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Dive into the research topics where Mercia Louw is active.

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Featured researches published by Mercia Louw.


Respiration | 2005

Utility of Rapid On-Site Evaluation of Transbronchial Needle Aspirates

Andreas H. Diacon; Macé M. Schuurmans; Johan Theron; Mercia Louw; Colleen A. Wright; Karen Brundyn; Chris T. Bolliger

Background: Rapid on-site evaluation has been proposed as a method to improve the yield of transbronchial needle aspiration. Objectives: This study investigated whether on-site analysis facilitates routine diagnostic bronchoscopy in terms of sampling, yield and cost. Methods: Patients with lesions accessible for transbronchial needle aspiration on computed tomography were investigated. A cytopathologist screened the needle aspirates on site for the presence of diagnostic material. The bronchoscopic sampling process was adjusted according to the results. In 90 consecutive patients with neoplastic disease (n = 70; 78%), non-neoplastic disease (n = 16; 18%) or undiagnosed lesions (n = 4; 4%) we aspirated 162 lung lesions (paratracheal tumours or lymph nodes: 7%; tracheobronchial lymph nodes: 68%; other: 25%). Results: The diagnostic yield of needle aspiration was 77 and 25% in patients with neoplastic and non-neoplastic lesions, respectively. Sampling could be terminated in 64% of patients after needle aspiration had been performed as the only diagnostic modality, and on-site analysis identified diagnostic material from the first site aspirated in 50% of patients. Only in 2 patients (2%) diagnostic aspirates were not recognized on site. On-site analysis was cost effective due to savings for disposable diagnostic tools, which exceeded the extra expense for the on-site cytology service provided. Conclusions: Rapid on-site analysis of transbronchial aspirates is a highly useful, accurate and cost-effective addition to routine diagnostic bronchoscopy.


Pediatric Blood & Cancer | 2005

The 2000 Burkitt lymphoma trial in Malawi.

P. B. Hesseling; Robin L. Broadhead; Erna P.G. Mansvelt; Mercia Louw; G. Wessels; Eric Borgstein; Johann W. Schneider; Elizabeth Molyneux

We previously reported 57% 12‐month event free survival (EFS) in Malawian children with stage I to III Burkitt lymphoma (BL) with an intermediate dose chemotherapy protocol lasting 77 days. This protocol was shortened to 42 days and evaluated in children with stage I to IV disease for EFS and toxicity.


Thorax | 2010

Direct comparison of the diagnostic yield of ultrasound-assisted Abrams and Tru-Cut needle biopsies for pleural tuberculosis

Coenraad F.N. Koegelenberg; Christoph Thomas Bolliger; Johan Theron; Gerhard Walzl; Colleen A. Wright; Mercia Louw; Andreas H. Diacon

Background Tuberculous pleuritis remains the commonest cause of exudative effusions in areas with a high prevalence of tuberculosis and histological and/or microbiological confirmation on pleural tissue is the gold standard for its diagnosis. Uncertainty remains regarding the choice of closed pleural biopsy needles. Objectives This prospective study compared ultrasound-assisted Abrams and Tru-Cut needle biopsies with regard to their diagnostic yield for pleural tuberculosis. Methods 89 patients (54 men) of mean±SD age 38.7±16.7 years with pleural effusions and a clinical suspicion of tuberculosis were enrolled in the study. Transthoracic ultrasound was performed on all patients, who were then randomly assigned to undergo ≥4 Abrams needle biopsies followed by ≥4 Tru-Cut needle biopsies or vice versa. Medical thoracoscopy was performed on cases with non-diagnostic closed biopsies. Histological and/or microbiological proof of tuberculosis on any pleural specimen was considered the gold standard for pleural tuberculosis. Results Pleural tuberculosis was diagnosed in 66 patients, alternative diagnoses were established in 20 patients and 3 remained undiagnosed. Pleural biopsy specimens obtained with Abrams needles contained pleural tissue in 81 patients (91.0%) and were diagnostic for tuberculosis in 54 patients (sensitivity 81.8%), whereas Tru-Cut needle biopsy specimens only contained pleural tissue in 70 patients (78.7%, p=0.015) and were diagnostic in 43 patients (sensitivity 65.2%, p=0.022). Conclusions Ultrasound-assisted pleural biopsies performed with an Abrams needle are more likely to contain pleura and have a significantly higher diagnostic sensitivity for pleural tuberculosis.


