Lymphoscintigraphy, the sentinel node concept, and the intraoperative gamma probe in melanoma, breast cancer, and other potential cancers

Localization of sentinel nodes in breast cancer: novel method and device to help pen marking of active nodes during gamma camera imaging

Gamma camera imaging with Tc-99m marking is a widely used method to locate sentinel lymph nodes (SNs) in breast cancer patients. Prior to SN biopsy, the anterior and lateral location of the SN is marked on the patient's skin using an ink pen. The pen marks guide the surgeon during an operation. However, in many cases the marking is difficult due to limited space under the detectors of a gamma camera. The aim of this study was to improve the pen marking method. Eleven female patients were imaged 3-4 h after injection of Tc-99m labelled Nanocol. Injection was performed to parenchyma surrounding the breast tumour. To facilitate pen marking, two polycarbonate (PC) plates with 40 x 32 holes (spacing=10 mm) were engineered for anterior and lateral side imaging and then installed on the bed of a dual-head gamma camera. Two drops of Tc-99m were placed into the top corners of both the PC plates, in order to trace the corresponding x-y coordinates first from the acquired images and then from the plates. After imaging, the x-y coordinates of the SN(s) were determined from the anterior and lateral side images. Subsequently, the location of each SN was marked with an ink pen on the skin through the small holes in the PC plates. According to the surgeon's evaluation, the distance between the marks and the true location of the SNs was 4.5+/-6.9 mm. Measurements with a custom made phantom revealed that the accuracy of the novel method was significantly (P=0.06) higher as compared with the traditional method (2.7+/-3.0 mm versus 9.2+/-3.0 mm). In addition, we were not able to mark the weakest activity (0.02 MBq) with the traditional method. Taken together, the marking process was considerably easier with the novel method, it had better accuracy and sensitivity than the traditional method and the device is simple enough to be adapted for most gamma cameras.

Role of lymphoscintigraphy for selective sentinel lymphadenectomy

An essential prerequisite for a successful sentinel node biopsy (SNB) procedure is an accurate map of the pattern of lymphatic drainage from the primary tumor site. The role of lymphoscintigraphy (LS) in SNB is to provide such a map in each patient. This map should indicate not only the location of all sentinel nodes but also the number of SNs at each location. Such mapping can be achieved using 99mTc-labeled small particle radiocolloids, high-resolution collimators with minimal septal penetration, and imaging protocols that detect all SNs in every patient regardless of their location. This is especially important in melanoma patients, since high-quality LS can identify the actual lymphatic collecting vessels as they drain into each SN. The SN is not always found in the nearest node field and is best defined as "any lymph node receiving direct lymphatic drainage from a primary tumor site." Reliable clinical prediction of lymphatic drainage from the skin or breast is not possible. Patterns of lymphatic drainage from the skin are highly variable from patient to patient, even from the same area of the skin. Unexpected lymphatic drainage has been found from the skin of the back to SNs in the triangular intermuscular space and in some patients through the posterior body wall to SNs in the para-aortic, paravertebral, and retroperitoneal areas. Lymphatic drainage from the head and neck frequently involves SNs in multiple node fields, and can occur from the base of the neck up to nodes in the occipital or upper cervical areas or from the scalp down to nodes at the neck base, bypassing many other node groups. Lymphatic drainage from the upper limb can be directly to SNs above the axilla. Drainage to the epitrochlear region from the hand and arm is more common than was previously thought as is drainage to the popliteal region from the foot and leg. Interval nodes, which lie along the course of a lymphatic vessel between a melanoma site and a recognised node field, are not uncommon especially on the trunk. Drainage across the midline of the body is quite frequent on the trunk and in the head and neck region. In breast cancer, although dynamic imaging is usually not possible, an early postmassage image will also often visualize the lymphatic vessels leading to the SN allowing them to be differentiated from any second tier nodes. Small radiocolloid particles are also needed to achieve migration from peritumoral injections sites and LS allows accurately detection of SNs outside the axilla, which occur in about 50% of patients. These nodes may lie in the internal mammary chain, the supraclavicular region, or the interpectoral region. Intramammary interval nodes can also be SNs in some patients. The location of the cancer in the breast is not a reliable guide to lymphatic drainage, since lymph flow often crosses the center line of the breast. Micrometastatic disease can be present in any SN regardless of its location, and for the SNB technique to be accurate all true SNs must be identified and removed in every patient. LS is an important first step in ensuring that this goal is achieved.

99mtc-labeled mannosyl-neoglycoalbumin for sentinel lymph node identification

99mTc-labeled mannosyl-neoglycoalbumin (NMA) was prepared and evaluated as a radiopharmaceutical for sentinel lymph node (SLN) identification, since 99mTc-labeled human serum albumin (HSA) rapidly cleared from injection sites. NMA was conjugated with 6-hydrazinopyridine-3-carboxylic acid (HYNIC) and reacted with [99mTc](tricine)2 to prepare [99mTc](HYNIC-NMA)(tricine)2. After subcutaneous injection of [99mTc](HYNIC-NMA)(tricine)2 from murine foot pad, radioactivity levels in the popliteal and lumbar lymph nodes, the injection site and other tissues were compared with those of [99mTc](HYNIC-HSA)(tricine)2 and 99mTc-labeled colloidal rhenium sulfate ([99mTc]colloid). [99mTc](HYNIC-NMA)(tricine)2 demonstrated significantly higher radioactivity levels in the popliteal lymph node, the SLN in this model, than did [99mTc](HYNIC-HSA)(tricine)2 and [99mTc]colloid at 0.5, 1, and 6 h post-injection. [99mTc](HYNIC-NMA)(tricine)2 showed a dose-dependent decrease in the popliteal accumulation while the radioactivity levels in the blood, liver and spleen increased with an increase in the molar dose of NMA. [99mTc]colloid registered a decrease in the radioactivity levels in the popliteal lymph node, blood, liver, and spleen with dilution. However, the radioactivity levels at the injection site increased with dilution of [99mTc] colloid. Both [99mTc](HYNIC-NMA)(tricine)2 and [99mTc](HYNIC-HSA)(tricine)2 showed the radioactivity levels at the injection site similar each other. These findings indicated that an addition of a macrophage binding function to 99mTc-labeled HSA provided high and selective accumulation of the radioactivity in the SLN without affecting the elimination rate from the injection site. Such characteristics render [99mTc](HYNIC-NMA)(tricine)2 attractive as a radiopharmaceutical for SLN identification. This study also demonstrated that the number of non-radiolabeled colloidal particles and the molar dose of mannosylated compounds play a crucial role in the SLN accumulation.

Molecular imaging in breast cancer

Since the 1960s, bone scanning has played a major role in the management of breast cancer. In the last decade, however, the role of radionuclide molecular imaging has expanded significantly in the clinical management of breast cancer because of fluorodeoxyglucose positron emission tomography, mammoscintigraphy, and sentinel lymph node techniques. Molecular imaging also is instrumental in drug development,gene therapy, and in basic science research of breast cancer. This article provides a comprehensive review of the role of molecular imaging of breast cancer in clinical practice and reports on the current state of research in this field.

