SLNs). Conventional planar scintigraphy cannot provide three-dimensional(3D) information for SLN biopsy. We applied stereoscopic imaging to preoperative lymphoscintigraphy to obtain 3D information and evaluated its usefulness.

METHODS

Forty-four clinical stage I breast cancer patients (1 male, 43 females; age, 59.4+/-11.4 years) were enrolled in this study. Three hours after the injection of Tc-99m, 10 degrees of oblique images and routine anterior and lateral images were acquired. Anterior and lateral stereoscopic images were obtained in all studies, except for 2 patients; only lateral views were done for those. Two experienced radiologists enumerated the visualized hot nodes.

RESULTS

Stereoscopic imaging delineated more hot axillary lymph nodes compared to routine planar imaging in 8 of 42 patients (19.0%) on anterior view, 5 of 44 patients (11.4%) on lateral view, and 11 of 44 patients (25.0%) on either the anterior or lateral view. Statistically significant differences were observed between stereoscopic and routine planar imaging method on the anterior (p=0.012) and the lateral views (p=0.043). The stereoscopic imaging provided 3D information and effectively separated closely located hot nodes that were viewed as one hot node on conventional planar images. Thirty-eight out of 42 cases (90%) with anterior stereoscopic images identified the same number or more axillary hot nodes compared with lateral stereoscopic images.

CONCLUSION

The stereoscopic imaging method could improve the preoperative identification of SLNs. This method is technically simple, and could be a powerful diagnostic tool for SLN imaging breast cancer.

Gastroesophageal carcinoma: individualized surgical therapy

During the twentieth century, surgical management of gastroesophageal carcinoma was developed by an establishment of standard procedures with lymph node dissection according to the metastatic distribution. The "fear" of invisible micrometastasis caused surgeons to perform more aggressive resection with lymphadenectomy to control the disease locally. Although several promising results of extensive lymph node dissection have been reported, the prognostic benefits of extensive surgery have not been proven by prospective randomized trials. A novel technology to detect micrometastasis without extensive surgical resection is required to gastroesophageal carcinoma. The lymphatic mapping technique is one of the attractive candidates for a novel tool to approach this issue.

Multimodal fusion imaging ensemble for targeted sentinel lymph node management: initial results of an innovative promising approach for anatomically difficult lymphatic drainage in different tumour entities

PURPOSE

There are situations where exact identification and localisation of sentinel lymph nodes (SLNs) are very difficult using lymphoscintigraphy, a hand-held gamma probe and vital dye, either a priori or a posteriori. We developed a new method using a simultaneous injection of two lymphotropic agents for exact topographical tomographic localisation and biopsy of draining SLNs. The purpose of this prospective pilot study was to investigate the feasibility and efficacy of this method ensemble.

METHODS

Fourteen patients with different tumour entities were enrolled. A mixture of (99m)Tc-nanocolloid and a dissolved superparamagnetic iron oxide was injected interstitially. Dynamic, sequential static lymphoscintigraphy and SPECT served as pathfinders. MR imaging was performed 2 h after injection. SPECT, contrast MRI and, if necessary, CT scan data sets were fused and evaluated with special regard to the topographical location of SLNs. The day after injection, nine patients underwent SLN biopsy and, in the presence of SLN metastasis, an elective lymph node dissection.

RESULTS

Twenty-five SLNs were localised in the 14 patients examined. A 100% fusion correlation was achieved in all patients. The anatomical sites of SLNs detected during surgery showed 100% agreement with those localised on the multimodal fusion images. SLNs could be excised in 11/14 patients, six of whom had nodal metastasis.

CONCLUSION

Our novel approach of multimodal fusion imaging for targeted SLN management in primary tumours with lymphatic drainage to anatomically difficult regions enables SLN biopsy even in patients with lymphatic drainage to obscure regions. Currently, we are testing its validity in larger patient groups and other tumour entities.

Potential role of a new hand-held miniature gamma camera in performing minimally invasive parathyroidectomy

PURPOSE

Sestamibi scans have increased the use of minimally invasive parathyroidectomy (MIP) to treat primary hyperparathyroidism (PHPT) when caused by a parathyroid single adenoma. The greatest concern for surgeons remains the proper identification of pathological glands in a limited surgical field. We have studied the usefulness of a new hand-held miniature gamma camera (MGC) when used intraoperatively to locate parathyroid adenomas. To our knowledge this is the first report published on this subject in the scientific literature.

METHODS

Five patients with PHPT secondary to a single adenoma, positively diagnosed by preoperative sestamibi scans, underwent a MIP. A gamma probe for radioguided surgery and the new hand-held MGC were used consecutively to locate the pathological glands. This new MGC has a module composed of a high-resolution interchangeable collimator and a CsI(Na) scintillating crystal. It has dimensions of around 15 cmx8 cmx9 cm and weighs 1 kg. The intraoperative assay of PTH (ioPTH) was used to confirm the complete resection of pathological tissue.

RESULTS

All cases were operated on successfully by a MIP. The ioPTH confirmed the excision of all pathological tissues. The MGC proved its usefulness in all patients, even in a difficult case in which the first attempt with the gamma probe failed. In all cases it offered real-time accurate intraoperative images.

CONCLUSION

The hand-held MGC is a useful instrument in MIP for PHPT. It may be used to complement the standard tools used to date, or may even replace them, at least in selected cases of single adenomas.

