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1.
Front Oncol ; 13: 1201464, 2023.
Article in English | MEDLINE | ID: mdl-37711195

ABSTRACT

Background: In most developed countries, the number of cancer survivors is expected to increase in the coming decades because of rising incidence and survival rates and an aging population. These patients are heterogeneous in terms of health service demands: from recently diagnosed patients requiring first-course therapy to patients with extensive care needs and severe disabilities to long-term survivors who only need minimal care. Therefore, in terms of providing healthcare planners and policymakers with useful indicators for addressing policies according to health service demands, it is worth supplying updated measures of prevalence for groups of patients based on the level of care they require. The aim of this paper is to illustrate a new method for estimating short-term projections of cancer prevalence by phase of care that applies to areas covered by cancer registration. Methods: The proposed method combines linear regression models to project limited duration prevalence derived from cancer registry data and a session of the freely available software COMPREV to estimate the projected complete prevalence into three distinct clinically relevant phases of care: initial, continuing, and final. The method is illustrated and validated using data from the Veneto region in Italy for breast, colorectal, and lung cancers. Results: Prevalence is expected to increase in 2015-2026 for all considered cancer sites and sexes, with average annual variations spanning from 2.6% for women with lung cancer to 0.5% for men with colorectal cancer. The only exception is lung cancer prevalence in men, which shows an average annual decrease of 1.9%. The majority of patients are in the continuing phase of care, followed by the initial and final phases, except for lung cancer, where the final phase of care prevails over the initial one. Discussion: The paper proposes a method for estimating (short-term) future cancer healthcare needs that is based on user-friendly and freely available software and linear regression models. Validation results confirm the applicability of our method to the most frequent cancer types, provided that cancer registry data with at least 15 years of registration are available. Evidence from this method is addressed to policymakers for planning future cancer care, thus improving the cancer survivorship experience for patients and caregivers.

2.
Front Public Health ; 10: 974505, 2022.
Article in English | MEDLINE | ID: mdl-36211660

ABSTRACT

Sustainability of cancer burden is becoming increasingly central in the policy makers' debate, and poses a challenge for the welfare systems, due to trends towards greater intensity of healthcare service use, which imply increasing costs of cancer care. Measuring and projecting the economic burden associated with cancer and identifying effective policies for minimising its impact are important issues for healthcare systems. Scope of this paper is to illustrate a novel comprehensive approach (called Epicost) to the estimation of the economic burden of cancer, based on micro-data collected from multiple data sources. It consists of a model of cost analysis to estimate the amount of reimbursement payed by the National Health Service to health service providers (hospitals, ambulatories, pharmacies) for the expenses incurred in the diagnoses and treatments of a cohort of cancer patients; these cancer costs are estimated in various phases of the disease reflecting patients' patterns of care: initial, monitoring and final phase. The main methodological features are illustrated using a cohort of colon cancer cases from a Cancer Registry in Italy. This approach has been successfully implemented in Italy and it has been adapted to other European countries, such as Belgium, Norway and Poland in the framework of the Innovative Partnership for Action Against Cancer (iPAAC) Joint Action, sponsored by the European Commission. It is replicable in countries/regions where population-based cancer registry data is available and linkable at individual level with administrative data on costs of care.


Subject(s)
Neoplasms , State Medicine , Europe , Hospitals , Humans , Italy/epidemiology , Neoplasms/therapy
3.
Eur J Health Econ ; 22(9): 1477-1485, 2021 Dec.
Article in English | MEDLINE | ID: mdl-34312745

