Clinical efficacy and problems with CT lymphography in identifying the sentinel node in breast cancer

Sentinel lymph node biopsy in breast cancer guided by CT lymphography; History, evolution and current applications

Sentinel lymph node biopsy (SLNB) has efficiently replaced axillary lymph node dissection (ALND) in axillary staging in node-negative breast cancer patients. Dual sentinel lymph node (SLN) localization using radioisotopes and blue dye is the standard technique for SLN mapping. Yet, nuclear medicine facilities are not widely available worldwide. In Japan, Computed tomography lymphography (CTLG) is presented as an SLN mapping technique which was first suggested in 2003 by Suga et al. Multiple subsequent studies confirmed the efficacy of CTLG in SLN mapping in breast cancer. Further applications of the technique followed; such as prediction of SLN metastasis using CTLG, the use of CTLG guided SLN biopsy after neoadjuvant therapy, video-assisted CTLG guided SLN biopsy, the use of real-time virtual sonography with 3-D CTLG, and preoperative localization of the CTLG mapped SLN using either real-time virtual sonography (RVS) guided Indocyanine green (ICG) injection or its marking using liquid charcoal and silver wire and the use of SPIO enhanced magnetic resonance imaging (MRI) for prediction of metastasis in SLNs detected by CTLG. This efficacy and variable applications open the door for conducting wide-scale randomized controlled trials to suggest using CTLG as an efficient alternative for the use of radioisotopes in SLN mapping in breast cancer patients, especially in low and middle-income countries.

Sentinel lymph node detection differs when comparing lymphoscintigraphy to lymphography using water soluble iodinated contrast medium and digital radiography in dogs

Sentinel lymph node (SLN) mapping by various means has become standard of care in certain types of human cancers and is receiving more attention in veterinary oncology. Current SLN mapping techniques can be costly and often require advanced imaging equipment. The objective of this prospective, method comparison study was to compare an SLN mapping protocol of lymphoscintigraphy to lymphography using water soluble iodinated contrast medium (WIC) and digital radiography for identification of an SLN. Lymphoscintigraphy and lymphography were performed on eight healthy purpose-bred dogs using technetium-99m sulfur colloid and WIC injected into the subcutaneous tissues in a four-quadrant technique around a predefined area of skin on the brachium. Images were obtained using a gamma camera and digital radiography at different time points post-injection. Image sequences were evaluated by one of two American College of Veterinary Radiology board-certified veterinary radiologists. Data obtained were compared between methods using descriptive statistics. An SLN was identified in all dogs with lymphoscintigraphy and seven of eight dogs with lymphography. Agreement between results of the lymphoscintigraphy and lymphography studies was a complete match in three dogs, a partial match in four dogs, and no match in one dog. The SLN detected differed based on the imaging modality used.

The effect of surgery on lymphoscintigraphy drainage patterns from the canine brachium in a simulated tumor model

OBJECTIVE

To determine the effect of surgery on lymphoscintigraphy drainage patterns from the canine brachium.

STUDY DESIGN

Experimental study.

ANIMALS

Eight healthy research beagles.

METHODS

A predefined area of skin measuring 2 × 1.5 cm in dimension was designated on either the right or left brachium. Preoperative lymphoscintigraphy was performed with technetium sulfur colloid injected into the subcutaneous tissues around the predefined anatomic location in a four-quadrant technique. Dogs underwent surgery for excision of the predefined area of skin, subcutis, and fascia of the lateral head of the triceps muscle with 1-cm margins. Eighteen days after surgery, lymphoscintigraphy was again performed with technetium sulfur colloid injected into the subcutaneous tissues around the surgical scar in a four-quadrant technique.

RESULTS

Sentinel lymph nodes were identified in eight of eight dogs preoperatively and in eight of eight dogs postoperatively. Agreement between the results of the preoperative and postoperative lymphoscintigraphy studies was identified as complete in four of eight dogs and partial in four of eight dogs. Sentinel lymph node identification occurred immediately in three of eight dogs preoperatively and in eight of eight dogs postoperatively.

CONCLUSION

Sentinel lymph node identification occurred faster postoperatively. Agreement or partial agreement between the results of the preoperative and postoperative lymphoscintigraphy studies was observed in eight of eight dogs.

