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David Cowan

Publications and source records attributed to David Cowan.

12 recordsLinked to original sources
PubMed2006

Race, breast cancer subtypes, and survival in the Carolina Breast Cancer Study.

CONTEXT: Gene expression analysis has identified several breast cancer subtypes, including basal-like, human epidermal growth factor receptor-2 positive/estrogen receptor negative (HER2+/ER-), luminal A, and luminal B. OBJECTIVES: To determine population-based distributions and clinical associations for breast cancer subtypes. DESIGN, SETTING, AND PARTICIPANTS: Immunohistochemical surrogates for each subtype were applied to 496 incident cases of invasive breast cancer from the Carolina Breast Cancer Study (ascertained between May 1993 and December 1996), a population-based, case-control study that oversampled premenopausal and African American women. Subtype definitions were as follows: luminal A (ER+ and/or progesterone receptor positive [PR+], HER2-), luminal B (ER+ and/or PR+, HER2+), basal-like (ER-, PR-, HER2-, cytokeratin 5/6 positive, and/or HER1+), HER2+/ER- (ER-, PR-, and HER2+), and unclassified (negative for all 5 markers). MAIN OUTCOME MEASURES: We examined the prevalence of breast cancer subtypes within racial and menopausal subsets and determined their associations with tumor size, axillary nodal status, mitotic index, nuclear pleomorphism, combined grade, p53 mutation status, and breast cancer-specific survival. RESULTS: The basal-like breast cancer subtype was more prevalent among premenopausal African American women (39%) compared with postmenopausal African American women (14%) and non-African American women (16%) of any age (P<.001), whereas the luminal A subtype was less prevalent (36% vs 59% and 54%, respectively). The HER2+/ER- subtype did not vary with race or menopausal status (6%-9%). Compared with luminal A, basal-like tumors had more TP53 mutations (44% vs 15%, P<.001), higher mitotic index (odds ratio [OR], 11.0; 95% confidence interval [CI], 5.6-21.7), more marked nuclear pleomorphism (OR, 9.7; 95% CI, 5.3-18.0), and higher combined grade (OR, 8.3; 95% CI, 4.4-15.6). Breast cancer-specific survival differed by subtype (P<.001), with shortest survival among HER2+/ER- and basal-like subtypes. CONCLUSIONS: Basal-like breast tumors occurred at a higher prevalence among premenopausal African American patients compared with postmenopausal African American and non-African American patients in this population-based study. A higher prevalence of basal-like breast tumors and a lower prevalence of luminal A tumors could contribute to the poor prognosis of young African American women with breast cancer.

Adult↗
PubMed2006

Molecular subtypes of breast cancer in relation to paclitaxel response and outcomes in women with metastatic disease: results from CALGB 9342.

INTRODUCTION: The response to paclitaxel varies widely in metastatic breast cancer. We analyzed data from CALGB 9342, which tested three doses of paclitaxel in women with advanced disease, to determine whether response and outcomes differed according to HER2, hormone receptor, and p53 status. METHODS: Among 474 women randomly assigned to paclitaxel at a dose of 175, 210, or 250 mg/m2, adequate primary tumor tissue was available from 175. Immunohistochemistry with two antibodies and fluorescence in situ hybridization were performed to evaluate HER2 status; p53 status was determined by immunohistochemistry and sequencing. Hormone receptor status was obtained from pathology reports. RESULTS: Objective response rate was not associated with HER2 or p53 status. There was a trend toward a shorter median time to treatment failure among women with HER2-positive tumors (2.3 versus 4.2 months; P = 0.067). HER2 status was not related to overall survival (OS). Hormone receptor expression was not associated with differences in response but was associated with longer OS (P = 0.003). In contrast, women with p53 over-expression had significantly shorter OS than those without p53 over-expression (11.5 versus 14.4 months; P = 0.002). In addition, triple negative tumors were more frequent in African-American than in Caucasian patients, and were associated with a significant reduction in OS (8.7 versus 12.9 months; P = 0.008). CONCLUSION: None of the biomarkers was predictive of treatment response in women with metastatic breast cancer; however, survival differed according to hormone receptor and p53 status. Triple negative tumors were more frequent in African-American patients and were associated with a shorter survival.

