George F. Sawaya

Screening for colorectal cancer: U.S. Preventive Services Task Force recommendation statement.

DESCRIPTION Update of the 2002 U.S. Preventive Services Task Force (USPSTF) recommendation statement on screening for colorectal cancer. METHODS To update its recommendation, the USPSTF commissioned 2 studies: 1) a targeted systematic evidence review on 4 selected questions relating to test characteristics and benefits and harms of screening technologies, and 2) a decision analytic modeling analysis using population modeling techniques to compare the expected health outcomes and resource requirements of available screening modalities when used in a programmatic way over time. RECOMMENDATIONS The USPSTF recommends screening for colorectal cancer using fecal occult blood testing, sigmoidoscopy, or colonoscopy in adults, beginning at age 50 years and continuing until age 75 years. The risks and benefits of these screening methods vary. (A recommendation). The USPSTF recommends against routine screening for colorectal cancer in adults 76 to 85 years of age. There may be considerations that support colorectal cancer screening in an individual patient. (C recommendation). The USPSTF recommends against screening for colorectal cancer in adults older than age 85 years. (D recommendation). The USPSTF concludes that the evidence is insufficient to assess the benefits and harms of computed tomographic colonography and fecal DNA testing as screening modalities for colorectal cancer. (I statement).

Aspirin for the Prevention of Cardiovascular Disease: U.S. Preventive Services Task Force Recommendation Statement

DESCRIPTION Update of the 2002 U.S. Preventive Services Task Force (USPSTF) recommendation about the use of aspirin for the prevention of coronary heart disease. METHODS Review of the literature since 2002, focusing on new evidence on the benefits and harms of aspirin for the primary prevention of cardiovascular disease, including myocardial infarction and stroke. The new evidence was reviewed and synthesized according to sex. RECOMMENDATIONS Encourage men age 45 to 79 years to use aspirin when the potential benefit of a reduction in myocardial infarctions outweighs the potential harm of an increase in gastrointestinal hemorrhage. (A recommendation) Encourage women age 55 to 79 years to use aspirin when the potential benefit of a reduction in ischemic strokes outweighs the potential harm of an increase in gastrointestinal hemorrhage. (A recommendation) Evidence is insufficient to assess the balance of benefits and harms of aspirin for cardiovascular disease prevention in men and women 80 years or older. (I statement) Do not encourage aspirin use for cardiovascular disease prevention in women younger than 55 years and in men younger than 45 years. (D recommendation).

Hysterectomy and urinary incontinence: a systematic review

BACKGROUND Serious complications after hysterectomy are estimated to occur in around six women per 10,000 hysterectomies in the USA. We did a systematic review of evidence that hysterectomy is associated with urinary incontinence. METHODS We identified English-language and non-English-language articles registered on MEDLINE from January, 1966, to December, 1997, did manual review of references, and consulted specialists. We identified 45 articles reporting on the association of urinary incontinence and hysterectomy. We selected reports that presented original data on development of incontinence in women who underwent hysterectomy compared with those who did not. Results were abstracted by two independent reviewers and summarised with a random-effects model. FINDINGS 12 papers met our selection criteria--eight cross-sectional studies, two prospective cohort studies, one case-control study, and one randomised controlled trial. The summary estimate was consistent with increased odds for incontinence in women with hysterectomy. Because incontinence might not develop for many years after hysterectomy, we stratified the findings by age at assessment of incontinence. Among women who were 60 years or older, the summary odds ratio for urinary incontinence was increased by 60% (1.6 [95% CI 1.4-1.8]) but odds were not increased for women younger than 60 years. INTERPRETATION When women are counselled about sequelae of hysterectomy, practitioners should discuss the possibility of an increased likelihood of incontinence in later life.

