Sentinel lymph node uptake of two different technetium-labeled radiocolloids,

Technetium-99m-labeled rituximab for use as a specific tracer of sentinel lymph node biopsy: a translational research study

PURPOSE

We aimed to develop and translate a CD20-antigen-targeted radiopharmaceutical, Technetium-99 m-labeled (99mTc) rituximab, for sentinel lymph node (SLN) detection.

METHODS

99mTc-rituximab was synthesized and tested for stability in human serum. The binding affinity to CD20 was evaluated in Raji cells by flow cytometric analysis. Biodistribution and sentinel node mapping were carried out in bal b/c mice. Eighty-five patients with breast cancer participated in this study. Dynamic sentinel lymphoscintigraphy was first assessed in 12 patients before planar lymphoscintigraphy was assessed in a larger cohort. All patients underwent sentinel lymph node biopsy (SLNB), followed by axillary lymph node dissection.

RESULTS

The cell-binding study showed that 99mTc-rituximab possessed compatible affinity to human CD20. In the mechanism study, 99mTc-labeled anti-mouse CD20 monoclonal antibodies could bind to mouse CD20 and accumulate in the SLN with 2.62±1.25 % of the percentage of injected activity, which could be blocked by excessive unlabeled antibody. Low uptake of non-sentinel nodes and fast clearance from the injection site were observed in the mice. Sentinel nodes were identified in 82 of 85 breast cancer patients (96.5%) by lymphoscintigraphy and SLNB. The sensitivity, specificity, and accuracy were 96.8% (30/31), 100% (51/51), and 98.8% (81/82), respectively.

CONCLUSION

99mTc-rituximab, specifically binding to CD20, met most of the requirements of an ideal sentinel mapping agent for use in clinical settings.

Targeted non-covalent self-assembled nanoparticles based on human serum albumin

Human serum albumin (HSA) is a biological nanocarrier that forms non-covalent complexes with a number of synthetic and biomolecules. Previously we demonstrated radiolabeled HSA-based nanoparticles can form non-covalent complexes with fluorescent cyanine dyes yielding imaging agents for surgical guidance towards tumor draining lymph nodes. Here the self-assembly approach enabled rapid clinical translation. Based on this experience we reasoned it would be interesting to expand this non-covalent technology to a targeted approach. Therefore, the ability of HSA to form non-covalent self-assembled complexes with peptides via near-infrared (NIR) cyanine dyes was explored. Föster resonance energy transfer (FRET) quenching interactions between HSA-Cy5 and the non-covalently bound fluorescent molecules indocyanine green (ICG), IR783-CO(2)H and three IR783-labeled targeting peptides were used to monitor complex assembly and disassembly. The host-guest interactions between HSA and IR783-labeled peptides enabled the formation of (bio)nanoparticles that are coated with peptides, which may target α(v)β(3)-integrins, the chemokine receptor 4 (CXCR4), or somatostatin receptors. The potential of CXCR4-targeted (bio)nanoparticles in sentinel lymph node procedures is demonstrated in vivo. By non-covalently binding NIR-dye labeled peptides to an already clinically approved HSA-scaffold, we have readily formed targeted bionanoparticles.

Guidelines for lymphoscintigraphy and F18 FDG PET scans in melanoma

Melanoma has a high potential to develop metastases. Accurate staging is essential for appropriate management. Sentinel node (SN) status is a powerful prognostic factor in early stage melanoma. Staging is assisted by SN biopsy after lymphoscintigraphy to locate all true SNs prior to biopsy. PET using F18-FDG can detect metastases and is used to restage patients with AJCC Stages III and IV disease before planning surgery with curative intent.

Incomplete sentinel node biopsy is not clearly related to survival or regional recurrence in cutaneous melanoma patients

BACKGROUND

In melanoma patients, we define incomplete sentinel node biopsy (I-SNB) as when fewer lymph nodes are removed during sentinel node biopsy (SNB) than identified on preoperative lymphoscintigraphy (LS). This study quantifies the frequency of I-SNB and evaluates any correlation with patient outcomes.

METHODS

Evaluation of a prospective database of consecutive patients having LS and negative SNB from 1996 to 2006. Additional LS information was obtained from a nuclear medicine database. All statistical analyses were performed using the IBM SPSS Statistic 19.0 software package.