Black or African American↗
PubMed2006

[Improving our mobility in Europe: The EHTAN Project].

To promote the mobility of nursing professionals among the countries members of the European Union may be an efficient measure to alleviate the shortage of nurses. An important limitation for this mobility consists in the lack of knowledge about the different cultures and with regards to the competencies, formation and nursing practices which exist in these distinct countries. At the present time, there is no method or instrument available which permits a comparison. The EHTAN, the European Healthcare Teaching and Accreditation Network, project proposes a methodology to evaluate and self-evaluate competencies by means of a tool, a competency matrix, developed for this purpose. In this article, the authors introduce the work carried out during the first phases of this project.

Career Mobility↗
PubMed2005

Comparison of HER2 status by fluorescence in situ hybridization and immunohistochemistry to predict benefit from dose escalation of adjuvant doxorubicin-based therapy in node-positive breast cancer patients.

PURPOSE: HER2 is a clinically important tumor marker in breast cancer; however, there is controversy regarding which method reliably measures HER2 status. We compared three HER2 laboratory methods: immunohistochemistry (IHC), fluorescence in situ hybridization (FISH) and polymerase chain reaction (PCR), to predict disease-free survival (DFS) and overall survival (OS) after adjuvant doxorubicin-based therapy in node-positive breast cancer patients. METHODS: This is a Cancer and Leukemia Group B (CALGB) study, using 524 tumor blocks collected from breast cancer patients registered to clinical trial CALGB 8541. IHC employed CB11 and AO-11-854 monoclonal antibodies; FISH used PathVysion HER2 DNA Probe kit; PCR utilized differential PCR (D-PCR) methodology. RESULTS: Cases HER2 positive by IHC, FISH and D-PCR were 24%, 17%, and 18%, respectively. FISH and IHC were clearly related (kappa = 64.8%). All three methods demonstrated a similar relationship for DFS and OS. By any method, for patients with HER2-negative tumors, there was little or no effect of dose of adjuvant doxorubicin-based therapy. For patients with HER2-positive tumors, all three methods predicted a benefit from dose-intense (high-dose) compared with low- or moderate-dose adjuvant doxorubicin-based therapy. CONCLUSION: FISH is a reliable method to predict clinical outcome following adjuvant doxorubicin-based therapy for stage II breast cancer patients. There is a moderate level of concordance among the three methods (IHC, FISH, PCR). None of the methods is clearly superior. Although IHC-positive/FISH-positive tumors yielded the greatest interaction with dose of therapy in predicting outcome, no combination of assays tested was statistically superior.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2005

Testosterone measurement by isotope-dilution liquid chromatography-tandem mass spectrometry: validation of a method for routine clinical practice.

BACKGROUND: Immunoassay is unsatisfactory for measuring the testosterone concentrations typically found in women. Bench-top tandem mass spectrometers are a viable alternative technology for measurements in the clinical laboratory. METHODS: We used stable-isotope dilution liquid chromatography-tandem mass spectrometry (ID/LC-MS/MS) to measure testosterone in plasma and serum. The sample volume was 50 muL in duplicate; preparation and analysis were carried out in a single tube, and a batch of 192 tubes was analyzed in 17.5 h. RESULTS: Intra- and interassay imprecision was <15% in the range 0.3-49 nmol/L. Recovery of testosterone added to samples at concentrations of 0.625-20 nmol/L was 96% (CV = 12%; n = 26). Six samples were serially diluted with double charcoal-stripped serum to demonstrate linearity. Correlation (r(2)) with isotope-dilution gas chromatography-mass spectrometry for 20 pools of clinical samples (range, 0.5-38.5 nmol/L) was 0.99. Correlations with our extraction RIA were 0.97 for clinical samples from men (range, 8-46.3 nmol/L) and 0.66 for samples from women (range, 0.7-3.0 nmol/L), but were 0.35 for male samples containing <3 nmol/L testosterone and 0.77 for female samples containing >8 nmol/L. Various steroids added to double charcoal-stripped serum showed no interference at the retention time of the testosterone peak. CONCLUSIONS: The ID/LC-MS/MS method has improved accuracy compared with immunoassay. The low sample volume and simplicity, rapidity, and robustness of the method make it suitable for use as a high-throughput assay in routine clinical biochemistry laboratories.

