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Biomedical subjects

R F Uren

Publications and source records attributed to R F Uren.

At least 19 recordsLinked to original sources
PubMed2001

Lymphatic mapping of the breast: locating the sentinel lymph nodes.

When the concept of sentinel lymph node biopsy was described in patients with melanoma, researchers quickly started to use lymphatic mapping techniques in breast cancer patients in an attempt to locate the sentinel node in the axilla. We have been performing mammary lymphoscintigraphy in this role for 6 years and have now studied 159 patients. Like others, we have found that most breast cancers (93%) have lymphatic drainage that includes the axilla, and we have found an average of 1.4 axillary sentinel nodes in these patients. Surgical biopsy of the axillary sentinel nodes accurately staged the node field in 96% of patients. We have also found, however, that the pattern of lymphatic drainage from the cancer site is unpredictable; and in 49% of patients lymphatic drainage occurred across the center line of the breast to axillary or internal mammary sentinel nodes. In more than half of our patients (56%) lymphatic drainage occurred to lymph nodes outside the axilla including the internal mammary (45%), supraclavicular (13%), and interpectoral and intramammary interval nodes (12%). These nodes are also sentinel nodes, and their presence indicates that a sentinel node biopsy procedure that stages only the status of the axillary lymph nodes has the potential to understage about half the patients with breast cancer. High quality lymphoscintigraphy allows accurate mapping of peritumoral lymphatic drainage in most patients with breast cancer. It is possible that in the future accurate nodal staging in each individual will involve biopsy of all sentinel lymph nodes, regardless of their location.

Axilla↗
PubMed2001

Sentinel lymph node biopsy in patients with melanoma and breast cancer.

Sentinel lymph node biopsy (SNLB) is a new method for staging regional node fields in patients with cancers that have a propensity to metastasise to lymph nodes. The majority of early experience has been obtained in patients with melanoma and breast cancer. The technique requires the close cooperation of nuclear medicine physicians, surgical oncologists and histopathologists to achieve the desired accuracy. It involves: (i) identification of all lymph nodes that directly drain a primary tumour site (the sentinel nodes) by the use of pre-operative lymphoscintigraphy, (ii) selective excision of these nodes by the surgeon, guided by pre-operative blue dye injection and a gamma detecting probe intra-operatively and (iii) careful histological examination of the sentinel nodes by the histopathologist using serial sections and immunohistochemical stains. If the nodes are normal it can be inferred with a high degree of accuracy that all nodes in the node field are normal. This means that radical dissections of draining node fields can be avoided in patients with normal lymph nodes. A further advantage of lyamphatic mapping is that drainage to sentinel nodes in unusual locations is identified, leading to more accurate nodal staging than could be achieved with routine dissection of the closest node field.

Breast Neoplasms↗
PubMed2001

Lymphatic mapping and sentinel node biopsy for melanoma.

Worldwide experience has now confirmed that the histological status of sentinel nodes (SNs) accurately reflects the status of regional lymph nodes in patients with melanoma. Preoperative lymphoscintigraphy has proved to be invaluable in identifying SNs and in demonstrating unusual lymphatic drainage pathways. Greatest accuracy at the time of surgery is achieved using both blue dye injection and a gamma-probe. Close cooperation between surgeons, nuclear medicine physicians and pathologists is required if the SN biopsy technique is to be reliable. The results of clinical trials will demonstrate whether SN biopsy has any therapeutic value. It is already clear, however, that SN examination provides very accurate staging, and SN biopsy is therefore essential for all melanoma patients entering adjuvant therapy trials.

Humans↗
PubMed2000

Interval nodes: the forgotten sentinel nodes in patients with melanoma.