Screening for chlamydial infection: U.S. Preventive Services Task Force recommendation statement

The U.S. Preventive Services Task Force (USPSTF) makes recommendations about preventive care services for patients without recognized signs or symptoms of the target condition. The USPSTF bases its recommendations on a systematic review of the evidence of the benefits and harms and an assessment of the net benefit of the service. The USPSTF recognizes that clinical or policy decisions involve more considerations than this body of evidence alone. Clinicians and policymakers should understand the evidence but individualize decision making to the specific patient or situation. Summary of Recommendation and Evidence The USPSTF recommends screening for chlamydial infection for all sexually active nonpregnant young women age 24 years or younger and older nonpregnant women who are at increased risk (Figure). This is a grade A recommendation. The USPSTF recommends screening for chlamydial infection for all pregnant women age 24 years or younger and for older pregnant women who are at increased risk (Figure). This is a grade B recommendation. The USPSTF recommends against routinely screening for chlamydial infection for women age 25 years or older, regardless of whether they are pregnant, if they are not at increased risk (Figure). This is a grade C recommendation. The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of screening for chlamydial infection for men (Figure). This is an I statement. See Table 1 for a description of the USPSTF grades and Table 2 for a description of the USPSTF classification of levels of certainty regarding net benefit. Both are also available at www.annals.org. Figure. Screening for chlamydial infection. For a summary of the evidence systematically reviewed in making these recommendations, the full recommendation statement, and supporting documents, please go to www.preventiveservices.ahrq.gov. *Chlamydial infection results in few sequelae in men. Therefore, the major benefit of screening men would be to reduce the likelihood that infected and untreated men would pass the infection to sexual partners. There is no evidence that screening men reduces the long-term consequences of chlamydial infection in women. Because of this lack of evidence, the USPSTF could not assess the balance of benefits and harms and concluded that the evidence is insufficient to recommend for or against routinely screening men. Information from reference 1. Table 1. What the U.S. Preventive Services Task Force Grades Mean and Suggestions for Practice* Table 2. U.S. Preventive Services Task Force Levels of Certainty Regarding Net Benefit See the Clinical Considerations section for discussion of assessing risk for chlamydial infection in women and suggestions for practice regarding screening for men. Rationale Importance Chlamydial infection is the most common sexually transmitted bacterial infection in the United States. In women, genital chlamydial infection may result in urethritis, cervicitis, pelvic inflammatory disease (PID), infertility, ectopic pregnancy, and chronic pelvic pain. Chlamydial infection during pregnancy is related to adverse pregnancy outcomes, including miscarriage, premature rupture of membranes, preterm labor, low birth weight, and infant mortality. Detection The USPSTF found fair evidence that nucleic acid amplification tests (NAATs) can identify chlamydial infection in asymptomatic men and women, including asymptomatic pregnant women, with high test specificity. In low-prevalence populations, however, a positive test result is more likely to be false positive than true positive, even with the most accurate tests available. Benefits of Detection and Early Intervention Nonpregnant Women at Increased Risk There is good evidence that screening for chlamydial infection in nonpregnant women who are at increased risk can reduce the incidence of PID. The USPSTF concluded that the benefits of screening nonpregnant women at increased risk are substantial. Pregnant Women at Increased Risk There are no studies evaluating the effectiveness of screening for chlamydial infection in pregnant women who are at increased risk. The USPSTF, however, found that 1) screening identifies infection in asymptomatic pregnant women, 2) there is a relatively high prevalence of infection among pregnant women who are at increased risk, and 3) there is fair evidence of improved pregnancy and birth outcomes for women who are treated for chlamydial infection. The USPSTF concluded that the benefits of screening pregnant women who are at increased risk are substantial. Women Not at Increased Risk The USPSTF identified no studies documenting the benefits of screening women, including pregnant women, who are not at increased risk for chlamydial infection. While recognizing the potential benefit to women identified through screening, the USPSTF concluded that the overall benefit of screening would be small, given the low prevalence of infection among