RESULTS

I-SNB occurred in 20% of the cohort (n = 2007). For axillary (n = 895), groin (n = 569), and neck/axial patients (n = 334) I-SNB occurred in 12%, 26%, and 28% of cases, respectively (P < .001). On univariate analysis, there was a significant association between I-SNB and worse disease-free survival (DFS), P = .007 and trend toward worse melanoma-specific survival (MSS), P = .056. I-SNB was not associated with worse regional recurrence-free survival (RRFS), P = .144. There was no relationship between I-SNB and worse DFS, RRFS, or MSS on multivariate analysis. Sentinel node region (axilla better than groin and neck/axial) had a significant association with RRFS (P = .039) on univariate analysis and DFS on univariate (P = .009) and multivariate analysis. Significantly worse outcomes for MSS, DFS, and RRFS were seen with male gender, increasing age, high mitotic count, ulceration, and increasing Breslow thickness.

CONCLUSION

This study demonstrates no statistically significant relationship between I-SNB and patient outcomes when adjusting for known prognostic factors. These data do not exclude the possibility that I-SNB may have a weak association with worse outcomes.

Comparison of efficacy of Tc-99m HIG and Tc-99m nanocolloid on sentinel lymph node mapping in patients with breast cancer

BACKGROUND AND AIM

This study compared the effectiveness of Tc-99m human polyclonal immunoglobulin (HIG) and Tc-99m nanocolloid at detecting sentinel lymph nodes (SLNs) with lymphoscintigraphy and an intraoperative gamma-probe (IGP) in patients with early breast cancer.

METHODS

The study group consisted of 50 women; 25 patients each were given Tc-99m HIG or Tc-99m nanocolloid for lymphoscintigraphy. Then, intraoperative SLN localization with IGP was performed. The results of IGP, lymphoscintigraphy, blue dye injected just before surgery, and pathology were compared.

RESULTS

In the Tc-99m HIG group, one patient had tumours in both breasts. In two patients, we could not detect SLNs with lymphoscintigraphy, although they were detected with IGP and blue dye. We found SLNs for all tumours with IGP. With the intraoperative blue dye, SLNs were identified for 25 tumours; for one tumour, no SLN was detected with blue dye. In the histopathological examination, 13 tumours showed metastasis in the SLN and in 11 of these 13, there were also metastases in the axilla. One patient had a skip metastasis. In the Tc-99m nanocolloid group, SLNs were identified in 24 patients with lymphoscintigraphy. IGP found SLNs in 24 patients. The blue dye detected SLNs in all patients. On histopathological examination, 10 patients had metastasis in the SLN and there were also metastases in the axilla in all of these patients.

CONCLUSION

Tc-99m HIG can be used in SLN detection with preoperative lymphoscintigraphy and IGP in early-stage breast cancer patients.

Identification of 6 sentinel lymph nodes in a case of malignant melanoma on the ungual region of the finger

We describe a case of malignant melanoma on the ungual region of the index finger with which 6 sentinel lymph nodes were detected in the axillary basin. Of these nodes, 1 of 3 brachial nodes and 2 of 3 central axillary nodes showed micrometastasis. Additional lymph nodes obtained at the subsequent complete axillary lymph node dissection showed no metastasis. Identification of as many as 6 sentinel lymph nodes was ascribed to a single lymph trunk that would branch off to afferent lymphatics draining to each nodal group; however, a gamma probe may have detected radioactive tracer passing to the sequential nodes as well as that remaining in true sentinel nodes.

A phase I/II trial of 125I methylene blue for one-stage sentinel lymph node biopsy

BACKGROUND

Sentinel lymph node biopsy can be associated with delays in operating room schedule and with significant pain during the preoperative Tc colloid injection. To avoid these problems, we developed a novel radiolabeled blue dye that can be injected intraoperatively.

METHODS

We performed a phase I/II trial (IND#70627) of sterile pyrogen-free I-methylene blue to identify sentinel nodes in patients with breast cancer. Twelve women were studied. Two women each were given peritumoral or circumareolar injections of 100, 200, 300, 400, 500, or 1000 microCi of I methylene blue.

RESULTS

Sentinel nodes were detected in 11 of 12 patients, with a low-dose 200 microCi patient being the single exception. The number of sentinel nodes detected per patient ranged from 0 to 3 (mean = 1.66 nodes/case). Radioactivity at the tumor injection site [counts per second (cps) averaged over 10 seconds] ranged from 3346 to 47,300 cps and was highly dose-dependent (r = 0.90, P = 0.0002). In contrast, the in vivo node counts ranged from 0 to 1228 cps, while ex vivo counts ranged from 0 to 1516 cps. The in vivo nodal counts were dose-dependent (r = 0.67, and P = 0.0231). Radiation was carefully monitored inside the operating room and in pathology. Even with the 1-mCi dose, the radioactive blue dye produced significantly lower personnel exposure than historically seen with Tc.

CONCLUSIONS

This method eliminates the painful preoperative injections of Tc colloid, is performed by the surgeon in the operating room, is associated with lower radiation exposures for personnel, and avoids the delays caused by nonoperating room personnel. These observations warrant a more extensive trial of this method using the 1000-microCi dose of I methylene blue dye for sentinel lymph node biopsies.

