Biomedical subjects

A Verdecchia

Publications and source records attributed to A Verdecchia.

At least 37 records · Page 2Linked to original sources

PubMed2000

Uncertainty of AIDS incubation time and its effects on back-calculation estimates.

Incubation time is the period from the onset of HIV infection to AIDS. The distribution of the incubation time is one of the main parameters of the back-calculation method for the estimation of incidence of HIV infection. Because of the long and variable incubation time, the assessment of its distribution is uncertain and this uncertainty spreads through the back-calculation method and affects the estimation of the precision of incidence of HIV infection. We propose a method to investigate the sensitivity of the estimates to variations of the incubation times, with particular regard to the covariate AGE in the modelling of the incubation period, making use of the parametric bootstrap. An application to the HIV epidemic in Italy is presented. The amplification of the uncertainty of the HIV incidence estimates resulting from the implementation of our proposed method tends to concentrate around the earlier periods of the epidemic, corresponding to the right tail of the incubation time distribution, which is very sensitive to small perturbations.

Acquired Immunodeficiency Syndrome↗

PubMed2000

Cancer incidence and mortality among flight personnel: a meta-analysis.

BACKGROUND: Increased cancer risk among flight personnel have previously been noted, including breast cancer among flight attendants and acute myeloid leukemia among pilots. HYPOTHESIS: Exposure to cosmic radiation and other physical or chemical agents may pose health risks for flight personnel. METHODS: We performed an exhaustive search for published and unpublished cohort studies of flight personnel from 1986-98. We combined relative risks (RR) for selected causes from four mortality and/or incidence studies of pilots and two incidence studies of flight attendants, using standard meta-analytic methods. Heterogeneity among the combined studies was explored and adjustments were made for possible confounding by socioeconomic status (SES), where indicated, using correction factors from published studies. RESULTS: SES-adjusted combined RRs were elevated (>1.2) among male pilots for mortality from melanoma 11.97 (95%, CI: 1.02-3.82)] and brain cancer [1.49 (0.89-2.20)], and for cancer incidence of the prostate [1.65 (1.19-2.29)] and the brain [1.74 (0.87-3.30)]. Among female flight attendants, increases were seen for incidence of all cancers [1.29 (0.98-1.70)], melanoma [11.54 (0.83-2.87)], and breast cancer [1.35 (1.00-1.83)]. CONCLUSIONS: Flight personnel appear to be at increased risk for several types of cancer. Both occupational exposures and well-established non-occupational risk factors may contribute to this increased risk. To better control for confounding factors and to identify exposures potentially amenable to preventive measures, future studies should compare risks within cohorts by flight routes, work history, and exposure to cosmic and UV radiation, electromagnetic fields, and chemical substances.

Adult↗

PubMed1999

Results from a historical survey of the survival of cancer patients given Di Bella multitherapy.

BACKGROUND: The Italian media have given wide coverage to a number of successes in treating cancer patients with an alternative therapy developed by Dr. Luigi Di Bella, a physician in Modena, Italy. In 1998, the Ministry of Health, under considerable pressure from the public, decided to promote studies to evaluate its efficacy. METHODS: Follow-up was conducted for cancer patients previously treated during the years 1971-1997 by Dr. Di Bella and registered in his archive. Identified cases were searched in cancer registries for diagnostic confirmation, date of diagnosis, and follow-up. Survival was compared with that in individually matched cancer cases derived from a pool of Italian cancer registries (the ITACARE data base). Kaplan-Meier survival curves were produced for all adult cancer patients as well as for children with leukemia and, in the matched analysis, for patients with cancer at the major anatomic sites and for all cancer patients combined. The homogeneity of survival curves between the two groups was tested by means of the log rank test. RESULTS: After several exclusions, 314 patients were entered into the study. Follow-up was completed for 79%. Only four patients received Di Bella Multitherapy (MDB) as their only anticancer therapy. Of these, only 1 is still alive 2 years after diagnosis. Five-year survival rates for children with leukemia and adult cancer patients were both 29.4%. Five-year survival was significantly lower in comparison with ITACARE cases for patients with childhood leukemia, breast carcinoma, and adult leukemia, and for all cancer patients combined. Twenty-seven MDB patients survived 10 years or longer after diagnosis. In only three cases was this long survival unexpected. CONCLUSIONS: The results for this series did not give any evidence that MDB improved the survival of the cancer patients. [See editorial on pages 1887-9 and commentaries on pages 1900-2 and 1903-11 this issue.]