women not at increased risk. Men While concluding that the direct benefit of screening in men was likely to be small, the USPSTF noted that screening for chlamydial infection in men may be beneficial if it were to lead to a decreased incidence of chlamydial infection in women. The USPSTF did not, however, find evidence to support this outcome and therefore concluded that the benefits of screening men are unknown. The USPSTF identified this as a critical gap in the evidence. Harms of Detection and Early Treatment The USPSTF concluded that the harms of screening for chlamydial infection are small, although few studies have been published on this subject. Potential harms include anxiety and relationship problems arising from false-positive results and overtreatment. The USPSTF identified the lack of evidence related to potential harms of screening as a gap in the evidence.The USPSTF reached the following conclusions: For nonpregnant women at increased risk, the certainty is high that the benefits of screening for chlamydial infection substantially outweigh the harms. This is a grade A recommendation. For pregnant women at increased risk, the certainty is moderate that the benefits substantially outweigh the harms of screening for chlamydial infection. This is a grade B recommendation. For women not at increased risk (including pregnant women not at increased risk), the certainty is moderate that the benefits outweigh the harms of screening to only a small degree. There may be considerations that support screening an individual patient. This is a grade C recommendation. For men, the benefits of screening are not known; thus, the USPSTF could not determine the balance of benefits and harms of screening men for chlamydial infection. This is an I statement. Clinical Considerations Patient Population under Consideration These recommendations target all sexually active individuals, including adolescents and pregnant women. Assessment of Risk All sexually active women 24 years of age or younger, including adolescents, are at increased risk for chlamydial infection. In addition to sexual activity and age, other risk factors for chlamydial infection include a history of chlamydial or other sexually transmitted infection, new or multiple sexual partners, inconsistent condom use, and exchanging sex for money or drugs. Risk factors for pregnant women are the same as for nonpregnant women. Prevalence of chlamydial infection varies widely among patient populations. African-American and Hispanic women have a higher prevalence of infection than the general population in many communities and settings. Among men and women, increased prevalence rates are also found in incarcerated populations, military recruits, and patients at public sexually transmitted infection clinics. Screening Tests Nucleic acid amplification tests have high specificity and sensitivity when used as screening tests for chlamydial infection. Nucleic acid amplification tests can be used with urine and vaginal swabs, enabling screening when a pelvic examination is not performed. Treatment Appropriate treatment of chlamydial infection has been outlined by the Centers for Disease Control and Prevention (CDC) (www.cdc.gov/std/treatment). In its 2006 sexually transmitted disease treatment guidelines, the CDC recommends that chlamydia infection be treated with 1 g of azithromycin in a single oral dose or with oral doxycycline, 100 mg twice daily for 7 days. Pregnant women with chlamydial infection may be treated with 1 g of azithromycin in a single oral dose or amoxicillin, 500 mg orally 3 times daily for 7 days (1). Because the CDC updates these recommendations regularly, clinicians are encouraged to access the CDC Web site (www.cdc.gov/std/treatment) to obtain the most up-to-date information. To prevent recurrent transmission, clinicians should ensure that all sexual partners of infected individuals are tested and treated if infected, or treated presumptively. Screening Intervals Screening pregnant women who are at increased risk for chlamydial infection is recommended at the first prenatal visit. For pregnant women who remain at increased risk and for those who acquire a new risk factor, such as a new sexual partner, a screening should be conducted during the third trimester. The optimal interval for screening for nonpregnant women is unknown. The CDC recommends at least annual screening for women at increased risk (1). Suggestions for Practice with regard to Insufficient Evidence on Screening in Men The USPSTF concluded that the evidence is insufficient to determine the balance of benefits and harms related to screening men for chlamydial infection. Specifically, the USPSTF did not find evidence that screening programs that target men result in a decreased incidence of infection in women. The USPSTF notes that programs that screen men as a means of reducing transmission to women are not common practice, that primary care clinicians can institute screening in men, that the costs of ad

