Assessment of sentinel lymph node detection by radioisotope scan and methylene blue alone in operable oral cavity cancer to assess its accuracy for metastasis

Background: Squamous cell carcinoma (SCC) is the most common malignancy affecting the oral cavity. It typically metastasizes into the regional cervical lymph nodes before spreading to distant organs.Methods: A prospective study on sentinel lymph node biopsy (SLNB) in early oral cancers using methylene blue dye and sentinel node localisation using pre-operative lymphoscintigraphy and intraoperative gamma probe in early oral cavity cancer.Results: Present study had a male to female ratio of 1.9:1, with (65.5%) male and (34.5%) female patients. Present study had a side distribution of disease more on left side with 138 patients (62.7%) and ratio of left to right was approximately 1.7:1. In present study most predominating gross morphological pattern of growth was ulcerative (35%) followed by ulcero-infilterative (25%). Buccal mucosa was the most common sub-site of origin of carcinoma in oral cavity, followed by tongue, with 83 (37.7%) and 64 (29.1%) patients. Identification rate of methylene blue dye was 91.7% (100 out of 109 patient). Identification rate of radionuclide tracer was 94.6% (105 out of 111 patient). In methylene blue dye group out of 103 metastatic sentinel lymph nodes, 9 metastatic sentinel lymph nodes were detected on IHC.Conclusions: With the above results it can be concluded the SLNB study is liable in detection of actual positive node and can avoid unnecessary neck dissections in patients with SCC with negative sentinel lymph node, as having very low risk of occult lymphatic metastases in the remaining lymphatic drainage.

Detection of melanoma, breast cancer and head and neck squamous cell cancer sentinel lymph nodes by Tc-99m Tilmanocept (Lymphoseek®)

Technetium-99m-labeled Tilmanocept or Lymphoseek® (Cardinal Health, Dublin, Ohio) is a soluble, synthetic molecule with a small diameter (7 nm), which is comprised of technetium-99m chelated to a dextran backbone containing multiple units of mannose ligands with a high affinity for CD206, a receptor located on the surface of macrophages and dendritic cells that are found in high concentration in lymph nodes. It enables quick transit from the injection site and rapid lymph node accumulation. The binding of mannose ligand and CD206 results in the internalization of the ligand and receptor into the cell. Once the Technetium-99m-labeled Tilmanocept (Lymphoseek®) reaches the lymph node, it is readily internalized by the macrophages and dendritic cells within the draining lymph nodes. Technetium-99m-labeled Tilmanocept (Lymphoseek®) has been extensively studied as a radioisotope for detection of sentinel lymph nodes in melanoma, breast cancer and head and neck squamous cell carcinoma in clinical trials. Based on its safety and ability to detect sentinel lymph nodes satisfactorily, it has been approved by the FDA to use as a radioisotope for preoperative lymphoscintigraphy for identification of sentinel lymph nodes in these types of cancer. Further, the FDA has expanded approval of Technetium-99m-labeled for sentinel lymph node mapping of all solid tumors as well as in pediatric patients.

The place of lymph dissection in the treatment of cancer and the choice of surgical tactics (review article)

Over the past years, due to increase of detection of patients with early-stage stomach cancer and colorectal cancer, and improvement of survival rate, the efforts have been made to gradually develop the concept of sentinel lymph nodes detection in order to improve postoperative quality of life. The article presents the review of the literature on the feasibility of sentinel lymph nodes intraoperative diagnosis the choice of surgical treatment of patients with tumors of the stomach and colon. Analytical work demonstrates that the real time intraoperative visualization of lymph sineses using fluorescent imaging of indocyanine green during laparoscopic surgery for stomach or colorectal cancer is possible and it is a useful method of the lymph nodes mapping, therefore it can lead to intraoperative changes at lymphadenectomy as well as to reduce the surgical injury. It indicates the need in further research and improvement of approach.

Does failed mapping predict sentinel lymph node metastasis in cN0 breast cancer?

Aims: The clinical significance of nonvisualized sentinel lymph nodes (non-vSLNs) is unknown. The authors sought to determine the incidence of non-vSLNs on lymphoscintigraphy, the identification rate during surgery, factors associated with non-vSLNs and related axillary management. Patients & methods: A total of 30,508 consecutive SLN procedures performed at a single institution from 2000 to 2017 were retrospectively studied. Associations between clinicopathological factors and the identification of SLNs during surgery were assessed. Results: Non-vSLN occurred in 525 of the procedures (1.7%). In 73.3%, at least one SLN was identified intraoperatively. Nodal involvement was only significantly associated with SLN nonidentification (p < 0.001). Conclusion: Patients with non-vSLN had an increased risk for SLN metastasis. The detection rate during surgery was consistent, reducing the amount of unnecessary axillary dissection.