Lymphatic drainage of the skin

A successful sentinel lymph node biopsy (SLNB) in melanoma patients requires an accurate map of the pattern of lymphatic drainage from the primary site. Lymphoscintigraphy (LS) can provide such a map. LS needs an understanding of lymphatic physiology, an appropriate small-particle radiocolloid, high-resolution collimators, and imaging protocols that detect all sentinel nodes (SNs). Patterns of lymphatic drainage from the skin are not clinically predictable. Unexpected drainage has been found from the skin of the back to SNs in the triangular intermuscular space (TIS) and the paraaortic, paravertebral, and retroperitoneal areas. It can also occur from the base of the neck up to nodes in the occipital or upper cervical areas or from the scalp down to nodes at the neck base, bypassing many node groups. Upper limb drainage can be to SNs above the axilla. Interval nodes not uncommonly can be SNs, especially on the trunk. Lymphatic drainage may involve SNs in multiple nodal fields, and drainage across the midline of the body is quite common. Because micrometastatic disease can be present in any SN regardless of its location, all true SNs must be biopsied. LS is an important first step to ensure this goal is achieved.

Nuclear medicine aspects of melanoma and breast lymphatic mapping

A successful sentinel lymph node biopsy (SLNB) procedure in melanoma or breast cancer patients requires an accurate map of the pattern of lymphatic drainage from the primary site. Lymphoscintigraphy (LS) can provide such a map in each patient. This requires an understanding of lymphatic physiology, an appropriate small particle radiocolloid, high resolution collimators, and imaging protocols that detect all sentinel nodes (SNs) in every patient regardless of their location. The SN is not always found in the nearest node field and is best defined as "any lymph node receiving direct lymphatic drainage from a primary tumor site." Patterns of lymphatic drainage from the skin are not clinically predictable and unexpected drainage has been found from the skin of the back to SNs in the triangular intermuscular space or through the posterior body wall to SNs in the paraaortic, paravertebral, and retroperitoneal areas. Drainage from the head and neck is to unexpected nodes in 30% of patients. Upper limb drainage can be to SNs above the axilla. Interval nodes are not uncommon as SNs, especially on the trunk. Lymphatic drainage may involve SNs in multiple node fields and drainage across the midline of the body is quite common. In the breast, although 94% of patients have a SN in the ipsilateral axilla, 46% also have SNs outside the axilla, especially in the internal mammary chain (40%). Failure to biopsy all SNs in each patient thus has the potential to understage a significant number of patients with breast cancer. Micrometastatic disease can be present in any SN regardless of its location, and for the SLNB technique to be accurate a biopsy most be performed on all true SNs in every patient. LS is an important first step to ensure this goal is achieved.

La technique du ganglion sentinelle et ses applications cliniques

INTRODUCTION

The sentinel lymph node (SLN) procedure consists of finding the first lymph node encountered by lymphatic vessels draining a tumor. This technique identifies the SLN histological status, which is representative of all the other draining area lymph nodes' status.

EXEGESIS

SLN identification requires the injection of a lymphatic tracer, which could be either a blue dye or radiolabeled particles, or both. Performing a lymphoscintigraphy, which identifies and quantitates SLNs is a possibility provided by the use of radiolabeled particles before a gamma probe guided search is performed intraoperatively. Finally, a specific histopathological methodology involving serial sections of the entire SLN and immunohistochemistry is also required.

CONCLUSION

This technique is applicable to melanoma in which the SLN status might be a stronger prognostic factor than Breslow's thickness; to breast cancer in order to avoid full axillary lymph node dissection in patients with small tumors; and potentially to other carcinomas.

Radioguided sentinel lymph node biopsy in patients with malignant cutaneous melanoma: the nuclear medicine contribution

As for other solid tumors, malignant cutaneous melanoma drains in a logical way through the lymphatic system, from the first to subsequent levels. Therefore, the first lymph node encountered (the sentinel node) will most likely be the first to be affected by metastasis, and a negative sentinel node makes it highly unlikely that other nodes in the same lymphatic basin are affected. Sentinel lymph node biopsy distinguishes patients without nodal metastases, who can avoid nodal basin dissection with its associated risk of lymphedema, and those with metastatic involvement who might benefit from additional therapy. This procedure represents a significant advantage as a minimally invasive procedure, considering that only an average 20% of melanoma patients with Breslow thickness between 1.5 and 4 mm harbour metastasis in their sentinel node(s) and are therefore candidates to elective lymph node dissection procedures. The cells that originate cutaneous melanomas are located between dermis and epidermis, a zone that drains to the inner lymphatic network in the reticular dermis, in turn to larger collecting lymphatics in subcutis. Therefore, the optimal modality of interstitial administration of radiocolloids for lymphoscintigraphy and subsequent radioguided sentinel lymph node biopsy is through intradermal/subdermal injection. (99m)Tc-labeled colloids in various size ranges are equally adequate for radioguided sentinel lymph node biopsy in patients with cutaneous melanoma, depending on local experience and availability. For melanomas located in the midline area of the head, neck, and trunk, particular consideration should be given to ambiguous lymphatic drainage, which frequently requires interstitial administration virtually all around the tumor or surgical scar from prior excision of the melanoma. Lymphoscintigraphy is an essential part of radioguided sentinel lymph node biopsy because images are used to direct the surgeon to the sites of the node(s). The sentinel lymph node should have a significantly higher count than that of background (at least 10:1 intraoperatively). After removal of the sentinel node, the surgical bed must be reexamined to ensure that all radioactive sites are identified and removed for analysis. The success rate of radioguidance in localizing the sentinel lymph node in melanoma patients is about 98% in institutions where a high number of procedures are performed, approaching 99% when combined with the vital blue dye technique. The procedure is becoming the standard of care for patients with cutaneous melanoma because of its high prognostic value that has led to include the procedure in the most recent version of the TNM staging system.

Understanding the radiolabelling mechanism of 99mTc-antimony sulphide colloid

The chemistry of antimony trisulphide colloid (ATC) was examined to elucidate the radiolabelling mechanism with 99mTcO4(-). Ion exchange chromatography and atomic absorption spectrophotometry techniques determined ATC to be resistant to hydrolysis in 0.1M hydrochloric acid (HCl) at 25 degrees C or 100 degrees C (>97% recovery, Sb3+ absent). Hydrogen sulphide gas detected did not participate in the mechanism, where antimony trisulphide and 99mTcO4(-) in HCl/100 degrees C yielded 96% 99mTc-product from a K2S-free formulation (versus 98% when K2S was present). 99mTcO4(-) was reduced >90% by DMSA or dithiothreitol under the same conditions, identifying involvement of thiol groups. Infrared analysis of Re-ATC showed S=O bonds, indicating excess thiol groups at the colloid surface were oxidised at the expense of 99mTcO4(-) reduction.

Near-infrared fluorescence imaging of lymph nodes using a new enzyme sensing activatable macromolecular optical probe

The aim of this study was to validate the use of near infrared fluorescence imaging (NIRF) using enzyme-sensitive optical probes for lymph node detection. An optical contrast probe that is activated by cystein proteases, such as cathepsin B, was used to visualize lymph nodes by NIRF reflectance imaging. In order to quantitate the uptake of the optical probe in lymphatic tissue, the biodistribution was assessed using the Indium-111 labeled optical probe. Sixteen Balb-c mice were injected either intravenously (i.v.) or subcutaneously (s.c.) with the NIRF-probe (2 micromol cyanine (Cy)/animal; i.v., n=10; s.c., n=6) and imaged 24 h after injection. Signal intensities and target-to-background ratios of various lymph nodes were measured by manual regions of interest (ROIs). Additional signal intensity measurements were performed of excised lymph nodes (n=21) from i.v. injected mice (24 h after injection) and compared with excised lymph nodes (n=8) of non-injected mice. The probe employed in this study was lymphotropic with approximately 3-4% accumulation in lymph nodes (3.4+/-0.8% ID/g). Measurements of the excised lymph nodes (after i.v. injection) confirmed a significant increase in lymph node fluorescence signal from baseline 26+/-7.6 arbitary units (AU) to 146+/-10.9 AU (p<0.0001). A significant increase in lymph node fluorescence signal was also seen in vivo throughout the body after i.v. injection (96+/-7.8 AU) and/or regionally after s.c. injection (141+/-11.5 AU) in comparison with baseline autofluorescence (26+/-7.6 AU). Target-to-background ratio was significantly higher after s.c. injection (6.6%+/-0.81) compared with i.v. injection (4.8+/-0.67%). Detection and visualization of lymph nodes is feasible by NIRF imaging using a cystein-protease sensitive optical probe.