Screening and Treatment for Major Depressive Disorder in Children and Adolescents: US Preventive Services Task Force Recommendation Statement

DESCRIPTION. This is an update of the 2002 US Preventive Services Task Force recommendation on screening for child and adolescent major depressive disorder. METHODS. The US Preventive Services Task Force weighed the benefits and harms of screening and treatment for major depressive disorder in children and adolescents, incorporating new evidence addressing gaps in the 2002 recommendation statement. Evidence examined included the benefits and harms of screening, the accuracy of primary care–feasible screening tests, and the benefits and risks of treating depression by using psychotherapy and/or medications in patients aged 7 to 18 years. RECOMMENDATIONS. Screen adolescents (12–18 years of age) for major depressive disorder when systems are in place to ensure accurate diagnosis, psychotherapy (cognitive-behavioral or interpersonal), and follow-up (B recommendation). Evidence is insufficient to warrant a recommendation to screen children (7–11 years of age) for major depressive disorder (I statement).

Using nontraditional risk factors in coronary heart disease risk assessment: U.S. Preventive Services Task Force recommendation statement.

DESCRIPTION New recommendation from the U.S. Preventive Services Task Force (USPSTF) on the use of nontraditional, or novel, risk factors in assessing the coronary heart disease (CHD) risk of asymptomatic persons. METHODS Systematic reviews were conducted of literature since 1996 on 9 proposed nontraditional markers of CHD risk: high-sensitivity C-reactive protein, ankle-brachial index, leukocyte count, fasting blood glucose, periodontal disease, carotid intima-media thickness, coronary artery calcification score on electron-beam computed tomography, homocysteine, and lipoprotein(a). The reviews followed a hierarchical approach aimed at determining which factors could practically and definitively reassign persons assessed as intermediate-risk according to their Framingham score to either a high-risk or low-risk strata, and thereby improve outcomes by means of aggressive risk-factor modification in those newly assigned to the high-risk stratum. RECOMMENDATION The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of using the nontraditional risk factors studied to screen asymptomatic men and women with no history of CHD to prevent CHD events. (I statement).

Screening for Colorectal Cancer: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

IMPORTANCE Colorectal cancer (CRC) remains a significant cause of morbidity and mortality in the United States. OBJECTIVE To systematically review the effectiveness, diagnostic accuracy, and harms of screening for CRC. DATA SOURCES Searches of MEDLINE, PubMed, and the Cochrane Central Register of Controlled Trials for relevant studies published from January 1, 2008, through December 31, 2014, with surveillance through February 23, 2016. STUDY SELECTION English-language studies conducted in asymptomatic populations at general risk of CRC. DATA EXTRACTION AND SYNTHESIS Two reviewers independently appraised the articles and extracted relevant study data from fair- or good-quality studies. Random-effects meta-analyses were conducted. MAIN OUTCOMES AND MEASURES Colorectal cancer incidence and mortality, test accuracy in detecting CRC or adenomas, and serious adverse events. RESULTS Four pragmatic randomized clinical trials (RCTs) evaluating 1-time or 2-time flexible sigmoidoscopy (n = 458,002) were associated with decreased CRC-specific mortality compared with no screening (incidence rate ratio, 0.73; 95% CI, 0.66-0.82). Five RCTs with multiple rounds of biennial screening with guaiac-based fecal occult blood testing (n = 419,966) showed reduced CRC-specific mortality (relative risk [RR], 0.91; 95% CI, 0.84-0.98, at 19.5 years to RR, 0.78; 95% CI, 0.65-0.93, at 30 years). Seven studies of computed tomographic colonography (CTC) with bowel preparation demonstrated per-person sensitivity and specificity to detect adenomas 6 mm and larger comparable with colonoscopy (sensitivity from 73% [95% CI, 58%-84%] to 98% [95% CI, 91%-100%]; specificity from 89% [95% CI, 84%-93%] to 91% [95% CI, 88%-93%]); variability and imprecision may be due to differences in study designs or CTC protocols. Sensitivity of colonoscopy to detect adenomas 6 mm or larger ranged from 75% (95% CI, 63%-84%) to 93% (95% CI, 88%-96%). On the basis of a single stool specimen, the most commonly evaluated families of fecal immunochemical tests (FITs) demonstrated good sensitivity (range, 73%-88%) and specificity (range, 90%-96%). One study (n = 9989) found that FIT plus stool DNA test had better sensitivity in detecting CRC than FIT alone (92%) but lower specificity (84%). Serious adverse events from colonoscopy in asymptomatic persons included perforations (4/10,000 procedures, 95% CI, 2-5 in 10,000) and major bleeds (8/10,000 procedures, 95% CI, 5-14 in 10,000). Computed tomographic colonography may have harms resulting from low-dose ionizing radiation exposure or identification of extracolonic findings. CONCLUSIONS AND RELEVANCE Colonoscopy, flexible sigmoidoscopy, CTC, and stool tests have differing levels of evidence to support their use, ability to detect cancer and precursor lesions, and risk of serious adverse events in average-risk adults. Although CRC screening has a large body of supporting evidence, additional research is still needed.