99mTc-phytate is better than 99mTc-human serum albumin as a radioactive tracer for sentinel lymph node biopsy in breast cancer

PURPOSE

Several radioactive agents are used for sentinel lymph node biopsy (SLNB) in breast cancer, but we are still unsure which of these is best. We retrospectively compared the effectiveness of two radioactive agents, 99mTc-phytate and 99mTc-human serum albumin (HSA), when used in combination with blue dye.

METHODS

A consecutive series of 533 clinically node-negative patients with a collective 539 breast carcinomas were divided into two groups for treatment with SLNB. The HSA-group consisted of 264 patients (with a collective 266 breast cancers) and the P-group consisted of 269 patients (with a collective 273 breast cancers) treated with 99mTc-HSA and 99mTc-phytate, respectively, in combination with blue dye. We analyzed the identification and radioactivity of SLNs in the two groups.

RESULTS

The identification rate of SLN was significantly higher in the P-group than in the HSA-group. The same results were produced by analysis using the radioactive agent alone, but not by using the blue dye alone. Most importantly, the highest radioactivity of SLNs per case was more than five times higher in the P-group than in the HSA-group, and this difference was significant.

CONCLUSION

Our historical analysis of the two radioactive agents used in different periods could not exclude the influence of the improved skill of the surgeons. However, because the specific accumulation of phytate in SLNs was greater than that of HSA, phytate might result in a higher SLN identification rate. Thus, 99mTc-phytate is better than 99mTc-HSA as a radioactive agent for SLNB in breast cancer.

[Intraoperative labeling of sentinel lymph nodes with a combination of vital dye and radionuclide tracer--results in sentinel lymph node-positive patients]

BACKGROUND

Sentinel lymph node biopsy enhances the accuracy of tumor staging in patients with malignant melanoma and can help select candidates for regional lymphadenectomy. There are two techniques for identifying the sentinel lymph node: intradermal injection of a radionuclide tracer or of a blue dye. We evaluated both methods to determine how they can be best utilized to locate a sentinel lymph node.

PATIENTS AND METHODS

In a retrospective study, 323 patients with melanoma (tumor thickness > or = 0.75 mm) who underwent sentinel lymph node biopsy after both radionuclide and blue dye injection were evaluated. The labeling of lymph nodes showing micrometastasis by histopathological examination was determined.

RESULTS

63 patients showed sentinel lymph nodes with micrometastasis. All of these nodes (100 %) were labeled with radionuclide tracer, but only 90 % with blue dye. In 5 patients, only radionuclide labeling identified the histopathologically-positive lymph node. In 36 patients, several sentinel lymph nodes were identified, with the histopathologically-positive nodes usually showing a higher radioactive signal intensity than the negative ones.

CONCLUSION

Since in some patients histopathologically-positive lymph nodes are only labeled by radionuclide tracer, radionuclide labeling is indispensable for locating sentinel lymph nodes. In contrast, labeling with blue dye represents a supplementary method, which can simplify the recognition of the sentinel lymph node during surgery.

Use of the gamma probe in sentinel lymph node biopsy in patients with prostate cancer

OBJECTIVE

To describe the reproducibility of the sentinel lymph node technique in patients with prostate cancer and verify if there is improved accuracy over modified lymphadenectomy.

MATERIAL AND METHODS

Twenty-three patients with biopsy proven prostate cancer were enrolled in this study. Lymphoscintigraphy was performed after the transrectal administration of Tc sulfur colloid guided by ultrasound, with one injection in each prostate lobe. Images were obtained 15 and 180 min after injection. Sentinel lymph node was harvested during surgery using a gamma probe, followed by extended lymphadenectomy.

RESULTS

The mean age of the patients in this study was 66 years. An average of 3.36 sentinel lymph nodes was found for each patient. Radioactive lymph nodes were identified by the gamma probe in 21 out of 23 patients. In one of the patients there was no radiopharmaceutical migration from the injection site and in another the sentinel lymph node was visualized by lymphoscintigraphy but was not found during surgery. Three patients had lymph node metastasis; in one of these patients the sentinel lymph node was the only positive node and was found outside the modified lymphadenectomy region (obturator fossa and the external iliac).

CONCLUSION

Sentinel lymph node biopsy in prostate cancer adds important information to the staging of patients, not always attained through the lymphadenectomy restricted to the obturator fossa and external iliac. Such information is essential for the choice of the best treatment to be applied.

