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Biomedical subjects

Theodore R Levin

Publications and source records attributed to Theodore R Levin.

28 records · Page 2Linked to original sources
PubMed2002

Flexible sigmoidoscopy for colorectal cancer screening: valid approach or short-sighted?

Flexible sigmoidoscopy is a safe, effective test that may be delivered feasibly on a large scale for mass colorectal cancer screening. Flexible sigmoidoscopy is 67% to 80% as sensitive as colonoscopy in a screening population, but is probably 10 to 20 times safer than colonoscopy in terms of complications. Several national guidelines recommend combining flexible sigmoidoscopy with fecal occult blood tests. There is limited evidence to support this practice, and the added benefit to an existing flexible sigmoidoscopy screening program although real, may be marginal. In the future, it is likely that flexible sigmoidoscopy screening among patients aged 50 to 65 will be supplemented with total colonic screening, using molecular-based fecal tests or virtual colonoscopy, after age 65.

Clinical Trials as Topic↗
PubMed2002

Flexible sigmoidoscopy: an important screening option for average-risk individuals.

Colorectal cancer screening techniques should be effective, acceptable to patients, affordable, widely available, and safe. For average-risk adults aged more than 50 years who do not have significant colorectal symptoms, significant family history, or significant predisposing conditions, flexible sigmoidoscopy is an important option for reducing the risk for colorectal cancer, meeting all criteria for an effective and feasible screening modality. This article discusses evidence supporting flexible sigmoidoscopy, practical issues in implementation, and current controversies.

Colonoscopy↗
PubMed2002

Surveillance and survival in Barrett's adenocarcinomas: a population-based study.

BACKGROUND & AIMS: Guidelines recommend periodic endoscopic surveillance of Barrett's esophagus (BE) patients to detect and treat early esophageal adenocarcinomas; however, no trials or population-based studies exist. We evaluated the association between endoscopic surveillance of BE and survival among esophageal/gastric cardia adenocarcinoma patients. METHODS: We studied a cohort of 23 BE patients, among 589 esophageal or gastric cardia adenocarcinoma patients diagnosed between 1990-1998 at Northern California Kaiser Permanente (a large health maintenance organization). We measured the presence of BE, detection of cancer by endoscopic surveillance, cancer stage, mortality, and potential confounders. RESULTS: BE was diagnosed in 135 of 589 adenocarcinoma patients, with 23 BE patients diagnosed greater than 6 months before cancer was diagnosed. Among these 23 patients, 73% of the surveillance-detected cancer patients (n = 15) were alive at the end of follow-up, compared with none of the patients without surveillance-detected cancers (n = 8; P = 0.001). All surveillance-detected cancer patients had low-stage disease and none died directly from cancer. The surveillance/survival association was not substantially altered by stratification for age at BE diagnosis or other potential confounders. CONCLUSIONS: Surveillance-detected BE-associated adenocarcinomas were associated with low-stage disease and improved survival. Additional studies are needed to evaluate potential biases and whether screening/surveillance programs decrease mortality among all patients in surveillance. Few patients (3.9%) had a BE diagnosed before their cancer. Thus, even if current surveillance techniques are effective, they are unlikely to substantially impact the population's mortality from esophageal cancer; better methods are needed to identify at risk patients.

Adenocarcinoma↗
PubMed2002

Hereditary nonpolyposis colorectal cancer in young colorectal cancer patients: high-risk clinic versus population-based registry.

BACKGROUND & AIMS: Early onset colorectal cancer (CRC) is an important feature of hereditary nonpolyposis colorectal cancer (HNPCC). We sought to compare rates of genetically defined HNPCC among individuals with early onset CRC drawn from a high-risk clinic and a population-based cancer registry. METHODS: Probands with CRC diagnosed before 36 years of age were enrolled from a high-risk CRC clinic at the University of California, San Francisco (UCSF), and a population-based Kaiser Permanente (KP) Health Plan cancer registry. Probands provided cancer family histories and tumors for microsatellite instability (MSI) testing and MSH2/MLH1 protein immunostaining. Germline MSH2 and MLH1 mutational analysis was performed. RESULTS: Forty-three probands were enrolled from UCSF and 23 from KP. The UCSF and KP probands had similar median age of onset of CRC (30 vs. 31 years) and the percentage with any personal or family history of another HNPCC-related cancer (70% vs. 74%). However, 28 of 40 (70%) of the UCSF tumors were MSI-H compared with 6 of 18 (33%) of KP tumors (P = 0.01), and 13 germline MSH2 or MLH1 mutations were found in the UCSF group compared with 0 in the KP group (P = 0.0001). In a multivariate analysis, institution (P = 0.002) and the total number of colorectal cancers in the family (P = 0.0001) were independent predictors of MSH2 or MLH1 mutation. CONCLUSIONS: Family history of cancer is an important feature of HNPCC, even among individuals with early onset CRC. Caution must be undertaken when extrapolating data regarding HNPCC from high-risk clinic populations to the general population.

Adaptor Proteins, Signal Transducing↗
PubMed2002

Complications of screening flexible sigmoidoscopy.