European Respiratory Journal | 2006

Transbronchial needle aspirates: how many passes per target site?

Andreas H. Diacon; Macé M. Schuurmans; Johan Theron; Karen Brundyn; Mercia Louw; Colleen A. Wright; Chris T. Bolliger

Transbronchial needle aspiration is a bronchoscopic sampling method for a variety of bronchial and pulmonary lesions. The present study investigated whether and how serial needle passes contribute to the yield of transbronchial needle aspiration at specific target sites. A total of 1,562 needle passes, performed at 374 target sites in 245 patients with neoplastic disease (82%), non-neoplastic disease (15%) or undiagnosed lesions (3%), were prospectively recorded and rated for anatomical location, size, bronchoscopic appearance and underlying disease. Positive aspirates were obtained in 75% of patients and at 68% of target sites. A diagnosis was established with the first, second, third and fourth needle pass at 64, 87, 95 and 98% of targets, respectively. The absolute yield varied strongly with target site features, but the stepwise increment to the maximum yield provided by serial passes was similar across target sites. In conclusion, three transbronchial needle passes per site are appropriate when only a tissue diagnosis is sought and when alternative sites or sampling modalities are available. At least four or five passes should be carried out at lymph node stations critical for the staging of lung cancer.


European Respiratory Journal | 2006

Ultrasound-assisted transthoracic biopsy: fine-needle aspiration or cutting-needle biopsy?

Andreas H. Diacon; Johan Theron; Pawel T. Schubert; Karen Brundyn; Mercia Louw; Colleen A. Wright; Chris T. Bolliger

The present study compared the diagnostic yield of ultrasound-assisted cutting-needle biopsy (CNB) and fine-needle aspiration biopsy (FNAB) in chest lesions. A physician performed ultrasound and FNAB with a 22-G spinal needle in all patients, directly followed by a 14-G CNB in patients without contraindication. A total of 155 consecutive lesions arising from the lung (74%), pleura (12%), mediastinum (11%) or chest wall (3%) in patients with a final diagnosis of lung carcinoma (74%), other malignant tumours (12%), non-neoplastic disease (9%) or unknown (5%) were prospectively included. The overall diagnostic yield was 87%. Combined specimens were obtained in 123 lesions (79%). In these, yields of FNAB, CNB and both methods combined were 82, 76 and 89%, respectively. FNAB was significantly better than CNB in lung carcinoma (95 versus 81%) but CNB was superior in noncarcinomatous tumours and in benign lesions. On-site cytology was 90% sensitive and 100% specific for predicting a positive FNAB. One patient required drainage for pneumothorax (0.6%). Ultrasound-assisted fine-needle aspiration biopsy performed by chest physicians is an accurate and safe initial diagnostic procedure in patients with a high clinical probability of lung carcinoma. All other patients should undergo concurrent fine-needle aspiration biopsy and cutting-needle biopsy.


Diagnostic Cytopathology | 2012

An interinstitutional review of the value of FNAB in pediatric oncology in resource‐limited countries

Rubina Razack; Pamela Michelow; Gladwyn Leiman; Anwari Harnekar; Janet Poole; G. Wessels; P. B. Hesseling; Cristina Stefan; Mercia Louw; Pawel T. Schubert; Herchel Clarke; Colleen A. Wright