Axillary sentinel lymph nodes in breast cancer: a single lymphatic pathway drains the entire mammary gland

AIM

To report the pattern of lymphatic mapping following intrasubdermal injections of radiocolloid and of blue dye in different sites of the breast.

METHODS

Prior to surgery 137 breast cancer patients underwent intrasubdermal injection of 30-50 MBq 99mTc-colloidal albumin over the tumour site (ISI group). Ten minutes before surgery, 2 ml patent blue was injected in the subareolar area (SAI group) in 117/137 patients, while 20 patients received intrasubdermal blue-dye in the quadrant opposite the tumour site (OQI group). The different injection routes were considered concordant when the hottest sLN was also blue.

RESULTS

In 134/137 patients radiocolloid drained to one or more axillary nodes, while blue nodes were found in 98/117 SAI patients and in 17/20 OQI patients. Multiple hot nodes were found in 63/134 cases and multiple blue nodes in 35/115. In patients in whom both tracers reached the axilla, the hottest node was also blue in 108/115 cases (93/98 SAI and 15/17 OQI patients). In the seven discordant cases, the hottest node was not blue, but in two cases the blue node was also radioactive.

CONCLUSIONS

Superficial lymphatic drainage from the breast most frequently merges to a single axillary lymph node, irrespective of the site of tracer injection. In a few cases different injection sites identify different, often closely interconnected sLNs.

Lymphatic Drainage Patterns on Early Versus Delayed Breast Lymphoscintigraphy Performed after Injection of Filtered Tc-99m Sulfur Colloid in Breast Cancer Patients Undergoing Sentinel Lymph Node Biopsy

The axillary lymph node status is the most important predictor of prognosis and aids in breast cancer treatment planning. Patients with breast cancer now frequently undergo sentinel lymph node (SLN) biopsy rather than axillary lymph node dissection to determine the status of the regional lymph nodes. However, the optimal timing of radionuclide injection relative to the timing of SLN biopsy remains controversial. The objective of this study was to compare the lymphatic drainage patterns on lymphoscintigraphy performed at 15 minutes to 4 hours and at 18 to 24 hours after injection of filtered Tc-99m sulfur colloid, and to determine whether, over time, radiocolloid migrates to second-echelon nodes that are not the SLNs. Fifteen women with breast cancer (mean age, 55 years; range, 38-78 years) were scheduled to undergo SLN biopsy after each received an injection of 18.5 MBq (0.5 mCi) filtered Tc-99m sulfur colloid into the breast parenchyma surrounding the tumor or biopsy cavity. Both early (15 minutes to 4 hours after radionuclide injection) and delayed (18-24 hours after radionuclide injection) lymphoscintigraphy was performed in each patient. SLN biopsy was performed, followed by completion axillary lymph node dissection and planned breast surgery. In each patient the patterns of distribution of the radionuclide in the lymph nodes were the same on early and delayed lymphoscintigrams. These findings, that the distributions of radionuclide in lymph nodes are identical on early and delayed images obtained after injection of filtered Tc-99m sulfur colloid, suggest that performing SLN biopsy on the day after injection does not diminish the accuracy of the technique in predicting the potential site of metastasis in the regional lymph nodes in patients undergoing this procedure for breast cancer.

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.

Number of Metastatic Sentinel Nodes As Predictor of Axillary Involvement in Patients with Breast Cancer

BACKGROUND AND OBJECTIVES

More than half of patients with positive sentinel node (SN) have no metastases in non-sentinel nodes (NSNs) on axillary lymph node dissection (ALND). The aim of this study was to investigate factors predictive of NSNs involvement, in order to identify patients with metastatic disease confined to the SN which might avoid ALND.

METHODS

ALND was performed in 167 patients with metastatic SN. Axillary NSNs status was correlated with the size of SN metastases, the size of the primary tumor and the occurrence of lymphovascular invasion. In 72 cases, the radiotracer (Tc-99m albumin colloid) marked multiple (in most cases 2 or 3) nodes. In this group, NSNs status was correlated with the number of metastatic radioactive nodes (1 or > 1), and with the above mentioned histopathologic factors.

RESULTS

NSNs metastases were found in 57/167 cases (34.1%), the rate increasing proportionate to the size of both SN metastases (p < 0.0001) and primary tumor (p = 0.0075), while no significant correlation was found for lymphovascular invasion (p = 0.1769). At univariate and multivariate analysis of findings from the 72 cases with multiple probe-detected hot nodes, positivity in more than one hot node was the strongest predictor of NSN involvement (p = 0.0019).

CONCLUSIONS

The identification and excision of multiple hot nodes can be useful in the prediction of NSNs involvement in patients with metastatic SN.

