Outcomes of "one-day" vs "two-day" injection protocols using Tc-99m tilmanocept for sentinel lymph node biopsy in breast cancer

Sentinel Lymph Node Mapping in Lung Cancer: A Pilot Study for the Detection of Micrometastases in Stage I Non-Small Cell Lung Cancer

Lymphadenectomy represents a fundamental step in the staging and treatment of non-small cell lung cancer (NSCLC). To date, the extension of lymphadenectomy in early-stage NSCLC is a debated topic due to its possible complications. The detection of sentinel lymph nodes (SLNs) is a strategy that can improve the selection of patients in which a more extended lymphadenectomy is necessary. This pilot study aimed to refine lymph nodal staging in early-stage NSCLC patients who underwent robotic lung resection through the application of innovative intraoperative sentinel lymph node (SLN) identification and the pathological evaluation using one-step nucleic acid amplification (OSNA). Clinical N0 NSCLC patients planning to undergo robotic lung resection were selected. The day before surgery, all patients underwent radionuclide computed tomography (CT)-guided marking of the primary lung lesion and subsequently Single Photon Emission Computed Tomography (SPECT) to identify tracer migration and, consequently, the area with higher radioactivity. On the day of surgery, the lymph nodal radioactivity was detected intraoperatively using a gamma camera. SLN was defined as the lymph node with the highest numerical value of radioactivity. The OSNA amplification, detecting the mRNA of CK19, was used for the detection of nodal metastases in the lymph nodes, including SLN. From March to July 2021, a total of 8 patients (3 female; 5 male), with a mean age of 66 years (range 48-77), were enrolled in the study. No complications relating to the CT-guided marking or preoperative SPECT were found. An average of 5.3 lymph nodal stations were examined (range 2-8). N2 positivity was found in 3 out of 8 patients (37.5%). Consequently, pathological examination of lymph nodes with OSNA resulted in three upstages from the clinical IB stage to pathological IIIA stage. Moreover, in 1 patient (18%) with nodal upstaging, a positive node was intraoperatively identified as SLN. Comparing this protocol to the usual practice, no difference was found in terms of the operating time, conversion rate, and complication rate. Our preliminary experience suggests that sentinel lymph node detection, in association with the accurate pathological staging of cN0 patients achieved using OSNA, is safe and effective in the identification of metastasis, which is usually undetected by standard diagnostic methods.

99mTc-Tilmanocept performance for sentinel node mapping in breast cancer, melanoma, and head and neck cancer: a systematic review and meta-analysis from a European expert panel

PURPOSE

Although multiple radiopharmaceuticals are currently available for sentinel node (SN) biopsy, 99mTc-tilmanocept is of particular interest due to its low molecular weight and specific binding capability for the mannose receptors of lymphatic reticuloendothelial cells. In the current systematic review and meta-analysis, we aimed to provide an update from a European expert panel on the performance of 99mTc-tilmanocept for SN biopsy.

METHODS

A systematic literature search of the PubMed/Medline and Embase databases was performed to identify studies on the use of 99mTc-tilmanocept for SN identification in oncological patients. The articles' methodological quality was assessed before inclusion. The pooled estimates of the pre-/intraoperative detection rates (DR; proportion of patients with ≥ 1 SN identified) and/or pN + sensitivity (SN + /pN + patients ratio), with 95% confidence intervals (CIs), were calculated for breast cancer, melanoma, and head and neck cancer.

RESULTS

Twenty-four articles were included in the systematic review, and twenty-one provided data for the meta-analysis. According to data availability, the 99mTc-tilmanocept-estimated pooled preoperative and intraoperative DRs were 0.94 (95%CI, 0.88-1.01) and 0.99 (0.98-1.00) for breast cancer, 0.98 (0.96-0.99) and 1.00 (0.99-1.00) for melanoma, and 0.97 (0.93-1.02) and 0.99 (0.96-1.01) for head and neck carcinoma. Finally, the pooled sensitivity for nodal metastasis in melanoma was 0.97 (95% CI, 0.92-1.03).