CLINICAL SIGNIFICANCE

Surgery appears to have an effect on lymphoscintigraphy drainage patterns. Additional studies are required to compare preoperative and postoperative sentinel lymph node mapping patterns in tumor-bearing dogs. However, this study provides preliminary information regarding the effect of surgery on sentinel lymph node identification.

Anatomical classification of breast sentinel lymph nodes using computed tomography-lymphography

To evaluate the anatomical classification and location of breast sentinel lymph nodes, preoperative computed tomography–lymphography examinations were retrospectively reviewed for sentinel lymph nodes in 464 cases clinically diagnosed with node-negative breast cancer between July 2007 and June 2016. Anatomical classification was performed based on the numbers of lymphatic routes and sentinel lymph nodes, the flow direction of lymphatic routes, and the location of sentinel lymph nodes. Of the 464 cases reviewed, anatomical classification could be performed in 434 (93.5 %). The largest number of cases showed single route/single sentinel lymph node (n = 296, 68.2 %), followed by multiple routes/multiple sentinel lymph nodes (n = 59, 13.6 %), single route/multiple sentinel lymph nodes (n = 53, 12.2 %), and multiple routes/single sentinel lymph node (n = 26, 6.0 %). Classification based on the flow direction of lymphatic routes showed that 429 cases (98.8 %) had outward flow on the superficial fascia toward axillary lymph nodes, whereas classification based on the height of sentinel lymph nodes showed that 323 cases (74.4 %) belonged to the upper pectoral group of axillary lymph nodes. There was wide variation in the number of lymphatic routes and their branching patterns and in the number, location, and direction of flow of sentinel lymph nodes. It is clinically very important to preoperatively understand the anatomical morphology of lymphatic routes and sentinel lymph nodes for optimal treatment of breast cancer, and computed tomography–lymphography is suitable for this purpose.

Dendrimer-Entrapped Gold Nanoparticles as Potential CT Contrast Agents for Localizing Sentinel Lymph Node via Indirect CT Lymphography on Rabbit Model

Objective

To investigate the potential use of indirect computed tomography lymphography (CT-LG) with dendrimer-entrapped gold nanoparticles (Au DENPs) in the localization and enhanced imaging of cervical sentinel lymph node (SLN) on rabbit model.

Methods

Twelve rabbits were randomly divided into two groups: the positive control group and the experimental group. In the control group, indirect CT-LG was performed with the injection of 0.5 ml activated carbon nanoparticles (ACNP) and Omnipaque mixture suspension in the right tongue submucosa. CT images were acquired before the injection and 1, 5, 10, and 15 min after the injection, respectively. In the experimental group, indirect CT-LG injection with 0.5 ml Au DENPs suspension was performed in the right tongue submucosa. CT images were obtained before the injection and 1, 5, 10, and 15 min and 1, 2, 6, 24, 48, and 72 h after the injection, respectively. Then, SLN identification and enhancement characteristics were evaluated.

Results

Indirect CT-LG revealed the enhancement of one right deep cervical lymph nodes in all animals, which was SLN. SLN location was marked with black color (ACNP dye) or purple-black color (Au DENPs dye). At each detection time point, the enhanced SLN attenuation values of control rabbits were statistically significantly higher than that of the plain scan, respectively (P < 0.05). Also the values of experimental rabbits were statistically significantly higher than that of the control at the same time point after injection (P < 0.05). The detection rate of SLN was 100%.

Conclusions

Indirect CT-LG with injection of Au DENPs as CT contrast agents can locate the SLN for a long period of time and enrich the SLN black dye. It is helpful for SLNs identification during the operation.

Long-term observation of indirect lymphography using gadolinium-loaded polyethylenimine-entrapped gold nanoparticles as a dual mode CT/MR contrast agent for rabbit lingual sentinel lymph node identification

CONCLUSIONS

The rabbit lingual sentinel lymph node (SLN) could be long-term visualized by indirect lymphography using gadolinium-loaded polyethylenimine-entrapped gold nanoparticles (Gd-Au PENPs) as CT/MR dual-modal contrast agent.

OBJECTIVE

To investigate duration and intensity of rabbit lingual SLN enhancement using Gd-Au PENPs as a CT/MR dual-modal contrast agent.

METHODS

Twelve rabbits were randomly divided into indirect CT lymphography (CT-LG) and MR lymphography (MR-LG) groups. In each group, two rabbits received unilateral injection and four received bilateral injection of Gd-Au PENPs in the sub-mucosa of the tongue. Then the enhancement characteristics of SLN were investigated.