BACKGROUND: Any sentinel lymph node that receives lymph drainage directly from a primary melanoma site, regardless of its location, may contain metastatic disease. This is true even if the sentinel node does not lie in a recognized node field. Interval (in-transit) nodes that lie along the course of a lymphatic vessel between a primary melanoma site and a recognized node field are sometimes seen during lymphatic mapping for sentinel node biopsy. If drainage to such interval nodes is ignored by the surgeon during sentinel node biopsy, metastatic melanoma will be missed in some patients. HYPOTHESIS: When lymph drains directly from a cutaneous melanoma site to an interval node, that sentinel node has the same chance of harboring micrometastatic disease as a sentinel node in a recognized node field. DESIGN: Preoperative lymphoscintigraphy with technetiumTc 99m antimony trisulfide colloid was performed to define lymphatic drainage patterns and, since 1992, to locate the sentinel lymph nodes for surgical biopsy or for permanent skin marking of their location with point tattoos. SETTING: Melanoma unit of a university teaching hospital. PATIENTS: A total of 2045 patients with cutaneous melanoma were studied in 13 years. RESULTS: Interval nodes were found in 148 patients (7.2%). The incidence of interval nodes varied with the site of the primary melanoma. Interval nodes were more common with melanomas on the trunk than with those on the lower limbs. Micrometastatic disease was found in 14% of interval nodes that underwent biopsy as sentinel nodes. This incidence is similar to that found in sentinel nodes located in recognized node fields, confirming the potential clinical importance of interval nodes. CONCLUSIONS: Interval nodes should be removed surgically along with any additional sentinel nodes in standard node fields if the sentinel node biopsy procedure is to be complete. In some patients, an interval node will be the only lymph node that contains metastatic disease.

Female↗
PubMed2000

Reliability of DMSA for the diagnosis of renal parenchymal abnormality in children.

The objective of this study was to evaluate the variability of technetium-99m dimercaptosuccinic acid (DMSA) scintigraphy interpretation by four nuclear medicine physicians for the diagnosis of renal parenchymal abnormality in children, and to compare variability among three different DMSA methods in clinical use: planar alone, single-photon emission tomography (SPET) alone, and planar with SPET. One hundred consecutive DMSA studies were independently interpreted 3 times by four participating nuclear medicine specialists from different departments and in random order. All scans were classified by the presence or absence of renal parenchymal abnormality using the modified four-level grading system of Goldraich. Indices of agreement were the percentage of agreement and the kappa statistic. Disagreement was analysed using children, kidneys and kidney zones (three zones per kidney). Using patients as the unit of analysis, agreement for planar and planar with SPET methods was 87%-88% (kappa 0.74) for the normal-abnormal scan classification. The corresponding agreement value for the SPET alone method was 78% (kappa 0.56). Similarly, substantial disagreement (disagreement > or = 2 categories) occurred in 2.5% and 1.3% of comparisons between observers for planar alone and planar with SPET, respectively, but in 5.2% of comparisons for SPET alone. These results did not vary appreciably whether interpretation of patients, kidneys or kidney zones was compared. It is concluded that the four experienced nuclear medicine physicians showed substantial agreement in the interpretation of planar alone and planar with SPET DMSA scintigraphic images. Interpretation of SPET DMSA images, without planar images, was significantly more variable than interpretation using the two other methods, disagreement occurring in more than 20% of comparisons. SPET DMSA scintigraphy, when used without planar images, does not provide a firm basis for clinical decision making in the care of children who may have renal damage. There is no apparent benefit of reduced variability from the extra provision of SPET data to nuclear medicine physicians who already have planar images.

Child↗
PubMed2000

Role of ischemia and infarction in late right ventricular dysfunction after atrial repair of transposition of the great arteries.

OBJECTIVES: This study was conducted to assess whether myocardial ischemia and/or infarction are involved in the pathogenesis of late right ventricular dysfunction in adult survivors of atrial baffle repair for transposition of the great arteries in infancy. BACKGROUND: The medium-term success of intraatrial baffle repair for transposition of the great arteries is good, with many patients surviving into adult life, but prognosis can be limited by progressive right ventricular dysfunction. We hypothesized that ongoing myocardial ischemia and/or infarction are important factors in the pathogenesis of this complication. Radionuclide techniques offer an opportunity to study both myocardial perfusion and concomitant ventricular wall motion. METHODS: Dipyridamole sestamibi single-photon emission computed tomography followed by rest sestamibi single-photon emission computed tomography was used to assess right ventricular myocardial perfusion, wall motion, wall thickening and ejection fraction in 22 adolescents/young adults who had undergone atrial baffle repair for simple transposition of the great arteries at median 6.7 (range 0.5 to 54) months of age. The patients were aged 10 to 25 (median 15.5) years; 19 in New York Heart Association class I, 2 in class II and 1 in class III. All were in a regular cardiac rhythm during the studies. The right ventricular tomographic images were examined in three parallel and two orthogonal planes, analyzed in 12 segments. RESULTS: Perfusion defects were evident in all patients in at least one segment, in either the rest or stress images. Twelve patients (55%) demonstrated fixed defects only, nine (41%) had fixed and reversible defects and one (4.5%) had reversible defects only. Concomitant wall-thickening abnormalities occurred in 83% of segments with fixed perfusion defects, mirrored by a reduction in wall motion in 91% of segments analyzed. Right ventricular ejection fraction was correlated with age (R = 0.62; p = 0.002), and with wall-thickening abnormalities (R = 0.60; p < 0.005). CONCLUSIONS: Reversible and fixed perfusion defects with concordant regional wall motion abnormalities occur in the right (systemic) ventricle 10 to 20 years after Mustard repair for transposition of the great arteries; this may be important in the pathogenesis of late right ventricular dysfunction in this group.

