Comparison of immunoradiometric assays for determination of thyroglobulin: a validation study.

In this study we compared and validated commercial immunoradiometric assays (IRMA) to determine thyroglobulin (Tg) levels in serum. From a set of 440 samples, 68 were selected to calculate the validation parameters and the clinical performance of the assays. The commercial kits evaluated were the Tg-CTK (DiaSorin), IRMAZenco Tg (ZenTech), and SELco-Tg (Medipan). We found that 21% of the collected samples were in the critical range of concentration. Detection limits were calculated as being below 3 microg/L. Intra- and inter-reproducibility were lower than 3.1% and 9.2%, respectively. Dilution and recovery studies provided quantitative determinations. Correlation regression coefficients from the results of the methods were obtained. The determined concentrations were compared with the clinical evidence of disease. Variation in the 125-iodine-labeled antibody concentration and control charts showed the robustness of the methods. Analysis time and the simplicity of the methods were also evaluated. Reliable Tg determination is important for monitoring patients with differentiated thyroid cancer (DTC), controlling other thyroid diseases, and assessing the quality of imaging techniques. A strategy for verification and comparison based on analytical parameters and clinical performance is proposed.

[Sentinel lymph node biopsy in cutaneous non-melanoma malignancies]. / Biopsia selectiva de ganglio centinela en tumores cutáneos no melanoma.

PURPOSE: To assess the feasibility of the Sentinel lymph node biopsy (SLNB) technique in cutaneous non-melanoma malignancies. MATERIALS AND METHODS: Nine patients were retrospectively evaluated performing a scintigraphy with 99mTc-nanocolloid. On the day of the surgery, an initial dynamic study and static images were obtained. The first drainage station visualized was considered the sentinel node (SLN). The SLN position was marked on the skin and after a correct localization in the surgical field with a gamma probe the SLN was obtained. Patients of this study have been followed up for 8 to 48 months. RESULTS: Lymphoscintigraphy detected the sentinel node in 88,8 % of our studies (the SLN was not observed in a patient with a Merkel's tumour on the back). The SLN was identified intraoperatively in those patients with positive imaging. Those cases without scintigraphic demonstrated migration were also not found intraoperatively. Histopathological analysis of the SLN showed non metastatic disease and none patient developed metastases or local recurrence in the monitoring period. CONCLUSIONS: Sentinel node biopsy can be applied to certain cutaneous non-melanoma malignancies. In patients with unclear drainage and to avoid unnecessary lymphadenectomy, the technique offers clear advantages. In our study the SLN analysis was related to the clinical progress. A large number of patients should be examined to truly assess the benefit of this technique in this kind of malignancies and to determinate when the technique must be performed.

Biopsia selectiva de ganglio centinela en tumores cutáneos no melanoma / Sentinel lymph node biopsy in cutaneous non-melanoma malignancies

Objetivo. Valorar la utilización de la biopsia selectiva del ganglio centinela (BSGC) en tumores cutáneos no melanoma. Material y métodos. Se evaluaron retrospectivamente 9 pacientes a los que se realizó linfogammagrafía con 99mTc-nanocoloides. El día de la cirugía se obtuvo un estudio dinámico inicial e imágenes estáticas posteriores. El primer ganglio de drenaje visualizado fue considerado como ganglio centinela (GC). La posición del GC fue marcada cutáneamente en varias proyecciones y posteriormente la correcta localización durante la extracción quirúrgica se realizó con sonda de detección externa. El seguimiento de los pacientes osciló entre 8 y 48 meses. Resultados. La linfogammagrafía localizó el ganglio centinela en 88,8 % de los casos. El GC no fue observado en un paciente con un tumor de Merkel localizado en la espalda. El GC fue identificado intraoperatoriamente en los pacientes que presentaron una imagen positiva. En aquellos casos en que no hubo migración gammagráfica tampoco se detectó intraoperatoriamente. La inmunohistopatología mostró adenopatías libres de metástasis, y los pacientes permanecieron sin afectación durante el periodo de seguimiento. Conclusiones. La utilización de la BSGC tiene una potencial aplicación en determinados tumores cutáneos no melanoma. En pacientes con drenaje linfático errático y la capacidad de evitar una linfadenectomía radical terapéutica, ofrece a la técnica destacadas ventajas. La situación del GC fue congruente con la evolución clínica de los pacientes. Sería necesario analizar un mayor número de pacientes para asegurar los beneficios de la técnica con el objeto de determinar los tumores más susceptibles para su realización y el estadio en el cual llevarla a cabo

Purpose. To assess the feasibility of the Sentinel lymph node biopsy (SLNB) technique in cutaneous non-melanoma malignancies. Materials and methods. Nine patients were retrospectively evaluated perfoming a scintigraphy with 99mTc-nanocolloid. On the day of the surgery, an initial dynamic study and static images were obtained. The first drainage station visualized was considered the sentinel node (SLN). The SLN position was marked on the skin and after a correct localization in the surgical field with a gamma probe the SLN was obtained. Patients of this study have been followed up for 8 to 48 months. Results. Lymphoscintigraphy detected the sentinel node in 88,8 % of our studies (the SLN was not observed in a patient with a Merkel's tumour on the back). The SLN was identified intraoperatively in those patients with positive imaging. Those cases without scintigraphic demonstrated migration were also not found intraoperatively. Histopathological analysis of the SLN showed non metastatic disease and none patient developed metastases or local recurrence in the monitoring period. Conclusions. Sentinel node biopsy can be applied to certain cutaneous non-melanoma malignancies. In patients with unclear drainage and to avoid unnecessary lymphadenectomy, the technique offers clear advantages. In our study the SLN analysis was related to the clinical progress. A large number of patients should be examined to truly assess the benefit of this technique in this kind of malignancies and to determinate when the technique must be perfomed