Update on the Methods of the U.S. Preventive Services Task Force: Estimating Certainty and Magnitude of Net Benefit

The major goal of the U.S. Preventive Services Task Force (USPSTF) is to provide clinicians and policymakers with a reliable and accurate source of evidence-based recommendations on a wide range of preventive services. To accomplish this goal, the USPSTF systematically reviews the evidence concerning both the benefits and harms of widespread implementation of a preventive service. It then assesses the certainty of the evidence and the magnitude of the benefits and harms. On the basis of this assessment, the USPSTF assigns a letter grade to each preventive service signifying its recommendation about provision of the service (Table 1). Table 1. U.S. Preventive Services Task Force Recommendation Grid* An important, but often challenging, step is determining the balance between benefits and harms to estimate net benefit (that is, benefits minus harms). In this issue, the Task Force reports an update to its recommendation for carotid artery stenosis screening (1, 2). Because carotid artery stenosis screening has both known benefits and harms, estimating net benefit was critical in the final USPSTF recommendation that clinicians not provide carotid artery stenosis screening in asymptomatic people (recommendation letter grade D). Release of this recommendation provides an opportunity for the Task Force to update and explain to a clinical audience the process by which it evaluates evidence, determines the certainty and magnitude of net benefit, and gives a letter grade to the recommendation. We will do this by considering 3 questions: 1) What evidence does the Task Force consider to estimate net benefit? 2) How does the Task Force estimate the certainty of net benefit? and 3) How does the Task Force estimate the magnitude of net benefit? What Evidence Does the Task Force Consider to Estimate Net Benefit? The overarching question that the Task Force seeks to answer for every preventive service is whether evidence suggests that provision of the service would improve health outcomes if implemented in a general primary care population. For screening topics, this standard could be met by a large randomized, controlled trial (RCT) in a representative asymptomatic population with follow-up of all members of both the group invited for screening and the group not invited for screening. For example, the Multicentre Aneurysm Screening Study (3) was a population-based RCT of screening for abdominal aortic aneurysm in which 67800 asymptomatic men age 65 to 74 years in the United Kingdom were randomly assigned to be invited or not to be invited for screening. Both groups were followed for a mean of 4.1 years, and abdominal aortic aneurysmrelated mortality and all-cause mortality were compared. No RCTs of carotid artery stenosis screening have been published; however, RCTs comparing carotid endarterectomy to medical management of asymptomatic carotid artery stenosis are available. The distinction between RCTs that randomly assign people to undergo screening versus RCTs that randomly assign people known to have a condition to an intervention is important. In contrast to the latter, RCTs of screening take into account the false-positive and false-negative rates of the screening test, the possibility of adverse events from the test, the accuracy and potential for adverse events of any subsequent confirmatory diagnostic tests, and the inevitable failure to follow through on the test or any subsequent steps needed before the therapeutic intervention is delivered. In addition, conditions detected by screening may have different biological characteristics than those detected in other ways. The benefits of treating screened individuals, therefore, cannot be assumed to be the same as those of treating symptomatic individuals. Screening trials directly answer a simple question important to the primary care setting: Does screening for a certain condition improve health outcomes? Direct RCT evidence about screening is often unavailable, so the Task Force considers indirect evidence. To guide its selection of indirect evidence, the Task Force constructs a chain of evidence within an analytic framework. Figure 1 of the evidence update (2) in this issue (page 861) shows the analytic framework for the Task Force assessment of carotid artery stenosis screening. Each arrow in the framework defines a key question, and each key question represents a link in the chain of evidence. Rectangles in the framework represent the intermediate outcomes (rounded corners) or the health outcomes (square corners); ovals represent harms. To form an unbroken chain, evidence must support each link in the chain, thereby connecting the target population (far left side of the framework) to the improved health outcome (far right side of the framework). For each key question, the body of pertinent literature is critically appraised, focusing on 6 questions (Table 2). The USPSTF will now describe its judgment about