A cost-effectiveness analysis of cervical cancer screening: health policy implications

Cervical cancer screening with AMIGAS: a cost-effectiveness analysis

BACKGROUND

Hispanic women have a higher incidence of cervical cancer than all other races and ethnicities. In Hispanic subgroups, Mexican American women were among the least likely to have received cervical cancer screening. In a recent RCT, Ayudando a las Mujeres con Información, Guia, y Amor para su Salud (AMIGAS) was shown to increase cervical cancer screening rates among women of Mexican descent at 6 months in all intervention arms compared to the control arm. Limited information exists about the economics of interventions to increase cervical cancer screening rates among women of Mexican descent.

PURPOSE

This study aims to estimate the cost-effectiveness of the alternative AMIGAS intervention methods for increasing cervical cancer screening among low-income women of Mexican descent in three U.S. communities.

METHODS

Cost data were collected from 2008 to 2011 alongside the AMIGAS study of 613 women. Receipt of Pap test within 6 months of intervention was the primary outcome measure in the cost-effectiveness analysis, conducted during 2012-2013.

RESULTS

The cost per additional woman screened comparing the video-only intervention to usual care was $980. The cost increased to $1,309 with participant time cost included. With an additional cost per participant of $3.90 compared to flipchart only, the full AMIGAS program (video plus flipchart) yielded 6.8% additional women screened.

CONCLUSIONS

Results on the average and incremental cost-effectiveness of the AMIGAS program elements may assist health policymakers and program managers to select and appropriately budget for interventions shown to increase cervical cancer screening among low-income women of Mexican descent.

The value of improving failures within a cervical cancer screening program: an example from Norway

Failures in cervical cancer (CC) screening include nonparticipation, underscreening and loss to follow-up of abnormal results. We estimated the long-term health benefits from and maximum investments in interventions targeted to improving compliance to guidelines while remaining cost-effective. We used a mathematical model empirically calibrated to simulate the natural history of CC in Norway. A baseline scenario reflecting current practice using cytology-based screening was compared to scenarios that target different sources of noncompliance: (i) failure to follow-up women with abnormal results, (ii) screening less frequently than recommended (i.e., underscreening) and (iii) absence of screening. A secondary analysis included human papillomavirus (HPV)-based screening as the primary test. Model outcomes included reductions in lifetime cancer risk and incremental net monetary benefit (INMB) resulting from improvements with compliance. Compared to the status quo, improving all sources of noncompliance leads to important health gains and produced positive INMBs across a range of developed-country willingness-to-pay (WTP) thresholds. For example, a 2% increase in compliance could reduce lifetime cancer risk by 1-3%, depending on the targeted source of noncompliance and primary screening method. Assuming a WTP threshold of $83,000 per year of life saved and cytology-based screening, interventions that increase follow-up of abnormal results yielded the highest INMB per 2% increase in coverage [$19 ($10-21)]. With HPV-based screening, recruiting nonscreeners resulted in the largest INMB [$23 ($18-32)]. Considerable funds could be allocated toward policies that improve compliance with screening under the current cytology-based program or toward adoption of primary HPV-based screening while remaining cost-effective.

Cancer screening in people who have chronic disease: the example of kidney disease

Cancer screening in people with chronic illness has been the subject of considerable debate recently. Despite the increased incidence of cancer and higher risk of cancer deaths in selected populations, such as those with kidney disease, the benefits-to-harms ratio of cancer screening is uncertain and is likely to be different to people without chronic illnesses because of the expected higher competing risk of death from disease other than cancer, and a higher risk of complications associated with the screening, the diagnostic, and the treatment processes. Using kidney disease as an example, the authors reviewed the current evidence for early cancer detection through screening in people with two or more coexistent chronic diseases, discussed the accepted principles underpinning cancer screening, and the applicability of these concepts to individuals with chronic disease. This review suggests that future research that evaluates the screening test accuracy, quality of life of having cancer, and cancer treatment effectiveness, targeting those with chronic illnesses are necessary for the development of an effective, safe, and acceptable cancer screening program among people with two or more chronic diseases.

Modeling screening, prevention, and delaying of Alzheimer's disease: an early-stage decision analytic model

Background

Alzheimer's Disease (AD) affects a growing proportion of the population each year. Novel therapies on the horizon may slow the progress of AD symptoms and avoid cases altogether. Initiating treatment for the underlying pathology of AD would ideally be based on biomarker screening tools identifying pre-symptomatic individuals. Early-stage modeling provides estimates of potential outcomes and informs policy development.