Adolescent↗

PubMed1999

Mixture models for cancer survival analysis: application to population-based data with covariates.

The interest in estimating the probability of cure has been increasing in cancer survival analysis as the curability of many cancer diseases is becoming a reality. Mixture survival models provide a way of modelling time to death when cure is possible, simultaneously estimating death hazard of fatal cases and the proportion of cured case. In this paper we propose an application of a parametric mixture model to relative survival rates of colon cancer patients from the Finnish population-based cancer registry, and including major survival determinants as explicative covariates. Disentangling survival into two different components greatly facilitates the analysis and the interpretation of the role of prognostic factors on survival patterns. For example, age plays a different role in determining, from one side, the probability of cure, and, from the other side, the life expectancy of fatal cases. The results support the hypothesis that observed survival trends are really due to a real prognostic gain for more recently diagnosed patients.

Age Factors↗

PubMed1999

Variations in survival for invasive cervical cancer among European women, 1978-89. EUROCARE Working Group.

OBJECTIVES: To analyze cervical cancer survival trends in 10 European countries using models that estimate the proportion of cured patients (having the same life expectancy as the general population) and the survival of fatal cases (who die from cervical cancer). METHODS: We considered 40,906 cases diagnosed over 12 years (1978-89) collected from cancer registries participating in EUROCARE. RESULTS: From 1978 to 1989, 5-year relative survival in Europe improved (60%-->63%). The proportion of cured patients increased slightly but significantly (53%-->55%, p = 0.05). For countries with poorer survival at the end of the 1970s the proportion of cured patients increased faster than average, particularly evident in England (49%-->56%) and Scotland (44%-->53%). By contrast, in Finland, Sweden and Germany with organized screening, 5-year survival and cure rate did not improve, but incidence declined to very low levels. CONCLUSIONS: Cervical screening can explain the trends in cervical cancer survival: this identifies premalignant lesions, reduces incidence and selectively prevents less aggressive cancers. The decreased proportion of the latter means that survival does not improve in countries with low incidence of cervical cancer. The increased proportion of cured patients with time shows that survival improvement was not due simply to earlier diagnosis with no patient advantage.

Adolescent↗

PubMed1999

Reconstruction of human immunodeficiency virus (HIV) sub-epidemics in Italian regions.

BACKGROUND: The spread of human immunodeficiency virus (HIV) infections is likely to consist of sub-epidemics in local areas and/or risk groups. Small-area risk group specific analyses may thus be a suitable means of better understanding and controlling the epidemic course. METHODS: An age, period, and cohort back-calculation method was used to reconstruct region-specific epidemics of HIV infection. The HIV infection incidence rates were estimated for individual Italian regions by using as denominator the specific risk category population (i.e. intravenous drug user population [IDU], homosexual/ bisexual population [MSWM], and Italian general population for heterosexual contacts [HST]). Incidence rates obtained in this way represent the risk of HIV infection conditional to belonging to the specific sub-group of the population. RESULTS: The HIV epidemic is heterogeneous in terms of gender, risk category and region. The highest risk of HIV infection has been estimated in the Lombardia region (North-West area) among men belonging to the IDU category in 1985. In recent years, a trend of decrease in HIV has been estimated, especially among IDU and MSWM. For the HST category, some regions have shown trends of great increase, particularly on the island of Sardegna and the regions of Puglia and Sicilia (Southern Italy). In 1987, most HIV infections were observed among IDU (39-90%), while in 1992 the MSWM and HST categories made the greatest contribution to the HIV epidemic. CONCLUSIONS: The results stress the idea of sub-epidemics rather than a single epidemic affecting the entire country. Some Southern regions emerge as areas in which the spread of HIV infections, although still at a rather low level, should cause considerable concern, particularly the trend of new infections by heterosexual transmission involving the general population. Detailed information on levels and trends of HIV infection epidemics at the local level are essential for surveillance purposes and for planning health care facilities, and can highlight areas in which preventive measures can be effective.

