Introduction of organised mammography screening in Tyrol: results following first year of complete rollout
© Oberaigner et al; licensee BioMed Central Ltd. 2011
Received: 20 May 2011
Accepted: 30 August 2011
Published: 30 August 2011
In Tyrol, Austria, the existing system of spontaneous mammography screening was switched in 2007 to an organised program by smoothly changing the established framework. This process followed most EU recommendations for organised mammography screening with the following exceptions: women aged 40-49 are part of the target population, screening is offered annually to the age group 40-59, breast ultrasound is available as an additional diagnostic tool, and double reading has not yet been implemented. After a pilot phase the program was rolled out to all of Tyrol in June 2008. The aim of this study was to analyse the performance of the organised screening system by comparing quality indices and recommended levels given in the well-established EU guidelines.
Working from the results of the pilot phase, we extended the organised mammography system to all counties in Tyrol. All women living in Tyrol and covered by compulsory social insurance were invited for a mammography, in the age group 40-59 annually and in the age group 60-69 biennially. Screening mammography was offered mainly by radiologists in private practice, with further assessment performed at hospitals. Using the screening database, all well-established performance indicators were analysed and compared with accepted/desired levels as per the EU guidelines.
From June 2008 to May 2009, 120,440 women were invited. Per 1000 mammograms, 14 women were recalled for further assessment, nine underwent biopsy and four cancer cases were detected. Of invasive breast cancer cases, 32.3% and 68.4% were ≤ 10 mm and ≤ 15 mm in size, respectively, and 79.2% were node-negative. The positive predictive value for further assessment and for biopsy was 25.9% and 39.9%, respectively. Estimated two-year participation rate was 57.0%. In total, 14 interval cancer cases were detected during one year of follow-up; this is 18.4% of the background incidence rate.
In Tyrol, Austria, an organised mammography screening program was implemented in a smooth transition from an existing spontaneous screening system and was completely rolled out within a short time. The high level of performance already seen in the pilot phase was maintained after rollout, and improvements resulting from the pilot phase were affirmed after one year of complete rollout.
Breast cancer is the leading cause of female cancer death in all industrialised countries (and also worldwide), and the breast is also the leading incident cancer site for females . Therefore, screening methods for breast cancer are of greatest public health importance. A recently published Cochrane Review, which assessed the effect of mammography screening for breast cancer on mortality and morbidity concluded that screening is likely to reduce breast cancer mortality .
In 2006, in Tyrol, Austria, the decision was made to change the existing spontaneous mammography screening system to an organised program while, on the one hand, making best possible use of the mammography screening network established over the previous fifteen years and, on the other hand, following most EU recommendations for organised mammography screening. After a pilot phase conducted in two central counties of Tyrol covering 40% of the population from June 2007 to May 2008 , the organised system was completely rolled out to all of Tyrol in June 2008. It was possible to establish a country-wide mammography screening program in a very short time, which differs only in the following aspects from the EU guidelines : women aged 40-49 are part of the target population, screening is offered annually in the age group 40-59, breast ultrasound is available as an additional diagnostic tool, and double reading has not yet been implemented.
To our knowledge, some European countries still have no organised mammography screening program or are in the process of planning to set up such a system [5, 6]. Therefore, the Tyrolean experience can make an important contribution to deciding how to switch a health system with spontaneous mammography screening to an organised screening program that meets well-accepted quality guidelines.
It was the aim of this study to analyse the performance of the organised mammography screening system after complete rollout to all counties in Tyrol by measuring the quality indicators recommended by the EU guidelines  and to determine whether the high quality observed in the pilot phase could be affirmed after rollout.
Study population, invitation
All mammography units registered basic information in a database. Screening and assessment information was transferred to a central database after pseudonymising the woman's social insurance number . In addition, data on tumour characteristics were collected by the Cancer Registry of Tyrol.
The screening and assessment data were realised as STATA datasets. Linkage between screening data, assessment data and Cancer Registry data is based on the pseudonym number. We reported numbers and proportions as defined in the EU guidelines . For some indices, population-based rates were computed using the official population data supplied by Statistics Austria. No statistical testing was applied. All reporting was done with STATA Version 11 .
Performance indicators were reported from all screens in women aged 40-69 between June 2008 and May 2009.
Participation rate was calculated following a cohort approach: we counted every woman only once in the observation period, which was either one year or two years. Due to the fact that nearly half of women aged 40 to 59, who attend screening regularly, do not return for screening in the first year although they are invited annually, we computed for that age group also a two-year participation rate, meaning an observation period of two years.