Adolescent↗
PubMed2000

Popliteal lymph node metastasis from primary cutaneous melanoma.

AIMS: To document the incidence of popliteal lymph node involvement by metastatic melanoma and to consider the implications of this information for clinical management. METHODS: From the computerized database of the Sydney Melanoma Unit, all patients with primary melanomas located at or distal to the knee were identified and their records were examined. Experience with those patients who developed popliteal node metastases was then reviewed. RESULTS: Thirteen of 4262 patients (0.31%) with primary melanomas of the distal lower limb developed popliteal node metastases. Six of the 13 patients had previous, synchronous or subsequent groin node metastases. CONCLUSIONS: Popliteal lymph node involvement by metastatic melanoma is a rare event. The study results suggest only two indications for full popliteal node clearance-either a histologically positive sentinel node in the popliteal fossa or clinical evidence of metastatic disease in a popliteal node.

Adolescent↗
PubMed1999

Location of sentinel lymph nodes in patients with cutaneous melanoma: new insights into lymphatic anatomy.

BACKGROUND: Accurate staging of melanoma patients by sentinel node (SN) biopsy can be achieved only if all SNs draining a given melanoma site are identified and removed for detailed histologic examination. Lymphoscintigraphy with a radiolabeled colloid provides an objective and reliable method of locating SNs and demonstrates that confident prediction of their location is not possible on clinical grounds. STUDY DESIGN: Lymphatic drainage pathways demonstrated by preoperative lymphoscintigraphy for 1,759 patients with primary cutaneous melanomas were reviewed, and locations of SNs in these patients were documented. An SN was defined as any node receiving direct lymphatic drainage from a primary melanoma site. RESULTS: In many instances the cutaneous lymphatic drainage pathways were found to be at variance with longheld concepts of lymphatic anatomy. Several new pathways were identified, draining to SNs in unexpected sites. These included triangular intermuscular space SNs (from upper back and, rarely, upper limb primaries), paraaortic and retroperitoneal SNs (from upper and lower back primaries), and costal margin SNs with onward drainage to internal mammary nodes (from periumbilical primaries). Occasional drainage to node fields on the opposite side of the body was noted from head, neck, and trunk primaries, and drainage to interval nodes (by definition, SNs) outside recognized lymph node fields was also observed. CONCLUSIONS: Knowledge of the possibility of these unusual lymphatic drainage patterns and SN sites should help to ensure the accuracy and completeness of SN identification. Preoperative lymphoscintigraphy to definitively locate SNs is recommended for every patient undergoing an SN biopsy procedure.

Antimony↗
PubMed1999

High-resolution ultrasound to diagnose melanoma metastases in patients with clinically palpable lymph nodes.

High-resolution ultrasound was used to determine if it could predict the presence of metastatic disease in 52 patients with melanoma who had developed newly palpable lymph nodes during clinical follow-up. Ultrasound proved accurate in diagnosing the presence of nodal metastases; it had a sensitivity of 94%, a specificity of 87% and an accuracy of 89%. The ultrasound features which together were diagnostic of the presence of nodal metastases were a node thickness greater than two-thirds of the node length and the presence of low-level echoes in the node. When these two features were both present on ultrasound, node metastases were present in every case. Ultrasound can be used to evaluate newly palpable lymph nodes in patients with melanoma. A normal ultrasound finding does not exclude micrometastases, but a lymph node showing the two key ultrasound features aforementioned is highly likely to contain metastatic disease and should be treated accordingly.

Diagnosis, Differential↗
PubMed1999

Direct lymphatic drainage from a melanoma on the back to paravertebral lymph nodes in the thorax.

Preoperative lymphoscintigraphy with Tc-99m antimony sulfide colloid was performed in a patient with cutaneous melanoma on the lower back just to the right of the midline. There was direct lymphatic drainage to paravertebral nodes in the chest on the right side at the level of the sixth and seventh thoracic vertebrae. There was also drainage directly to the right groin and via a series of interval nodes to the right axilla. Knowledge of the presence of such drainage may influence the surgical management of patients.

Antimony↗