RESULTS

The enhanced SLNs were observed in 100% in all rabbits by indirect CT-LG and MR-LG simultaneously at 1 min after injection. Then SLN enhancement was improved rapidly and the first peaks were observed at 25 min for CT-LG and 1 h for MR-LG, respectively, then SLN enhancement decreased gradually to a minimum at 2 h for CT-LG and 3 h for MR-LG. Afterwards, the enhancement intensity increased again and second peaks were observed at 24 h for both CT-LG and MR-LG. Hereafter, the intensity dropped slowly and weak enhancement was also observed at the 40th week for CT-LG and 31st day for MR-LG. Black-stained SLNs were visualized in 100% at autopsy in all rabbits.

Short-Term Dynamic Observation of the Color Change and Enhancement Effect of Polyethylenimine-Entrapped Gold Nanoparticles Used for Indirect Lymphography

AIMS

To dynamically observe the color change and enhancement effect of gadolinium-loaded polyethylenimine-entrapped gold nanoparticles (Gd-Au PENPs) as a dual-mode CT/MRI contrast agent for sentinel lymph node (SLN) identification.

METHODS

In 6 rabbits, Gd-Au PENPs were injected into the right side tongue submucosa, after which the color change of cervical draining lymph nodes was observed. Then the draining lymph nodes were examined by CT/MRI scan. Another 6 rabbits were randomly divided into a CT lymphography (CT-LG) and a MRI lymphography (MRI-LG) group and examined by CT/MRI scan 1 and 30 min after injection. Then SLNs were identified under the guidance of CT/MRI-LG.

RESULTS

The ipsilateral afferent lymphatic vessels, cervical draining lymph nodes and efferent lymphatic vessels were stained black orderly and constantly after Gd-Au PENPs injection. Thirty minutes after injection, all cervical lymph nodes were excised to be examined by CT/MRI scan, and only the black-stained draining lymph nodes were enhanced. The 6 rabbits with CT/MRI-LG showed clear enhancement of SLNs. With indirect lymphography, the black-stained SLNs were easily visualized at autopsy. In all rabbits, the identification rate of lingual SLNs was 100%.

CONCLUSIONS

Rabbit lingual SLNs could be identified with indirect lymphography using Gd-Au PENPs as a dual-mode contrast agent.

Sentinel lymph node biopsy using computed tomographic lymphography in patients with early tongue cancer

Conclusions: Because computed tomography (CT) lymphography provides preoperative images of anatomic relationships between a tumor, its associated lymph vessels, and the sentinel lymph node (SLN), it may aid in directing the SLN biopsy for management of early tongue cancer. Objectives: SLN biopsy using a radioisotope (RI) generally has been performed in head and neck cancer. However, this method can be performed only at institutions that are licenced for its use. In this study, we evaluated the utility of performing SLN biopsy in patients with early tongue cancer using the newly developed technique of CT lymphography. Methods: Enrolled in this study were 31 patients with T1N0 or T2N0 tongue cancer. CT images were obtained before and after injection of iopamidol into the peritumoral region and the SLN was identified as the first enhanced lymph node. SLN biopsy was performed using CT lymphographic guidance combined with blue dye injection. Results: The SLN was detected by CT lymphography in 28 cases (90.3%). By intraoperative frozen section examination, metastases to SLNs were found in 4 (14.3%) (T1N0, 1 patient; T2N0, 3 patients) of the 28 patients. Of these four, SLN micrometastases were found in one patient.

Breast sentinel lymph node navigation with three-dimensional computed tomography-lymphography: a 12-year study

PURPOSE

To evaluate the utility of three-dimensional (3D) computed tomography (CT)-lymphography (LG) breast sentinel lymph node navigation in our institute.

PATIENTS AND METHODS

Between 2002 and 2013, we preoperatively identified sentinel lymph nodes (SLNs) in 576 clinically node-negative breast cancer patients with T1 and T2 breast cancer using 3D CT-LG method. SLN biopsy (SLNB) was performed in 557 of 576 patients using both the images of 3D CT-LG for guidance and the blue dye method.

