![]() ![]() However, because of the close structural relationship of these vital dyes, cross-reactivity may indeed exist. It is also known as E 131 and is still on the market as a food colorant. Patent blue V has a slightly different chemical structure and can also be found under the name patent blue violet, food blue 5, acid blue 3, and disulfine blue. Isosulfan blue is a structural isomer of patent blue (not patent blue V) and is known under the trade name lymphazurine. The sodium salt of patent blue is also called sulfan blue, food blue 3, patent blue VF, and acid blue 1. These agents include patent blue, isosulfan blue and methylene blue. Blue dyes used for lymphatic mapping in sentinel lymph node biopsy cause intraoperative anaphylactic reactions in up to 2.7% of patients. In the United States the most commonly used agents are technetium sulphur colloid and isosulfan blue dye, whereas in Europe technetium labelled albumin and patent blue. There has been observed no cross-reactivity between these two agents. History of allergy to the radio-colloid and/or blue dye should be considered contraindication to the use of that specific agent. In patients with clinically suspicious nodes and negative FNA cytology, SLNB can be performed if bearing in mind that any clinically suspicious palpable axillary nodes encountered during the procedure should be excised and examined, regardless of whether they take up dye or radio-colloid, even if they are not the true sentinel node(s). In node positive patients a standard level I and II axillary clearance is indicated and SLNB is not performed. Approximately, 40% of patients with positive axillary nodes can be diagnosed preoperatively with ultrasonography and FNA cytology alone. However, for those patients with suspicious axillary findings, preoperative ultrasound and fine needle aspiration (FNA) cytology can provide further information on the status of the nodes and help surgical planning. Sentinel lymph node biopsy is best reserved for breast cancer patients with clinically negative axillary nodes, except perhaps in the setting of clinical trials. This could prevent the identification of the true sentinel node(s) and result in failure of the procedure or false negative results. It has been suggested that in such cases, the path of the dye or the radio-colloid agent may be blocked from tumor cells infiltrating the lymph vessels. ![]() ![]() According to the American Society of Clinical Oncology Guideline Recommendations for Sentinel Lymph Node Biopsy in 2005 and the 2001 Proceedings of the Consensus Conference on the Role of SLNB in Carcinoma of the Breast in Philadelphia, patients with clinically positive axilla (N1) are not candidates for the procedure. When there is clinically suspicious axillary lymphadenopathy or when fine needle aspiration cytology and/or core biopsy of palpable axillary lymph nodes confirm tumor infiltration, the procedure is contraindicated. The absolute contraindications for the SLNB are quite clear and straightforward. We review the literature in respect to each and every one of those factors and discuss the impact they may have on the degree of accuracy and efficacy of the procedure. Certain authors suggest that when present, these factors may affect negatively the accuracy of the SLNB, resulting in failure of the procedure or higher than acceptable false negative results. Furthermore, safety issues like radiation levels to patient (especially during pregnancy) and medical stuff as well as storage and disposal of radioactive waste, still remain debatable issues. These contraindications include host factors such as disturbed lymphatics due to prior breast and axillary biopsy and/or surgery, age, body-mass index, pregnancy, and tumor biologic characteristics such as tumor size, multifocal or multicentric disease and histological type (in situ carcinomas). To ensure and maintain the high accuracy and low false-negative rate of the SLNB procedure, several selection criteria and relative contraindications for the procedure have been reported, together with few safety issues. When performed by an experienced multi-disciplinary team, the SLNB is a highly effective and accurate alternative to standard level I and II axillary clearance. Sentinel lymph node biopsy (SLNB) has become a widely accepted evaluation and staging procedure for the axilla in patients with breast cancer, and this is mainly due to the minimal morbidity and the high degree of histological accuracy it provides. ![]() The pathologic status of the axillary lymph nodes remains the most important prognostic indicator for patients with breast cancer and a major determinant of adjuvant treatment. ![]()
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