Disease Outbreaks↗

PubMed1998

Survival of women with breast cancer in Europe: variation with age, year of diagnosis and country. The EUROCARE Working Group.

Breast cancer is the most frequent malignancy among women in developed countries. Prognosis is better than for other major cancers, and an improvement in survival has been reported for several populations in recent decades. Within the framework of EUROCARE, a population-based project concerned with the survival and care of cancer patients in Europe, we analysed data from 119,139 women diagnosed with breast cancer between 1978 and 1985 in 12 countries and followed for at least 6 years. Multiple regression models of relative survival, which take mortality from all other causes in each area into account, were used to estimate the effect of age, period of diagnosis and country on survival. For the comparison between countries, survival rates were age-standardised to the age structure of the entire study population. Women aged 40-49 years at diagnosis had the best prognosis in all countries and throughout the study period. Women younger than 30 years at diagnosis had a worse prognosis than those aged 30-39. The highest relative survival at 5 years was in Finland and Switzerland (about 74%), intermediate levels were found for Italy, France, The Netherlands, Denmark and Germany (about 70%) and the lowest rates were in Spain, the United Kingdom, Estonia and Poland (55-64%). During the 6 months following diagnosis, survival was highly dependent on age and was sharply lower in women older than 49 years. For women surviving more than 6 months after diagnosis, survival was similar for all ages, although women aged 40-49 still had the better prognosis. The average rate of death from breast cancer fell by about 2.5% for each year of diagnosis between 1978 and 1985. This improvement manifested mainly in younger and older women, for whom survival was initially less good. The largest improvement was seen in Poland (-15% death risk per year). We suggest that the better survival of women aged 40-49 at diagnosis is related to lower levels of circulating sex hormones, resulting in reduced stimulation of tumour cell growth. Early diagnosis may also be important in the peri-menopausal period due to increased diagnostic attention. Low survival in the United Kingdom may be due to inadequate adherence to consensus treatment guidelines and greater variation in treatment.

Adult↗

PubMed1998

The cure for colon cancer: results from the EUROCARE study.

The interpretation of time trends and geographical differences of population-based survival rates is generally not easy, due to the difficulty in disentangling the effects of observational biases, diagnostic and therapeutic procedures and their interactions. Whereas descriptive analysis of relative survival is generally based on survival levels estimated at fixed time since diagnosis, interpretation issues can take advantage from the analysis of the shape of the considered relative survival. Parametric survival models allowing the estimation of the fraction of cured patients are applied here to analyze and discuss the differences in colon cancer relative survival between European countries, according to age and period of diagnosis. The survival curves of colon cancer patients are described according to 2 parameters: the proportion of cured patients and the mean survival time of fatal cases. These parameters are estimated by least square nonlinear regression of relative survival values derived from the EUROCARE Project publication. Exponential and Weibull survival functions are used to model the relative survival curve for the fraction of fatal cases. The Weibull model gives generally a better fit with respect to the exponential model, thus indicating that the mortality rate for fatal cases is decreasing with time since diagnosis. For the youngest patients, however, the 2 survival functions give practically overlapping estimates. The overall proportion of colon cancer patients in Europe that are estimated to be cured was 38.6%. This proportion increased from 36% to 40% for patients diagnosed in 1978-1980 and in 1983-1985, respectively. Accordingly, mean survival time of fatal cases increased from 1.18 to 1.52 years. According to age, the proportion of cured patients present a marked decrease from young (48.4% at age 15-44 years) to middle-aged patients (38.6% at age 5564 years) and only a mild decrease from these to the oldest patients (34.4% at age 75 or more). The opposite effect was shown by survival time of fatal cases, i.e., 1.71, 1.75 and 0.77 years for the same age classes, respectively. Proportion of cured cases and mean survival time of fatal cases tended to be positively correlated with each other across countries. Our results are consistent with the hypothesis that a real improvement in colon cancer survival took place in Europe during the years 1978-1985 and also suggest that the well-known decrease of relative survival with age at diagnosis could be mostly due to a decreasing efficacy of early diagnosis for patients under 60 years old and to less effective therapies for older patients.