RESULTS

Using 3D CT-LG, SLNs were visualized in 569 (99%) of 576 patients. Of 569 patients, both lymphatic draining ducts and SLNs from the peritumoral and periareolar areas were visualized in 549 (96%) patients. Only SLNs without lymphatic draining ducts were visualized in 20 patients. Drainage lymphatic pathways visualized with 3D CT-LG (549 cases) were classified into four patterns: single route/single SLN (355 cases, 65%), multiple routes/single SLN (59 cases, 11%) single route/multiple SLNs (62 cases, 11%) and multiple routes/multiple SLNs (73 cases, 13%). SLNs were detected in 556 (99.8%) of 557 patients during SLNB.

CONCLUSION

CT-LG is useful for preoperative visualization of SLNs and breast lymphatic draining routes. This preoperative method should contribute greatly to the easy detection of SLNs during SLNB.

Triple assessment of sentinel lymph node metastasis in early breast cancer using preoperative CTLG, intraoperative fluorescence navigation and OSNA

BACKGROUND

Sentinel lymph node biopsy (SLNB) became a standard surgical procedure for patients with early breast cancer; however, the optimal method of sentinel lymph node (SLN) identification remains controversial. The current study presents the protocol of our institution for preoperative and intraoperative SLN detection.

METHODS

Fifty female patients with early breast cancer and clinically node-negative axilla were enrolled in this study. All patients underwent preoperative CT lymphography (CTLG), intraoperative SLNB using fluorescence navigation, intraoperative one-step nucleic acid amplification (OSNA) and postoperative hematoxylin and eosin histopathological analysis. Prediction of metastasis by CTLG and detection of metastasis by OSNA were compared to results of histopathology as standard reference.

RESULTS

SLN were identified by preoperative CTLG and intraoperative SLNB with fluorescence navigation in all patients, the identification rate was 100 %. SLN metastases were detected as positive by OSNA in 9 patients (18 %), 4 were (++), 4 were (+) and 1 was (+I). SLN metastases were detected as positive by histopathology in 10 patients (20 %). The concordance rate between OSNA and permanent sections was 90 %. The negative predictive value of CTLG was 80 %.

CONCLUSION

Use of CTLG and fluorescence navigation made performing SLNB with high accuracy possible in institutions that cannot use the radioisotope method. OSNA provided accurate intraoperative method, allowing for completion of axillary node dissection during surgery and avoidance of second surgical procedure in patients with positive SLNs, thereby reducing patient distress and, finally, saving hospital costs.

Current and future lymphatic imaging modalities for tumor staging

Tumor progression is supported by the lymphatic system which should be scanned efficiently for tumor staging as well as the enhanced therapeutic outcomes. Poor resolution and low sensitivity is a limitation of traditional lymphatic imaging modalities; thus new noninvasive approaches like nanocarriers, magnetic resonance imaging, positron-emission tomography, and quantum dots are advantageous. Some newer modalities, which are under development, and their potential uses will also be discussed in this review.

Evaluation of lymph node metastasis in patients with gastric cancer: a comparison of the directionality of lymph node metastasis and the total number of metastatic lymph nodes

PURPOSE

The clinical impact of the directionality of lymph node (LN) metastasis was assessed in comparison with the staging by the Japanese Classification of Gastric Carcinoma (JCGC), a numerical LN staging system.

METHODS

Two hundred forty-one gastric cancer patients who were diagnosed pathologically to have LN metastasis, and 54 patients who underwent preoperative multidetector-row computed tomography (MDCT) with an image thickness of 1 mm were classified into three groups (unidirectional [Uni-], bidirectional [Bi-], and tridirectional [Tri-] groups) depending on the directionality of their LN metastasis.

RESULTS

The prognosis of the Uni-group was better than that of the Bi- or the Tri-group when assessed on the basis of the pathological findings of metastatic LN and also the preoperative MDCT findings. The exact preoperative evaluation was 70.2 % for the directionality system and 61.7 % for the JCGC system, respectively. The stages were less frequently underestimated by the directionality system than the JCGC system (P < 0.02, 19.1 vs. 34.0 %), and the staging could be more precisely performed by both systems in combination.

CONCLUSIONS

More precise preoperative evaluation of disease stage could be obtained by the directionality system and the JCGC system in combination.

