Comparison of indirect computed tomographic lymphography and near‐infrared fluorescence sentinel lymph node mapping for integumentary canine mast cell tumors

Abstract

Objective: To compare the independent and combined use of indirect computed tomographic lymphography (ICTL) and near-infrared fluorescence (NIRF) for sentinel lymph node (SLN) mapping in dogs with integumentary mast cell tumors (MCT) and report the metastatic LN rate. Study design: Prospective clinical study. Animals: Twenty client-owned dogs.Methods: Dogs underwent preoperative ICTL, then intraoperative NIRF SLN mapping and excision of the anatomic lymph node (ALN) and/or SLN, and primary MCT. Technique agreement was complete if the same SLN was detected, and partial if the same SLN was detected along with additional SLN. No agreement occurred if the techniques detected different or no SLN. MCT were graded using two-and three-tier schemes, and LN were graded from HN0-3; HN2-3 were considered metastatic.Results: Complete, partial, and no agreement between ICTL and NIRF was seen in 8/20 (40%), 8/20 (40%), and 4/20 (20%) dogs, respectively. Detection of ICTL-SLN and NIRF-SLN failed in 1/20 (5%) and 4/20 (20%), respectively.Tumors were grade II/low-grade in 19/20 (95%) and grade III/high-grade in 1/20 (5%) dogs. Nineteen out of 20 (95%) dogs had HN2-3 LN.Conclusions: Technique agreement of at least one SLN was seen in 16/20 (80%) dogs. Although most MCT were classified as intermediate to low grade, LN metastases were commonly detected.

Weishaar's classification system for nodal metastasis in sentinel lymph nodes: Clinical outcome in 94 dogs with mast cell tumor

“…In addition, intraoperative gamma probe use allowed the measurement of residual radioactivity that led to straight‐forward decision‐making during the dissection of the SLCs, since its absence indicates that there are no more SLN to be removed within the SLC. On the other hand, the inability to directly visualize a node, either blue or nonblue, does not exclude the presence of other “hot” SLNs within the same SLC, 11,50 and the use of intraoperative gamma probe allows avoiding missing any lymph node 52 that could belong to a different HN class 53 . For these reasons, the surgeons might be enticed in exploring more SLCs and remove more SLNs when using a high‐performance tracer that allows for an intraoperative guidance such as Technetium‐99 or indocyanine green in near‐infrared fluorescence 19,54,55 …”

The Use of Sentinel Lymph Node Mapping for Canine Mast Cell Tumors

“…In recent years, a variety of mapping techniques for MCTs have emerged, each offering unique advantages in terms of efficacy and invasiveness. These techniques include the following: lymphoscintigraphy, colorimetric SLN mapping (utilizing the peritumoral injection of blue dye or indocyanine green), radiographic lymphography (also known as indirect lymphography or radiographic indirect lymphangiography), computed tomography lymphangiography (CTL), near-infrared fluorescence/near-infrared fluorescent imageguided lymphography (NIR/NIR-LND) and contrast-enhanced ultrasound (CEUS), and the techniques employed in [3,5,11,29,35]. All of these techniques are minimally invasive compared to radical lymphadenectomy, with diagnostic rates ranging between 77,9% and 100% depending on the technique used (Table 2).…”

“…Direct intratumoral injections should be avoided. After administration, the marker is taken up by lymphatic vessels that drain the tumor mass, eventually reaching single or multiple SLNs [11,29].…”

“…The SLN is the first lymph node that drains the lymph of the primary tumor. The use of SLN mapping has become a gold standard in human medicine for breast cancer, endometrial cancer, and melanoma [3,10,11]. The SLN can be a predictor of metastatic disease as it can be the first site where metastasis occurs [9].…”

Ki67 Index in Patnaik Grade 2/Kiupel Low-Grade Canine Cutaneous Mast Cell Tumors with Early Lymph Node Metastasis: A Descriptive Study

“…In the last decade, the number of studies focusing on canine cutaneous mast cell tumors (cMCTs) has exponentially risen, especially those describing different techniques of sentinel lymph node (LN) mapping and prognostic factors [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ]. The recent inclusion of normal-size or non-palpable LN excision as part of the surgical treatment of cMCTs and Weishaar classification of lymph nodes has increased the range of available histopathological prognostic variables [ 1 , 2 , 3 , 4 , 5 ].…”