Chromatography, High Pressure Liquid↗
PubMed2005

High focal adhesion kinase expression in invasive breast carcinomas is associated with an aggressive phenotype.

Focal adhesion kinase (FAK) is a protein tyrosine kinase expressed in invasive breast cancer that regulates antiapoptotic signaling. We have examined FAK expression by immunohistochemistry using anti-FAK 4.47 in breast tumor samples from a large population-based, case-control study of women participating in the University of North Carolina Breast Specialized Programs of Research Excellence (SPORE), Carolina Breast Cancer Study. In this population, 629 formalin-fixed, paraffin-embedded tissue sections were stained for FAK and scored as high (3+ or 4+ intensity and > or = 90% positive cells) or otherwise. High FAK expression was associated with poor prognostic indicators including high mitotic index (>10 mitoses per 10 consecutive high-power fields), nuclear grade 3, architectural grade 3, estrogen and progesterone receptor negative, and HER-2/neu overexpressed using CB11 antibody. The association of high FAK expression with HER-2/neu overexpression lends further support that HER-2/neu and FAK collaborate to promote tumorigenesis. The presence of strong FAK expression in many high grade, estrogen- and progesterone-negative breast carcinomas indicates that FAK may be an attractive target for therapeutic intervention.

Adult↗
PubMed2005

Prospective analysis of the effect of physician experience with the FAST examination in reducing the use of CT scans.

OBJECTIVE: The objective of this study was to examine the effect of ultrasound experience level on emergency physicians' Focused Assessment with Sonography for Trauma (FAST) exam accuracy and emergency physicians' confidence in using FAST findings to assist in managing patients with blunt trauma. METHODS: This prospective, consecutive enrolment study evaluated adult trauma team activation blunt trauma patients. Based on the number of post-training FAST exams carried out, 11 attending emergency physicians were grouped into A (<25 exams, n = 4), B (26-50 exams, n = 4) or C (>50 exams, n = 3). The FAST exam was carried out prior to other diagnostic studies. The emergency physicians were asked to prospectively judge their perception of the need for surgery, abdominal CT or no further tests. All study patients ultimately underwent CT, diagnostic peritoneal lavage or laparotomy. Among each physician group, the number of subsequent CT scans deemed necessary by the emergency physician after a 'normal' FAST was calculated and compared. RESULTS: Accuracy was greatest in group C. Sixty-nine of 80 patients in group A had a normal FAST exam; emergency physicians deemed CT necessary in 68/69 cases (99%; confidence interval [CI] 92-100%). Eighty-two of 98 patients in group C had a normal FAST exam; emergency physicians deemed CT necessary in 19/82 cases (23%; CI 15-34%). Physicians in groups B and C were less likely to order CT after a normal FAST than group A (P < 0.001). CONCLUSIONS: FAST accuracy was greatest among more experienced emergency physicians. A normal FAST exam assisted more experienced emergency physicians with the perceived need to order significantly fewer CT scans than less experienced emergency physicians.

Adult↗
PubMed2004

Upregulation of focal adhesion kinase (FAK) expression in ductal carcinoma in situ (DCIS) is an early event in breast tumorigenesis.