ABSTRACT

OBJECTIVES: To identify and provide lists of procedures and drugs related to diagnosis and treatment of breast cancer. These lists can be used for the estimation of the cost of illness. METHODS: The method consists of identifying lists of procedures/interventions/drugs related to the tumour of interest, drawn by a panel of expert clinicians and oncologists on the basis of clinical guidelines and current practice. The lists are applied to data referring to breast cancer female patients, collected by population-based Cancer Registries and linked at individual level with information on health care treatments. A comparison with lists obtained via the matched control method is implemented. RESULTS: The distribution of administered procedures and drug prescriptions is coherent with the patient clinical pathway: surgery is the main cause of hospitalization in the first year since diagnosis, diagnostic and monitoring interventions are more frequent in the following years (recurrences detection), and at end-of-life (palliative care). Most outpatient services are due to diagnosis and monitoring, one third of services in the first year since diagnosis is radiotherapy and chemotherapy. Drugs prescribed to patients and sold in pharmacy include hormonal drugs as first course treatment and analgesics as palliative care. CONCLUSIONS: This direct method represents a valid alternative to the matched control method in describing patterns of care and costs related to the entire disease pathway. It is particularly suitable in case of cancer sites with complex patterns of care, such as breast cancer. The lists of codes developed here are based on international classification systems and can be easily applicable to other countries.


Subject(s)
Breast Neoplasms , Breast Neoplasms/diagnosis , Breast Neoplasms/therapy , Drug Prescriptions , Female , Health Services , Hospitalization , Humans , Neoplasm Recurrence, Local
4.
Article in English | MEDLINE | ID: mdl-33430156

ABSTRACT

Costs of cancer care are increasing worldwide, and sustainability of cancer burden is critical. In this study, the economic impact of rectal cancer on the Italian healthcare system, measured as public healthcare expenditure related to investigation and treatment of rectal cancer patients is estimated. A cross-sectional cohort of 9358 rectal cancer patients is linked, on an individual basis, to claims associated to rectal cancer diagnosis and treatments. Costs refer mainly to years 2010-2011 and are estimated by phase of care, as healthcare needs vary along the care pathway: diagnostic procedures are mainly provided in the first year, surveillance procedures are addressed to chronically ill patients, and end-of-life procedures are given in the terminal status. Clinical approaches and corresponding costs are specific by cancer type and vary by phase of care, stage at diagnosis, and age. Surgery is undertaken by the great majority of patients. Thus, hospitalization is the main cost driver. The evidence produced can be used to improve planning and allocation of healthcare resources. In particular, early diagnosis of rectal cancer is a gain in healthcare budget. Policies raising spreading of and adherence to screening plans, above all when addressed to people living in Southern Italy, should be strongly encouraged.


Subject(s)
Health Expenditures , Rectal Neoplasms , Cross-Sectional Studies , Delivery of Health Care , Health Care Costs , Humans , Italy/epidemiology , Rectal Neoplasms/diagnosis , Rectal Neoplasms/epidemiology , Rectal Neoplasms/therapy
5.
Tumori ; 107(4): 311-317, 2021 Aug.
Article in English | MEDLINE | ID: mdl-33095121

ABSTRACT

INTRODUCTION: Cancer prevalence (people alive on a certain date in a population who previously had a cancer diagnosis) is expected to increase in the United States and Europe due to improvements in survival and population aging. Examination of prevalence by phase of care allows us to identify subgroups of patients according to their care trajectories, thus allowing us to improve health care planning, resource allocation, and calculation of costs. METHODS: A new method to estimate prevalence by phase of care using grouped data is illustrated. Prevalence is divided into 3 mutually exclusive phases: initial, continuing, and end-of-life. An application to US and Italian data is applied to prevalent cases diagnosed with colon-rectum, stomach, lung, or breast cancer. RESULTS: The distribution of phase of care prevalence estimated by cancer type and sex and results from the two datasets are very similar. Most survivors are in the continuing phase; the end-of-life phase is larger for cancers with worse prognosis. All phases prevalence is generally higher in the Italian than in the US dataset, except for lung cancer in women, where prevalence proportion in the Italian dataset is 30% lower than in the United States. DISCUSSION: Incidence, survival, and population age structure are the main determinants of prevalence and they can affect differences in all phases of prevalence, as well as in discrete phases. Incidence is the most influential determinant. Ours is the first study that compares prevalence by phase of care between two populations in Italy and the United States. Despite great differences in health care management in the two countries, we found extremely similar distribution of survivors by phase of care for most cancer sites under study.