Sentinel node mapping in patients with malignant melanoma using melanoma Tc-99m colloidal rhenium sulfide

PURPOSE

The aim of the study was to localize the sentinel lymph node using lymphoscintigraphy aided by Tc-99m colloidal rhenium sulfide.

MATERIALS AND METHODS

Thirty consecutive patients with histologically proved melanoma, but no clinical evidence of metastases, were examined before operation by injecting 20 to 40 MBq (0.5 to 1.1 mCi) Tc-99m colloidal rhenium sulfide with a mean particle size of 100 nm (range, 50 to 200 nm) intradermally around the lesion. Lymphoscintigraphy was performed immediately after injection. In addition, blue dye was injected before operation. A hand-held gamma probe guided the sentinel node biopsy.

RESULTS

Lymphoscintigraphy revealed hot spots in all patients. During surgery, the sentinel node was identified in all 30 patients. The number of sentinel nodes per patient ranged from 1 to 4 (mean, 1.9). Histologic examination confirmed the metastatic involvement of the sentinel lymph node in 11 of 30 patients. The sentinel lymph node-positive rate was 22.4%, which was comparable to findings using Tc-99m-labeled nanocolloids.

CONCLUSION

The findings indicate that Tc-99m-bound colloidal rhenium sulfide is suitable for sentinel node mapping.

[Preliminary results of the relevance the sentinel node in head and neck tumors]

OBJECTIVES

The objective of this study is to assess the value of the sentinel node (SN) in head and neck tumours and to create a lymphatic mapping of these tumors.

PATIENTS AND METHODS

We prospectively studied 13 patients with head and neck tumours N0. We divided these patients in two groups depending on the location of the primary tumour. We injected colloidal particles of serum albumin labeled with Tc-99 peritumoraly and we located the SN intraoperatively. The SN was then sent for anatomopathological study.

RESULTS

In the oropharynx and oral cavity group, with 5 patients, the SN correctly predicted the pathological status of the neck in all of them. In the group of larynx and hypopharynx, with 8 patients, in 6, the SN correctly predicted the pathological status of the neck. In 2 patients, the SN was negative for metastases but there were metastases in the neck dissection.

CONCLUSIONS

This technique represents an advance over selective dissection as an accurate method of neck staging, but its value in this field remains unclear.

Clinical significance of sentinel lymph node involvement in malignant melanoma

In the period 1997-2002, sentinel lymph node (SLN) surgery was performed on 179 primary skin melanoma patients, one to two months after the removal of the primary. Staining with patent blue was combined with an isotope technique. Histological evaluation of the sentinel lymph nodes was performed in serial sections. Immunohistochemical detection of S100, HMB-45, or Melan-A was used in the case of suspected micrometastases. Demonstration of positive sentinel lymph node was followed, preferably within 2-3 weeks, by regional block dissection. In these cases interferon-a2 in low doses or BCG immune therapy were applied as adjuvant therapy. Bimonthly follow-up of the patients included physical examination and the use of imaging techniques as specified in the melanoma protocol. Sentinel lymph node surgery was successful in 177/179 cases (98%). Positive sentinel lymph node was identified in 26/177 patients (14.7%). In node positive patients the thickness of the primary tumour was significantly greater than that of node negative ones (p<0.00001). Patients with micrometastases had significantly poorer symptom-free and overall survival by the Mantel-Cox test than those of the other group (p=0.0001 and p=0.0007 respectively). Comparison of the tumor thickness and positive SLN by discriminance analysis, yielded 81.7% and 79.9%, respectively for correct classification rates. Based on our study and data from the literature, we suggest SLN-positivity as equally strong poor prognosis factor for skin melanoma as the tumor thickness.

Pan and Sentinel Lymph Node Visualization Using a Near-Infrared Fluorescent Probe

A number of different types of agents have been employed to aid in the visualization of lymph nodes, particularly the sentinel lymph node, and to decrease the tissue destruction associated with the diagnosis of nodal metastases. The current study was performed to see if a novel macromolecular near-infrared fluorescent (NIRF) probe could be used to visualize lymph nodes after intravenous administration (pan-node visualization) or subcutaneous administration (sentinel node visualization), and serve as method for guiding dissection with interventional radiologic and surgical procedures. Cy5.5-PGC, the near-infrared dye Cy5.5 coupled to a protected graft copolymer (PGC), was injected (iv or sc) into nude mice. Twenty-four hours later white light and NIRF images were obtained on (i) the live animal, (ii) a partially dissected animal, and (iii) tissue specimens. With Cy5.5-PGC administered intravenously, axillary nodes were visualized from outside a living mouse. With partial dissection, iliac and aortic nodes were visible as concentrated foci of high-intensity NIRF signals. With subcutaneous injection in the front extremity, axillary and brachial nodes draining the injection site were easily visualized. NIRF imaging provides a nonradioactive method of visualizing lymph nodes through layers of tissue that can be employed with intravenous or subcutaneous injection.

Further data on the usefulness of sentinel lymph node identification and ultrastaging in vulvar squamous cell carcinoma

OBJECTIVE

The aim was to determine the feasibility of surgical identification and pathological ultrastaging of sentinel nodes (SNs) in vulvar carcinoma and to evaluate whether SN negativity rules out the possibility of metastasis in other nodes and can therefore avoid conventional lymphadenectomy.

MATERIAL AND METHODS

In 26 patients with vulvar squamous cell carcinoma the SNs were detected using both peritumoral injection of (99m)Tc and blue dye (isosulfan or methylene) before the surgical procedure. Dissection of the SNs was followed by standard lymphadenectomy and vulvar exeresis. For pathological ultrastaging at least eight histological sections of every node separated 400 microm were evaluated using hematoxylin & eosin and immunostaining against cytokeratin.

RESULTS

We identified the SNs in 25/26 patients (96%). In 19 patients (76%) the SN was unilateral and in 6 (24%) it was bilateral. A total of 46 SNs were isolated. Metastatic carcinoma was identified in 9 SNs from 8 patients (30.8%). Thirty-eight percent (3 of 8) patients with metastatic SNs presented micrometastasis detected only in ultrastaging. Seven (3.3%) of 239 nonsentinel nodes (non-SNs) showed metastasis. No metastatic implant was detected in non-SNs when SNs were negative in patients without clinical suspicious adenopathy (100% negative predictive value).

CONCLUSION

Inguinofemoral lymph nodes can be confidently avoided when sentinel node metastases are excluded by histological ultrastaging. This may reduce the surgical morbidity of conventional inguinofemoral lymphadenectomy, without worsening vulvar cancer prognosis.

