Breast Cancer Prevalence Measured by the Lombardy Cancer Registry

Cancer Prevalence in Italian Regions with Local Cancer Registries

Objective

To provide estimates and projections of cancer incidence and prevalence for those Italian regions whose population is partially covered by a cancer registry (CR) and to determine to what extent local CRs can be considered representative of the region, thus improving the potential of the information provided by CRs.

Methods

A statistical method, MIAMOD (mortality-incidence analysis model), was used to estimate regional cancer incidence and prevalence from regional cancer mortality data and patient survival data recorded by the cancer registries. Estimates of the cancer incidence and prevalence in the various regions have thus been obtained for a number of major cancer sites. A first and important step in validating the regional estimates has been the comparison of the MIAMOD estimates in the areas covered by the cancer registries with empirical incidence and prevalence observed by CRs, in order to assess the consistency in data, methods and assumptions. Empirical prevalence has been calculated by counting patients with a diagnosis of cancer who were alive on the reference date by PREVAL method. A correction factor has been applied to include patients diagnosed before the period of activity of the registry.

Results

General consistency was found between empirical and estimated (by MIAMOD) incidence and prevalence in the registry areas, which is indicative of the quality and the completeness of all data involved as well as the appropriateness of model choices. The prevalence of all cancers combined for Italian regions with CRs was estimated and projected to the year 2000 as ranging between 1,240 per 100,000 in Sicilia and 2,781 in Emilia-Romagna for men, while for women these figures were 1,765 in Sicilia and 4,019 in Liguria. Comparison of cancer prevalence in CR areas with regional estimates shows quite good consistency for Piemonte, Liguria and Lombardia, which means that the local CRs (of Torino, Genova and Varese, respectively) are representative of their respective regions. Prevalence in Emilia-Romagna appears to be rather well represented by only one, the Parma CR, of the three local CRs. The southern Italian registries of Latina and Ragusa recorded a lower cancer prevalence than was actually estimated in their respective regions.

Discussion

Cancer registries with a longer period of activity showed better agreement between empirical and estimated figures due to the more precise information provided, particularly regarding survival and incidence trends. In conclusion, this work shows the potential of the cancer registries not only to represent their population with respect to cancer morbidity but also as an invaluable tool to extrapolate this information to the larger areas they represent.

Cancer Prevalence in the Elderly

Aims and Background

To describe the cancer prevalence in elderly Italian people and analyze the differences, if any, with the prevalence among younger subjects.

Methods & Study Design

The cancer prevalence among elderly patients (65 years and over), the three age classes encompassing elderly age (65-74 years, 75-84 years, 85 years and over) and younger patients (0-64 years) was computed using the PREVAL method on the basis of the incident cases over the period 1976-1992 followed up to 31 December 1992 (prevalence reference date). Data were collected by 11 Italian cancer registries.

Results

The observed prevalence figures for all cancers (except skin epitheliomas), both sexes combined and considering the whole elderly group, were 1,090 and 3,601 cases per 100,000 one and five years since diagnosis, respectively; the prevalence increased up to the 75-84 age group and showed a slight decrease after age 85. With regard to specific cancer sites, in men bladder and prostate had the highest prevalence 5 years from diagnosis (more than 800 cases per 100,000), followed by colon and lung (about 500 cases per 100,000) stomach and rectum (about 300 cases per 100,000); in women breast cancer ranked first (more than 1,000 cases per 100,000), followed by colon (about 350 cases per 100,000), corpus uteri, stomach and rectum cancers (between 150 and 200 cases per 100,000). For all malignancies and the two sexes combined the prevalence figures were about six times higher in the older than in the younger age group.

Conclusions

These figures confirm the important role of aging in determining the increase in cancer prevalence. The resulting prevalence figures clearly indicate the cancer burden placed on health care services; moreover, the figures will probably increase in the next decades due to a possible improvement in survival and to the dramatic aging of the population, assuming a stable trend for incidence rates. This picture will represent a major challenge for politicians and those dealing with health care planning and social policies in general, especially in the light of the reduction of the available financial resources and the specific features of medical and social needs in the elderly.

Cancer Prevalence in Italian Cancer Registry Areas: The Itapreval Study

Aim

To present data on cancer prevalence for the areas covered by Italian cancer registries, by using a standardized set of data collection and elaboration criteria, and a single method of data analysis.

Subjects and Methods

Data on over 250,000 patients with cancer, diagnosed between 1978 and 1992, from 11 Italian cancer registries covering about 12% of the Italian population were collected, validated and analyzed according to the unified protocol of the ITAPREVAL project. The method implemented in the PREVAL computer program was used to provide prevalence estimates for the period covered by cancer registration. The total prevalence for each registry and for the pool of all registries was then estimated by correcting for incomplete observations due to the period in which the registration was not yet activated. All prevalence estimates were for 1992.