Subject(s)
Cancer Survivors/statistics & numerical data , Delivery of Health Care/standards , Health Services/statistics & numerical data , Needs Assessment/statistics & numerical data , Neoplasms/epidemiology , Registries/statistics & numerical data , Adolescent , Adult , Aged , Aged, 80 and over , Child , Child, Preschool , Female , Follow-Up Studies , Humans , Incidence , Infant , Infant, Newborn , Italy/epidemiology , Male , Middle Aged , Prognosis , Survival Rate , United States/epidemiology , Young Adult
6.
Int J Epidemiol ; 49(5): 1517-1525, 2020 10 01.
Article in English | MEDLINE | ID: mdl-32984907

ABSTRACT

BACKGROUND: Few studies have estimated the probability of being cured for cancer patients. This study aims to estimate population-based indicators of cancer cure in Europe by type, sex, age and period. METHODS: 7.2 million cancer patients (42 population-based cancer registries in 17 European countries) diagnosed at ages 15-74 years in 1990-2007 with follow-up to 2008 were selected from the EUROCARE-5 dataset. Mixture-cure models were used to estimate: (i) life expectancy of fatal cases (LEF); (ii) cure fraction (CF) as proportion of patients with same death rates as the general population; (iii) time to cure (TTC) as time to reach 5-year conditional relative survival (CRS) >95%. RESULTS: LEF ranged from 10 years for chronic lymphocytic leukaemia patients to <6 months for those with liver, pancreas, brain, gallbladder and lung cancers. It was 7.7 years for patients with prostate cancer at age 65-74 years and >5 years for women with breast cancer. The CF was 94% for testis, 87% for thyroid cancer in women and 70% in men, 86% for skin melanoma in women and 76% in men, 66% for breast, 63% for prostate and <10% for liver, lung and pancreatic cancers. TTC was <5 years for testis and thyroid cancer patients diagnosed below age 55 years, and <10 years for stomach, colorectal, corpus uteri and melanoma patients of all ages. For breast and prostate cancers, a small excess (CRS < 95%) remained for at least 15 years. CONCLUSIONS: Estimates from this analysis should help to reduce unneeded medicalization and costs. They represent an opportunity to improve patients' quality of life.


Subject(s)
Melanoma , Neoplasms , Skin Neoplasms , Adolescent , Adult , Aged , Europe/epidemiology , Female , Humans , Life Expectancy , Male , Middle Aged , Neoplasms/epidemiology , Neoplasms/therapy , Quality of Life , Registries , Survival Rate , Young Adult
7.
Eur J Health Econ ; 21(7): 1003-1013, 2020 Sep.
Article in English | MEDLINE | ID: mdl-32399781

ABSTRACT

OBJECTIVES: To estimate total direct health care costs associated to diagnosis and treatment of women with breast cancer in Italy, and to investigate their distribution by service type according to the disease pathway and patient characteristics. METHODS: Data on patients provided by population-based Cancer Registries are linked at individual level with data on health-care services and corresponding claims from administrative databases. A combination of cross-sectional approach and a threephase of care decomposition model with initial, continuing and final phases-of-care defined according to time occurred since diagnosis and disease outcome is adopted. Direct estimation of cancer-related costs is obtained. RESULTS: Study cohort included 49,272 patients, 15.2% were in the initial phase absorbing 42% of resources, 79.7% in the continuing phase absorbing 44% of resources and 5.1% in the final phase absorbing 14% of resources. Hospitalization was the most important cost driver, accounting for over 55% of the total costs. CONCLUSIONS: This paper represents the first attempt in Italy to estimate the economic burden of cancer at population level taking into account the entire disease pathway and using multiple current health care databases. The evidence produced by the study can be used to better plan resources allocation. The model proposed is replicable to countries with individual health care information on services and claims.