Fine‐needle aspiration biopsy (FNAB) has been widely accepted as a reliable diagnostic modality in the general pediatric population, but its role in pediatric oncology still remains elusive. With new treatment protocols subscribing to preoperative chemotherapy, the need for a quick, minimally invasive, and accurate diagnostic procedure has arisen. This study assesses the feasibility of FNAB in childhood malignancies to render a specific diagnosis on which treatment can be initiated. An 11‐year retrospective study was done on FNABs in patients 19 years and under referred for clinically malignant mass lesions. Cases were confirmed with histology, immunocytochemistry, flow cytometry, or clinical follow‐up. Of the 357 patients referred for FNABs, 36 patients were lost to follow‐up and 31 FNABS were inadequate. A total of 290 cases were included in the study, of which 68 (23%) cases were benign and 222 (77%) were malignant. The most frequently occurring tumors were nephroblastoma (68), non‐Hodgkins lymphoma (39), rhabdomyosarcoma (22), Hodgkins lymphoma (22), and neuroblastoma (22). The sensitivity of the procedure for neoplasia was 96.6%, the specificity 97.0%, positive predictive value 99.0%, and negative predictive value 90.1%, with a diagnostic accuracy of 96.7%. The ability of FNAB to enable a specific diagnosis to be made, that is correct and accurate subtyping of the tumor on which chemotherapy or radiotherapy could be commenced was 75.7%. This study shows that FNAB can be used with confidence to confirm malignancy in children. With clinicoradiological correlation and the aid of ancillary techniques, FNAB allows a rapid and accurate preoperative diagnosis for definitive therapy commencement in most cases. Diagn. Cytopathol. 2012.


European Respiratory Journal | 2009

Diagnostic yield and safety of ultrasound-assisted biopsies in superior vena cava syndrome

Coenraad F.N. Koegelenberg; Chris T. Bolliger; Plekker D; Colleen A. Wright; Karen Brundyn; Mercia Louw; Pawel T. Schubert; M. M. Van Den Heuvel; Andreas H. Diacon

The yield and safety of ultrasound (US)-assisted transthoracic fine needle aspirations (TTFNA) and cutting needle biopsies (CNB) in the setting of superior vena cava (SVC) syndrome are unknown. The aims of the present prospective study were to asses the diagnostic yield and safety of US-assisted TTFNA and CNB in SVC syndrome with an associated mass lesion abutting the chest wall. Over a 3-yr period, the present authors screened 59 patients with SVC syndrome, and enrolled 25 patients who had an associated mass lesion that extended to the chest wall. US-assisted TTFNA with rapid on-site evaluation (ROSE) was performed in all cases. CNBs were performed where a provisional diagnosis of bronchogenic carcinoma could not be established, and in 57.1% of patients with bronchogenic carcinoma (limited due to safety constraints). ROSE of US-assisted TTFNA confirmed diagnostically useful material in 24 patients, and cytological diagnoses were ultimately made in all of these cases (diagnostic yield 96%). US-assisted CNB had a diagnostic yield of 87.5%. Minor haemorrhage occurred in one out of 25 TTFNA and three out of 16 CNB. Neither procedure resulted in major haemorrhage nor pneumothoraces. US-assisted TTFNA and CNB have a high diagnostic yield and are safe in the setting of SVC syndrome with an associated mass lesion abutting the chest wall.


European Respiratory Journal | 2010

Rapid on-site evaluation of transbronchial aspirates: Randomised comparison of two methods

Andreas H. Diacon; Coenraad F.N. Koegelenberg; Pawel T. Schubert; Karen Brundyn; Mercia Louw; Colleen A. Wright; Chris T. Bolliger

The value of different staining methods for rapid analysis of transbronchial needle aspirates during bronchoscopy has not been explored. In the present study, we compared a Papanicolaou-based rapid stain, prepared by a technologist and read by a cytopathologist, and a Wright–Giemsa-based rapid stain, prepared and read by a cytopathologist alone. Gold standard was the final laboratory report issued on each aspirate. We harvested 827 aspirates from 218 target sites in 126 consecutive patients. At least one positive aspirate was found in 99 (79%) patients. In those 99 patients, 288 of 574 (50%) aspirates were positive for neoplastic (83%) or non-neoplastic (17%) disease. False-negative aspirates and target sites were more frequent with the rapid Wright–Giemsa than with the rapid Papanicolaou stain (14.2 versus 7.3%, p = 0.008, and 13.7 versus 3.6%, p = 0.021, respectively). The sensitivity of the Wright–Giemsa-based and Papanicolaou-based rapid stains for detecting diagnostic material was 93 and 100% in patients, 83.1 and 95.5% in target sites, and 72.8 and 84.9% in aspirates, respectively. Specificity was 100% for both methods in patients and target sites, and 90.4 and 95% in aspirates. We concluded that a Papanicolaou-based stain has superior yield and accuracy to a Wright–Giemsa-based stain for rapid on-site evaluation of transbronchial needle aspirates.