Sentinel node biopsy with technetium-99m colloidal rhenium sulphide in patients with breast cancer

Background

Sentinel node biopsy is emerging as a technique to replace routine axillary lymph node dissection. The lymphatic mapping technique is still at a developmental stage and no standard technique exists. This study used technetium-99m colloidal rhenium sulphide with a mean particle size of 100 (range 50–200) nm for sentinel node mapping.

Methods

Eighty-seven patients with breast cancer, but no clinical evidence of axillary metastasis, were studied. One day before operation technetium-99m colloidal rhenium sulphide was injected at four points into breast tissue surrounding the tumour. Lymphoscintigraphy was performed 2 h after injection, and surgery was usually performed after 20 h. A hand-held γ probe guided sentinel node biopsy.

Results

Lymphoscintigraphy revealed axillary hot spots in all patients. During operation, the sentinel node was identified in all 87 patients (100 per cent). The number of sentinel nodes per patient ranged from 1 to 5 (mean 2). Metastatic sentinel nodes were identified in 37 of 87 patients. There were no false negatives.

Conclusion

This study suggests that technetium-99m rhenium sulphide is a suitable agent for sentinel node mapping in patients with breast cancer.

Gastrointestinal cancer and sentinel node navigation surgery

In the twentieth century, lymph node dissection based on metastatic distribution has developed as the standard procedure for surgical management of gastrointestinal cancer [1]. The fear that invisible micrometastases might be present has encouraged aggressive resection with lymphadenectomy to control the disease. However, the prognostic benefits of extensive surgery are still unknown and the universal application of radical surgery may affect surgical morbidity, mortality, and quality of life after surgery, particularly in patients without lymphatic spread. In the twenty-first century, a novel technology to detect micrometastases without extensive surgical resection is required to establish an individualized surgical management approach to gastrointestinal cancer. Lymphatic mapping techniques are now used in the control of superficial malignancies, such as malignant melanoma and breast cancer, providing a novel tool that may also be of use for gastrointestinal cancers.

Sentinel node biopsy in the breast cancer: Possibility of the avoidance of axillary node dissection

(Conclusion) This researching, and many others, indicates that in certain patients (especially T1a and T1b), under precise criteria, when SN metastases are not present, axillary dissection in the breast cancer (10, 22) and all its consequences (lymphoedeama, numbness, pain, limited movement in the shoulder joint) could be avoided. We should remember that nowadays at least 50% of women undergo axillary nodes dissection within the breast cancer operative treatment because of histopathologically negative nodes.

Localization of sentinel nodes in head and neck tumours by combined lymphoscintigraphy and bone scintigraphy

Sentinel node scintigraphy in tumours of the head and neck region was combined with bone scintigraphy to provide anatomical landmarks in order to better locate the lymph node uptake. 99Tc(m)-nanocolloid (40 MBq) was injected in the peritumour region 1 h after the administration of bone-seeking 99Tc(m)-methylene diphosphonate (200 MBq). After 5 min, A-P and lateral projections of the head and neck region were acquired. In all the 26 patients examined, the surrounding anatomy was clearly depicted. In 23 patients, the lymphatic drainage was identified within 30 min. In these patients, all hot spots appearing outside the deposited activity could be located according to the neck region classification system of the Memorial Sloan-Kettering Hospital. No lymphatic drainage was visualized in the remaining three patients. The injection of bone-seeking activity 1 h before deposition of the radiocolloid provided images visualizing soft tissues as well as skeletal structures, thus improving the topical diagnosis. Correlation with the results of surgery was not performed. The administration of a small amount of bone-seeking activity prior to sentinel node scintigraphy of head and neck tumours improves the anatomical localization of the lymph node activity.

Value of sentinel node biopsy in the management of breast cancer

AIMS

To determine the rate of detection of the sentinel node using both blue dye and radioisotope, and the accuracy with which the sentinel node histology reflects the nodal status of the axilla in a series of patients with clinically node-negative breast cancer.

PATIENTS AND METHODS

During a 32-month period from May 1998 to December 2000, 73 patients with clinically node-negative breast cancer underwent sentinel node biopsy immediately followed by formal axillary lymphadenectomy. The sentinel node(s) was identified using a combination of lymphoscintigraphy, blue dye and an intraoperative hand-held gamma probe.

RESULTS

The mean age of the 73 patients was 58 years (range 32-83 years). Twenty-six per cent (19/73) had previous surgical/excisional biopsy. Pre-operative lymphoscintigraphy was positive in 74% (54/73) of patients. Combination of blue dye and radioisotope was better than either method in isolation for identifying the sentinel node, yielding a success rate of 96% (70/73). A total of 32 cases proved to have positive nodal disease on histological examination. In 44% (14/32) of patients, the sentinel node was the only positive node. Forty-seven per cent (15/32) of patients in whom the sentinel node was positive also had positive nodes in the axillary nodal basin. There were 3/32 false negative cases, giving a false negative rate of 9.4%.

CONCLUSION

Sentinel node biopsy will have a role in the management of breast cancer. However, widespread adaptation of this technique awaits the results of prospective, randomised trials.

Lymphoscintigraphy of melanoma: lymphatic channel activity guides localization of sentinel lymph nodes, and gamma camera imaging/counting confirms presence of radiotracer in excised nodes

Lymphoscintigraphy has become a standard preoperative procedure to map the cutaneous lymphatic channel for progression of nodal metastasis of melanoma of the skin. Lymphoscintigraphy was employed to visualize lymphatic channels as a guide to identify sentinel lymph nodes (SLNs). Excised tissue was imaged with a gamma camera to verify the findings of presurgical lymphoscintigraphy. Percent counts of SLN(s) among the total counts of the excised melanoma tumor or scar tissue and SLN(s) were calculated.

METHODS

Eleven patients with cutaneous melanoma received four to ten intradermal injections of Tc-99m sulfur colloid at elual distances around the melanoma site. Images were made immediately after injection: 1 minute per image for 15 min; and then 5 minutes or 1,000,000 counts per image for 30 min. After surgery, the excised melanoma tumor or scar and SLN(s) were imaged/counted with a gamma camera. Percent counts of SLNs among the total counts of the excised melanoma tumor or scar tissue and SLNs were calculated. To validate the specimen count accuracy, an experimental phantom study was done.

RESULTS

Linear lymphatic channels were identified between the injected sites and the SLNs in each patient. Gamma camera images demonstrated radioactivity in the SLNs of all patients, verifying the lymphoscintigraphy findings. Uptake in the SLNs of ten of the eleven patients ranged from 0.4 to 7.2% (mean 2.2%) of the total counts in excised tissue. We noted that a node with lower uptake should not be ignored because a lower percent of SLN activity does not necessarily rule out existing metastasis. In two of eleven patients, histopathologic showed metastases. One patient's melanoma on the middle back had lymphatic channel activity directed to both axillae. The results of the phantom study validated accuracy of our specimen counts.

CONCLUSIONS

Because linear lymphatic channels existed between lymph nodes and the injected sites in all eleven patients, these lymphatic channels could be used as a guide for localizing SLNs. The SLNs indicated by presurgical lymphoscintigraphy were verified by postoperative gamma camera imaging, and radiotracer localization in the SLNs averaged 2.2%.

Detection of lymph node metastases in colorectal carcinoma

The detection of lymph node metastases is the single most important prognostic factor for patients with colorectal cancer. This review outlines the difficulties and methods of detecting positive lymph node metastases in this disease. An outline of traditional diagnostic methods including preoperative ultrasound and cross sectional imaging techniques are evaluated alongside newer modalities including immunoscintography and PET scanning and intraoperative radioguided imaging. Pathological methods of detecting positive nodal disease using standard histopathological staging, enhanced lymph node harvesting and determination of micrometastases are also discussed.