The Hottest Sentinel Lymph Node is Not Always the Positive Node

The technique of identifying the sentinel lymph node (SLN) varies from each individual institution. Generally, the highest isotope count in a lymph node is considered the SLN, whereas other radioactive nodes might also be removed. The purpose of our study was to determine if the hottest node was always the tumor-containing node. Two hundred forty-seven breast cancer patients underwent SLN biopsy from April 1998 to April 2002. Lymphatic mapping involved a radiocolloid injection and lymphoscintigraphy followed by intraoperative assessment with a hand-held gamma probe. All SLN(s) with radioactive counts 10 per cent or more of the ex vivo counts of the most radioactive SLN were removed. The SLN were sliced at 2-mm intervals with 4–μm step-sections (92–μm spacing) and evaluated by microscopy and immunohistochemistry. One hundred twenty (49%) of the 247 patients had 2 or more nodes resected. Of these 120 patients, 33 (28%) had a tumor-bearing node. In 25 (74%) cases, the tumor-bearing node was the most radioactive; however, in 8 (26%) cases, the positive node was a lesser reactive node. Although the most radioactive node in a draining basin is considered the SLN, this is often not the metastatic node. Therefore, all nodes with significant radioactive counts must be removed to ensure accurate staging.

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.

The ability of lymphoscintigraphy to direct sentinel node biopsy in the clinically N0 neck for patients with head and neck squamous cell carcinoma

This study aimed to evaluate the ability of lymphoscintigraphy (LSG) to direct sentinel node biopsy (SNB) in the identification of occult metastases in the clinically N0 neck for patients with head and neck squamous cell carcinoma (HNSCC). 57 clinically N0 neck sides in 48 patients were assessed using the triple diagnostic approach of pre-operative LSG, intra-operative use of a gamma probe and blue dye. SNB was performed after radiocolloid and blue dye injection. Pre-operative LSG and the intra-operative use of a gamma probe identified radioactive sentinel nodes, and visualization of blue stained lymphatics identified blue sentinel nodes. 104 sentinel nodes were harvested from 43 patients. The identification rate was 90% (43 of 48). Of the 104 nodes harvested, 17 of 62 (27%) nodes identified as both radioactive and blue were positive for occult metastases compared with 5 of 42 (12%) nodes identified as hot or blue only (p<0.05). Sentinel nodes were identified in 39 of 48 (81%) patients using LSG. Of 39 patients in whom sentinel nodes were identified using LSG, 37 of 39 (95%) had radioactive sentinel nodes harvested intra-operatively. In patients who had no sentinel nodes identified on LSG, 4 of 9 (44%) had radioactive sentinel nodes harvested intra-operatively. This difference was statistically significant using the t-test (p<0.05). LSG directs SNB and is essential in the identification of occult metastases within the clinically N0 neck for patients with HNSCC.

Sentinel lymph node drainage in multicentric breast cancers

Axillary lymph node status is the most important prognostic marker in patients with breast cancer; the presence of axillary metastases impacts prognosis as well as subsequent systemic therapy. Axillary lymph node dissection (ALND) is associated with significant morbidity and psychological distress; the introduction of sentinel lymph node (SLN) biopsy with lymphatic mapping affords the ability to identify those patients most likely to benefit from ALND, sparing node-negative patients. The lymphatic drainage of the breast is poorly understood, and the situation is further complicated by the lack of standardization of the SLN biopsy technique among institutions. Multicentricity has generally been considered to be a contraindication to SLN biopsy due to concerns about potential inaccuracies. Here we report five cases of patients with multicentric breast cancers (two tumors in two distinct quadrants). In each case, injection of one site with technetium-labeled sulfur colloid and the second site with isosulfan blue dye resulted in successful identification of at least one node that was both hot and blue within the axilla. These observations suggest that the lymphatic drainage of the entire breast coincides with drainage of the tumor bed, regardless of the quadrant. However, further studies are needed to validate the accuracy of SLN biopsy in multicentric breast cancers.

Highest isotope count does not predict sentinel node positivity in all breast cancer patients

BACKGROUND

Radioisotope mapping is an essential technical component of sentinel lymph node (SLN) biopsy, and most authors define isotope success by an arbitrary threshold SLN-to-background ratio. Few studies have examined the degree to which the relative level of SLN counts correlates with the presence of metastasis. Having removed the SLN with the highest counts, how far should the surgeon persist in removing additional SLN which contain much lower levels of isotope?

METHODS

We performed SLN biopsy, using both radioisotope and blue dye, in 2285 consecutive patients with stage I-II breast cancer. Successful isotope localization was defined as an ex vivo SLN-to-axillary background count ratio of at least 4:1, and enhanced pathologic analysis (serial sections and immunohistochemistry) was used throughout.