Advances in lymphatic imaging and drug delivery

Cancer remains the second leading cause of death after heart disease in the US. While metastasized cancers such as breast, prostate, and colon are incurable, before their distant spread, these diseases have invaded the lymphatic system as a first step in their progression. Hence, proper evaluation of the disease state of the lymphatics which drain a tumor site is crucial to staging and the formation of a treatment plan. Current lymphatic imaging modalities with visible dyes and radionucleotide tracers offer limited sensitivity and poor resolution; however, newer tools using nanocarriers, quantum dots, and magnetic resonance imaging promise to vastly improve the staging of lymphatic spread without needless biopsies. Concurrent with the improvement of lymphatic imaging agents, has been the development of drug carriers that can localize chemotherapy to the lymphatic system, thus improving the treatment of localized disease while minimizing the exposure of healthy organs to cytotoxic drugs. This review will focus on the use of various nanoparticulate and polymeric systems that have been developed for imaging and drug delivery to the lymph system, how these new devices improve upon current technologies, and where further improvement is needed.

Assessment of cervical lymph node metastases using indirect computed tomography lymphography with iopamidol in a tongue VX2 carcinoma model

OBJECTIVE

To investigate the performance of indirect computed tomography lymphography with iopamidol for detecting cervical lymph node metastases in a tongue VX2 carcinoma model.

MATERIALS AND METHODS

A metastatic cervical lymph node model was created by implanting VX2 carcinoma suspension into the tongue submucosa of 21 rabbits. Computed tomography images were obtained 1, 3, 5, 10, 15 and 20 minutes after iopamidol injection, on days 11, 14, 21 (six rabbits each) and 28 (three rabbits) after carcinoma transplantation. Computed tomography lymphography was performed, and lymph node filling defects and enhancement characteristics evaluated.

RESULTS

Indirect computed tomography lymphography revealed bilateral enhancement of cervical lymph nodes in all animals, except for one animal imaged on day 28. There was significantly slower evacuation of contrast in metastatic than non-metastatic nodes. A total of 41 enhanced lymph nodes displayed an oval or round shape, or local filling defects. One lymph node with an oval shape was metastatic (one of 11, 9.1 per cent), while 21 nodes with filling defects were metastatic (21/30, 70 per cent). The sensitivity, specificity, accuracy, and positive and negative predictive values when using a filling defect diameter of 1.5 mm as a diagnostic criterion were 86.4, 78.9, 82.9, 82.6 and 83.3 per cent, respectively.

CONCLUSION

When using indirect computed tomography lymphography to detect metastatic lymph nodes, filling defects and slow evacuation of contrast agent are important diagnostic features.

Localization of the sentinel lymph node in tongue VX2 carcinoma via indirect CT lymphography combined with methylene blue dye injection

CONCLUSIONS

Indirect computed tomography lymphography (CT-LG) combined with blue dye injection can locate the sentinel lymph node (SLN) in tongue carcinoma.

OBJECTIVE

To localize the SLN in tongue VX2 carcinoma using indirect CT-LG combined with methylene blue injection.

METHODS

Eighteen rabbits were placed into three groups: metastasis, hyperplasia, and control. Indirect CT-LG was performed with an iohexol injection into the tongue submucosa. CT images were acquired at 1, 5, and 15 min after injection. Methylene blue was injected into the same area 24 h after indirect CT-LG, followed by SLN identification and histopathological examination.

RESULTS

SLNs were visualized with an identification rate of 100%. SLN location identified using CT lymphography was confirmed by methylene blue dye. Control and hyperplastic enhanced SLNs were round or oval without any filling defects. Control rabbits had enhanced SLN attenuation values of 689.2 +/- 55.4 HU, 278.4 +/- 33.5 HU, and 71.7 +/- 9.2 HU at 1, 5, and 15 min after injection, respectively. Hyperplastic rabbits had values of 877.4 +/- 69.4 HU, 352.5 +/- 43.3 HU, and 80.2 +/- 11.5 HU. Filling defects were only observed in the ipsilateral metastatic SLNs of the metastasis group. CT attenuation values of the metastatic SLNs were 687.4 +/- 55.6 HU, 535.1 +/- 86.6 HU, and 282.3 +/- 19.4 HU at 1, 5, and 15 min, respectively, after iohexol injection. Metastatic lymph node attenuation values were significantly greater than those of the control or hyperplastic nodes at 5 (p < 0.001) and 15 min (p < 0.001) after injection.