Oblique view of preoperative lymphoscintigraphy improves detection of sentinel lymph nodes in esophageal cancer

Because sentinel lymph nodes (SLNs) of esophageal cancer can be widely located between the neck and the upper abdomen, lymphoscintigraphy plays an important role in their detection, but some modifications are required to clearly visualize their locations. Recently, we applied the stereoscopic imaging method by adding the 10-degree oblique view to the conventional lymphoscintigraphy for SLNs, so that we could better determine SLN locations on the basis of depth information. In this report, we describe a case in which the oblique view of the lymphoscintigram contributed to improving the visualization of a mediastinal SLN of esophageal cancer. Evaluation of the patient's chest CT image validated the notion that gamma rays from SLN are less absorbed by the surrounding soft tissues and the sternum in acquisition from the oblique view than from the true anterior view. The additional oblique view of the lymphoscintigram is useful for evaluation of the SLNs of esophageal cancer.

The feasibility and reliability of sentinel node mapping in colorectal cancer

AIMS

Sentinel node mapping (SNM) has been introduced in colorectal cancer (CRC) to improve staging by facilitating occult tumour cell (OTC) assessment in lymph nodes that are most likely to be tumour-positive. In this paper, studies on the feasibility and reliability of SNM in CRC are reviewed.

METHODS

A literature search was conducted in the National Library of Medicine by using the keywords colonic, rectal, colorectal, neoplasm, adenocarcinoma, cancer and sentinel. Additional articles were identified by cross-referencing from papers retrieved in the initial search.

RESULTS

There is a large variation in identification rates and false-negative rates mainly due to the learning curve effect, differences in SNM technique and tumour stage.

CONCLUSIONS

We conclude that SNM in CRC is technically feasible. Standardization of SNM procedures is mandatory to resolve the debate on the reliability of sentinel node status for predicting the tumour status of all lymph nodes. Only then can adjuvant treatment of patients upstaged by OTC detection in sentinel nodes be justified.

Multimodal treatment of gastrointestinal tract tumors: consequences for surgery

Formerly an exclusive business of surgery, gastrointestinal (GI) tumors are nowadays increasingly approached with multimodal strategies. Neoadjuvant concepts have had a particularly far-reaching impact on surgery and have contributed to improved survival. Modern pre-treatment staging and risk assessment provide the basis for decision on one of three general treatment concepts (1) Early cancers, confined to the mucosal/submucosal layers, are approached with primary surgery, without prior antineoplastic therapy. (2) Systemically metastasized tumors receive merely palliative treatment. (3) Locally advanced cancers are increasingly approached with neoadjuvant strategies. The benefit from these preoperative protocols is proven for diverse entities, but is evidently confined to a specific subgroup patients, i.e., the responders to neoadjuvant treatment. These are the ones benefiting most from subsequent surgical resection, which is required to ensure complete removal of the residual tumor tissue, as complete tumor regression occurs very rarely and cannot be proven without a specimen. The fact that responders will benefit and non-responders will not benefit or will even deteriorate during the neoadjuvant treatment makes early response prediction most demanding. An amazing new approach is the use of position emission tomography with fluro-desoxyglucose (FDG-PET) to assess the "metabolic response," which is possible as early as 14 days after initiation of the neoadjuvant protocol. This strategy offers the chance for modulating the surgical approach in accord i.e., with such metrobolic response termination of the protocol and proceeding to resection in the case of nonresponse. The future of GI cancer surgery is multimodal therapy in a response-based fashion and requires reponse-based trials for further evaluation.

Organic Alternatives to Quantum Dots for Intraoperative Near-Infrared Fluorescent Sentinel Lymph Node Mapping

Intraoperative near-infrared (NIR) fluorescence imaging provides the surgeon with real-time image guidance during cancer and other surgeries. We have previously reported the use of NIR fluorescent quantum dots (QDs) for sentinel lymph node (SLN) mapping. However, because of concerns over potential toxicity, organic alternatives to QDs will be required for initial clinical studies. We describe a family of 800 nm organic heptamethine indocyanine-based contrast agents for SLN mapping spanning a spectrum from 775 Da small molecules to 7 MDa nanocolloids. We provide a detailed characterization of the optical and physical properties of these contrast agents and discuss the advantages and disadvantages of each. We present robust methods for the covalent conjugation, purification, and characterization of proteins with tetra-sulfonated heptamethine indocyanines, including mass spectroscopic site mapping of highly substituted molecules. One contrast agent, NIR fluorescent human serum albumin (HSA800), emerged as the molecule with the best overall performance with respect to entry to lymphatics, flow to the SLN, retention in the SLN, fluorescence yield and reproducibility. This preclinical study, performed on large animals approaching the size of humans, should serve as a foundation for future clinical studies.

Credentialing of nuclear medicine physicians, surgeons, and pathologists as a multidisciplinary team for selective sentinel lymphadenectomy

There are several possible applications of the sentinel lymph node (SLN) concept with different technological aspects such as individualized surgical management of solid tumors, multidisciplinary treatments, and novel therapeutic approaches. To achieve these clinical applications, multidisciplinary teamwork with surgeons, nuclear medicine physicians, and pathologists would be critically required. Interdisciplinary issues should be resolved in order to develop optimal standard procedures of SLN dissection for various solid tumors.