the evidence for each key question as convincing, adequate, or inadequate. Evidence may be considered convincing when derived from several high-quality studies with consistent, logical results that are generalizable to the U.S. primary care population and setting. Evidence may be deemed adequate when, on the basis of judgment, most but not all of these 6 questions are answered favorably. When evidence is conflicting or the studies are of poor quality individually or in aggregate, the evidence for a key question is considered inadequate. Inadequate evidence may create a critical gap in the evidence chain. Table 2. Questions Considered by the U.S. Preventive Services Task Force for Evaluating Evidence Related Both to Key Questions and to the Overall Certainty of the Evidence of Net Benefit for the Preventive Service How Does the Task Force Estimate the Certainty of Net Benefit? The next step in the Task Force process is to use the evidence from the key questions to assess whether there would be net benefit if the service were implemented. In 2001, the USPSTF published an article that documented its systematic processes of evidence evaluation and recommendation development (4). At that time, the Task Forces overall assessment of evidence was described as good, fair, or poor. The Task Force realized that this rating seemed to apply only to how well studies were conducted and did not fully capture all of the issues that go into an overall assessment of the evidence about net benefit. To avoid confusion, the USPSTF has changed its terminology. Whereas individual study quality will continue to be characterized as good, fair, or poor, the term certainty will now be used to describe the Task Forces assessment of the overall body of evidence about net benefit of a preventive service and the likelihood that the assessment is correct. Certainty will be determined by considering all 6 questions in Table 2; the judgment about certainty will be described as high, moderate, or low. In making its assessment of certainty about net benefit, the evaluation of the evidence from each key question plays a primary role. It is important to note that the Task Force makes recommendations for real-world medical practice in the United States and must determine to what extent the evidence for each key questioneven evidence from screening RCTs or treatment RCTscan be applied to the general primary care population. Frequently, studies are conducted in highly selected populations under special conditions. The Task Force must consider differences between the general primary care population and the populations studied in RCTs and make judgments about the likelihood of observing the same effect in actual practice. For carotid artery stenosis screening, the Task Force searched for evidence about the true prevalence of high-grade carotid artery stenosis in the general population, the generalizability of treatment effectiveness estimates based on RCTs conducted in selected populations, and the complication rate from carotid endarterectomy in asymptomatic individuals if performed in nontrial settings (for example, community hospitals). It is also important to note that 1 of the key questions in the analytic framework refers to the potential harms of the preventive service. The Task Force considers the evidence about the benefits and harms of preventive services separately and equally. Data about harms are often obtained from observational studies because harms observed in RCTs may not be representative of those found in usual practice and because some harms are not completely measured and reported in RCTs. For example, the surgeons who enrolled patients in RCTs of carotid artery stenosis were selected on the basis of their low postoperative stroke and mortality rates. Widespread screening for carotid artery stenosis would invariably lead to surgical treatment provided in hospitals (or by surgeons) with higher rates of complications. The harms of screening for carotid artery stenosis, including the harms from carotid angiography to confirm the diagnosis of carotid artery stenosis in patients screening positive by carotid ultrasonography, were not captured in some treatment RCTs. Putting the body of evidence for all key questions together as a chain, the Task Force assesses the certainty of net benefit of a preventive service by asking the 6 major questions in Table 2. The Task Force would rate a body of convincing evidence about the benefits of a service that, for example, derives from several RCTs of screening in which the estimate of benefits can be generalized to the general primary care population as high certainty (Table 3). The Task Force would rate a body of evidence that was not clearly applicable to general practice or has other defects in quality, research design, or consistency of studies as moderate certainty. Certainty is low when, for example, there are gaps in the evidence linking parts of the analytic framework, when evidence to determine the harms of treatment is unavailable, or when