Adult↗

PubMed1998

Survival of European women with gynaecological tumours, during the period 1978-1989. EUROCARE Working Group.

This study concerns the survival of European patients diagnosed between 1978 and 1989 with cancer of corpus and cervix uteri and ovary. Variations in survival in relation to age, country and period of diagnosis were examined. Data from the EUROCARE study were supplied by population-based cancer registries in 17 countries to a common protocol. Five years after diagnosis, relative survival rates were 75, 62 and 35% for cancers of the endometrium, cervix and ovary, respectively. Survival decreased markedly with age. The decrease was especially evident for ovarian cancer, which declined from 65% (15-45 years) to 18% (75+ years). In 1985-1989 there were important inter-country differences in survival for European women with gynaecological cancers: Eastern European countries were characterised by low 5-year relative survival whilst in Sweden, Austria, The Netherlands and Switzerland survival was generally higher than for other European countries. From 1978-1989, 5-year relative survival improved slightly for cervical cancer and improved more among the oldest patients. Prognosis also improved slightly for patients with ovarian tumours and this increase (around 20%) was concentrated among patients between 15 and 64 years of age. Intercountry differences in survival did not in general reduce over time, although for ovarian cancer survival differences narrowed probably in relation to the more widespread use of more effective chemotherapy. Intercountry and time differences in survival for cervical cancer are almost certainly related to variations in the effectiveness of cervical screening programmes. For corpus uteri cancer there was no improvement in survival over the period of this study and intercountry survival differences for this cancer are probably related to differences in patient management.

Adolescent↗

PubMed1998

Variation in survival of adult patients with haematological malignancies in Europe since 1978. EUROCARE Working Group.

Data on 73,070 patients for seven major haematological malignancies diagnosed in Europe between 1985 and 1989 from 39 population-based cancer registries in 17 countries are included in the EUROCARE database. Relative survival was analysed by country and age between 1985 and 1989 and time trends were analysed from 1978-1989 for 13 countries which collaborated in EUROCARE for this entire period. The European weighted age-standardised 5-year relative survival rate was 72% for patients with Hodgkin's disease (HD, ranging from 45 to 76% in 13 countries), 63% for chronic lymphocytic leukaemia (CLL, range 51-79%, 14 countries), 46% for patients with non-Hodgkin's lymphoma (NHL, range 25-63%, 17 countries), 31% for patients with chronic myelocytic leukaemia (CML, range 8-40%, 13 countries), 28% for patients with multiple myeloma (MM, range 18-36%, 14 countries), 25% for patients with acute lymphoblastic leukaemia (ALL, range 19-33%, 7 countries) and 10% for patients with acute myeloblastic leukaemia (AML, range 4-15%, 11 countries). In all countries, relative survival declined with age, most markedly for patients with acute leukaemias. Patients in Northern and Western Europe had better survival rates, particularly in younger patients (15-45 years of age), whilst those in Eastern European countries tended to have poorer rates. Compared with 1978-1979, relative 5-year survival improved in 1987-1989 for most haematological malignancies (relative risk (RR) of death for CLL 0.65, AML 0.75, HD 0.76, ALL 0.79, NHL 0.82), with only CML (RR 0.95) and MM (RR 1.00) showing little or no change. These results suggest that generally and particularly in Eastern Europe there is room for improvement in the diagnosis and treatment of haematological malignancies. The intercountry differences also highlight the importance of socio-economic conditions to health status.

Adult↗

PubMed1998

The impact of the 1993 European revision of the AIDS case definition on back-calculation estimates: an application in Italy.