Subject(s)
Breast Neoplasms/economics , Delivery of Health Care/economics , Delivery of Health Care/statistics & numerical data , Health Expenditures/statistics & numerical data , Breast Neoplasms/pathology , Cross-Sectional Studies , Female , Hospitalization/economics , Humans , Insurance Claim Review , Italy , Registries , Retrospective Studies
8.
Cancer Med ; 8(9): 4497-4507, 2019 08.
Article in English | MEDLINE | ID: mdl-31207165

ABSTRACT

BACKGROUND: Increasing evidence of cure for some neoplasms has emerged in recent years. The study aimed to estimate population-based indicators of cancer cure. METHODS: Information on more than half a million cancer patients aged 15-74 years collected by population-based Italian cancer registries and mixture cure models were used to estimate the life expectancy of fatal tumors (LEFT), proportions of patients with similar death rates of the general population (cure fraction), and time to reach 5-year conditional relative survival (CRS) >90% or 95% (time to cure). RESULTS: Between 1990 and 2000, the median LEFT increased >1 year for breast (from 8.1 to 9.4 years) and prostate cancers (from 5.2 to 7.4 years). Median LEFT in 1990 was >5 years for testicular cancers (5.8) and Hodgkin lymphoma (6.3) below 45 years of age. In both sexes, it was ≤0.5 years for pancreatic cancers and NHL in 1990 and in 2000. The cure fraction showed a 10% increase between 1990 and 2000. It was 95% for thyroid cancer in women, 94% for testis, 75% for prostate, 67% for breast cancers, and <20% for liver, lung, and pancreatic cancers. Time to 5-year CRS >95% was <10 years for testis, thyroid, colon cancers, and melanoma. For breast and prostate cancers, the 5-year CRS >90% was reached in <10 years but a small excess remained for >15 years. CONCLUSIONS: The study findings confirmed that several cancer types are curable. Became aware of the possibility of cancer cure has relevant clinical and social impacts.


Subject(s)
Cancer Survivors/statistics & numerical data , Neoplasms/classification , Neoplasms/epidemiology , Adolescent , Adult , Aged , Female , Humans , Italy/epidemiology , Life Expectancy , Male , Middle Aged , Models, Theoretical , Neoplasms/mortality , Prognosis , Time Factors , Young Adult
10.
BMC Cancer ; 18(1): 169, 2018 02 09.
Article in English | MEDLINE | ID: mdl-29426306

ABSTRACT

BACKGROUND: Estimates of cancer prevalence are widely based on limited duration, often including patients living after a cancer diagnosis made in the previous 5 years and less frequently on complete prevalence (i.e., including all patients regardless of the time elapsed since diagnosis). This study aims to provide estimates of complete cancer prevalence in Italy by sex, age, and time since diagnosis for all cancers combined, and for selected cancer types. Projections were made up to 2020, overall and by time since diagnosis. METHODS: Data were from 27 Italian population-based cancer registries, covering 32% of the Italian population, able to provide at least 7 years of registration as of December 2009 and follow-up of vital status as of December 2013. The data were used to compute the limited-duration prevalence, in order to estimate the complete prevalence by means of the COMPREV software. RESULTS: In 2010, 2,637,975 persons were estimated to live in Italy after a cancer diagnosis, 1.2 million men and 1.4 million women, or 4.6% of the Italian population. A quarter of male prevalent cases had prostate cancer (n = 305,044), while 42% of prevalent women had breast cancer (n = 604,841). More than 1.5 million people (2.7% of Italians) were alive since 5 or more years after diagnosis and 20% since ≥15 years. It is projected that, in 2020 in Italy, there will be 3.6 million prevalent cancer cases (+ 37% vs 2010). The largest 10-year increases are foreseen for prostate (+ 85%) and for thyroid cancers (+ 79%), and for long-term survivors diagnosed since 20 or more years (+ 45%). Among the population aged ≥75 years, 22% will have had a previous cancer diagnosis. CONCLUSIONS: The number of persons living after a cancer diagnosis is estimated to rise of approximately 3% per year in Italy. The availability of detailed estimates and projections of the complete prevalence are intended to help the implementation of guidelines aimed to enhance the long-term follow-up of cancer survivors and to contribute their rehabilitation needs.