Focal adhesion kinase (FAK) is a protein tyrosine kinase that is overexpressed in a subset of invasive breast cancers. FAK transmits signals that mediate several functions including tumor cell proliferation, migration, adhesion and survival. We used immunohistochemical techniques to assess FAK expression in patients with fibrocystic disease (FCD), atypical ductal hyperplasia (ADH), ductal carcinoma in situ (DCIS) and infiltrating ductal carcinoma (IDC). Formalin-fixed, paraffin-embedded (FFPE) tissue sections were obtained from 119 patients (12 FCD, 38 ADH, 51 DCIS and 18 IDC). The anti-FAK 4.47 monoclonal antibody was used to detect FAK expression. FAK expression was scored as high (3 or 4 intensity and > or =90% positive cells) or low. The DCIS tissue sections demonstrated high FAK expression in 34/51 (66%) of the sections. High FAK expression was demonstrated in 6/18 (33%) of the IDC tissue sections and 8/38 (21%) of the ADH tissue sections. None (0/12) of the FCD tissues sections stained high for FAK. The pattern of FAK expression in DCIS was significantly higher than ADH (p < 0.0001) and IDC (p = 0.02). We conclude that FAK overexpression in preinvasive, DCIS tumors precedes tumor cell invasion or metastasis, suggesting that FAK may function as a survival signal and be an early event in breast tumorigenesis.

Breast Diseases↗
PubMed2003

HER2 codon 655 polymorphism and risk of breast cancer in African Americans and whites.

BACKGROUND: Several recent epidemiologic studies examined the association between breast cancer risk and an inherited, single-nucleotide polymorphism in the HER2 gene, codon 655 G to A, which leads to an amino acid substitution of Ile to Val. Results of previous studies have been mixed, with most studies showing no association but some suggesting an association in younger women or women with a family history of breast cancer. METHODS: We conducted an association study of HER2 codon 655 genotype and breast cancer within the Carolina Breast Cancer study, a population-based, case-control study of in situ and invasive breast cancer in African American and white women in North Carolina. A total of 2015 cases and 1808 controls were genotyped. RESULTS: We observed no overall association between HER2 genotype and breast cancer. However, a modest positive association (OR = 2.3, 95% CI 1.0-5.3) was observed for Val/Val + Ile/Val versus Ile/Ile genotypes in women age 45 or younger with a family history of breast cancer. Val/Val homozygotes were more common among cases with in situ versus invasive disease (P = 0.002). Breast tumors from women with Val/Val genotype were more likely to exhibit HER2 overexpression, but the results were not statistically significant (P = 0.17). CONCLUSIONS: The HER2 codon 655 polymorphism may be one of many low-penetrant genes that make a minor contribution to breast cancer, particularly in subgroups of women. Additional large studies, as well as data pooling, will be needed to estimate the contribution of such genes to breast cancer risk.

Adult↗
PubMed2002

Medicines management in care homes for older people: the nurse's role.

Increasing attention is being paid to the inappropriate use of medicines in UK care homes for older people. While polypharmacy may sometimes be necessary, older people can be particularly sensitive to the effects of medicines due to physiological chances, while the effect of a mixture of medicines is often unknown. The harmful consequences of inappropriate prescribing for older people unnecessarily add to overall health-care expenditure and the workload of staff. Community nurses can play an important role in attenuating some of these problems while enhancing the quality of life of older people in care homes. The growing population of older people and burgeoning health-care expenditure on medicines demands that greater attention is given to medicine management among older people so that the efficacy of therapeutic regimes are maximized.

Aged↗
PubMed2002

Using general population data to project idiopathic physical symptoms in the U.S. Army.

Many personnel deployed to the 1991 Persian Gulf War complained of symptoms that sometimes remained unexplained after comprehensive clinical examinations. We used existing population-based data from the Epidemiologic Catchment Area survey to estimate the expected incidence, prevalence, resolution, and mortality for multiple idiopathic physical symptoms (MIPS) among Army active duty personnel. Multinomial logistic regression was used to model the relationship between sociodemographic characteristics and the distribution of MIPS in U.S. workers. We used logit coefficients and known sociodemographic characteristics of U.S. Army active duty personnel to predict MIPS status in the Army. High, medium, and low estimates of MIPS incidence, prevalence, resolution, and MIPS-related mortality were obtained by altering logit intercepts. Among workers, the estimated MIPS prevalence and annual incidence, resolution, and mortality were 4.62%, 2.11%, 63.85%, and 0.26%, respectively. In contrast, the same predicted rates among Army active duty personnel were 3.89%, 1.64%, 71.33%, and 0.15%.

Adult↗