CONCLUSION

99mTc-tilmanocept is a promising radiotracer for SN mapping in patients with breast cancer, melanoma, or head and neck cancer. We strongly believe that multicenter trials are still needed to assess if 99mTc-tilmanocept is superior to other radiotracers used in clinical routine.

Lymphoscintigraphy Using Tilmanocept Detects Multiple Sentinel Lymph Nodes in Melanoma Patients

BACKGROUND

Technetium-99m-labeled Tilmanocept, a multivalent mannose, is readily internalized by the CD206 surface receptor on macrophages and dendritic cells which are abundantly present in lymph nodes. We want to examine the drainage patterns of Technetium-99m-labeled Tilmanocept to sentinel lymph nodes (SLNs) in melanoma patients following the 10% rule.

METHODS

Multi-center retrospective review of patients with cutaneous melanoma undergoing SLN biopsy using Technetium-99m-labeled Tilmanocept between 2008 and 2014 was conducted. Statistical methods were used for data analyses.

RESULTS

Of the 564 patients (mean age of 60.3 and 62% male) with preoperative lymphoscintigraphy showing at least one SLN, several primary tumor sites were included: 27% head/neck, 33% trunk, 21% upper extremity and 19% lower extremity. For the head/neck primary site, 36.5% of patients had multiple draining basins; for the trunk site, 36.4% of patients; for the upper extremity site, 13% of patients; and for the lower extremity, 27.4% of patients. A median of 3 (range 1-18) SLNs were identified and resected. Overall, 78% of patients had >1 SLN identified by Technetium-99m-labeled Tilmanocept. In a multivariate model, patients with >1 SLN were significantly associated with age, Breslow depth, tumor location and higher AJCC tumor stage. A total of 17.7% of patients (100/564) had a positive SLN identified. A total of 145 positive SLNs were identified out of 1,812 SLNs with a positive SLN rate of 8%. Positive SLN status was significantly associated with younger age, greater Breslow depth, mitosis rate, higher AJCC tumor stage, presence of ulceration and angiolymphatic invasion.

CONCLUSIONS

Using the 10% rule, Technetium-99m-labeled Tilmanocept detects multiple SLNs in most melanoma patients.

Comparison of [99mTc]Tc-tilmanocept with [99mTc]Tc-sulphur colloids and [99mTc]Tc-albumin colloids for sentinel lymph node detection in patients with cutaneous malignancies of the head

PURPOSE

Sentinel lymph node (SLN) biopsy is a staging procedure in the management of cutaneous malignancies of the head. The ideal radiopharmaceutical is controversial. This study aimed to compare [^99mTc]Tc-tilmanocept (TcTM) with [^99mTc]Tc-sulphur colloid (TcSC) and [^99mTc]Tc-albumin colloid (TcAC) for SLN detection in the head and neck region.

METHODS

Data from 62 patients with cutaneous malignancies of the head who were injected with TcTM, TcSC, or TcAC before SLN imaging (SLN-I) and SLN excision (SLN-E) between 2012 and 2021 were retrospectively analysed. SLN-I was performed using planar lymphoscintigraphy and SPECT/CT, and a gamma probe was used for SLN-E. The SLN-I localisation rate (patients with SLNs) and degree (SLN number) and SLN-E relocalisation rate (patients with SLNs) and ratio (SLN number in SLN-E/SLN number in SLN-I) were compared between TcTM, TcSC, and TcAC.

RESULTS

TcTM showed similar SLN-I localisation rates for primaries in the anterior and posterior head region compared with TcSC (84.6% vs. 72.4%, p=0.680; both 100.0%) and TcAC (84.6% vs. 75.0%, p=1.000; both 100.0%). The SLN-I localisation degree for TcTM was higher for primaries in the anterior head region and similar for primaries in the posterior head region compared with TcSC (3.2 vs. 2.3, p=0.034; and 1.8 vs. 2.2, p=0.506) and TcAC (3.2 vs. 2.0, p=0.038; and 1.8 vs. 2.7, p=0.329). The SLN-E relocalisation rates and ratios were similar for all.

CONCLUSION

On the basis of a limited study design that compared three different tracers in three different patient groups, TcTM showed comparable overall performance to TcSC and TcAC.