Methods

A time-to-event (TTE) simulation provided estimates of screening asymptomatic patients in the general population age ≥55 and treatment impact on the number of patients reaching AD. Patients were followed from AD screen until all-cause death. Baseline sensitivity and specificity were 0.87 and 0.78, with treatment on positive screen. Treatment slowed progression by 50%. Events were scheduled using literature-based age-dependent incidences of AD and death.

Results

The base case results indicated increased AD free years (AD-FYs) through delays in onset and a reduction of 20 AD cases per 1000 screened individuals. Patients completely avoiding AD accounted for 61% of the incremental AD-FYs gained. Total years of treatment per 1000 screened patients was 2,611. The number-needed-to-screen was 51 and the number-needed-to-treat was 12 to avoid one case of AD. One-way sensitivity analysis indicated that duration of screening sensitivity and rescreen interval impact AD-FYs the most. A two-way sensitivity analysis found that for a test with an extended duration of sensitivity (15 years) the number of AD cases avoided was 6,000-7,000 cases for a test with higher sensitivity and specificity (0.90,0.90).

Conclusions

This study yielded valuable parameter range estimates at an early stage in the study of screening for AD. Analysis identified duration of screening sensitivity as a key variable that may be unavailable from clinical trials.

The health and economic impact of cervical cancer screening and human papillomavirus vaccination in kidney transplant recipients

BACKGROUND

The risk of cervical cancer in women who are kidney transplant recipients is increased, but little is known about the effectiveness of screening and human papillomavirus (HPV) vaccination in this group of women. We sought to determine the cost effectiveness of annual screening for cervical cancers using conventional cytology, liquid-based cytology (LBC), and pretransplant HPV vaccination in kidney transplant recipients.

METHODS

Three deterministic Markov models were developed to compare the costs and health outcomes in a cohort of women (n=1000) with kidney transplants aged 18 to 69 who underwent annual screening using conventional cytology, LBC, and HPV vaccination in HPV naïve women.

RESULTS

After a screening period of 50 years, the incremental benefits of screening using conventional cytology compared with no screening were 0.05 life years saved (LYS) (18.2 days of lives saved), the incremental costs were $608, giving an incremental cost-effectiveness ratio of $12,160 per LYS. Compared with conventional cytology alone, the incremental cost-effectiveness ratios of annual screening using LBC and HPV vaccination before transplantation (assuming nonwaning efficacy) were $127,000 and $152,333 per LYS, respectively.

CONCLUSION

The recommended policy of annual screening using conventional cytology is cost effective. The replacement of conventional cytology with LBC is likely to provide minimal survival benefits but considerable costs. Assuming the reported trial-based vaccine efficacy in HPV naïve women, a program of HPV vaccination before kidney transplantation is unlikely to be cost effective. Additional data about the long-term efficacy and safety of HPV vaccination is required before it should be included as standard care of renal transplant recipients.

Calibration methods used in cancer simulation models and suggested reporting guidelines

Increasingly, computer simulation models are used for economic and policy evaluation in cancer prevention and control. A model's predictions of key outcomes, such as screening effectiveness, depend on the values of unobservable natural history parameters. Calibration is the process of determining the values of unobservable parameters by constraining model output to replicate observed data. Because there are many approaches for model calibration and little consensus on best practices, we surveyed the literature to catalogue the use and reporting of these methods in cancer simulation models. We conducted a MEDLINE search (1980 through 2006) for articles on cancer-screening models and supplemented search results with articles from our personal reference databases. For each article, two authors independently abstracted pre-determined items using a standard form. Data items included cancer site, model type, methods used for determination of unobservable parameter values and description of any calibration protocol. All authors reached consensus on items of disagreement. Reviews and non-cancer models were excluded. Articles describing analytical models, which estimate parameters with statistical approaches (e.g. maximum likelihood) were catalogued separately. Models that included unobservable parameters were analysed and classified by whether calibration methods were reported and if so, the methods used. The review process yielded 154 articles that met our inclusion criteria and, of these, we concluded that 131 may have used calibration methods to determine model parameters. Although the term 'calibration' was not always used, descriptions of calibration or 'model fitting' were found in 50% (n = 66) of the articles, with an additional 16% (n = 21) providing a reference to methods. Calibration target data were identified in nearly all of these articles. Other methodological details, such as the goodness-of-fit metric, were discussed in 54% (n = 47 of 87) of the articles reporting calibration methods, while few details were provided on the algorithms used to search the parameter space. Our review shows that the use of cancer simulation modelling is increasing, although thorough descriptions of calibration procedures are rare in the published literature for these models. Calibration is a key component of model development and is central to the validity and credibility of subsequent analyses and inferences drawn from model predictions. To aid peer-review and facilitate discussion of modelling methods, we propose a standardized Calibration Reporting Checklist for model documentation.

