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Biomedical subjects

J Buscombe

Publications and source records attributed to J Buscombe.

11 recordsLinked to original sources

Radioguided sentinel lymph node biopsy in breast cancer surgery.

The concept of sentinel lymph node biopsy in breast cancer surgery relates to the fact that the tumor drains in a logical way through the lymphatic system, from the first to upper levels. Therefore, the first lymph node met (the sentinel node) will most likely be the first to be affected by metastasis, and a negative sentinel node makes it highly unlikely that other nodes are affected. Because axillary node dissection does not improve prognosis of patients with breast cancer (being important only to stage the axilla), sentinel lymph node biopsy might replace complete axillary dissection to stage the axilla in clinically N0 patients. Sentinel lymph node biopsy would represent a significant advantage as a minimally invasive procedure, considering that, after surgery, about 70% of patients are found to be free from metastatic disease, yet axillary node dissection can lead to significant morbidity. Furthermore, histologic sampling errors can be reduced if a single (sentinel) node is assessed extensively rather than few histologic sections in a high number of lymph nodes per patient. Although the pattern of lymph drainage from breast cancer can be variable, the mammary gland and the overlying skin can be considered as a biologic unit in which lymphatics tend to follow the vasculature. Therefore, considering that tumor lymphatics are disorganized and relatively ineffective, subdermal and peritumoral injection of small aliquots of radiotracer is preferred to intratumoral administration. (99m)Tc-labeled colloids with most of the particles in the 100- to 200-nm size range would be ideal for radioguided sentinel node biopsy in breast cancer. Lymphoscintigraphy is an essential part of radioguided sentinel lymph node biopsy because images are used to direct the surgeon to the site of the node. The sentinel lymph node should have a significantly higher count than that of background (at least 10:1 intraoperatively). After removal of the sentinel node, the axilla must be reexamined to ensure that all radioactive sites are identified and removed for analysis. The sentinel lymph node should be processed for intraoperative frozen section examination in its entirety, based on conventional histopathology and, when needed, immune staining with anticytokeratin antibody. The success rate of radioguidance in localizing the sentinel lymph node in breast cancer surgery is about 94%--97% in institutions where a high number of procedures are performed and approaches 99% when combined with the vital blue dye technique. At present, there is no definite evidence that negative sentinel lymph node biopsy is invariably correlated with negative axillary status, except perhaps for T1a-b breast cancers, with a size of < or =1 cm. Randomized clinical trials should elucidate the impact of avoiding axillary node dissection on patients with a negative sentinel lymph node on the long-term clinical outcome of patients.

Breast Neoplasms↗

Multimodality treatment for gastric carcinoid tumor with liver metastases.

Carcinoid tumors are the most common neuroendocrine tumors in the gastrointestinal tract, and between 10% and 30% of these tumors are gastric in origin. Three types of gastric carcinoid tumors are recognized: type I, associated with chronic atrophic gastritis type A; type II, associated with multiple endocrine neoplasia; and type III, sporadic and the most malignant. We present a patient with an aggressive, sporadic-type gastric carcinoid that metastasized to the liver. Her symptomatic treatment included the somatostatin analog octreotide. Octreotide scintigraphy demonstrated that this tumor avidly bound the peptide. The patient's gastric carcinoid (assessed by endoscopy and endoscopic ultrasound) regressed and she underwent hepatic artery embolization for her liver metastases. After initial partial CT resolution the tumor grew, compressing the inferior vena cava. The patient underwent orthotopic liver transplant with excellent recovery, although she was subsequently found to have two small lung metastases. She has responded well to adjuvant Indium-111 octreotide receptor targeted therapy. This case highlights the therapeutic options for metastatic neuroendocrine tumors, including liver transplantation and adjuvant receptor targeted therapy.

Adult↗

Inter-observer agreement in the reporting of 99Tcm-DMSA renal studies.

The early identification of renal cortical scarring secondary to urinary reflux and/or renal infection is important in the management of patients with recurrent disease. Scintigraphic imaging of the renal cortex using 99Tcm-dimercaptosuccinic acid (DMSA) is often considered the standard method for the diagnosis of renal scars in both adults and children. Consistent reporting of 99Tcm-DMSA is nevertheless essential in ensuring that the clinician can act on the data reported. In this study, seven experienced observers were asked to report, independently, 99Tcm-DMSA data sets from 32 patients. The observers were asked to note the presence of a space occupying lesion or of a renal cortical scar(s) and to conclude if the kidney was normal or abnormal. There was marked variation in the number of renal cortical scars reported, the total number of scars seen and whether or not the kidney was normal or abnormal. After peer review of all data, consensus and referenced criteria were arrived at for a reanalysis of data. All scans were reread by the observers. There was some improvement in the concordant reporting of kidneys with renal scars (51 vs 61%) and whether or not the kidney was normal or abnormal (53 vs 63%). However, this was not statistically significant (at a level of P < 0.05). This study demonstrated significant inter-observer variation regarding the reporting of 99Tcm-DMSA studies. A consensus with agreed guidelines for data interpretation did not significantly affect this apparent lack of consistency of reporting.

Adolescent↗

Radiolabelled human immunoglobulins.

Radiolabelled human immunoglobulins have been available for 5 years. Within that time there have been many publications on the use of these agents labelled with both technetium-99m (99Tcm) and indium-111 (111In). The results of these data appear contradictory and only now do we understand both some of the mechanisms of radiolabelled immunoglobulins and some of their limitations. While 111In-polyclonal immunoglobulin seems to have a wide range of clinical applications in infection and inflammation, the more readily available 99Tcm-labelled product is best suited to the localization of peripheral bone and joint disease. The ease of producing these agents from commercially available immunoglobulins will ensure continued interest and research into these new tracers.

Arthritis↗