Prescreening Period Research Articles

In situ breast cancer: Incidence trend and organised screening programmes in Italy

The effect of mammography screening programmes on the incidence of in situ breast cancer (CIS) is described by analysis of the CIS incidence trend in the 1990s and comparison of pre-screening and screening periods in six areas of Italy. All 1069 CIS arising in women aged 40–79 years between 1988 and 1999 were analysed through age-standardised rates and Poisson regression models. The results show that, for the whole series, ductal carcinoma in situ (DCIS) represented 89% and lobular carcinoma in situ (LCIS) 11% of CIS detected. For all six areas, the introduction of screening increased the incidence of DCIS (screening/pre-screening ratio, range 1.12–1.77). Overall, DCIS represented 11% (226/2022) of all screening-detected cancers. A significant increasing trend in DCIS incidence during the 1990s and a modification in pattern of age-specific incidence rates after the beginning of screening programmes were observed. This increase can largely be explained by screening programmes. The incidence observed during the screening period was a persistent 39% higher than during the pre-screening period, after adjustment for the “percentage of cases diagnosed by screening”. The increase also involves women at an age not targeted by screening programmes. In conclusion, as the increasing trend in DCIS is not completely explained by the effect of the screening programmes, this supports the use of mammography as a “spontaneous” preventive practice during ongoing organised screening programmes, particularly among age groups not usually invited for screening. Therefore, the effect of mammography on stage-specific incidence of CIS may be more marked than expected on the basis of the effect of screening programmes.

Pre-Screening Via Sleep Logs in Sleep-Disordered Patients - Adaptational Effects, Yes or No?. Finden sich Adaptationseffekte bei der Bearbeitung von Schlaftagebuchern durch Schlafgestorte?

Sleep logs are common tools in sleep research and clinical routine. Usually sleep logs have to be completed during a 2-week period, with the first week serving as an adaptation to the instrument itself. In the present study, we investigated whether there is indeed such an adaptation bias or not. A total of 236 chronically sleep-disordered outpatients completed the standardized sleep log ‘Abend-Morgen-Protokoll’ during a 2-week pre-screening period prior to the first visit in our sleep ambulance. Two sets of items were established, the ‘instrumental’ and the ‘therapeutic’ set. The respective ratings of the first and second week (week A, B) were compared to evaluate clinically relevant changes. The ratings of several ‘instrumental’ items significantly differed between week A and B. However, these changes—on average—were only marginal and therefore of little clinical importance. Regarding the ‘therapeutic’ set of items, no systematic variations could be ascertained over the assessment period. The present investigation could not confirm the presence of adaptation biases (instrumental, therapeutic) in a large sample of chronically sleep-disordered outpatients. Therefore, we consider a 1-week pre-screening period via sleep log as sufficient for the diagnostic process in these patients.

The impact of organised screening programmes on the stage-specific incidence of breast cancer in some Italian areas

The aim of this study was to examine the effects of mammographic screening programmes on stage-specific incidence of breast cancer. The study compared prescreening and screening periods in seven areas in Italy, primarily evaluating the first screening round. All 17 617 breast cancers (16 554 invasive, 1063 in situ) registered in women aged 40–79 years between 1988 and 1999 were analysed through age-standardised rates and Poisson regression models. For all areas, independent of the baseline rates, the introduction of screening increased incidence for invasive cancers overall and, more markedly, for early cancers (screening/prescreening ratio: range 1.07–1.47 and 1.23–1.82, respectively), modifying the pattern of age-specific rates. The multiple regression analysis showed that the percentage of cases diagnosed at screening explained most of the increase; a residual effect of diagnosis period (screening versus prescreening) suggested a role for ‘spontaneous’ early detection in ages outside of the screening programme. Advanced cases did not show consistent variations across the registries for those aged 40–79 years (range: 0.91–1.21), whereas a more coherent picture was observed for those aged 50–69 years. In one area, a moderate reduction in the number of ‘advanced’ cases in the second screening period was observed. For all stages, the age-specific incidence rates of cases diagnosed outside of the screening programme for the age groups 50–69 years were lower than the corresponding rates in the prescreening period, suggesting a shift from the usual clinical services to the screening programme. Our results confirmed the increase in early-stage cancers occurring at the start of screening, and substantially explained the rise in breast cancer incidence. In addition, our study confirms the importance of cancer registries in monitoring the effect of breast cancer screening and the validity, for this purpose, of the linkage between cancer registries and screening programme databases.

The impact of organized mammography service screening on breast carcinoma mortality in seven Swedish counties.