BACKGROUND & AIMS: Flexible sigmoidoscopy (FS) is recommended for mass screening for colorectal cancer (CRC), yet little is known about the risk of adverse events when FS is used in general clinical practice. We aimed to determine the incidence of gastrointestinal complications and acute myocardial infarction (MI) after screening FS. METHODS: Northern California Kaiser Permanente Medical Care Program members of average risk for CRC (n = 107,704) who underwent screening FS during 1994 to 1996 (109,534 FS), as part of the Colorectal Cancer Prevention (CoCaP) program. The main outcome measure was hospitalization for gastrointestinal complications or acute MI within 4 weeks of FS. RESULTS: The mean age of subjects was 61 years, and 48.8% were female. Nongastroenterologist physicians, nurses, or physician assistants performed 72% of FS. Overall, 24 persons were hospitalized for a gastrointestinal complication. Of these, 7 were serious (2 perforations, 2 episodes of diverticulitis requiring surgery, 2 cases of bleeding requiring transfusion, and 1 episode of unexplained colitis). In multivariate models, complications were significantly more common in men than in women (odds ratio, 3.34; 95% confidence interval [CI], 1.34-10.13). MI occurred in 33 persons within 4 weeks of FS, but the incidence for this period was similar to that in the subsequent 48 weeks (rate ratio, 0.8; 95% CI, 0.6-1.2). CONCLUSIONS: The risk of serious complications after screening FS in this setting appears to be modest. Although MI occurs after FS, the risk during the 4 weeks after the procedure appears to be similar to expectations for persons of screening age.

Aged↗
PubMedDate not supplied

Guidelines for colonoscopy surveillance after polypectomy: a consensus update by the US Multi-Society Task Force on Colorectal Cancer and the American Cancer Society.

Adenomatous polyps are the most common neoplastic findings uncovered in people who undergo colorectal screening or have a diagnostic workup for symptoms. It was common practice in the 1970s for these patients to have annual follow-up surveillance examinations to detect additional new adenomas as well as missed synchronous adenomas. As a result of the National Polyp Study report in 1993, which demonstrated clearly in a randomized design that the first postpolypectomy examination could be deferred for 3 years, guidelines published by a gastrointestinal consortium in 1997 recommended that the first follow-up surveillance be 3 years after polypectomy for most patients. In 2003, these guidelines were updated, colonoscopy was recommended as the only follow-up examination, and stratification at baseline into lower and higher risk for subsequent adenomas was suggested. The 1997 and 2003 guidelines dealt with both screening and surveillance. However, it has become increasingly clear that postpolypectomy surveillance is now a large part of endoscopic practice, draining resources from screening and diagnosis. In addition, surveys have demonstrated that a large proportion of endoscopists are conducting surveillance examinations at shorter intervals than recommended in the guidelines. In the present paper, a careful analytic approach was designed addressing all evidence available in the literature to delineate predictors of advanced pathology, both cancer and advanced adenomas, so that patients can be more definitely stratified at their baseline colonoscopy into those at lower or increased risk for a subsequent advanced neoplasia. People at increased risk have either three or more adenomas, or high-grade dysplasia, or villous features, or an adenoma > or =1 cm in size. It is recommended that they have a 3-year follow-up colonoscopy. People at lower risk who have one or two small (< 1 cm) tubular adenomas with no high-grade dysplasia can have a follow-up in 5 to 10 years, whereas people with hyperplastic polyps only should have a 10-year follow-up as average-risk people. Recent papers have reported a significant number of missed cancers by colonoscopy. However, high-quality baseline colonoscopy with excellent patient preparation and adequate withdrawal time should minimize this and reduce clinicians' concerns. These guidelines were developed jointly by the US Multi-Society Task Force on Colorectal Cancer and the American Cancer Society to provide a broader consensus and thereby increase utilization of the recommendations by endoscopists. Adoption of these guidelines nationally can have a dramatic impact on shifting available resources from intensive surveillance to screening. It has been shown that the first screening colonoscopy and polypectomy produces the greatest effects on reducing the incidence of colorectal cancer in patients with adenomatous polyps.

Adenomatous Polyps↗
PubMedDate not supplied

Guidelines for colonoscopy surveillance after cancer resection: a consensus update by the American Cancer Society and US Multi-Society Task Force on Colorectal Cancer.

Patients with resected colorectal cancer are at risk for recurrent cancer and metachronous neoplasms in the colon. This joint update of guidelines by the American Cancer Society (ACS) and US Multi-Society Task Force on Colorectal Cancer addresses only the use of endoscopy in the surveillance of these patients. Patients with endoscopically resected Stage I colorectal cancer, surgically resected Stage II and III cancers, and Stage IV cancer resected for cure (isolated hepatic or pulmonary metastasis) are candidates for endoscopic surveillance. The colorectum should be carefully cleared of synchronous neoplasia in the perioperative period. In nonobstructed colons, colonoscopy should be performed preoperatively. In obstructed colons, double contrast barium enema or computed tomography colonography should be done preoperatively, and colonoscopy should be performed 3 to 6 months after surgery. These steps complete the process of clearing synchronous disease. After clearing for synchronous disease, another colonoscopy should be performed in 1 year to look for metachronous lesions. This recommendation is based on reports of a high incidence of apparently metachronous second cancers in the first 2 years after resection. If the examination at 1 year is normal, then the interval before the next subsequent examination should be 3 years. If that colonoscopy is normal, then the interval before the next subsequent examination should be 5 years. Shorter intervals may be indicated by associated adenoma findings (see Postpolypectomy Surveillance Guideline). Shorter intervals are also indicated if the patient's age, family history, or tumor testing indicate definite or probable hereditary nonpolyposis colorectal cancer. Patients undergoing low anterior resection of rectal cancer generally have higher rates of local cancer recurrence, compared with those with colon cancer. Although effectiveness is not proven, performance of endoscopic ultrasound or flexible sigmoidoscopy at 3- to 6-month intervals for the first 2 years after resection can be considered for the purpose of detecting a surgically curable recurrence of the original rectal cancer.

American Cancer Society↗