Sentinel node staging of early breast cancer using lymphoscintigraphy and the intraoperative gamma detecting probe

Lymphoscintigraphy combined with intraoperative gamma-probe detection of sentinel lymph nodes in patients with inoperable early primary breast cancers is effective for staging the disease. The clinical alternative is axillary lymph node dissection, which is a far more invasive procedure and is accompanied by significant morbidity. Accuracy of staging is enhanced by immunohistochemical staining of micrometastases, which pathologists can easily perform for one to three sentinel lymph nodes, but not for 20 to 30 nodes, using axillary dissection procedure. Optimum methodology is presented for performing sentinel lymph node imaging and is important for accurate identification of sentinel node(s).

Sentinel lymph node mapping in melanoma with technetium-99m dextran

PURPOSE

The aim of this work is to evaluate the capability of Tc99m B Dextran as a lymphoscintigraphic agent in the detection of the sentinel node in skin lesions.

MATERIALS AND METHODS

Forty-one patients with melanomas (39) and Merkel cell tumors (2) had perilesional intradermal injection of Tc99m-Dextran 2 hours before surgery. Serial gamma camera images and a handheld gamma probe were used to direct sentinel node biopsy.

RESULTS

In 39/41 patients, lymph channels and 52 sentinel nodes (one to three sentinel nodes/patient) could be visualized. In one patient, with a dorsal melanoma, no lymph channels or lymph nodes could be demonstrated on the images and only minimal radioactivity was found in the regional nodes with the probe. Another patient with a facial lesion failed to demonstrate lymph channels or nodes. No adverse reactions were observed.

CONCLUSION

Tc99m-Dextran provided good definition of lymph channels and sentinel node localization, without the risks related to the use of potentially hazardous labeled materials of biological origin.

Evaluation of [(99m)Tc] liposomes as lymphoscintigraphic agents: comparison with [(99m)Tc] sulfur colloid and [(99m)Tc] human serum albumin

This study investigates the use of [(99m)Tc] liposomes for the detection of sentinel lymph nodes. A variety of [(99m)Tc] liposome formulations were compared with common lymphoscintigraphic agents including [(99m)Tc] regular-sulfur colloid (SC), [(99m)Tc] 0.22 microfiltered-SC, [(99m)Tc] reduced heating time 0.22 microfiltered-SC, and [(99m)Tc] human serum albumin (HSA) in rabbits. Images were acquired for the first 60 minutes and at 24 hours, followed by tissue biodistribution study. All agents except [(99m)Tc] regular SC demonstrated good migration from the injection site. Agents were retained in the popliteal node at 24 hours to varying degrees as follows: both [(99m)Tc] filtered SC preparations > [(99m)Tc] regular SC > [(99m)Tc] liposomes > [(99m)Tc] HSA. [(99m)Tc] liposome imaging can be used to develop novel liposome compositions with improved lymph node diagnostic and drug delivery characteristics.

Can preoperative lymphoscintigraphy be used as a guide in treatment planning of breast cancer?

PURPOSE

The purpose of this study was to map the lymphatic drainage patterns of breast cancer with lymphoscintigraphy to evaluate the variability of drainage and to determine whether lymphatic mapping can help to increase the certainty of breast cancer staging.

MATERIALS AND METHODS

Fifty women with breast cancer (mean age, 49 years) were included in the study. Lymphoscintigraphy was performed with 1 mCi Tc-99m rhenium sulfide colloid in a 2-ml volume injected into the four quadrants of the peritumoral area using a 25-gauge needle. Ten-minute dynamic images and 2-hour delayed static images were obtained in the anterior and lateral positions using a gamma camera with a high-resolution collimator. All patients had a modified radical mastectomy and axillary dissection. The results were evaluated with histopathologic findings of the axilla.

RESULTS

Six patients had excision biopsies before surgery. Of 13 patients with centrally located tumors, 84% had axillary lymphatic drainage, whereas 53% drained to internal mammary lymphatics. Of 23 patients with outer quadrant tumors, 4 showed no lymphatic drainage and all of them had metastatic tumor in the axillary lymph nodes. Axillary drainage was seen in 82% of patients and internal mammary lymphatic drainage in 23%. Of eight patients with inner quadrant tumors, one patient with no lymphatic drainage was found to have metastases in the axilla. In this group, 62% had axillary and 50% had internal mammary lymphatic drainage, and one patient had supraclavicular drainage.

CONCLUSIONS

Lymphoscintigraphy indicates that drainage routes may vary, and thus it may play a guiding role in patients with breast cancer who need radiotherapy. In patients with internal mammary lymphatic drainage, the accuracy of radiotherapy planning may increase if internal mammary lymphoscintigraphy is added to the protocol. In patients with internal mammary drainage, obtaining an internal mammary lymphatic biopsy during surgery will also increase the accuracy of staging.

The Role of Lymphoscintigraphy in the Management of the Patient With Breast Cancer

INTRODUCTION

Regional nodal status is the most powerful predictor of recurrence and survival in women with breast cancer. Lymphatic mapping and sentinel lymph node (SLN) biopsy have been found to accurately predict the regional nodal status. Preoperative lymphoscintigraphy has been used in melanoma patients to identify the basins at risk for metastases when primary sites are located in watershed areas of the body. This study was performed to define the role of lymphoscintigraphy for axillary nodal staging in women with breast cancer. Specifically, can preoperative lymphoscintigraphy define a population of women with breast cancer who have multidirectional drainage or who do not drain to the axilla and need no axillary dissection?

METHODS

516 patients with invasive breast cancer were accrued in a national breast lymphatic mapping trial sponsored by the U.S. Department of Defense. Preoperative lymphoscintigraphy images were produced using filtered technetium-99 sulfur colloid. Lymphatic drainage to axillary and internal mammary sites was noted.

RESULTS

Drainage to an axillary SLN was found in 335 (65%) patients, and internal mammary or extra-axillary drainage was noted in 52 (10%) patients. By using sensitive hand-held probes and vital blue dye intraoperatively, the overall success rate of finding an axillary SLN was 85%. Of the 335 patients who had an axillary SLN identified with imaging, all had successful SLN biopsy procedures. Although no SLNs could be imaged in 181 patients, 153 (85%) of these patients had an axillary SLN identified with intraoperative mapping. For 28 patients in which lymphoscintigraphy was negative and intraoperative mapping was unsuccessful, complete axillary node dissection was performed, and 13 (46%) of these patients were found to have metastatic disease in the basin.

CONCLUSIONS

Preoperative lymphoscintigraphy can identify those women with primary breast cancers who have extra-axillary regional basin drainage such as internal mammary. The ability to image an axillary SLN was associated with a high success rate of being able to find the node intraoperatively with a combination mapping technique. In a high percentage of patients with negative lymphoscintigraphy, the SLN was identified with more sensitive hand-held probes. Therefore, patients who have a negative preoperative lymphoscintigraphy and intraoperatively are found to have no "hot" spot in the axilla with the hand-held probe still need an axillary node dissection, because 46% of these patients contain metastatic disease in the axilla.