Evaluation of the Radiation Dose of an Embryo/Fetus during Lymphoscintigraphy (Sentinel Lymph Node Mapping) in Pregnant Patients with Breast Cancer

Purpose: To develop a method for evaluation of the radiation dose of an embryo/fetus during lymphoscintigraphy (sentinel lymph node mapping) in pregnant patients with breast cancer.Material and methods: Two pregnant women (aged 43 and 30) with breast cancer stage IIA (T2N0M0), during the second trimester of pregnancy. We used a lymphotropic colloidal radiopharmaceutical labeled with 99mTc. To evaluate the radiation dose of an embryo, each patient had 6 individual dosimeters, which were placed around the abdomen using an elastic bandage at equal distances around the abdomen. Additionally, we placed the 7th dosimeter, it was placed near the injection site (under the mammary gland). After installing individual dosimeters, radiocolloid was injected into the affected mammary gland at four points (periareolar). The administered activity of radiopharmaceutical was 32.5 MBq, and 51.5 MBq. Lymphoscintigraphy was performed 1 hour after injection. First patient underwent sector resection of the left breast with SLN biopsy. The second patient underwent right mastectomy with SLN biopsy and breast reconstruction surgery using a tissue expander.Results: Based on the results of the study, the dose rate was calculated, on the basis of which the fetal radiation doses were calculated in both patients. Comparison of the mathematical data of both patients shows that, the calculated and experimental values of radiation exposure to the fetus during the radionuclide study of sentinel lymph nodes practically coincide. The obtained data shows that during pregnancy (280 days) the embryo/fetus will accumulate a natural radiation background dose of 1960 μSv, which is 2 times higher than the dose from the radionuclide study of sentinel lymph nodes. Thus these results verify the safety of SLN biopsy technology in pregnancy.Conclusion: 1. Radionuclide diagnostic studies of pregnant women determine radiation doses to the embryo/fetus that do not cause any radiation-induced effects in the prenatal period, and the probability of the occurrence of stochastic radiation-induced effects is several times lower than the incidence of endogenous cancers. 2. Radionuclide examination of sentinel lymph nodes appears to be safe for the fetus when conducted in pregnant women diagnosed with breast cancer. 3. In Russian Federation this method is used for the first time in pregnant women with diagnosed breast cancer. This technology has not been previously described in Russian literature.

Challenging Visualization of Sentinel Lymph Nodes in Upper Urinary Tract Urothelial Carcinoma

Purpose: The purpose of this study was to assess the possibility of detecting sentinel lymph nodes (SLNs) and to perform analysis of lymphatic outflow in patients with suspicion of upper tract urothelial carcinoma (UTUC) with the use of a radioisotope-based technique. Methods: During 2018–2021, a prospective study was conducted on 19 patients with the suspicion of UTUC and for whom diagnostic ureterorenoscopy (URS) was planned. Technetium-99m (99mTc) nanocolloid radioactive tracer injection and a tumor biopsy were performed for staging procedures. Three-dimensional (3D) reconstruction and fusion of images were performed for better localization of lymph nodes (LNs). Detection of SLNs and the analysis of the radiotracer outflow was conducted with the use of single-photon emission-computed tomography/computed tomography (SPECT/CT) lymphangiography. Results: The mean age of the patients was 73.4 years; 7 (36%) were male. Pathological staging from the biopsy was T0—8 (42%), Ta—7 (36%), T1—4 (21%). SLNs were detected in two of 19 cases (10%). In one patient a single SLN (5.3%) was visualized, and in another case (5.3%), multiple (double) radioactive lymph nodes were visualized. In 17 out of the 19 (89.5%) cases, no lymphatic outflow was observed, and out of these five cases (26.3%) of gravitational leakage of injected radiotracer to the retroperitoneal space was noted. Conclusions: We demonstrated that detection of SLNs in the upper urinary tract is possible yet challenging. Radiotracer injection in the upper urinary tract during ureterorenoscopy is difficult to perform, and the expected result of injection is unsatisfactory. Lymphatic outflow from the tumor site to the first LNs in our studied group of patients is visible in 10.5% of cases. SPECT/CT lymphangiography in cases of UTUC may provide valuable information about a patient’s individual anatomy of the lymphatic system and the position of the first lymph nodes draining lymph with potential metastatic cells from the tumor.