OBJECTIVES: The revision of the case definition for AIDS within a given observation period causes discontinuity points on the epidemic curve to which back-calculation procedures can be sensitive. The aim of this work is to characterize the impact of the 1993 European revision of AIDS case definition and to evaluate the degree of distortion by which back-calculation estimates obtained on Italian data are affected. METHODS: The back-calculation procedure used, is a generalization of standard methods for estimating and projecting the AIDS epidemic. Age at onset of HIV infection, incubation time distribution, susceptible population and competitive non-AIDS mortality rates for infected persons are included in the estimation process. RESULTS: Back-calculation estimates resulted to be sensitive to the discontinuity point that the 1993 revision of AIDS case definition induced on the epidemic curve. The resulting effect is a tendency to overestimate HIV incidence in recent years by 20-40%. The maximum effect was found using data with end of AIDS cases at December 1993. The overestimation is a transient effect, that is, it is expected to almost disappear in 1995-1996. CONCLUSIONS: The introduction of the 1993 European revision of AIDS case definition caused distortion of back-calculation estimates in Italy, leading to overestimate incidence and prevalence of HIV infection for recent years. It is believed that this effect has occurred in all countries that adopted the 1993 European revision of AIDS case definition, and its characterization is potentially useful for further changes of AIDS case definition in the future.

Acquired Immunodeficiency Syndrome↗

PubMed1997

Estimating population-based incidence and prevalence of major coronary events.

Population-based data on major coronary events (MCE) are generally lacking for large areas, such as at the nationwide level. While mortality data are currently and exhaustively collected in all developed countries and in most developing countries, incidence and prevalence are often available only for certain subgroups of the population under study. We propose a mathematical method to estimate incidence and prevalence using morality and survival data as input, and to forecast MCE occurrence using an age, period, and cohort approach. An application of the method is given to reconstruct incidence and prevalence of MCE in Italy from 1970 to 1990 and to project trends up to the year 2000. MCE incidence has been decreasing since 1974, four years before the observed mortality decline. Conversely, prevalence continues to increase up to the middle of the 1980, and declines thereafter.

Adult↗

PubMed1997

Estimation and projections of colorectal cancer trends in Italy.

BACKGROUND: Occurrence of and prognosis for tumours of the colon and rectum are thought to be changing rapidly due to simultaneous changes in risk factor prevalence, early diagnosis and treatment. In this paper time trends of morbidity, survival and mortality for colorectal cancer during the period 1970-1990 are estimated and analysed. METHODS: Mortality trends were obtained from official death certificates. Relative survival rates were computed from population-based cancer registries. Incidence and prevalence rates were estimated from mortality and survival data. RESULTS: Incidence rates were increasing during the period considered, with a lower rate of increase for the youngest birth cohorts. Relative survival rates of both colon and rectum cancers were higher for women, and for younger age groups, and were positively associated with period of diagnosis. No significant survival difference among the cancer registries used was found. A total of about 155,000 prevalent cases, 40% of which had been diagnosed > or = 7 years before, were estimated in the Italian population for the year 1990. Mortality rates were slightly increasing for men and stable for women. Projections of colorectal cancer trends to the year 2000 indicate major expected rises in both incidence and prevalence. CONCLUSION: Colorectal cancer represents a problem of growing impact for health services in Italy. This conclusion can probably be extended to many developed countries.

Adult↗

PubMed1996

[Survival for digestive system tumors: Italian population-based data and international comparisons].

Survival for malignant tumour of the upper digestive tract, oesophagus, stomach and pancreas are analysed from the data of 5042 cases observed during the period 1976-1985 by the Italian cancer registries (CRs) of Varese, Latina, Ragusa and Florence. Three-year relative survival rates were 42% for patients with tumours of the upper digestive tract and 7% for those tumour of the oesophagus. Five-year relative survival for patients with stomach cancer was 20%. A worse prognosis was found for cases from the Latina and Ragusa CRs. One-year relative survival for patients with pancreatitic cancer was 17%. Younger age, histologic confirmation, period of diagnosis (for upper tract, stomach and pancreatitic cancers), and female gender (for tumours of the upper tract) resulted as positively associated to survival.

Adolescent↗

PubMed1996

[Incidence and prevalence of digestive system tumors in Italy: estimates from mortality data].

