Pre-operative axillary lymphoscintigraphy in breast cancer: experience with sub-areolar injection of 99Tcm-nanocolloidal albumin

Challenges in Preparation of Albumin Nanoparticle-Based Radiopharmaceuticals

Albumin nanocolloids have been used as radiopharmaceuticals for more than 40 years. Their main use is in lymphoscintigraphy and the detection of the sentinel lymph node as part of the surgical treatment of a variety of solid tumours. The main licensed products are labelled with the gamma emitter technetium-99m. Recently, two analogues labelled with positron emitters have been reported, using gallium-68 and zirconium-89. For about 10 years, there has been interest in dual-modal agents with both radioactive and fluorescent labels to improve the localisation of the sentinel lymph node. Indocyanine green (ICG) has been the most widely used fluorescent label, largely due to its availability as a licensed agent and its ease of application. The further development of alternative radiolabels or improved fluorescent tags will require investment in the development and licensing. There is also a vast potential for the targeting of albumin nanocolloids using existing strategies, which could be promising for the development of both diagnostic and therapeutic agents.

Subareolar Injection of Radioactive Colloid for Sentinel Lymph Node Identification in Breast Cancer Patients

Sentinel lymph node biopsy (SLNB) is becoming the standard for staging the axilla in breast cancer patients in many institutions. The best method of injection is still questionable. The purpose of this study was to compare the results of SLNB using the peritumoral or the subareolar injection site. Between December 1997 and March 2000, we performed 100 SLNBs. Technecium-labeled colloidal human serum albumin was injected peritumorally (Group A, 31 patients; Group B, 31 patients) or subareolarly (Group C, 38 patients). Patent blue dye was given periareolarly (Group A) or peritumorally (Groups B and C). Preoperative lymphoscintigraphy was performed in all patients. SLNB was successful in 94 patients (94%). The identification rate improved from 80 per cent (first 25 patients) to 99 per cent (last 75). The subareolar injection of the colloid did not adversely influence the results of SLNB compared with the peritumoral injection (identification rate, 100% vs 97%; false negative rate, 6% vs 14%). The subareolar injection of colloid is a simple and at least as accurate technique as the peritumoral one. This technique can also improve the identification rate of SLNB for breast cancer patients.

Concordance and validation study of sentinel lymph node biopsy for breast cancer using subareolar injection of blue dye and technetium 99m sulfur colloid

BACKGROUND

We have previously demonstrated the utility, accuracy, and advantages of a subareolar (SA) site of injection for blue dye compared with an intraparenchymal site. In later studies we advocated the additional use of preoperative SA-injected technetium 99m-labeled sulfur colloid as a directional aid in finding blue-stained sentinel lymph nodes (SLNs). Paramount to the usefulness of this dual-tracer, same-site technique is the degree to which SA-injected blue dye and SA-injected radiocolloid migrate concordantly and are deposited within the same sentinel nodes. The purpose of this study was to document the correlation and accuracy of SLN biopsy using blue dye and radiocolloid when both nodal markers are injected by the same SA route.

STUDY DESIGN

Between September 1999 and February 2002 (29 months), 185 consecutive patients with 187 operable breast cancers underwent 187 attempted SLN biopsies by a dual-tracer, same-site injection technique using the SA approach for both agents. Unfiltered technetium 99m-labeled sulfur colloid (1 mCi [37 MBq]) was SA-injected 30 to 45 minutes preoperatively; and just after anesthetic induction, 3 mL of 1% isosulfan blue dye was injected by the same SA route. SLN biopsies or complete axillary dissections were carried out, and SLNs identified during these procedures were classified as containing both blue dye and radioactivity ("blue-hot" nodes), radioactivity alone ("hot-only" nodes), or blue dye alone ("blue-only" nodes). Cases were categorized and tabulated based on the presence or absence of these three types of SLNs.

RESULTS

Of the 187 procedures, a SLN was identified successfully in 184 cases, indicating an SLN identification rate of 98.4% (95% confidence interval, 96.6% to 100.2%). In these 184 cases, a blue-hot node was present in 94.5% (n = 174 of 184). An SLN was positive in 50 cases, or 27.2% of the total group (n = 50 of 184). A blue-hot node was the only positive SLN in 43 of these 50 cases, or 86% of the node-positive cases. There were no false negatives in 20 confirmatory axillary node dissections carried out to document the findings of a negative SLN. A correlation analysis revealed that in 98.9% of cases (174 of 176), blue nodes were also radioactive ("blue-hot" case concordance = 98.9%). In 95.1% of cases (174 of 183), hot nodes had also taken up blue dye ("hot-blue" case concordance = 95.1%).