Screening for type 2 diabetes mellitus in adults: U.S. preventive services task force recommendation statement

DESCRIPTION Updated U.S. Preventive Services Task Force (USPSTF) recommendation about screening for type 2 diabetes mellitus in adults. METHODS To estimate the balance of benefits and harms of screening, the USPSTF updated its 2003 evidence review, adding evidence from new trials as well as updates on earlier studies. The review for this current recommendation focused on evidence that early treatment prevented long-term adverse outcomes of diabetes, including cardiovascular events, visual impairment, renal failure, and amputation. RECOMMENDATIONS Screen for type 2 diabetes in asymptomatic adults with sustained blood pressure (either treated or untreated) greater than 135/80 mm Hg. (B recommendation) Current evidence is insufficient to assess the balance of benefits and harms of routine screening in asymptomatic adults with blood pressure of 135/80 mm Hg or lower. (I statement).

Cervical Intraepithelial Neoplasia Outcomes After Treatment: Long-term Follow-up From the British Columbia Cohort Study

BACKGROUND Information on the long-term risk of cervical intraepithelial neoplasia (CIN) recurrence among women treated for CIN is limited yet critical for evidence-based surveillance recommendations. METHODS We retrospectively identified 37,142 women treated for CIN 1, 2, or 3 from January 1, 1986, through December 31, 2000 (CIN cohort), from the British Columbia Cancer Agency cytology database and linked their records with cancer registry and vital statistics data. Treatment included cryotherapy, loop electrosurgical excision procedure, cone biopsy, and laser vaporization or excision. A comparison cohort contained 71,213 women with normal cytology and no previous CIN diagnosis. Follow-up continued through December 31, 2004. Among women in both cohorts under active surveillance, we compared rates of CIN 2 or 3 (CIN 2/3) and cervical cancer. Cumulative incidence rates of CIN 2/3 and 95% confidence intervals (CIs) were estimated by a life table approach by using annual rates. Cumulative rates of invasive cancer were examined by the person-years method. RESULTS Overall observed cumulative rates of CIN 2/3 in the first 6 years after treatment were 14.0% (95% CI = 13.84% to 14.15%) for women originally treated for CIN 3, 9.3% (95% CI = 9.09% to 9.42%) for CIN 2, and 5.6% (95% CI = 4.91% to 5.21%) for CIN 1. Annual rates of CIN 2/3 were less than 1% after 6 years. Initial diagnosis, age, and treatment type were associated with a diagnosis of CIN 2/3 after treatment, with 6-year adjusted rates for women aged 40-49 years ranging from 2.6% (95% CI = 1.9% to 3.4%) for treatment of CIN 1 with the loop electrosurgical excision procedure to 34.0% (95% CI = 30.9% to 37.1%) for treatment of CIN 3 with cryotherapy. Overall incidence of invasive cancer (per 100,000 woman-years) was higher in the CIN cohort (37 invasive cancers, 95% CI = 30.6 to 42.5 cancers) than in the comparison cohort (six cancers, 95% CI = 4.3 to 7.7 cancers). Cryotherapy, compared with other treatments, was associated with the highest rate of subsequent disease (adjusted odds ratio for invasive cancer = 2.98, 95% CI = 2.09 to 4.60). CONCLUSION Risk of CIN 2/3 after treatment was associated with initial CIN grade, treatment type, and age. Long-term risk of invasive cancer remained higher among women treated for CIN, particularly those treated with cryotherapy.