Improved sentinel node visualization in breast cancer by optimizing the colloid particle concentration and tracer dosage

Faint lymph uptake may hamper sentinel node (SN) identification by scintigraphy and subsequent gamma probe localization. The aim of the present study was to evaluate an adjustment in the colloid particle concentration and tracer dosage to optimize mammary lymphoscintigraphy. Scintigraphy was performed in 151 patients with a palpable breast carcinoma and clinically negative axilla: for the first 75 patients (group A) a standard labelling of 0.5 mg nanocolloid with 99Tcm was performed, for the subsequent 76 patients (group B) the labelling dilution volume was reduced from 4 to 2 ml. For both groups the volume of injection was 0.2 ml. Lymph node uptake was evaluated by a 4-step visual score (from 0 = absent to 3+ = very intense), and by count quantification of at 4 h in the first draining SN. The SN visualization rate increased from 93% (70/75) in group A (mean dosage 93.4 MBq, range 57-130 MBq) to 99% (75/76) in group B (mean dosage 106.5 MBq, range 74-139 MBq). The percentage of patients with uptake 3+ was significantly higher (P = 0.001) in group B (51% vs 35% in group A). SN counts were significantly higher for group B (P<0.001). The percentage of patients with less than 2000 counts/node diminished from 45% in group A to 9% in group B (P = 0.001). In group B (P = 0.033) more lymph channels (53% vs 35% in group A) were visualized and for a longer time (26% vs 4% at 4 h). Axillary drainage was seen in 96% in group A and 98% in group B whereas non-axillary drainage was observed in 19% and 25%, respectively. Intraoperative SN identification rate was 97% in group A and 100% in group B. SN metastases were found in 41% of group A and 47% of group B. It is concluded that enhancement of colloid particle concentration and adjustment of tracer dosage led to improved SN identification by substantial increase in lymph node uptake and lymph vessel depiction. A significant reduction of cases with faint SN uptake enables better surgical efficacy.

Revolutionary impact of lymphoscintigraphy and intraoperative sentinel node mapping in the clinical practice of oncology

Intraoperative lymphatic mapping is a rapidly emerging diagnostic approach that is revolutionizing the management of patients who have solid malignant tumors. The procedure is being performed for the most part with radiopharmaceuticals and vital blue dyes. It is widely believed that passive trapping of radioactive particles determines the sentinel lymph node (SLN) for intraoperative delineation of potential draining sites. In this article, we show that dendritic cells within the SLN actively take up and trap radioactive particles and thus define the SLN immunologically. The role of preoperative lymphoscintigraphy and the selection of the site of placement of mapping reagents for intraoperative lymphatic mapping are established for patients with melanoma. For patients with breast cancer, the role of preoperative lymphoscintigraphy is controversial. We have shown that this procedure can be performed with success in identifying SLN as hot spots 87% of the time, with 20% of the cases showing draining nodes to other basins in addition to or independent of the axilla. The use of preoperative lymphoscintigraphy for patients with breast cancer can therefore be justified. The selection of the site for placement of radiotracer and blue dye can vary for patients with breast cancer depending on the primary site of the lesion. However, based on data from our institution and others, the delivery of the mapping reagents (both radioactive tracers and blue dye) to the subareolar space may help to standardize breast cancer SLN mapping.

The predictive value of the sentinel lymph node in malignant melanomas

At the beginning of a lymphogenous metastasizing process in malignant melanomas, the first tumor cells are found in the so-called sentinel lymph node (SLN), defined as the first tumor-draining lymph node. Its removal and histopathological examination enable us to discover metastases of malignant melanomas long before their possibility of detection by any other method. Since the beginning of 1995, we have performed more than 350 gamma-probe-guided sentinel lymphonodectomies (gamma-SLNE), without any clinical evidence of metastases as determined by lymphoscintigraphy. Using gamma-SLNE, the detection and excision of the SLN succeeded in nearly all patients. The SLNs were fixed in formalin, completely cut into 1-mm thin slices and stained for routine H&E histology and with S-100 and HMB-45. In persons with melanomas thinner than 0.75 mm, we never found micrometastases. However, the SLNs were positive in melanomas from 0.76 to 1.50 mm in about 7% of patients, in melanomas from 1.51 to 4.00 mm in about 21% and in tumors thicker than 4 mm in about 44%. In primary melanomas with satellite or in-transit metastases, the SLNs contained metastases in 75% of patients. Normally, a radical lymph node dissection (RLND) follows, as it is considered to be the necessary consequence following detection of tumor cells. The lymph nodes of the RLNDs contained further metastases in about 30% of patients. The probability of the involvement of lymph nodes other than the SLN correlates with the extension of tumor cells in the SLN. During our 4-year-follow-up, we observed only a single lymph node recurrence in a patient with a negative SLN (false negative rate of about 0.4%). The development of systemic metastasis correlates not only with the Breslow tumor thickness, but also with the extent of the involvement of the melanoma metastasis in the SLN. Summarizing, it can be said that gamma-SLNE has revolutionized melanoma surgery. Based on our data, it is absolutely necessary in the staging of malignant melanoma. In our opinion, the existing classification systems for staging lymph node involvement have to be revised in light of the results of SLNE.

Systemic treatment after sentinel lymph node biopsy in breast cancer: who, what, and why?

SLNB, although subject to numerous technical problems, has nonetheless shown great promise in predicting the status of the remaining axillary lymph nodes. The growing use of SLNB has presented the opportunity of using immunohistochemical and molecular markers to detect occult micrometastases. These micrometastases may be important for more accurate staging and prediction of patient outcomes. Current standards for the use of systemic therapy recommend multidrug chemotherapy for all but the most favorable disease (T1a/b, NO). The detection of micrometastases by SLNB in this low-risk group may change treatment recommendations to include systemic therapy. Because of the significant frequency of false-negative results in SLNB, which will depend upon the surgeon's experience, caution is urged in determining when ALND can be safely eliminated in patients with a negative SLNB.

Non-visualization of sentinel lymph node in patients with breast cancer

Histological evaluation of the first draining lymph node (sentinel node) in the axilla of patients with breast cancer has dramatically altered the surgical approach to these patients, with sparing of the axilla if no tumour cells are identified. In a fraction of patients imaged after peri-tumoural injection of the breast, there is no visualization of the sentinel node. We retrospectively analysed the status of patients whose nodes were visualized and of patients whose nodes failed to visualize, to define the variables associated with non-visualization of the sentinel node. Seventy-four breast cancer patients were imaged following peri-tumoural injection of filtered 99Tc(m)-sulfur colloid, immediately and up to 5.5 h post-injection. The scintigraphic data were analysed with reference to the patient's age, histology, grade, site and size of tumour, previous diagnostic procedure and time interval to scan, using univariate analysis and a logistic regression model. A sentinel node was visualized in 53 of 74 women (72%). Comparison of patients with non-visualized versus visualized sentinel nodes disclosed no statistically significant univariate relation to age of the patients (P = 0.10), size of tumour (P = 0.46), site (P = 0.26), histology [invasive ductal carcinoma in 16 of 20 (80%) non-visualized cases, and in 43 of 53 (81%) visualized patients], prior excision biopsy (P = 0.36) and time interval to surgery (P = 0.29). Tumour grade was the only significant variable on univariate analysis (P = 0.03), though multivariate analysis showed that none of the independent parameters were statistically significant. In 39 patients with an upper outer quadrant tumour, the location of the sentinel node was not limited to the axilla and even crossed the midline of the breast. Our results show that none of the independent variables is associated with non-visualization of sentinel lymph node on preoperative lymphoscintigraphy of patients with breast cancer, though the tumour grade may have contributed to non-visualization of this node. The non-axillary drainage from upper outer quadrant tumours suggests the routine use of lymphoscintigraphy prior to axillary dissection.