Subject(s)
Neoplasms/epidemiology , Survivors/statistics & numerical data , Adolescent , Adult , Age Distribution , Aged , Aged, 80 and over , Child , Child, Preschool , Female , Forecasting , Humans , Infant , Infant, Newborn , Italy/epidemiology , Male , Middle Aged , Prevalence , Registries , Sex Distribution , Young Adult
11.
Int J Cancer ; 140(11): 2444-2450, 2017 06 01.
Article in English | MEDLINE | ID: mdl-28233308

ABSTRACT

Cancers diagnosed in children below the age of 15 years represent 1.2% of all cancer cases, and survival after a childhood cancer has greatly improved over the past 40 years in all high income countries. This study aims to estimate the number of people living in Italy after a childhood cancer for all cancers combined and for a selection of cancer types. We computed 15-year prevalence using data from 15 Italian population-based cancer registries (covering 19% of Italian population) and estimated complete prevalence for Italy by using the CHILDPREV method, implemented in the COMPREV software. A total of 44,135 persons were alive at January 1st, 2010 after a cancer diagnosed during childhood. This number corresponds to a proportion of 73 per 100,000 Italians and to about 2% of all prevalent cases. Among them, 54% were males and 64% had survived after being diagnosed before 1995, the start of the observation period. A quarter of all childhood prevalent cases were diagnosed with brain and central nervous system tumors, a quarter with acute lymphoid leukemia, and 7% with Hodgkin lymphoma. Nearly a quarter of prevalent patients were aged 40 years and older. Information about the number of people living after a childhood cancer in Italy by cancer type and their specific health care needs may be helpful to health-care planners and clinicians in the development of guidelines aimed to reduce the burden of late effect of treatments during childhood.


Subject(s)
Neoplasms/mortality , Adolescent , Child , Child, Preschool , Female , Humans , Infant , Infant, Newborn , Italy/epidemiology , Male , Neoplasms/epidemiology , Prevalence , Registries , Survival Rate
13.
J Natl Cancer Inst Monogr ; 2013(46): 88-98, 2013.
Article in English | MEDLINE | ID: mdl-23962512

ABSTRACT

Cancer is a major component of health-care expenditures in most developed countries. The costs of cancer care are expected to increase due to rising incidence (as the population ages) and increasing use of targeted anticancer therapies. However, epidemiological analysis of patterns of care may be required prior to empirically well-grounded cost analyses. Additionally, comparisons of care between health-care delivery systems and countries can identify opportunities to improve practice. They can also increase understanding of patient outcomes and economic consequences of differences in policies related to cancer screening, treatment, and programs of care. In this study, we compared patterns of colorectal cancer treatment during the first year following diagnosis in two cohorts of elderly patients from some areas of Italy and the United States using cancer registry linked to administrative data. We evaluated hospital use, initial treatments (surgery, chemotherapy, and radiation), and timeliness of surgery and adjuvant therapy, taking into account patient characteristics and clinical features, such as stage at diagnosis and the cancer subsite. We observed greater use of adjuvant chemotherapy in stage III and IV colon cancer patients and adjuvant therapy in all stages of rectal cancer patients in the US cohort. We found a higher rate of open surgeries in the Italian cohort, a similar rate of hospitalization, but a higher number of hospital days in the Italian cohort. However, in spite of structural differences between the United States and Italy in health-care organization and delivery as well as in data collection, patterns of care and the timing of care in the year after diagnosis are generally similar among patients within stage of disease at diagnosis. Comparative studies of the costs associated with patterns of cancer care will be important for future research.