This work presents estimates and middle-term projections of incidence and prevalence levels in Italy for cancers of the oral cavity and pharynx, of the stomach, and of colon and rectum. The estimation procedure was previously validated using incidence data observed by Italian cancer registries operating in limited geographical areas. Projections up to the year 2000 of mortality, incidence, and prevalence rates and estimated cohort effects are reported for stomach and colorectal cancers only. For both cancer sites, cohort effects, rather than period effects, result to be responsible for mortality and incidence dynamics. Incidence levels show a general decreasing trend for stomach cancer and an increasing one for colorectal cancer. Cumulative risk trend tends, however, to level-off for the youngest cohorts. Moreover, the well known geographical differences between the North and the South of the country seem to be progressively reducing.

Adolescent↗

PubMed1995

Comparisons of colon-cancer survival among European countries: The Eurocare Study.

Under the aegis of EUROCARE, a European Union project to assemble survival data from population-based cancer registries and analyze them according to standardized procedures, we have investigated and compared colon-cancer survival in 10 European countries. We analyzed 68,283 colon-cancer cases diagnosed between 1978 and 1985 and followed for at least 6 years. After calculating relative survival, putative factors prognostic for survival were investigated by univariate and multiple-regression analyses. Important intercountry colon-cancer survival differences exist within Europe, which are not explained by methodological differences, nor by demographic confounders. In patients aged 60 to 69, the mean European 5-year cumulative relative survival was 40%. Switzerland, Finland and The Netherlands had significantly higher 5-year relative survival, while one area in the UK and Cracow in Poland had significantly lower survival than this European estimate. Prognosis improved over time: from 1978 to 1985, the risk of death was reduced by about 4% per year in all countries studied. Age at diagnosis is inversely related to prognosis. Differences in health provision and hence in quality of care and stage at presentation seem largely responsible for the differences in colon-cancer survival found in the EUROCARE countries.

Adult↗

PubMed1995

A back-calculation method to estimate the age and period HIV infection intensity, considering the susceptible population.

An extension of the back-calculation method to reconstruct the past history of HIV infections is presented. In this method the HIV infection intensity, as a function of age and calendar time, is assumed to belong to a family of parametric functions and is back-calculated from the observed AIDS incidence cases, knowledge of the incubation period and of the susceptible population, the final model being chosen as the one that gives the best fit. The model allows for the interaction between age and calendar time. The application to the main risk groups in Italy, male IVDUs and homosexuals, showed that age and the susceptible population were important in estimating the epidemic among IVDUs; interaction between age and calendar time was found to be significant, showing that among young IVDUs the risk of infection decreased faster than among older IVDUs. Sensitivity of the estimates to the assumption of population and choice of the infection function is investigated.

Acquired Immunodeficiency Syndrome↗

PubMed1995

Use of AIDS surveillance data to describe subepidemic dynamics.

BACKGROUND: Official reports on AIDS surveillance mainly consist of absolute numbers of AIDS cases or cumulative incidence rates. More detailed analyses focusing on the clusters of subepidemics within Italy seemed necessary for a better understanding and more accurate description of the epidemic. METHODS: Age-specific AIDS incidence rates were calculated with reference to resident population by sex, calendar time and geographical area. Age-standardized incidence rates, with the Italian resident population in 1990 as standard, were used to present time trends and geographical distributions. All analyses were repeated for injecting drug users, homosexual/bisexual men, heterosexual contacts and individuals with other or undetermined risk factors. RESULTS: Annual incidence rates for AIDS in Italy increased over the study period. The highest rates were observed in the North and in Sardinia, while Southern regions showed generally lower rates. This heterogeneity was more evident when examining small geographical areas (i.e. provinces). Epidemics in some of the smaller provinces, such as Imperia and Livorno (Northwestern port towns), were shown to be important in that they greatly affect AIDS incidence rates in the regions in which they are located. CONCLUSIONS: According to our analysis, the crude presentation of data from the Italian AIDS Registry is not adequate for understanding the national spread of the AIDS epidemic in terms of several local subepidemics, which may differ by size, temporal trend, and risk group composition. Classifying cases according to their place of residence, which we considered as a good proxy of the place of life, was fundamental for correctly locating these subepidemics. Furthermore, the use of age-standardized rates allowed for unbiased comparisons between regions whose population may have a different age structure and dynamics.

Acquired Immunodeficiency Syndrome↗