How much time is enough? Sentinel lymph node mapping time depends on the radiotracer agent

BACKGROUND

In 2014, technetium-99m tilmanocept (TcTM) replaced technetium-99m sulfur colloid (TcSC) as the standard lymphoscintigraphy (LS) mapping agent in melanoma patients undergoing sentinel lymph node biopsy (SLNB). The aim of this study was to examine differences in mapping time, intra-operative identification of sentinel lymph node (SLN), and false negative rate (FNR) between patients who underwent SLNB with TcTM compared to TcSC.

METHODS

Patients who underwent SLNB between 2010 and 2018 were retrospectively identified. Patient demographic, tumor, and imaging data was stratified by receipt of TcSC (n = 258) or TcTM (n = 133). Student's t test and χ² test were used to compare characteristics and outcomes.

RESULTS

Both cohorts were similar in demographic, primary tumor characteristics, and total number of SLN identified (TcTM 3.56 vs. TcSC 3.28, p = 0.244). TcTM was associated with significantly shorter LS mapping times (51.8 vs. 195.1 min, p < 0.01). There was no significant difference in the number of patients with positive SLN (TcTM 11.3 vs. TcSC 17.4%, p = 0.109) and the FNR was similar between both groups (TcTM 25% vs. TcSC 22%).

CONCLUSION

TcTM was associated with significantly shorter LS mapping time while identifying similar numbers of SLN. Our results support further study to ensure similar FNR and oncologic outcomes between agents.

Early Institutional Experience of Dual Tracer and Single-Photon Emission Computed-Tomography/Computed-Tomography Mapping for Sentinel Node Biopsy: A Report of Two Early-Stage Breast Cancer

Intraoperative sentinel lymph node mapping (SLNM) with methylene blue dye (MBD) tracer has been the recommended method to detect SLN in early-stage breast cancer patients in low-resource settings. However, the use of MBD alone is hampered by the high false-negative rate; thus, it requires coupling with other mapping methods if the appropriate infrastructure and services are available. In this article, we present two prospective cases detailing our initial experience using the gold-standard dual tracer technique (DTT: MBD and 99mTc-nanocolloid radioisotope) in combination with hybrid single-photon emission computed-tomography/computed-tomography (SPECT/CT) preoperative mapping for image-guided SLN biopsy (SLNB). Overall, both studies were successful in identifying the SLNs, which aided in mapping the possible anatomical spread of the disease.

Does 99mTc-tilmanocept, as next generation radiotracer, meet with the requirements for improved sentinel node imaging?

INTRODUCTION AND OBJECTIVES

To evaluate the migration of ^99mTc-tilmanocept from the injection site (IS) as well as the uptake in sentinel nodes (SNs) and non-SNs for lymphatic mapping in patients with breast cancer and melanoma, scheduled for SN biopsy after interstitial tracer administration.

MATERIALS AND METHODS

For 29 primary tumours in 28 patients (mean age: 62y, range: 45-81y) scheduled for SN biopsy planar images were acquired 10 and 120 min after administration of 74 MBq ^99mTc-tilmanocept, in order to evaluate lymphatic drainage as well as uptake ratios between injection site (IS), SN and non-SN. SPECT/CT was performed immediately after delayed planar images to enable anatomical lymph node localization.

RESULTS

SNs were visualized in all patients (100%) with drainage to 34 basins. Uptake in non-SNs was perceived in 16 basins (47%). Number of SNs was concordant between early and delayed images in all basins excepting five (86%). In 24 patients tracer migrated to one lymph node basin (LNB), in three to 2 and in one to 4. When IS was included (n = 29) on image, IS/SN ratio could be measured per LNB. The IS/SN ratio at 2 h compared to 15 min decreased with an average of 66% (range: 15-96%). SN/non-SN 2 h ratio in LNBs with visible non-SNs averaged 6.6 (range: 2.3-15.6). In 9 patients with two SNs SN1/SN2 ratio averaged 1.9 on delayed images. At histopathology, SNs were found to be tumour positive in 7 basins (20%).