Subject(s)
Colorectal Neoplasms/therapy , Delivery of Health Care , Health Expenditures , Age Factors , Aged , Aged, 80 and over , Chemotherapy, Adjuvant , Cohort Studies , Colorectal Neoplasms/economics , Colorectal Neoplasms/epidemiology , Combined Modality Therapy , Female , Humans , Italy/epidemiology , Male , Medicare/economics , Neoplasm Staging , SEER Program , United States/epidemiology
15.
BMC Cancer ; 13: 329, 2013 Jul 05.
Article in English | MEDLINE | ID: mdl-23826976

ABSTRACT

BACKGROUND: Due to changes in cancer-related risk factors, improvements in diagnostic procedures and treatments, and the aging of the population, in most developed countries cancer accounts for an increasing proportion of health care expenditures. The analysis of cancer-related costs is a topic of several economic and epidemiological studies and represents a research area of great interest to public health planners and policy makers. In Italy studies are limited either to some specific types of expenditures or to specific groups of cancer patients. Aim of the paper is to estimate the distribution of cancer survivors and associated health care expenditures according to a disease pathway which identifies three clinically relevant phases: initial (one year following diagnosis), continuing (between initial and final) and final (one year before death). METHODS: The methodology proposed is based on the reconstruction of patterns of care at individual level by combining different data sources, surveillance data and administrative data, in areas covered by cancer registration. RESULTS: A total colorectal cancer-related expenditure of 77.8 million Euros for 18012 patients (corresponding to about 4300 Euros per capita) is estimated in 2006 in two Italian areas located in Tuscany and Veneto regions, respectively. Cost of care varies according to the care pathway: 11% of patients were in the initial phase, and consumed 34% of total expenditure; patients in the final (6%) and in the continuing (83%) phase consumed 23% and 43% of the budget, respectively. There is an association between patterns of care/costs and patients characteristics such as stage and age at diagnosis. CONCLUSIONS: This paper represents the first attempt to attribute health care expenditures in Italy to specific phases of disease, according to varying treatment approaches, surveillance strategies and management of relapses, palliative care. The association between stage at diagnosis, profile of therapies and costs supports the idea that primary prevention and early detection play an important role in a public health perspective. Results from this pilot study encourage the use of such analyses in a public health perspective, to increase understanding of patient outcomes and economic consequences of differences in policies related to cancer screening, treatment, and programs of care.


Subject(s)
Colorectal Neoplasms/economics , Adolescent , Adult , Aged , Aged, 80 and over , Colorectal Neoplasms/epidemiology , Female , Health Care Costs , Health Expenditures , Humans , Italy/epidemiology , Male , Middle Aged , Registries , Young Adult
16.
Ann Ist Super Sanita ; 49(1): 73-8, 2013.
Article in English | MEDLINE | ID: mdl-23535133

ABSTRACT

OBJECTIVES: Cancer accounts for a major proportion of national health expenditures, which are expected to increase in the future. This paper aims to identify major challenges with estimating cancer related costs, and discuss international comparisons, and recommendations for future research. METHODS: It starts from the experience of an international workshop aimed at comparing cancer burden evaluation methods, improving results comparability, discussing strengths and criticisms of different approaches. RESULTS: Three methodological themes necessary to inform the analysis are identified and discussed: data availability; costs definition; epidemiological measures. CONCLUSIONS: Cost evaluation is applied to cancer control interventions and is relevant for public health planners. Despite their complexity, international comparisons are fundamental to improve, generalize and extend cost evaluation to different contexts.


Subject(s)
Costs and Cost Analysis/trends , Neoplasms/economics , Neoplasms/therapy , Cost of Illness , Epidemiologic Methods , Health Expenditures , Humans
18.
Health Care Manag Sci ; 11(2): 111-20, 2008 Jun.
Article in English | MEDLINE | ID: mdl-18581817

ABSTRACT

The paper develops a general method for evaluating geographical differences in the outcome of acute myocardial infarction patients, by looking at the process of disease occurrence from infarction to hospitalization and possible death or recovery. The method is applied to regional data in Italy, where the long history of geographical diversities in economical, social and cultural fields is reflected in health care. Specific features of AMI, such as high fatality and fast course of the disease, make it a suitable tracer condition to investigate into the differences of regional health systems during the acute phase of hospitalization. The paper combines administrative and official statistics by region and offers a tool providing suggestions to policy-makers where further eventual investigations are needed around the care pathway and also what possible actions might be undertaken to improve the outcomes.