Cost effectiveness of preventive home visits to the elderly: economic evaluation alongside randomized controlled study

We evaluated the cost effectiveness of preventive home visits to elderly persons in Denmark alongside a 3-year randomized controlled study. The main outcome measure was incremental costs per active life-year gained. The number of active life-years was defined as those during which the person is able independently to transfer, walk indoors, go outdoors, walk outdoors in both pleasant and poor weather, and climb stairs. In 17 of 34 municipalities health visitors and general practitioners were offered geriatric training, which focused on early signs of disability, physical activity, and interdisciplinary follow-up. The remaining 17 municipalities offered preventive home visits as usual. Outcomes were measured in 4,034 persons aged 75 or 80 years old and dwelling at home. The difference in mean total costs between the intervention and the control group discounted at 3% was -856 euro (95% CI -2,455 to 744) in 75-year-olds and 694 euro (-2,684 to 4,071) in 80-year-olds. The discounted difference in mean active life-years was 0.034 (-0.058 to 0.125) and 0.197 (0.013 to 0.380), respectively. The study did not provide conclusive evidence on the cost effectiveness of the programs under consideration.

Nonattendance is still the main limitation for the effectiveness of screening for cervical cancer in the Netherlands

Although mass screening for cervical cancer has been operational for more than 2 decades in the Netherlands, 700 women are still diagnosed with this cancer each year (9 per 100,000). We investigated these cases, in order to evaluate opportunities to further increase the effectiveness of the programme. We analyzed the screening history of women diagnosed with cervical cancer between 1994-1997 using the Dutch national pathology file that includes cervical cytology and histological results. More than half of the cases did not have previous preventive cervical smears, and another 30% had never been invited to the programme because of their age. In the future, we estimate that two thirds of all Dutch women with invasive cervical cancer will be unscreened or under-screened, based on current screening participation of more than 70%. We conclude that increasing screening participation has much more potential for further reducing cervical cancer incidence than reducing the screening interval, increasing the age range or having a screening test with higher sensitivity.

Indirect costs of cervical and breast cancers in Spain

This study estimated the indirect costs (productivity loss) caused by mortality and morbidity of cervical and breast cancers in Spain. We used two alternative methods: (a) the traditional human capital (HC) approach and (b) the friction cost (FC) method. The annual costs were Euro 43.4 and 288.7 for cervical and breast cancer, respectively, by the HC approach and Euro 1.1 and 11.6 million by the FC approach. Cost-of-illness studies help to illustrate the real dimension of health problems and should be a major concern for health policies. Indirect costs are relevant information about diseases. However, the estimated indirect costs depend heavily on the approach adopted.

Characteristics of Participation in Cervical Cancer Screening

Although Papanicolaou test screening rates are reportedly high, a significant proportion of women remain unscreened. With recent revision of Papanicolaou test guidelines, it is critical that interventions and programs for cervical cancer directed toward low participating groups or individuals be developed. The purpose of the study was to examine factors that influence participation in cervical cancer screening by quantifying characteristics of women who engage in Papanicolaou test screening in a 12-month period. Using the 2000 National Health Interview Survey and Cancer Topical Module, the sample (N = 18,388) consisted of women who were older than 18 years. The dependent variable was nominally identified as whether a woman had had a Papanicolaou test in the last 12 months. Independent variables examined were insurance, level of education, place for care, age, race, employment, place of residence, and income level. Using logistic regression, all variables except race and income level were found to be significant for participation in cervical cancer screening (P < .000). Each variable is discussed within the framework of the Institute of Medicine model of access to personal healthcare services. Study findings provide insight and guidance for the development and implementation of methods for accessing women who have lower participation rates.

Cost-effectiveness analyses in gynecologic oncology: methodological quality and trends

OBJECTIVES

To evaluate methodological quality and trends of cost-effectiveness analyses (CEA) published in gynecologic oncology.