Sentinel lymph node biopsy in breast cancer patients: subdermal versus peritumoural radiocolloid injection

BACKGROUND AND AIMS

Sentinel lymph node (SLN) biopsy has been widely used in the management of melanoma and breast cancer. The aims of this study were (1) to compare the results obtained with the two main injection techniques, the peritumoural and subdermal; and (2) to determine the reliability of SLN to predict the regional lymph node status.

METHOD

We prospectively studied 80 women (mean age 56 years) with breast cancer. Thirty-four of them were T1 and the remaining 46 were T2. Patients were divided into two groups. Group A, 36 patients were injected subdermally, surrounding the tumour site. Group B, 44 patients were injected peritumourally guided by ultrasound if non-palpable. Planar images were performed 15 min after the injection and continued until SLN identification. Before surgery, blue dye injection was administered similarly to the radiocolloid. After incision, a hand-held gamma probe was used to reach the SLN. All nodes harvested were analysed by classic pathology techniques.

RESULTS

Overall, lymphoscintigraphy allowed the detection of SLN in 75/80 patients (94%). All subdermal lymphoscintigraphies were positive (36/36) compared with 89% of peritumoural (39/44). Blue dye detected SLN in 23/31 patients (74%) after subdermal injection and in 24/34 patients (71%) after peritumoural injection. The sensitivity to localize the SLN with lymphoscintigraphy+blue dye+gamma probe was 92% (33/36) within the subdermal group and 91% (40/44) within the peritumoural group. Overall, five false negative SLN were found. All of these corresponded to T2 tumours with a size greater than 2.5 cm. The negative predictive value and the accuracy were 93% and 94%, respectively, for the subdermal group and 90% and 93% for the peritumoural group.

CONCLUSIONS

(1) Our results indicate that both techniques have similar results. However, we suggest that T2 tumours with a size greater than 2.5 cm should be excluded from the SLN technique, in order to improve the accuracy and negative predictive value. (2) Lymphoscintigraphy is essential for visualizing the SLN, and blue dye can be helpful when the gamma probe does not localize the SLN.

[Scintigraphy with 99mTc-MIBI in the diagnosis of axillary lymph node invasion of breast cancer]

The presence of affected locoregional lymph nodes should be considered as one of the most important prognostic factors of breast cancer. At present, the clinician is conditioned by an absolute lack of an efficient methodology to evaluate the possible invasion of the axillary lymph nodes, which if negative, would make it possible to avoid surgical excision. In this study, we will evaluate the use of the 99mTc-MIBI scintigraphy in the pre-surgical diagnosis of axillary lymph node invasion and will analyze the relationship between the 99mTc-MIBI uptake and the number of lymph nodes affected.

MATERIAL AND METHODS

84 patients diagnosed of breast cancer were analyzed in this study. All of them underwent a 99mTc-MIBI scintigraphy, and the tumor/background ratio was determined semiquantitively for each image. The axillary lymph node invasion was determined following surgery.

RESULTS

The sensitivity of the breast scintigraphy with 99mTc-MIBI for detection of lymph node invasion is 36% and the specificity is 100%. The positive predictive value is 100% and the negative one 48%. In the current study, we failed to detect correlation between the intensity of 99mTc-MIBI uptake in the primary tumor and the number of affected axillary lymph nodes.

CONCLUSION

99mTc-MIBI breast scintigraphy can provide complementary information for the presurgical diagnosis of breast cancer axillary lymph node invasion. 99mTc-MIBI breast scintigraphy shows high specificity and a high predictive value.

Time trends of surgical treatment and the prognosis for Japanese patients with gastric cancer

The incidence of gastric cancer is much higher in Japan than in other countries even though diagnostics and treatments of such patients have improved. The objective of this study was to present an overview of the past, present and future of surgical treatment for our patients with gastric cancer. We analysed data on 2152 Japanese men and women with gastric cancer who underwent surgical resection from 1965 to 1995 at Kyushu University in Fukuoka, Japan, based on a univariate and the multivariate analysis. We focused on time trends of surgical treatment and the postoperative outcome. Over the years, there have been favourable changes in the numbers of patients with early gastric cancer. In all cases of gastric cancer, the rate of 18% in the first six year period (group 1) was 57% in the last 5 year period (group 6). Size of the tumour was smaller, well-differentiated tumour tissue was more common, and lymphatic involvement was less frequent. Lymph node metastasis, liver metastasis and peritoneal dissemination all decreased. Extensive lymph node dissection was more frequently done and the rate of curative resection (curability A and B) increased. With increases in identifying the early stage of cancer and better perioperative care, mortality rates 30 days after the surgery greatly decreased. Multivariate analysis revealed that the 10 factors of depth of invasion, lymph node metastasis, lymph node dissection, tumour size, liver metastasis, peritoneal dissemination, lymphatic invasion, vascular invasion, lesion in the whole stomach and lesion in the middle stomach were independent factors for determining the prognosis. Detection of the tumour in an early stage, standardized surgical treatment, including routine lymph node dissection, close follow-up schedules and better perioperative management are expected to increase survival time for patients with this malignancy.

[Usefulness of the quantification of (99M)Tc-MIBI uptake in breast neoplasms in the preoperative assessment of tumor aggressiveness]

(99m)Tc-MIBI has been proposed as an imaging diagnostic method in a large variety of human malignant tumors. At present, the mechanism by which (99m)Tc-MIBI is uptaken and concentrated by the malignant cells is not totally known. Some mammary neoplasms do not show any uptake of (99m)Tc-MIBI. This study aims to determine if there is any correlation between the uptake of (99m)Tc-MIBI by the tumor and the different histopathological parameters involved in tumoral aggressiveness. To do so, we have studied 100 patients with breast cancer. All of them underwent a breast scintimammography with (99m)Tc-MIBI with semiquantitative analysis by means of a tumor-to-background ratio calculated in every projection. After surgery, an experienced pathologist determined tumor size, axillary lymph node metastases, histological grade (Scarff Bloom Richardson) (SCBR), nuclear grade, mitotic index, presence of cellular atypia and estrogen and progesterone receptor expression.

RESULTS

A statistically significant correlation (p < 0.005) has been found between tumor-to-background (T/B) ratios of (99m)Tc-MIBI uptake and tumor SCBR histological grade. A correlation between (99m)Tc-MIBI uptake and the mitotic index, cellular atypia and nuclear grade has also been found. No correlation was found in our study with tumor size, hormone receptor expression or axillary lymph node metastases.

CONCLUSIONS

(99m)Tc-MIBI uptake in breast cancer is correlated with the tumoral differentiation grade: the smaller the tumoral cellular differentiation (greater aggressiveness), the greater the uptake. On the other hand, no correlation was found between the uptake of (99m)Tc-MIBI and the classical pathological parameters that define tumoral aggressiveness, such as size and axillary lymph node metastasis.

Sentinel Lymph Node Biopsy in Breast Cancer

One of the most important prognostic indicators in patients with breast cancer is axillary lymph node status. Sentinel lymph node (SLN) biopsy has emerged as a potential alternative to routine axillary dissection in clinically node-negative early breast cancer. This procedure requires a specialized but multidisciplinary approach utilizing the surgeon, nuclear radiologist and pathologist. SLN biopsy allows adequate assessment of the axillary nodal status in patients with early breast cancer, with minimal—if any—morbidity. Blue dye and lymphoscintigraphy are complementary techniques, and the success rate is maximized when the two methods are used together. Focused histopathologic examination on one or two lymph nodes most likely to contain metastases [SLN(s)], using serial sectioning and immunohistochemical techniques, allows an improved staging to be performed. Detection of metastases on SLN(s) is not only a prognostic indicator, but it also dictates whether the patient should receive further surgery and adjuvant chemotherapy. Until data regarding the long-term results of the SLN biopsy are available, this method should be considered investigational and be performed by surgeons experienced in this technique to achieve a failure rate of less than 2 per cent.