RESULTS

Among the 1566 patients with more than one SLN site identified, the SLN contained metastasis in 463 (30%). In 369 (80%) of these SLN-positive cases, the SLN with the highest count contained tumor, but in 94 (20%) it was benign. Among these 94: (1) the counts of the hottest benign SLN exceeded those of the histologically positive SLN by a ratio of at least 10:1 in 31% (29 of 94) of cases, (2) the counts of the positive SLN were < 4:1 those of the axillary background in 16% (15 of 94) of cases, and (3) blue dye failed to identify 27% of positive SLN. No optimum ratio of SLN-to-SLN or SLN-to-background counts identified the positive SLN in all cases.

CONCLUSION

Although the SLN with the highest counts is positive in 80% of breast cancer patients with multiple SLN, neither a relatively high isotope count nor the presence of blue dye consistently predict SLN positivity in all breast cancer patients. For maximum accuracy, SLN biopsy requires (1) the removal of all nodes containing isotope regardless of the relative magnitude of counts, (2) the concurrent use of blue dye to salvage those procedures in which isotope fails, and (3) the removal of all clinically suspicious non-SLN.

In vivo evaluation of three different 99mTc-labelled radiopharmaceuticals for sentinel lymph node identification

This work was designed to compare sentinel lymph node (SLN) uptake of 99mTc-labelled human serum albumin colloid (99mTc-HSAC), 99mTc-labelled antimony sulphur colloid (99mTc-SC) and a 99mTc-labelled dextran 70 solution (99mTc-Dx) and their selectivity in the identification of this node in the right rear footpad (RRF) of normal mice and tumour bearing mice. Radiopharmaceutical uptake in the SLN (popliteal lymph node) and the lumbar lymph node (LLN), the second lymphatic node station from RRF, were measured at different time points post-intradermal or intratumoural injection into the RRF of NIH normal mice and of Balb/c mice harbouring the murine mammary tumour M2. 99mTc-HSAC uptake in the SLN was significantly higher than LLN uptake. The 99mTc-SC demonstrated high uptake in SLN, but accumulation in LLN was also high. 99mTc-Dx showed low uptakes in both SLN and LLN. The intradermal injection resulted in a more effective radiopharmaceutical accumulation in SLN than did the intratumoural inoculation. Data also show that increments in tumour volume reduced radiopharmaceutical uptake in the SLN. Our results show that 99mTc-HSAC exhibits the highest uptake in the SLN combined with the smallest amounts of radiopharmaceutical passing through to the LLN. Therefore, 99mTc-HSAC appears to be the best radiopharmaceutical for sentinel node detection.

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.

A new radiocolloid for sentinel node detection in breast cancer

BACKGROUND

The optimal radioactive tracer and technique for sentinel lymph node localization in breast cancer is yet to be determined. The dilemma of small particle size with dispersion to second echelon nodes versus failure of migration of larger radiocolloids needs to be resolved. A new radiocolloid preparation with particle size under 0.1 micron was developed with excellent primary/post lymphatic entrapment ratio.

OBJECTIVE

To assess the feasibility of a new 99mTc radiocolloid cysteine-rhenium colloid in sentinel lymph node (SLN) localization for breast cancer.

METHODS

Forty-seven patients with newly diagnosed T1 or T2 breast cancer underwent injection of 99mTc-labeled cysteine-rhenium colloid followed by lymphoscintigraphy. Same day SLN biopsy with patent blue dye and intraoperative gamma probe to identify SLNs were performed.

RESULTS

SLN mapping and intraoperative localization were successful in 46/47 (98%) of patients. The blue dye radioactive tracer concordance was 94%. There was one false-negative in a patient with a nonpalpable tumor that underwent ultrasound-guided peritumoral radiocolloid injection.

CONCLUSIONS

99mTc-cysteine-rhenium colloid is highly effective in identifying SLNs. It has the advantage of smaller particle size than sulfur colloid with easier lymphatic migration. It has a more neutral pH with less pain on injection and does not require filtration, thereby minimizing radiation exposure to technologists.

[Sentinel node and operable breast cancer: utilization of blue dye injection. Pilot study]

STUDY AIM

Sentinel node detection in breast cancer can be realized with colorimetric and isotopic procedures often associated. The aim of this study was to report results obtained with blue dye injection only.

PATIENTS AND METHOD

From September 1998 to July 1999, blue dye injection was performed in 73 consecutive patients (mean age: 51 years, range: 36-71 years); 51/70 70% were post-menopausal and half of them were under substitute hormonal treatment; 70% of cancers were discovered through routine mammography. There were 12 bilateral cancers, six of them synchronous, and 84% of cancers were located in the external quadrants. Individualization of sentinel node was performed through blue dye injection into the tumor in case of preoperative diagnosis or in the tumoral site in case of discovery of the cancer through extemporaneous histological examination.

