PubMed Health⌕ Search

Biomedical subjects

Douglas B Nelson

Publications and source records attributed to Douglas B Nelson.

At least 19 recordsLinked to original sources
PubMed2006

Should patients with anemia and low normal or normal serum ferritin undergo colonoscopy?

BACKGROUND: Patients with unexplained iron deficiency anemia have a greater prevalence of colonic neoplasia, and should be evaluated for a colonoscopy. The approach to patients with anemia without iron deficiency remains unclear. OBJECTIVE: To compare the prevalence of colonic neoplasia in anemic patients with normal ferritin (>50 ng/mL), to those with ferritin < or =50 ng/mL, and nonanemic individuals. METHODS: Patients referred for colonoscopy for anemia evaluation were stratified into 3 groups: ferritin < or =50 ng/mL, 51-100 ng/mL, and >100 ng/mL. We compared these groups to each other, and to asymptomatic nonanemic individuals undergoing screening colonoscopy. The prevalence of advanced colonic neoplasia was determined for each group using existing records. RESULTS: During the study period, 414 patients who underwent colonoscopy for anemia evaluation and 323 nonanemic individuals who underwent colonoscopy for cancer screening met inclusion criteria. Study subjects were mostly men. The prevalence of advanced colonic neoplasia in subjects with ferritin 51-100 ng/mL was 7.2% (95% CI 2.4-17.9%), similar to 7.9% (95% CI 5.1-11.9%) in those with ferritin < or =50 ng/mL. The incidence of advanced colonic neoplasia in subjects with ferritin >100 ng/mL was 1.7% (95% CI 0.1-6.6%), similar to 1.2% (95% CI 0.4-3.3%) in the asymptomatic nonanemic group. After adjusting for age, patients with ferritin < or =50 ng/mL and 51-100 ng/mL were almost 5 times more likely to harbor advanced colonic neoplasia than the other groups. The addition of other laboratory parameters did not improve the predictive value of ferritin. CONCLUSION: A ferritin cutoff of 100 ng/mL can be used to determine the need for colonoscopy in men with anemia.

Aged↗
PubMed2006

Colorectal cancers found after a complete colonoscopy.

BACKGROUND & AIMS: The incidence of colorectal cancer in patients undergoing colonoscopic surveillance is higher than previously thought. A better understanding of interval cancers is needed to improve surveillance strategies. The objectives of this study were to determine whether interval colorectal cancers were associated with an inadequate earlier colonoscopy, incomplete polypectomy, or aggressive biologic behavior. METHODS: We searched our institution's cancer registry. Interval cancers were defined as colorectal cancers that developed within 5 years of a complete colonoscopy. These were frequency matched in a 1:2 ratio to patients with sporadic cancers, which were defined as colorectal cancers diagnosed on a patient's first recorded colonoscopy. Patient, colonoscopy, and tumor characteristics of interval and sporadic cancers were compared. RESULTS: Of the 830 colorectal cancers diagnosed during the study period, 45 patients developed an interval cancer (5.4%; 95% confidence interval, 4.1%-7.2%). Twenty-seven percent of interval cancers developed at previous polypectomy segments, and location of polypectomy segments was predictive of the location of subsequent interval cancers. Interval cancers were 3 times more likely to occur in the right colon and were smaller in size than sporadic cancers. Quality of bowel preparation, individual endoscopist, endoscopist experience, and trainee involvement were not associated with interval cancers. No difference in TNM stage at diagnosis, histologic type or grade, carcinoembryonic antigen level, or 5-year survival was found between interval and sporadic cancers. CONCLUSIONS: Incomplete polypectomy might play an important role in the development of interval colorectal cancer. No association between other colonoscopy-related factors or tumor characteristics and interval cancers was found.

Aged↗
PubMed2006

Endoscopic ultrasound and positron emission tomography for lung cancer staging.

BACKGROUND AND AIMS: Accurate assessment of mediastinal lymph nodes is vital for optimum treatment allocation in lung cancer patients. Currently available strategies fail to identify many patients with advanced mediastinal disease, resulting in unnecessary surgery. We prospectively compared 2 promising new modalities, positron emission tomography (PET) and endoscopic ultrasound (EUS), for staging mediastinal lymph nodes. METHODS: Consenting patients with lung cancer who also were suitable candidates for surgery were enrolled in the study. Patients underwent both PET and EUS. Outcomes were analyzed by surgery results or follow-up with serial imaging. RESULTS: Seventy-two eligible patients were enrolled, and adequate data were available for 65 patients. The final diagnosis was based on tissue analysis in 59 patients and 1-year radiologic follow-up evaluation in 6 patients. PET correctly diagnosed mediastinal lymph node status in 77% of patients, and EUS fine-needle aspiration was correct in 94% of patients (P = .012). The overall sensitivity, specificity, and accuracy of PET were 61%, 91%, and 77% compared with 87%, 100%, and 94% for EUS. We estimated that EUS obviated a surgical procedure in 55% (95% confidence interval, 40%-69%) of patients with radiologic evidence of mediastinal metastasis, and in 22% (95% confidence interval, 10%-41%) of patients without radiologic evidence of mediastinal metastasis. CONCLUSIONS: EUS fine-needle aspiration was more accurate than PET in staging mediastinal lymph nodes in lung cancer patients, and resulted in a substantial reduction in mediastinoscopy and thoracotomy.

Aged↗
PubMed2006

EUS-guided FNA for the diagnosis of advanced lung cancer.