METHODS

A medical literature search of articles from 1966 through 2002 was performed to identify original, English-language articles that included economic analyses in gynecologic oncology. We included articles that were cost-effectiveness or cost-benefit analyses or performed these analyses as part of their study. Ten methodological principles that should be incorporated in CEAs were assessed for each study. Each article was given a score of 0, 1, or 2 for each of the 10 methodological principles (max score = 20). Data were analyzed using the Student t test, ANOVA, and linear regression.

RESULTS

We screened 693 articles to identify 68 that met our inclusion criteria. The articles focused on cervical cancer (n = 53; 78%), ovarian cancer (n = 11; 16%), uterine cancer (n = 2; 3%), and general perioperative care (n = 2; 3%). The mean (+/-SD) methodological principle score was 16.1 (+/-4.1) and we observed a significant improvement in the total score over time (P = 0.01). Primary CEA's (CEA identified as the objective of the study) were of higher quality than secondary CEA's (primary objective of the study was not CEA but CEA was included in the study; total scores 18.2 vs. 11.6, respectively; P<0.0001). Studies with at least one investigator in public health or healthcare economies also had higher quality (mean total score 17.7 vs. 15.2; P=0.006). The most common limitations of published CEAs were in methodology or presentation of incremental analyses, sensitivity analyses, and discounting.

CONCLUSIONS

Cost-effectiveness analyses in gynecologic oncology showed significant improvement in quality over the last two decades. Despite this progress, methodological improvement is still needed in the areas of incremental comparisons and sensitivity analysis. Understanding the methodology of cost-effectiveness analysis is critical for researchers, editors, and readers to accurately interpret results of the growing body of CEA articles.

Low risk of cervical cancer during a long period after negative screening in the Netherlands

A condition for effective cervical cancer screening is a low incidence of cervical cancer after negative screening compared to that in the absence of screening. This relative risk was studied for the period 1994-1997 in the Netherlands and compared with previous studies. All cases of invasive cervical cancer diagnosed from 1994 to 1997 in the Netherlands were related to woman-years at risk, stratified by age, number of preceding negative screenings and time since the preceding negative screening. These incidence rates were compared with that before screening started in the Netherlands. The relative risk increases from 0.13 in the first year after screening to 0.24 after more than 6 years after screening for women with one previous negative screening. These figures reduce to 0.06 and 0.18, respectively, for women with two or more previous screenings. However, these estimates are less favourable when account is taken of the likely decrease in risk for cervical cancer in the period studied. Our data show a low relative risk of cervical cancer for several years following the last negative Pap smear. However, the denominator of the relative risk, that is, the incidence without screening, may have been overestimated. This applies also to the IARC multicountry study, and may have caused too optimistic expectations about the effectiveness of cervical cancer screening.

The cost-effectiveness of screening for colorectal cancer

Screening policies for colorectal cancer are costly, as they are to be applied to a large potential population. Cost-effectiveness analysis of potential screening policies is therefore warranted and depends on local circumstances and healthcare systems. Most studies have used modeling approaches, with a few exceptions on the use of fecal occult blood tests. Current conclusions of economic studies tend to favor either double barium contrast enema or sigmoidoscopy as a mass screening tool, although colonoscopy might prove cost-effective in some circumstances. Further research is needed to assess the cost-benefit of mixed strategies in large populations.

Analysing public preferences for cancer screening programmes

Economic evaluations generally fail to incorporate elements of intangible costs and benefits, such as anxiety and discomfort associated with the screening test and diagnostic test, as well as the magnitude of utility associated with a reduction in the risk of dying from cancer. In the present analysis, 750 respondents were interviewed and asked to rank, according to priority, a number of alternative screening programme set-ups. Focus was on colorectal cancer screening and breast cancer screening. The alternative programmes varied with respect to number of tests performed, risk reduction obtained, probability of a false positive outcome and extent of co-payment. Stated preferences were analysed using discrete ranking modelling and the relative weighting of the programme attributes identified. Applying discrete choice methods to elicit preferences within this area of health care seems justified by the face validity of the results. The signs of the coefficients are in accordance with a priori hypotheses. This paper suggests that large-scale surveys focusing on individuals' preferences for cancer screening programmes may contribute significantly to the quality of economic evaluations within this field of health care.