CONCLUSION

^99mTc-tilmanocept appears to meet the requirements for improved SN imaging in breast cancer and melanoma on the basis of early and persistent SN visualization frequently accompanied by no or markedly less non-SN uptake. This is associated to rapid migration from the injection site together with increasing SN uptake and retention as expressed by decreasing IS/SN and persistently high SN/non-SN ratios. Further head-to-head comparison of ^99mTc-tilmanocept with standard SN radiotracers in larger series of patients is necessary.

Does 99mTc-tilmanocept, as next generation radiotracer, meet with the requirements for improved sentinel node imaging?

INTRODUCTION AND OBJECTIVES

To evaluate the migration of ^99mTc-tilmanocept from the injection site (IS) as well as the uptake in sentinel nodes (SNs) and non-SNs for lymphatic mapping in patients with breast cancer and melanoma, scheduled for SN biopsy after interstitial tracer administration.

MATERIALS AND METHODS

For 29 primary tumours in 28 patients (mean age: 62y, range: 45-81y) scheduled for SN biopsy planar images were acquired 10 and 120min after administration of 74MBq ^99mTc-tilmanocept, in order to evaluate lymphatic drainage as well as uptake ratios between injection site (IS), SN and non-SN. SPECT-CT was performed immediately after delayed planar images to enable anatomical lymph node localization.

RESULTS

SNs were visualized in all patients (100%) with drainage to 34 basins. Uptake in non-SNs was perceived in 16 basins (47%). Number of SNs was concordant between early and delayed images in all basins excepting five (86%). In 24 patients tracer migrated to one lymph node basin (LNB), in three to 2 and in one to 4. When IS was included (N=29) on image, IS/SN ratio could be measured per LNB. The IS/SN ratio at 2h compared to 15min decreased with an average of 66% (range: 15-96%). SN/non-SN 2h ratio in LNBs with visible non-SNs averaged 6.6 (range: 2.3-15.6). In 9 patients with two SNs SN1/SN2 ratio averaged 1.9 on delayed images. At histopathology, SNs were found to be tumour positive in 7 basins (20%).

CONCLUSION

^99mTc-tilmanocept appears to meet the requirements for improved SN imaging in breast cancer and melanoma on the basis of early and persistent SN visualization frequently accompanied by no or markedly less non-SN uptake. This is associated to rapid migration from the injection site together with increasing SN uptake and retention as expressed by decreasing IS/SN and persistently high SN/non-SN ratios. Further head-to-head comparison of ^99mTc-tilmanocept with standard SN radiotracers in larger series of patients is necessary.

Sentinel Lymph Node Biopsy in Breast Cancer with 99mTc-Tilmanocept: A Multicenter Study on Real-Life Use of a Novel Tracer

^99mTc-tilmanocept is a novel radiopharmaceutical for sentinel lymph node (SLN) biopsy in breast cancer. Our aim was to describe results with ^99mTc-tilmanocept in a heterogeneous group of breast cancer patients scheduled for SLN biopsy. Methods: Radiotracer preparation followed the manufacturer's indications. Local protocols for SLN detection within 9 participant centers were not changed for the entire duration of the study. In total, 344 patients with T1-T4, N0-N2 breast cancer (352 lesions) were included. Superficial (intradermal or periareolar) or deep (peritumoral or intratumoral) injections were performed. The doses were adjusted depending on the scheduled time for surgery. Results: Lymphoscintigraphy was able to depict at least 1 SLN in 339 of 352 breast lesions (96.3%), and the intraoperative SLN detection rate reached 97.2%. On univariable analysis, SLN detection rates did not differ by age, clinical T or N stage, tumor location, histologic subtype, or prior neoadjuvant therapy. Lymphoscintigraphy showed higher SLN detection in patients with a normal weight (body mass index < 25) than in those who were overweight or obese (body mass index ≥ 25), at 99.2% versus 94.6%, respectively (P = 0.031). The proportion of patients with preoperative lymphoscintigraphic detection or excised SLNs was higher with superficial than deep injections. Reinjected cases were significantly lower when superficial injection was chosen first (P < 0.001). Injection site and the tumor markers human epidermal growth factor receptor 2 and estrogen receptor had an impact on preoperative SLN visualization and intraoperative localization. In 80 cases, SLN biopsy resulted in a positive lymph node. During a mean follow-up of 19 mo, no axillary recurrences were observed. Conclusion: Whatever the protocol, ^99mTc-tilmanocept showed good results in a heterogeneous breast cancer population, although the best results were achieved when a superficial injection was chosen.