Lymphatic mapping with sentinel node biopsy in pediatric patients

BACKGROUND/PURPOSE

Lymphatic mapping with sentinel node biopsy is used widely in adult melanoma and breast cancer to determine nodal status without the morbidity associated with elective lymph node dissection. This technique can be used in children to determine lymph node status with limited dissection and accurate interpretation. The authors report their initial experience.

METHODS

The charts of patients who underwent lymphatic mapping with sentinel node biopsy were reviewed retrospectively. Lymphoscintigraphy was performed in patients with truncal lesions 24 hours before surgery to determine the draining nodal basin (for surgical mapping). The tumors were injected 1 hour preoperatively with technetium sulfur colloid and in the operating room with Lymphazurin blue. The draining basin was examined using a radioisotope detector. The blue nodes with high counts were localized and removed. If nodal metastases were identified, lymph node dissection was recommended. Four patients were injected only with Lymphazurin blue.

RESULTS

Thirteen children (7 girls, 6 boys; mean age, 7 years) underwent lymphatic mapping with sentinel node biopsy. The tumor types were as follows: 8 malignant melanoma (6 extremity, 2 truncal), 1 malignant peripheral nerve sheath tumor, 1 alveolar soft part sarcoma, and 3 rhabdomyosarcoma. A mean of 2.4 nodes (range, 1 to 6) were removed from each patient. Six patients had a positive sentinel node. Formal lymph node dissection was performed on 4 of the 6 patients, 1 of whom had further nodal disease with 2 of 13 nodes containing micrometastases. One of the 6 patients refused lymph node dissection and adjuvant therapy; the final patient had rhabdomyosarcoma, a malignancy for which lymph node dissection is not indicated. Pulmonary metastasis developed 26 months after diagnoses in the patient with alveolar soft part sarcoma and a negative sentinel node. This patient was injected only with Lymphazurin blue at the time of sentinel node biopsy and refused adjuvant therapy. There have been no other recurrences. There were no complications related to lymphatic mapping or sentinel node biopsy.

CONCLUSIONS

Lymphatic mapping with sentinel node biopsy, using both technetium-labeled sulfur colloid and Lymphazurin blue, can be performed safely in pediatric skin and soft tissue malignancies. Further study with long-term follow-up will determine the utility and accuracy of this technique in pediatric malignancies.

Use of a reusable shielded marker to enhance the accuracy, safety, and efficacy of nuclear medicine procedures

Three cases illustrate the use of a reusable, shielded marker to identify anatomic structures and mark pathologic lesions. No other nuclear medicine marker is available with a shutter mechanism designed to interrupt radiation, thus protecting the patient and technologist from unnecessary radiation and minimizing image artifacts.

Sentinel node detection in malignant melanoma

The initial application of intraoperative lymphatic mapping and sentinel lymphadenectomy followed by selective complete lymphadenectomy (LM/SL/SCLND) was in melanoma. This arose as a solution to the ongoing debate concerning immediate vs. delayed lymph node dissection. Acceptance of the concept and advances in nuclear medicine, surgery, and pathology aspects of the sentinel node procedure have brought it into widespread use for melanoma and have expanded its application for other solid tumors that progress through the lymphatic route. Although the diagnostic accuracy of the procedure has been demonstrated in multicenter trials, caution should be exercised regarding therapeutic aspects until definitive benefit can be shown from well-designed clinical trials. Current issues of active discussion and debate are reviewed including ideal nomenclature, clinical significance of occult metastatic disease, quality assurance, and the role of LM/SL/SCLND outside high-volume melanoma centers.

The intraoperative gamma probe: basic principles and choices available

By taking advantage of the proximity to radioactive sentinel nodes and occult tumors achievable in an operative setting, intraoperative probes are becoming increasingly important in the surgical management of cancer. This article begins with a discussion of the statistical limitations of radiation detection and measurement and of the key performance parameters (sensitivity, energy resolution, and spatial resolution) that characterize detectors. The basic design and operating principle of radiation detectors used in intraoperative probes, scintillation and semiconductor detectors, are then reviewed. Scintillation detector-based intraoperative probes, generally using a NaI(T1) or a CsI(T1) crystal connected to a photomultiplier tube by a fiberoptic cable, have the advantages of reliability, relatively low cost, and high sensitivity, especially for medium- to high-energy photons. Disadvantages include poor energy resolution and scatter rejection, and bulkiness. Semiconductor (CdZn, CdZnTe, HgI2)-based probes are compact and have excellent energy resolution and scatter rejection, but with complex energy spectra reflecting charge-carrier trapping. Their main disadvantage is lower sensitivity. The performance parameters of various commercially available intraoperative probes are then compared. The article concludes with a discussion of the practical considerations in selecting and using intraoperative probes, including ergonomic and other design features, as well as performance parameters.

Melanoma lymphoscintigraphy and lymphatic mapping

Lymphoscintigraphy in melanoma has proven to be a reliable method to identify regional lymph nodes at risk for metastases. The first lymph node to drain a cutaneous lesion, the sentinel lymph node (SLN), is predictive of the metastatic status of the regional lymph node group. Lymphatic mapping allows for the identification of the SLN and for selective lymph node sampling. Selective lymph node sampling is less invasive and because only a small quantity of high-risk tissue is submitted for pathological examination, it allows for a more complete and comprehensive pathological examination, which identifies melanoma with up to 100 times the sensitivity of conventional examinations.

Sentinel node staging of early breast cancer using lymphoscintigraphy and the intraoperative gamma-detecting probe

Sentinel node staging for breast cancer is increasingly used in place of axillary lymph node dissection but is not yet universally accepted. The problems of non-standardized methodologies and lack of consensus on the optimum techniques to identify sentinel nodes are being addressed. Complementary use of radionuclide imaging before surgery, intraoperative probe detection, and blue dye have yielded the best reported sensitivities for finding a sentinel node (94%). The importance of imaging is summarized as identifying sentinel node(s), distinguishing sentinel from secondary nodes, guiding surgical incision planning, and facilitating lower doses. The learning curve phenomenon, which applies to the surgeon and the nuclear medicine physician, has been recognized; measures to minimize it are being implemented. Radiation exposure to operating room and pathology personnel is very low; estimates of exposure to the surgeon's hands are 0.2% of the annual whole body dose received by every human being from natural background and cosmic sources.

Lymphoscintigraphy and gamma probe-guided surgery in papillary thyroid carcinoma: the sentinel lymph node concept in thyroid carcinoma

The authors report the use of lymphoscintigraphy and gamma probe-guided resection of the sentinel lymph node in a 65-year-old woman with clinically and cytologically indicated metastasizing papillary thyroid carcinoma. The results of the preoperative lymphoscintigraphy corresponded well with FDG PET and histologic findings, which gives promise of its validity in thyroid carcinoma. With experience in ultrasound-guided fine-needle aspiration biopsy, this method can be performed without any serious side effects for the patient. The validity of the sentinel lymph node concept in thyroid carcinoma and a possible improvement of nodal staging and local recurrence rate must still be proved.