Diagnostic Cytopathology | 2012

Comparison of the quality of smears in transbronchial fine-needle aspirates using two staining methods for rapid on-site evaluation

Mercia Louw; Karen Brundyn; M.I.A.C. Pawel T. Schubert M.D.; F.I.A.C. Colleen A. Wright M.D.; Chris T. Bolliger; Andreas H. Diacon

Transbronchial needle aspiration (TBNA) via flexible bronchoscopy is a well‐established sampling modality for lung masses. The procedure is useful in the diagnosis of neoplastic and non‐neoplastic lesions as well as for staging of bronchogenic carcinoma. Rapid on‐site evaluation (ROSE) adds value as it has the advantage of triaging material during the procedure so avoiding a battery of investigations. Frequently used rapid stains are the modified Wright‐Giemsa water‐based stain (WG‐ROSE) and the alcohol‐based modified Papanicolaou stain (Pap‐ROSE). Final review of laboratory‐based Giemsa and Pap stains supplemented by ancillary investigations is essential for quality assurance. To investigate whether and how ROSE influenced the quantity and quality of the material submitted to the laboratory we randomized 126 patients to WG‐ROSE, requiring only one pathologist on‐site, or combined WG‐ and Pap‐ROSE, requiring an additional person on‐site to assist with staining. In those patients with positive TBNA we graded the laboratory‐based slides of the first pass containing diagnostic material into insufficient, suspicious, adequate and excellent. The first diagnostic pass was found after 3.06 ± 1.94 (SD) passes and 3.13 ± 2.16 passes with WG‐ROSE and combined ROSE (P = 0.87), respectively. Following WG‐ROSE and combined ROSE 69% and 71.1% (P = 0.509) of slides were diagnostic (adequate or excellent) on laboratory‐based Giemsa stains, and 93.3% and 100% (P = 0.134) were scored adequate or excellent on laboratory‐based Pap stains. We concluded that the less costly and labour intensive WG‐ROSE procedure is adequate for TBNA. This has cost implications especially in resource poor settings. Diagn. Cytopathol. 2012.


Journal of Thoracic Oncology | 2011

Radiologic Features, Staging, and Operability of Primary Lung Cancer in the Western Cape, South Africa: A 1-Year Retrospective Study

Aldoph B. Nanguzgambo; Kushroo Aubeelack; Florian von Groote-Bidlingmaier; Susanna M. Hattingh; Mercia Louw; Coenraad F.N. Koegelenberg; Chris T. Bolliger

Introduction: This retrospective study was performed to evaluate the radiologic features, staging, and resectability of lung cancer at the time of presentation in patients from the Western Cape of South Africa. Method: We included all patients with primary lung cancer reviewed during a 12-month period (January 2009 to December 2009) who had a definite tissue diagnosis and whose staging computed tomography scans were available. Fifteen radiologic parameters were assessed. Results: Data were complete in 204 patients. The proportion and median size of the various histologic subtypes were as follows: adenocarcinoma 53.9%, 53.4 mm; squamous cell 25.9%, 80.2 mm; small cell 14.2%, 80.8 mm; large cell 2.4%, 74.2 mm; bronchioloalveolar carcinoma 1.5%, 50.0 mm; and others 2%, 57.6 mm, respectively. The overall median size of tumor was 61.5 mm. Tumors were located centrally in 43.6%, peripherally in 46.6%, indeterminate in 9.8%, mediastinal in 11.3%, right lung in 53.4%, and in the left lung in 35.3%. Tuberculosis-related lung fibrosis was present in 16%, but only 5.4% patients had coexisting tumor and fibrosis at the same site. We observed no difference in the proportion of coexisting fibrosis between adenocarcinoma and squamous carcinoma. Only 16.2% of the patients were potential candidates for radical treatment, with an actual resection rate of 4.4%. Conclusions: In the Western Cape, adenocarcinoma is the commonest histologic subtype of bronchogenic carcinoma. Most patients present with late-stage primary tumors, and the percentage of patients with potentially resectable cancer is much lower than in Europe.

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Johan Theron

Stellenbosch University

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G. Wessels

Stellenbosch University

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