Results

Prevalence figures are presented by cancer site, age, sex, years from diagnosis and registry area. For all malignancies combined, total prevalence ranged from 1,350 per 100,000 inhabitants in Ragusa to 3,650 per 100,000 inhabitants in Romagna, the ratio between these two extremes being 2.7. For the pool of the areas covered by registration cancer prevalence was 3,100 per 100,000 females and 2,250 per 100,000 males. About a third of the total female cases and about half the male cases were diagnosed in the previous five years. Among those aged over 75 years, total prevalence was higher for males than for females: 11,300 versus 8,900 per 100,000 respectively.

Conclusions

This is the first large-scale estimate of the burden of cancer in Italy. It is also one of the first studies in the world which was aimed to study cancer prevalence in detail. These data are necessary for predicting health service needs and help in the evaluation of differences in health service demand by sex, age and Italian regions.

The Prevalence of Cancer: A Review of the Available Data

Aims and Background

Cancer prevalence in a population, defined as the proportion – or the number – of people who were diagnosed with a cancer during their lives and are still alive at a given date, is a crucial indicator for heath care planning and resource allocation. Long-term population-based cancer registries (CR) are the appropriate tools to produce prevalence figures, which, however, are scarcely available. This paper contains a review up to 1999 of the published data world-wide (reports and articles) on cancer prevalence: including measured and estimated figures.

Materials and Methods

Data on cancer prevalence from CRs are available for the Nordic countries, Connecticut, and Italy. In addition, electronic data are available for the European Union (EU). Data for the Nordic countries were first published in the mid-seventies, reporting the prevalence for 1970. The first data from Connecticut were available 10 years later. Estimates for all EU countries were published by the International Agency for Research on Cancer (IARC) in 1997. In Italy, observed and estimated data on the prevalence of respiratory and digestive tract cancer and breast cancer have been published during the nineties, followed by a systematic analysis for all cancers in 1999. By using information obtained from CRs, cancer prevalence data were calculated directly (observed prevalence) by means of incidence and follow-up information on individual cancer patients, or indirectly (estimated prevalence) by means of mathematical models, which generally use epidemiological information at the aggregate level.

Results

Cancer prevalence for all cancers combined (proportions per 100,000 inhabitants) showed values of less than 700 in males and less than 800 in females in 1970 (Finland) to over 2,300 in males and over 3,000 in females in 1992 (Italian registries). With few exceptions, in each country and period considered the cancer sites contributing most to cancer prevalence are lung, colon-rectum, prostate and bladder in males, colon-rectum, breast, uterus (both cervix and corpus) and ovary in females. At present, comparison of measurements from different areas is difficult because there exists no standardized mode of presentation.

Conclusions

In spite of their being potentially useful for health care planning, prevalence data have been produced inconsistently and late by cancer registries, at least in comparison with the systematic availability of incidence and survival statistics. The available data can be compared only to a limited extent due to differences in completeness, in the choice of indicators, in the standard populations, and in the frequency of publication. It would be desirable that in the future data will be produced systematically, with a higher level of standardization compared to the past, and, most importantly, on the same geographic and administrative scale as health-care decision-making.

Contrasts in cancer prevalence in Connecticut, Iowa, and Utah

BACKGROUND

Cancer prevalence--the proportion of a population with cancer, including those recently diagnosed, those in treatment, and survivors--is an important indicator of future health care requirements. Only limited information on cancer prevalence is available for the United States. In particular, comparative interstate studies are not available. In this study, we estimate and analyze the prevalence of seven major cancers in Connecticut, lowa, and Utah using the tried and tested PREVAL method applied to National Cancer Institute registry data.

METHODS

We analyzed data on 242,851 carcinomas of the stomach, colorectum, pancreas, breast, uterus (corpus), ovary, and non-Hodgkin lymphoma (NHL), diagnosed in white Americans from 1973 through 1992. Observed prevalence was estimated by applying the PREVAL method to incidence and life status data from the cancer registries. Complete prevalence was estimated by applying correction factors obtained by modeling incidence and survival rates.

RESULTS

The ratio of the highest to the lowest prevalence (as proportions) ranged from 1.69 for uterine carcinoma to 2.73 for stomach carcinoma, showing that marked differences in cancer prevalence exist within the United States. Utah had the lowest prevalence for each carcinoma. Connecticut and lowa had similar prevalence levels for carcinomas of the colorectum, pancreas, and ovary and for NHL. Breast carcinoma was the most prevalent, with 826 cases per 100,000 of population in Utah, 1518 per 100,000 in lowa, and 1619 per 100,000 in Connecticut. Cancer survival did not differ greatly among the three registry populations. The major determinants of prevalence differences were incidence and the population age distribution.