CONCLUSIONS

Using SA injections of both blue dye and radiocolloid, we achieved an SLN identification rate of 98.4% (184 of 187 cases), a false-negative rate of 0% (0 of 20 cases), and an accuracy in predicting the malignant status of the axilla of 100% (70 of 70 cases). The case concordance rate ranged between 98.9% ("blue-hot concordance") and 95.1% ("hot-blue concordance"). The present study is the first to evaluate dual-tracer, same-site SA injections of blue dye and radiocolloid. By demonstrating a high case concordance rate, a high SLN identification rate, and a 0% false-negative rate, this study adds further support to the validity and accuracy of same-site SA injections of both blue dye and radiocolloid during SLN biopsy in breast cancer.

Preoperative lymphoscintigraphy during lymphatic mapping for breast cancer: improved sentinel node imaging using subareolar injection of technetium 99m sulfur colloid

BACKGROUND

Preoperative lymphoscintigraphy has been recommended to confirm the successful uptake and direction of migration of radiotracer into sentinel nodes during lymphatic mapping for breast cancer. In addition, preoperative lymphatic mapping may provide a visually useful aid to the relative location of sentinel nodes within a nodal basin. One common method of breast lymphoscintigraphy involves injections of unfiltered technetium 99m sulfur colloid (Tc-99m-SC) directly into parenchymal tissues surrounding a tumor or biopsy cavity (IP injection). Because of the many imaging failures and prolonged imaging times of IP lymphoscintigraphy, the procedure has fallen into disfavor by oncologic surgeons. The purpose of this study is to document the increased success rate of preoperative breast lymphoscintigraphy using a new anatomic site of injection, the subareolar lymphatic plexus (SA injection).

STUDY DESIGN

In the 12 months between December 1, 1998, and December 29, 1999, 42 women with stage I and II breast cancer underwent preoperative lymphoscintigraphy by either the IP (n = 12, December 1998 to May 1999) or SA (n = 30, May 1999 to December 1999) route of injection. Both groups were injected with 1 mCi (37 MBq) of unfiltered Tc-99m-SC followed immediately by external gamma-camera imaging. The success rate for preoperative sentinel node imaging and the total imaging time were recorded in both groups.

RESULTS

The success rate of identifying a sentinel node by SA lymphoscintigraphy was 90% (n = 27 of 30 patients), compared with 50% (n = 6 of 12 patients) for IP lymphoscintigraphy (p = 0.009). The imaging time in the SA injection group was 34 +/- 16 minutes, which was 59% shorter than the imaging time in the IP injection group of 82 +/- 48 minutes (p < 0.001). No uptake into internal mammary nodes was seen in either group.

CONCLUSIONS

Moving the site of injection ofunfiltered Tc-99m-SC to the subareolar lymphatic plexus (SA injection) increased the success rate of preoperative lymphoscintigraphy to 90%, compared with 50% using IP injections. Preoperative SA lymphoscintigraphy resulted in the rapid visualization of axillary sentinel nodes within 30 minutes of SA injection, enabling a visual determination of the approximate number of sentinel nodes and their relative locations within the axilla. We conclude SA injection of unfiltered Tc-99m-SC is superior to IP injections when performing preoperative breast lymphoscintigraphy and is a visually useful aid to lymphatic mapping for breast cancer.

The biological characteristics of a water soluble porphyrin in rat lymph nodes

The biological characteristics of a radiolabeled metalloporphyrin, 5,10,15,20-tetrakis(4-carboxyphenyl)-porphinato [67Cu]copper (II) [( 67Cu]TCPP), in rat lymph nodes, surrounding muscle, fat, and blood were determined. Lymphatic tissue localized greater amounts of [67Cu]TCPP than did surrounding muscle and fat. Inflamed lymph nodes localized greater amounts of [67Cu]TCPP than did noninflamed lymph nodes. Time course studies suggest that the uptake of [67Cu]TCPP in noninflamed and in inflamed lymph nodes may involve different biological processes. The affinity of [67Cu]TCPP for inflamed lymph nodes may be influenced by the degree of inflammation. If further studies confirm these results, [67Cu]TCPP may be useful as a potential radiopharmaceutical for imaging inflamed lymph nodes.