RESULTS

71 out of 73 cancers were classified pT1 and 70% measured 10 mm and over. Individualization of sentinel node failed in two obese patients. Sentinel node invasion concerned one node (n = 7), two nodes (n = 1) and three nodes (n = 1). Conservative treatment was performed in 72 patients out of 73; in case of sentinel node invasion, axillary irradiation was performed without reoperation.

CONCLUSION

Blue dye injection for sentinel node individualization is an accurate technique in selected patients in case of small tumors. Reoperation can be avoided and replaced by axillary irradiation in case of N+ tumors. Duration of hospitalization was 48 hours or under in 70/73 patients. Nevertheless isotopic procedure must be recommended as a routine technique in learning centers and for most surgical teams.

Active macromolecule uptake by lymph node antigen-presenting cells: a novel mechanism in determining sentinel lymph node status

BACKGROUND

Although sentinel lymph node (SLN) biopsy is a powerful staging tool for patients with melanoma and breast cancer, controversy remains regarding specific aspects of technique. We examined particle uptake by antigen-presenting cells (APCs) to determine if this mechanism is responsible for the differential retention of radioactivity in SLNs relative to nonsentinel lymph nodes (NSLNs).

METHODS

Mapping was conducted in pigs injected with vital blue dye, fluoroscein isothiocyanate-labeled human serum albumin (FITC-HSA), and one of two 99mtechnetium-labeled tracers, i.e., human serum albumin, a small macromolecule, or unfiltered sulfur colloid, a mixture of small and large particles. Macromolecule uptake by APCs was studied in vitro by using FITC-HSA and measured by fluorescence-activated cell sorting (FACS). SLNs and NSLNs were analyzed by fluorescence microscopy or FACS, with counterstaining for leukocyte cell surface markers.

RESULTS

Both radiotracers were effective. Cultured APCs rapidly took up FITC-HSA. Microscopy showed FITC-HSA in the subcapsular sinus of SLNs shortly after injection and subsequent distribution to interfollicular areas. FACS revealed increasing amounts of FITC-HSA in SLNs over time. Cells responsible for uptake were APCs, expressing major histocompatibility (locus) class II.

CONCLUSIONS

This report establishes active macromolecule uptake as a mechanism that determines SLN status. This mechanism has important implications for performing SLN biopsy.

The pathologist's role in sentinel lymph node evaluation

Patients with high-risk (thick, deeply invasive) primary melanoma were, in the past, managed by wide local excision and elective node dissection or wide local excision alone, with subsequent lymphadenectomy if the regional nodes developed clinically detectable metastases. We recently developed a more logical approach called selective lymph node dissection. To be effective, this requires close collaboration of surgeons, pathologists, and nuclear medicine physicians. The draining lymph node basin is identified preoperatively by lymphoscintigraphy. During surgery, a marker dye (isosulfan blue) and radioactive technetium labeled albumin are injected intradermally around the primary melanoma and the afferent lymphatics are followed up to the first lymph nodes of the ipsilateral regional nodal basin. The surgeon excises the blue-colored and maximally radioactive sentinel nodes and the pathologist critically evaluates these for the presence of a metastatic tumor. If the sentinel nodes are tumor free, no further nodal dissection is undertaken; if a tumor is present, a complete dissection of the nodal basin is performed. We have examined 1,119 sentinel lymph nodes from 669 patients treated by selective lymph node dissection. We identified melanoma cells in sentinel nodes from 126 patients (17.8%). A single node contained tumors in 67% of patients, 2 nodes were positive in 25%, and the remaining 12% of patients had three tumor-containing nodes. Melanoma cells were dispersed singly or in variably sized groups, usually in the peripheral nodal sinus. In around 40% of patients, immunohistochemistry is required to identify minute numbers of tumor cells. With experience, pathologists identify tumors in hematoxylin and eosin (H&E) preparations in an increasing proportion of lymph nodes. Tumor cells are more frequent in the sentinel nodes of patients with primary tumors of deeper Clark level and greater Breslow thickness. Tumor cells must be discriminated from capsular nevus cells, interdigitating dendritic leukocytes, macrophages, and intranodal neural tissues.

Sentinel node biopsy in the staging of breast cancer

BACKGROUND

The role of axillary lymph node dissection (ALND) in breast cancer is currently being reevaluated. Sentinel node biopsy (SNB) holds promise for replacing full dissection in a large number of patients with breast cancer.

MATERIALS

We evaluated SNB utilizing an intraoperative gamma probe localization technique following injection of technetium sulfur colloid in 80 patients with primary breast cancer and clinically negative axillae. Forty-eight patients were evaluated at Baptist Medical Center, Montgomery, Alabama, and 32 at Rush-Presbyterian-St. Luke's Medical Center in Chicago, Illinois.