CONCLUSIONS

PREVAL provides reliable estimates of the numbers of living people in a population who have had a cancer diagnosis. Prevalence depends on incidence and survival and on the age structure of population. All these factors have changed markedly in recent years and will continue to do so in the future. Cancer prevalence should be monitored over time to evaluate changes by area, sex, age, and cancer site. The prevalence figures presented are directly comparable with those from European cancer registries.

Cancer prevalence estimates based on tumour registry data in the Surveillance, Epidemiology, and End Results (SEER) Program

BACKGROUND

The Connecticut Tumor Registry (CTR) has collected cancer data for a sufficiently long period of time to capture essentially all prevalent cases of cancer, and to provide unbiased estimates of cancer prevalence. However, prevalence proportions estimated from Connecticut data may not be representative of the total US, particularly for racial/ethnic subgroups. The purpose of this study is to apply the modelling approach developed by Capocaccia and De Angelis to cancer data from the Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute to obtain more representative US site-specific cancer prevalence proportion estimates for white and black patients.

METHODS

Incidence and relative survival were modelled and used to obtain estimated completeness indices of SEER prevalence proportions for all cancer sites combined, stomach, cervix uteri, skin melanomas, non-Hodgkin's lymphomas, lung and bronchus, colon/rectum, female breast, and prostate. For validation purposes, modelled completeness indices were computed for Connecticut and compared with empirical completeness indices (the ratio of Connecticut based prevalence proportion estimates using 1973-1993 data to 1940-1993 data). The SEER-based modelled completeness indices were used to adjust SEER prevalence proportion estimates for white and black patients.

RESULTS

Model validation showed that the adjusted SEER cancer prevalence proportions provided reasonably unbiased prevalence proportion estimates in general, although more complex modelling of the completeness indices is necessary for female cancers of the colon, melanoma, breast, cervix, and all cancers combined. The SEER-based cancer prevalence proportions are incomplete for most cancer sites, more so for women, whites, and at older ages. For all cancers combined, prevalence proportions tended to be higher for whites than blacks. For the site-specific cancers this was true for stomach, prostate, cervix uteri, and lung and bronchus (men only). For colon/rectal cancers the prevalence proportions were higher for blacks through ages 59 (men) and 64 (women), and then for the remaining ages they were higher for whites. Prevalence proportions were lowest for stomach cancer and highest for prostate and female breast cancers. Men experienced higher prevalence proportions than women for skin melanomas, non-Hodgkin's lymphomas, lung and bronchus, and colon/rectal cancers.

CONCLUSION

The modelling approach applied to SEER data generally provided reasonable estimates of cancer prevalence. These estimates are useful because they are more representative of cancer prevalence than previously obtained and reported in the US.

The Prevalence of Tumors of the Breast and Female Genital Tract in Italy

Data from 10 Italian population-based cancer registries were used to estimate the prevalence of female tumors of the breast and genital tract. The total prevalence, expressed in number per 100,000, was highest for breast cancer (1,117), followed by cancer of the corpus (264) and cervix uteri (146), ovary (110), and vagina and vulva (23). For all tumors the prevalence increased with age at diagnosis.

The cancer prevalence was divided into intervals from diagnosis, expressing different health needs in terms of therapy and intensity of clinical follow-up. For all tumors considered, 1-year prevalence was higher than 1-2-year prevalence, reflecting a high death risk due to perioperative mortality and to the proportion of patients diagnosed at advanced stages. The prevalence decreased in the following intervals considered.

Noticeable geographic variability was observed in the prevalence across Italy, with higher proportions being registered in the northern-central regions than in the South. The two extreme 0-5-year prevalence figures (per 100,000) were: for breast cancer 568 (Genova) and 259 (Ragusa); for corpus uteri cancer 94 (Romagna) and 21 (Latina); for cervix uteri cancer 63 (Romagna) and 26 (Latina); for ovarian cancer 49 (Parma) and 21 (Latina); for cancer of the vagina and vulva 17 (Genova) and 5 (Ragusa). This variability depends mainly on incidence and on the proportion of elderly in the general population.

From 1987 to 1992 there was an increase in the prevalence of tumors of the breast, ovary and vagina and vulva, especially in the elderly. The prevalence of corpus uteri cancer decreased slightly in the elderly only, whereas that of cervix uteri cancer decreased at all ages.