BACKGROUND: A majority of patients with lung cancer are incurable but are symptomatic and may benefit from palliative therapy. Currently available diagnostic methods are either too risky or unsuccessful in obtaining a tissue diagnosis in up to 30% of patients. OBJECTIVE: To evaluate the role of EUS-guided FNA in obtaining a tissue diagnosis in patients with advanced lung cancer. DESIGN: Prospective, uncontrolled. SETTING: Veterans Administration Medical Center. SUBJECTS AND METHODS: Patients with suspected lung cancer who were not candidates for curative therapy were prospectively identified. CT scans were reviewed, and patients with lesions considered suitable for sampling by EUS were enrolled. Outcomes were analyzed by a final tissue diagnosis or by serial imaging. RESULTS: Sixty-nine patients met inclusion criteria, of which 3 refused participation. The remaining 66 patients constituted the study population. EUS was technically successful in 95% of patients. A final diagnosis was based on tissue in 63 of 66 patients, serial imaging in 1 of 66 patients, and was unavailable in 2 of 66 patients. A lung mass was sampled in 21 patients, and a metastatic lesion was sampled in 45 patients. EUS made a correct diagnosis in 55 of 64 patients (86%, 95% confidence interval [CI] 77%-93%), including 24% that had undergone a failed prior attempt at diagnosis. The sensitivity of EUS was 86%, and the specificity was 100%. Sampling a metastasis was more likely to yield a correct diagnosis than sampling a lung mass (P = .02). Two self-limited complications were noted during the study. CONCLUSIONS: EUS was an accurate and a safe method for obtaining a tissue diagnosis in patients with advanced incurable lung cancer.

Adult↗
PubMed2006

Microsatellite instability in interval colon cancers.

BACKGROUND & AIMS: Colon cancers that develop after a complete colonoscopy may be the result of "failure of colonoscopy" or rapid tumor growth. Tumors that develop via the mismatch repair gene pathway demonstrate rapid tumor growth. The aim of this study was to determine if interval colon cancers were more likely than noninterval cancers to result from the loss of function of mismatch repair genes and hence demonstrate microsatellite instability (MSI). METHODS: We searched our institution's cancer registry for interval cancers, defined as colon cancers that developed within 5 years of a complete colonoscopy. These were frequency matched in a 1:2 ratio by age and sex to patients with noninterval cancers (defined as colon cancers diagnosed on a patient's first recorded colonoscopy). Archived cancer specimens for all subjects were retrieved and tested for MSI. RESULTS: Of the 993 colon cancers diagnosed during the study period, 51 (5.1%) were identified as an interval cancer, and 112 subjects with noninterval cancer served as a comparison group. Study subjects were almost all men. MSI was found in 30.4% of interval cancers compared with 10.3% of noninterval cancers (P = .003). After adjusting for age, interval cancers were 3.7 times more likely to show MSI than noninterval cancers (95% confidence interval, 1.5-9.1). This association was strongest for tumors located in the distal colon (odds ratio, 17.5; P = .008). No difference in TNM stage at diagnosis, histologic type or grade, or 5-year survival was found between groups. CONCLUSIONS: Interval colon cancers were almost 4 times as likely as noninterval colon cancers to be associated with mismatch repair gene dysfunction.

Aged↗
PubMed2005

Recent advances in epidemiology and prevention of gastrointestinal endoscopy related infections.

PURPOSE OF REVIEW: This article reviews recent publications relevant to endoscope reprocessing and the potential for transmission of infection during gastrointestinal endoscopy. RECENT FINDINGS: There have been a number of established reprocessing failures of gastrointestinal endoscopes at various healthcare facilities across the US resulting in patient notifications. These episodes have been associated with user errors and reprocessing equipment failures, highlighting the need for increased compliance with established guidelines. Surveillance cultures may be useful to monitor the outcome of reprocessing, although their use is controversial. New technology to allow point-of-use monitoring is promising. Biofilm accumulation may be an issue when reprocessing gastrointestinal endoscopes. Although peracetic acid has been promoted as superior to aldehyde-type liquid chemical germicides with regard to soil fixation, it may only be a modest improvement. Electrolyzed acid water is an emerging liquid chemical germicide that may be equivalent to currently accepted disinfectants. There appears to be no benefit to an additional reprocessing cycle before use for endoscopes that have been appropriately cleaned, disinfected, and stored. SUMMARY: With the recent media attention on gastrointestinal endoscope reprocessing failures, despite the absence of documented transmission of infection, increased compliance with existing guidelines and new initiatives to enhance endoscope reprocessing are increasingly important to maintain public confidence.

Biofilms↗
PubMed2003

Infection control during gastrointestinal endoscopy.

Infection-control issues during gastrointestinal endoscopy, which are becoming increasingly important, can generally be divided into three major areas: (1) infectious complications resulting from a patient's own microbial flora (autologous), (2) infections transmitted from patient to patient by way of the endoscope (exogenous), and (3) infections transmitted between the patient and the health-care provider. The mean frequency of postprocedure bacteremia ranges from 0.5% for flexible sigmoidoscopy to 2.2% for colonoscopy, 4.2% for esophagogastroduodenoscopy, 8.9% for variceal ligation, 11% for endoscopic retrograde cholangiopancreatography, 15.4% for variceal sclerotherapy, and 22.8% for esophageal dilation. Although postprocedure bacteremia is not uncommon, it seldom results in infectious complications. Exogenous infections transmitted during endoscopy, which are extremely rare, generally result from failure to follow accepted guidelines for the cleaning and disinfection of gastrointestinal endoscopes, underscoring the importance of meticulous attention to endoscope reprocessing. Finally, although the risk of patient-staff transmission of infection is also rare, standard infection-control recommendations are important in protecting both patients and health-care providers.

Antibiotic Prophylaxis↗