Subject(s)
Models, Statistical , Myocardial Infarction/mortality , Outcome Assessment, Health Care/statistics & numerical data , Age Distribution , Aged , Female , Geography , Healthcare Disparities , Hospital Mortality , Hospitalization/statistics & numerical data , Humans , Italy/epidemiology , Male , Middle Aged , Sex Distribution
19.
Stat Med ; 27(7): 990-1007, 2008 Mar 30.
Article in English | MEDLINE | ID: mdl-17724784

ABSTRACT

A method of estimating the complete prevalence of cancers diagnosed in childhood called CHILDPREV (CHILDhood PREValence), is presented. It is a semi-parametric method based on cancer registry data and on the completeness index method. It allows estimating prevalence even when no observation is available (typically older patients alive at the prevalence date may have been diagnosed with cancer before the introduction of the registry). The method was validated on Connecticut Tumor Registry data, which has 62 years of follow-up and provides complete prevalence, and compared with the fully parametric PIAMOD method. Results of complete childhood prevalence estimates based on SEER-9 cancer registries data for acute lymphocytic leukemia and all cancer sites combined are presented.


Subject(s)
Models, Statistical , Neoplasms/epidemiology , Registries/statistics & numerical data , Adolescent , Adult , Age Distribution , Aged , Aged, 80 and over , Child , Child, Preschool , Connecticut/epidemiology , Female , Humans , Infant , Infant, Newborn , Male , Middle Aged , Precursor Cell Lymphoblastic Leukemia-Lymphoma/epidemiology , Prevalence , Reproducibility of Results , SEER Program/statistics & numerical data
20.
Stat Methods Med Res ; 15(3): 235-53, 2006 Jun.
Article in English | MEDLINE | ID: mdl-16768298

ABSTRACT

Cancer prevalence is the proportion of people in a population diagnosed with cancer in the past and still alive. One way to estimate prevalence is via population-based registries, where data on diagnosis and life status of all incidence cases occurring in the covered population are collected. In this paper, a method to estimate the complete prevalence and its variance from population-based registries is presented. In order to obtain unbiased estimates of the complete prevalence, its calculation can be thought as made by three steps. Step 1 counts the incidence cases diagnosed during the period of registration and still alive. Step 2 estimates the expected number of survivors among cases lost to follow-up. Step 3 estimates the complete prevalence by taking into account cases diagnosed before the start of registration. The combination of steps 1+2 is defined as the counting method, to estimate the limited duration prevalence; step 3 is the completeness index method, to estimate the complete prevalence. For early established registries, steps 1+2 are more important than step 3, because observation time is long enough to include all past diagnosed cases still alive in the prevalence data. For more recently established registries, step 3 is by far the most critical because a large part of prevalence might have been diagnosed before the period of registration (Corazziari I, Mariotto A, Capocaccia R. Correcting the completeness bias of observed prevalence. Tumori 1999; 85: 370-81). The work by Clegg LX, Gail MH, Feuer EJ. Estimating the variance of disease-prevalence estimates from population-based registries. Biometrics 2002; 55: 1137-44. considers the problem of the variability of the estimated prevalence up to step 2. To our knowledge, no other work has considered the variability induced by correcting for the unobserved cases diagnosed before the period of registration, crucial to estimate the prevalence in recent registries. An analytic approach is considered to calculate the variance of step 3. A unified expression for the variance of the prevalence allowing for steps 1 through 3 is obtained. Some applications to cancer data are presented.


Subject(s)
Colonic Neoplasms/epidemiology , Models, Statistical , Registries , Adult , Aged , Aged, 80 and over , Bias , Epidemiologic Methods , Female , Humans , Incidence , Italy/epidemiology , Male , Middle Aged , Prevalence , SEER Program
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