Ontario health technology assessment series
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This review considered the role of the anal Pap test as a screening test for anal dysplasia in patients at high risk of anal SCC. The screening process is now thought to be improved with the addition of testing for the human papillomavirus (HPV) in high-risk populations. High-resolution anoscopy (a method to view the rectal area, using an anoscope, a lighted instrument inserted into the rectum) rather than routine anoscopy-guided biopsy, is also now considered to be the diagnostic standard. ⋯ No direct evidence exists to support the effectiveness of an anal Pap test screening program to reduce anal cancer mortality or morbidity. There are, however, strong parallels with cervical pap testing for cervical cancer. Sexually transmitted HPV viral infection is currently the acknowledged common causative agent for both anal and cervical cancer. Anal cancer rates in high-risk populations are approaching those of cervical cancer before the implementation of Pap testing. The anal Pap test, although it has been mainly evaluated only in HIV-positive males, has similar operating characteristics of sensitivity and specificity as the cervical Pap test. In general, the treatment options for precancer dysplasia in the cervix and the anus are similar, but treatment involving a definitive surgical resection in the anus is more limited because of the higher risk of complications. A range of ablative therapies has been applied for anal dysplasia, but evidence on treatment effectiveness, tolerability and durability, particularly in the HIV-positive patient, is limited.
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Ont Health Technol Assess Ser · Jan 2007
Low-density lipoprotein apheresis: an evidence-based analysis.
To assess the effectiveness and safety of low-density lipoprotein (LDL) apheresis performed with the heparin-induced extracorporeal LDL precipitation (HELP) system for the treatment of patients with refractory homozygous (HMZ) and heterozygous (HTZ) familial hypercholesterolemia (FH). BACKGROUND ON FAMILIAL HYPERCHOLESTEROLEMIA: Familial hypercholesterolemia is a genetic autosomal dominant disorder that is caused by several mutations in the LDL-receptor gene. The reduced number or absence of functional LDL receptors results in impaired hepatic clearance of circulating low-density lipoprotein cholesterol (LDL-C) particles, which results in extremely high levels of LDL-C in the bloodstream. Familial hypercholesterolemia is characterized by excess LDL-C deposits in tendons and arterial walls, early onset of atherosclerotic disease, and premature cardiac death. Familial hypercholesterolemia occurs in both HTZ and HMZ forms. Heterozygous FH is one of the most common monogenic metabolic disorders in the general population, occurring in approximately 1 in 500 individuals. Nevertheless, HTZ FH is largely undiagnosed and an accurate diagnosis occurs in only about 15% of affected patients in Canada. Thus, it is estimated that there are approximately 3,800 diagnosed and 21,680 undiagnosed cases of HTZ FH in Ontario. In HTZ FH patients, half of the LDL receptors do not work properly or are absent, resulting in plasma LDL-C levels 2- to 3-fold higher than normal (range 7-15mmol/L or 300-500mg/dL). Most HTZ FH patients are not diagnosed until middle age when either they or one of their siblings present with symptomatic coronary artery disease (CAD). Without lipid-lowering treatment, 50% of males die before the age of 50 and 25% of females die before the age of 60, from myocardial infarction or sudden death. In contrast to the HTZ form, HMZ FH is rare (occurring in 1 case per million persons) and more severe, with a 6- to 8-fold elevation in plasma LDL-C levels (range 15-25mmol/L or 500-1000mg/dL). Homozygous FH patients are typically diagnosed in infancy, usually due to the presence of cholesterol deposits in the skin and tendons. The main complication of HMZ FH is supravalvular aortic stenosis, which is caused by cholesterol deposits on the aortic valve and in the ascending aorta. The average life expectancy of affected individuals is 23 to 25 years. In Ontario, it is estimated that there are 13 to 15 cases of HMZ FH. An Ontario clinical expert confirmed that 9 HMZ FH patients have been identified to date. ⋯ The search identified 398 articles published from January 1, 1998 to May 30, 2007. Eight studies met the inclusion criteria. Five case series, 2 case series nested within comparative studies, and one retrospective review, were included in the analysis. A health technology assessment conducted by the Alberta Heritage Foundation for Medical Research, and a review by the United States Food and Drug Administration were also included. Large heterogeneity among the studies was observed. Studies varied in inclusion criteria, baseline patient characteristics and methodology. Overall, the mean acute relative decrease in LDL-C with HELP LDL apheresis ranged from 53 to 77%. The mean acute relative reductions ranged as follows: total cholesterol (TC) 47 to 64%, HDL-C +0. (ABSTRACT TRUNCATED)
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Ont Health Technol Assess Ser · Jan 2007
Screening mammography for women aged 40 to 49 years at average risk for breast cancer: an evidence-based analysis.
The aim of this review was to determine the effectiveness of screening mammography in women aged 40 to 49 years at average risk for breast cancer. ⋯ There is Level 1 evidence that screening mammography in women aged 40 to 49 years at average risk for breast cancer is not effective in reducing mortality. Moreover, risks associated with exposure to mammographic radiation, the increased risk of missed cancers due to lower mammographic sensitivity, and the psychological impact of false positives, are not inconsequential. The UK Age Trial results published in December 2006 did not change these conclusions.