The evaluation of organized mammographic service screening programs is a major challenge in public health. In particular, there is a need to evaluate the effect of the screening program on the mortality of breast carcinoma, uncontaminated in the screening epoch by mortality from 1) cases diagnosed in the prescreening period and 2) cases diagnosed among unscreened women (i.e., nonattenders) after the initiation of organized screening. In the current study, the authors ascertained breast carcinoma deaths in the prescreening and screening epochs in 7 Swedish counties from tumors diagnosed in these epochs and in the age group 40-69 years in 6 counties and 50-69 years in 1 county. Data regarding deaths were obtained from the Uppsala Regional Oncologic Center in conjunction with the National Cause of Death Register. The total number of women in the eligible age range living in each county was obtained from the annual population data of Statistics Sweden. Detailed screening data were provided by the screening centers in the seven counties, including the number of invited, the number attended, and whether each individual breast carcinoma case was exposed (screen-detected and interval cases combined) or unexposed (not-invited or nonattenders) to mammographic screening. There were 2044 breast carcinoma deaths from 14,092 incident tumors diagnosed in the prescreening and screening epochs, and the total number of person-years was 7.5 million. Data were analyzed using Poisson regression with corrections for self-selection bias and lead-time bias when appropriate. The mortality reduction for breast carcinoma in all 7 counties combined for women actually exposed to screening compared with the prescreening period was 44% (relative risk [RR] = 0.56; 95% confidence interval [95% CI], 0.50-0.62). When all incident tumors were considered, both those exposed and those unexposed to screening combined, counties with > 10 years of screening were found to demonstrate a significant 32% mortality reduction (RR = 0.68; 95% CI, 0.60-0.77) and counties with < or = 10 years of screening showed a significant 18% reduction in breast carcinoma mortality (RR = 0.82; 95% CI, 0.72-0.94) for the screening epoch compared with the prescreening epoch. Within the screening epoch, after adjustment for self-selection bias, a 39% mortality reduction (RR = 0.61; 95%CI, 0.55-0.68) was observed in association with invitation to screening. Organized service screening in 7 Swedish counties, covering approximately 33% of the population of Sweden, resulted in a 40-45% reduction in breast carcinoma mortality among women actually screened. The policy of offering screening is associated with a mortality reduction in breast carcinoma of 30% in the invited population, exposed and unexposed combined. The results of the current study indicate that the majority of the breast carcinoma mortality reduction is indeed due to the screening.

Epidemiology of Familial Adenomatous Polyposis in Sweden: Changes over Time and Differences in Phenotype between Males and Females

Background: The Swedish Polyposis Registry was set up in Sweden in the late 1950s to promote screening of familial adenomatous polyposis (FAP). The aim of this study was to examine the epidemiology of FAP in Sweden, including the influence of screening on morbidity and mortality in colorectal cancer (CRC). Methods: Four hundred and thirty-one patients (213 males and 218 females) with FAP from 145 families recorded by the Swedish Polyposis Registry were investigated. The effect of screening on morbidity and mortality in CRC was evaluated by comparing the 216 probands with the 215 call-up patients. Three different periods were studied: the pre-screening period (1912-1956), the first screening period (1957-1976), and the second screening period (1977-1996). Results: The mean annual incidence rates during the three periods were 0.2, 1.38, and 0.86 per million, respectively. The birth frequency was calculated to be 1 in 18,000 between 1947 and 1966, and the prevalence was 32 per million at the end of 1996. The proportion of new mutants among the FAP patients born between 1927 and 1966 was estimated to be 11%. The median age at diagnosis of probands was 39 (range, 11-71) years and did not change over time, although an increase was seen in the subgroup with CRC at diagnosis (P = 0.02). In the call-up group the median age at diagnosis was 22 (range, 3-65) years. Sixty-seven per cent of the probands and 3.3% of the call-up patients had CRC at diagnosis, and the corresponding mortality figures were 44% and 1.9%. The risk among probands of having CRC at diagnosis decreased from 81% to 49% (P = 0.0006). Female probands were diagnosed with symptoms (P = 0.03) and CRC (P = 0.04) earlier than male probands. Conclusions: A nationwide screening program facilitates detection and early diagnosis of FAP. A decrease in CRC morbidity among probands contributed to the improved prognosis. An earlier onset of symptoms and CRC in females indicate that the course of FAP is influenced by sex.

The influence of mammography screening on the pathological panorama of breast cancer.

The pathologist describes the biological domain of breast cancer in which the clinician works. Over the last 20 years there have been indications that the biological domain has shifted following the introduction of fine-needle biopsies, clinical mammography, and later screening mammography. The most commonly used parameters for staging, classification and grading of cancer in some respects probably reflect the biological domain. We describe how the pathological panorama of breast cancer has changed with the introduction of population-based mammography screening. Our experiences are based on a consecutive series of 1961 breast cancers diagnosed from 1977 to 1994 in a region where screening mammography was introduced in 1988. All results, including histological classification and grading were prospectively registered in a computerized data base. There were more comedo than tubuloductal carcinomas and there was a corresponding preponderance of grade III tumours in the youngest and a high incidence of tubuloductal, lobular and colloid cancers in the oldest age group. The proportion of women with comedo carcinoma decreased after 1987. Looking at changes in the grade distribution after 1987, the proportion of women with grade I tumours increased and grade III tumours decreased in women over 50 years of age, but in the youngest women only marginal changes were noted. Very few in situ carcinomas were diagnosed in the prescreening period. About 11% of all tumours were in situ after 1987. The percentage of node-positive cancer decreased in the screening period in all histological types of cancer regardless of tumour size. The percentage of small tumours < or = 20 mm increased with time, though less so for comedo carcinomas. Comedo carcinomas dominate among the largest cancers most frequently detected clinically. From a biological standpoint it is interesting to note that screening seems to entail a larger shift in the biological domain in older as compared to younger women. Furthermore, comedo carcinomas seem to be less well detected by the screening procedure.

Incidence of neuroblastoma in Sapporo City

The incidence of neuroblastoma in Sapporo City for the period before the enforcement of the mass screening of neuroblastoma (1974 to 1980) was compared with the period after it (1981 to 1987). No large difference was found in incidence between them. In 1981 to 1987 the occurrence cluster at 2 to 4 years of age found in the prescreening period disappeared and an accumulation of patients at 0 year of age was noted. The sensitivity of the mass screening was almost stable (76.9% to 80.0%) throughout the 7 years. By the mass screening system of Sapporo City, early detection will be expected in 60% to 70% of all the neuroblastoma patients, the deficiency of which is due to the patients who neglected the mass screening.