Early withdrawal from cervical cancer screening: the question of cost-effectiveness

In countries such as the UK, mass population screening for cervical cancer has been undertaken since the 1960s. Although of established effectiveness, no formal evaluation of the screening protocol was carried out prior to its implementation. On the basis of a published mathematical modelling exercise, it has been speculated that withdrawing women from the screening programme at an earlier age than at present, whilst leading to a higher rate of invasive cervical cancer (ICC), could reduce resource use. Using estimates of screening and treatment costs, and of expected life-years lost following earlier withdrawal, we simulated cost-effectiveness ratios for various scenarios described by the model. Median cost savings resulting from a life-year lost never exceeded pound10000 for any scenario, although the estimates were particularly sensitive to the assumed age at cancer presentation and the rate of cancer progression. Our findings seem to offer little economic support for the early withdrawal of subjects from the cervical screening programme.

Cost implications of routine mammography screening of women 50-69 years in the county of Funen, Denmark

In order to estimate the net costs of introducing mammography screening to women 50-69 years of age, unit costs of all relevant activities related to detection and treatment of breast cancer were estimated using activity based costing methods. In order to determine the overall impact of mammography screening, activity data collected from the second screening round (1996-1997) were compared with expected activity levels in the case no screening had taken place in this time period. The direct health care costs associated with the screening activity, excluding effects on treatment and diagnostics but including women's transport and time costs, were estimated at DKK 305 per attendee. The cost of clinical mammography decreases with the introduction of screening due to a decrease in the total number of women undergoing this introductory diagnostic activity, while surgery costs increases, whereas cost incurred by adjuvant treatment and treatment of recurrences will be significantly reduced. Overall, inclusion of effects on course of treatment decreases the net cost of screening by 30-40% to DKK 208 and DKK 128 including and excluding the women's time and transport costs, respectively.

Methodologic principles of cost analyses in the nursing, medical, and health services literature, 1990-1996

BACKGROUND

Cost analyses are needed to inform resource decisions. Oftentimes, however cost-benefit analysis (CBA), cost-effectiveness analysis (CEA), cost-minimization analysis (CMA), and cost-utility analysis (CUA) are performed using untested techniques and adhering to a variety of questionable principles.

OBJECTIVES

To analyze, compare, and present a set of useful principles for the main types and methods of cost analyses through a synthesis of current information in the published literature.

METHODS

The area of interest included all reports of cost research published as full articles in professional journals from January 1990 to August 1996 in the nursing, medical, and health services fields. In all, 88 sampled articles met the criteria for inclusion. A four-page data collection guide with 28 items grouped as demographics, cost-analysis types, methods, and principles was designed for the review. Incremental testing for interrater reliability using the kappa statistic for two raters was performed. Sampling, process-oriented, construct, and correlational validity were assessed.

RESULTS

The 88 articles included 4 from nursing, 59 from medical, and 25 from health services journals. Of these articles, 45 (51%) reported CBA, 36 (41%) CEA, 2 CMA, 4 CUA, and 1 both CBA and CEA. Three nursing studies were authored only by nurses. Three fourths of the medical and four fifths of the health services publications had interdisciplinary authorship. Existing databases were the primary source of data in 61 (69%) publications. Adherence to six main methodologic principles was apparent in 19 (22%) articles. None of the nursing studies adhered to all six principles, whereas 16% of the health services and 25% of the medical studies did.

CONCLUSIONS

Funded cost analyses of nursing interventions that adhere to the six known methodologic principles are needed to inform policy-level health care decisions. Because of the complexity of cost analysis methodology, including sensitivity analysis, future interdisciplinary efforts using existing databases may prove most effective. The six methodologic principles presented in this article can be useful for future nursing education and cost-analysis research designed to control cost and increase the quality of health care.

Fecal occult blood tests. A cost-effectiveness analysis

A range of fecal occult blood tests are presently on the market and could potentially be used in population screening programs for the detection of colorectal neoplasms. This paper estimates the relative cost-effectiveness of alternative tests and concludes that the unhydrated Hemoccult II is the most cost-effective. However, the incremental costs per life-year of the HemeSelect test and the rehydrated Hemoccult II test are in line with incremental costs observed in breast cancer and cervical cancer programs.

Is it cost effective to introduce screening programmes for colorectal cancer? Illustrating the principles of optimal resource allocation

This paper seeks to shed light on the relative cost effectiveness of colorectal cancer by comparing the cost effectiveness of this programme with the economics of another screening programme which is widely implemented: cervical cancer screening. The paper illustrates the principles of optimal resource allocation, and discusses the limitations and strengths of the analysis presented. The paper concludes that colorectal cancer is a cost effective option relative to cervical cancer screening when health is seen as the only outcome of the screening programmes. However, further insight into consumer preferences and inclusion of intangible costs and benefits is necessary in order to guarantee optimal resource allocation.