Sentinel Node Imaging and Radioguided Surgery in the Era of SPECT/CT and PET/CT: Toward New Interventional Nuclear Medicine Strategies

We review recent technological advances and new clinical indications for sentinel node (SN) and radioguided surgery in order to delineate future tendencies of interventional nuclear medicine in this field. A literature research was performed in PubMed to select relevant articles to be used as key references for analysis of the current approaches and tendencies in SN and radioguided surgery, as well as the evolving contribution of nuclear medicine intervention techniques to the various clinical applications. For classic indications such as melanoma and breast cancer, the incorporation of the SN approach based on the combined use of existing and new preoperative and intraoperative technologies in high-risk patient categories is becoming an emerging area of clinical indication. For SN biopsy staging in other malignancies with more complex lymphatic drainage, the incorporation of sophisticated tools is most helpful. The consecutive use of PET/CT and the SN procedure is increasing as a potential combined approach for the management of specific areas such as the axilla and the pelvis in patients at high risk of regional dissemination. Also, for the management of locoregional metastasis and oligometastatic disease, interventional nuclear medicine techniques are becoming valuable alternatives. The extended experience with SN biopsy is leading to technological advances facilitating the incorporation of this procedure to stage other malignancies with complex lymphatic drainage. New nuclear medicine-based approaches, incorporating SPECT/CT and PET/CT to guide resection of SNs and occult metastases, have recently been gaining ground.

Lymphoscintigraphy for Sentinel Lymph Node Biopsy in Breast Cancer: Do We Need a Delayed Image?

Background

Sentinel lymph node biopsy has become a standard of care in the treatment of patients with early breast cancer, but clinical guidelines continue to be vague on details of the procedure. We were interested in the results of our 2-day protocol, which includes delayed lymphoscintigraphy at 18 h.

Methods

We reviewed the results of preoperative lymphoscintigrams in patients undergoing surgery for breast cancer. Lymphoscintigraphy was performed 2 h after periareolar injection of 4 × 37 MBq ^99mTc nanocolloid (early lymphoscintigraphy) and 18 h following injection (delayed lymphoscintigraphy). The early results were compared with the late results.

Results

A total of 238 lymphoscintigraphies were performed in 232 patients (6 bilateral). At 2 h, ≥1 sentinel nodes were visualized in 154/238 (65%) cases; in 84 (35%), no sentinel node was visualized. Delayed lymphoscintigraphy visualized a sentinel node in 40 of 76 (53%) cases with no visualization at 2 h and failed to show a sentinel node in 36 (47%) of these cases (in 8 cases, no delayed lymphoscintigram was obtained).

Conclusions

Delayed lymphoscintigraphy was useful in about 50% of the breast cancer patients in whom immediate scintigraphy failed to demonstrate a sentinel lymph node.

Next generation of radiotracers for sentinel lymph node biopsy: What is still necessary to establish new imaging paradigms?

Sentinel lymph node (SLN) biopsy is now the standard of care for regional staging in several solid tumors. The interstitial administration of a radiotracer around the primary tumor provide the possibility to sequentially obtain images with a gamma camera and visualize lymphatic mapping and the SLN. There is, however, a large geographical variability in those radiotracers and nanocolloids ranging from 15-100nm which are most widely employed in Europe, while filtered and unfiltered ^99mTc-sulfur colloid (range 20-1000nm) is usually used in the USA with different drawbacks in its use. The new radiotracer ^99mTc-Tilmanocept, designed specifically for the identification of SLNs and recently becoming commercially available in USA and Europe, appears to have the potency to overcome the shortcomings described for the conventional radiotracers used until now for SLN biopsy and at the same time to transform current imaging paradigms. After delineating the challenges for the next generation of radiotracers, this paper discusses the properties of ^99mTc-Tilmanocept, its validation process for SLN biopsy and its emerging clinical applications in various malignancies.