RESULTS

At least one sentinel node was found in 70 of the 80 patients (88%). One patient had a sentinel node in both the axilla and internal mammary chain. The remainder had axillary sentinel nodes only. The sentinel nodes accurately predicted the status of the axilla in 69 of the 70 patients (99%). One of 14 node-positive patients would have been missed with sentinel node biopsy alone, for a false negative rate of 7%. Four node-positive patients would have been missed with routine ALND without serial sectioning (SS) and immunohistochemical staining (IH) of the sentinel node.

CONCLUSIONS

Sentinel node biopsy with SS and IH more precisely predicted the status of the axilla than routine ALND in this group of patients. SNB will likely replace full axillary dissection in the majority of patients with breast cancer.

Demonstration of second-tier lymph nodes during preoperative lymphoscintigraphy for melanoma: incidence varies with primary tumor site

BACKGROUND

Preoperative cutaneous lymphoscintigraphy (LS) to identify sentinel (first-tier) lymph nodes was performed in 250 consecutive melanoma patients before wide local excision only or wide local excision with sentinel node biopsy.

METHODS

The location of the sentinel nodes was marked on the overlying skin in all patients. Whether or not tracer was present in second-tier lymph nodes on the delayed scans was recorded for each patient and related to the lesion site at which the tracer had initially been injected. For 100 consecutive patients the rate of tracer movement through the lymphatic channels was compared to the incidence of second-tier drainage.

RESULTS

Second-tier nodes were visualized in all patients with melanomas on the leg and thigh, and in almost all patients with melanomas on the forearm and hand, but were seen less often in patients with more centrally located melanomas. There was a significant correlation between the rate of lymph flow and the incidence of demonstrable second-tier drainage.

CONCLUSION

The results suggest that the physiology of the lymphatic system varies depending on the origin of the lymphatic vessel. These findings have important implications for application of the sentinel node biopsy technique in individual patients.

Sentinel node biopsy in breast cancer

BACKGROUND

Sentinel lymph node biopsy (SNB) in breast cancer may be used in place of axillary lymph node dissection (ALND) if SNB accurately stages the axilla. This study assessed the success and accuracy of axillary SNB with isosulfan blue (ISB) and technetium-99 sulfur colloid (TSC) compared to ALND.

METHODS

Forty-two women with T1 or T2 breast cancer underwent SNB and ALND. Sixty to 90 minutes before anesthetic induction, a mixture of 3 mL ISB and 1 mCi TSC was injected around the primary cancer or prior biopsy site. Intraoperatively, the SLN was identified using a gamma detector (Neoprobe 1000) or by visualization of the blue-stained lymph node and afferent lymphatics. The SLN was excised separately, and a level I/II ALND was completed. The histologic findings of the axillary contents and SLN were compared.

RESULTS

An axillary SLN was found in 38 of 42 (90%) cases. SLN localization rate and predictive value were the same for women who had and those who had not undergone excisional biopsy before the date of SNB. Fifteen of 42 (36%) patients had lymph node metastases. The SLN was positive in all women with axillary metastases (negative predictive value, 100%).

CONCLUSIONS

If confirmed by larger series, a negative SNB may eliminate the need for ALND for select women with breast cancer.

Lack of effect of particle size on the identification of the sentinel node in cutaneous malignancies

BACKGROUND

Radiotracers have become a routine technical component of the new procedure of intraoperative lymphatic mapping and selective lymphadenectomy. Because different colloids have differing physicochemical properties, their distribution and uptake may be different. For this reason, the optimal colloid to identify and localize the sentinel node remains controversial.

METHODS

Nineteen consecutive patients with cutaneous malignancies underwent diagnostic lymphoscintigraphy with 99mTc-labeled human serum albumin (99mTc-HSA) and preoperative lymphoscintigraphy with 99mTc-labeled sulfur colloid (99mTc-SC). The results of intraoperative lymphatic mapping and selective lymphadenectomy were reviewed.

RESULTS

Intraoperative lymphatic mapping and selective node dissection were successful in 21 of 22 lymphatic basins (18 of 19 patients). There was excellent correlation between the "hot" marker placed on the skin surface when 99mTc-HSA was used compared with the use of 99mTc-SC. In 20 of 21 lymphatic basins the sentinel node both was "hot" and was stained with isosulfan blue.

CONCLUSIONS

No discernible difference between the ability to localize in the sentinel node with these two radiocolloids was identified. For logistical reasons, 99mTC-SC appears to be the colloid of choice in intraoperative lymphatic mapping.