Data on all mammography investigations performed in Tyrol are transferred to the screening database. A small portion (5.9%) of the women refused consent for data transfer to the screening database and we therefore receive only an empty dataset. Of all other mammography data, 76% belong to the screening population. By assuming this same proportion of 76% for the empty dataset, we calculated a proportion of 4.5% to be added to the observed participation rate accounting for empty datasets describing real numbers of mammography screening investigations.
As spontaneous mammography screening was already introduced to Tyrol in the early 1990s, the underlying background incidence rate (BIR) was defined by years of diagnosis 1988-1990.
This study was conducted in conformity with the Helsinki Declaration . The project was approved by the Ethics Committee of Innsbruck Medical University.
Invitation system: Number of women invited and participation rates
Observed one-year participation rate
Estimated one-year participation rate
Observed two-year participation rate
Estimated two-year participation rate
Additional ultrasound at screening
Ultrasound following mammography screening
Reason for ultrasound:
Breast density (ACR 3/4)
Recall for further assessment rate [per 1000 screens] and number of recalls 2)
Intermediate screening test recommended in six months
Screening result unknown3)
Biopsy rate [per 1000 screens]
Cancer detection rate [per 1000 screens]
Proportion of in situ cases
Ratio screening breast cancer detection rate vs. background incidence rate 4)
Of 139 invasive cancers diagnosed in screening, four changed to "in situ cancer" after final diagnosis. Two invasive cancer cases did not undergo surgery because of metastatic disease. Finally, three invasive cancer cases underwent neoadjuvant therapy and it was not possible to identify preoperative staging.
Of all invasive cancers detected and finally proven, 32.3% and 68.4% showed tumour size ≤10 mm and ≤15 mm, respectively. Lymph node involvement was observed in 20.8% of invasive cancer cases (Table 4).
For invasive cancers, 90.6% of further assessments were carried out within five working days after screening and 87.1% and 90.1% underwent surgery within ten days and 15 days after decision to operate, respectively. For all cases except invasive cancers, 73.7% underwent assessment within five working days and 17.1% after ten or more working days (Table 5).
Characteristics of invasive cancer cases
Tumour size (mm): N = 133
Tumour size (mm):
< = 10 mm
< = 15 mm
> 20 mm
Lymph node involvement
Staging according to UICC
Screening to assessment
≤ 5 wd
> 10 wd
Decision to operate to date of therapy
≤ 10 wd
> 30 wd
All screens except those ending in invasive cancers
Screening to assessment
≤ 5 wd
> 10 wd
Interval cancer rate within first year
Interval cancer rate per 100,000 screens (number of cases in brackets)
Proportion of background incidence rate1) (in percent)
EU Guidelines, quality indicators (with accepted and desired levels)
Participation rate (after two years of observation)
Recall for further assessment rate1)
Breast cancer detection rate
2.0 * BIR
Interval cancer rate/Background incidence rate (BIR) 0-11 months
Proportion of screen-detected cancers that were invasive
Proportion of screen-detected cancers that were stage II+
Node-negative cancer/Total invasive cancers screen-detected
Invasive cancers ≤ 10 mm/Total invasive cancers
Proportion of invasive cancers that were ≤ 15 mm in size
Time between results of screening and assessment < = 5 wd3)
Time between decision to operate and surgery < = 15 wd4)
We analysed performance after one year of rolling out an organised mammography screening program to all counties in Tyrol. The organised program was established in a smooth transition from an existing spontaneous mammography screening system, instead of setting up a completely new screening system, and was previously tested in a pilot phase comprising 40% of the target population . Although not all EU recommendations were followed, most quality indicators are in the range of accepted/desired levels given by the EU guidelines . The only parameter that clearly missed the EU guidelines was the participation rate: the two-year participation rate was 57% as compared to the 75% recommended by the EU guidelines. In our opinion, a cumulative participation rate of 57% after two years of observation looks successful when compared to neighbouring countries [10–12]. Nevertheless, it is not the goal we aimed for.
The strengths of the Tyrolean breast cancer screening program are its implementation and performance: we were able to set up an organised population-based screening program within a short time with minimal additional resources that shows good performance. In summary, the recall for further assessment rate and the biopsy rate are fairly low, PPV was good as compared to other programs, only few open biopsies were performed, and despite the lack of double reading the interval cancer rate of 20% of the underlying BIR is rather good as compared to other programs [10, 13–15].
However, this study has several weaknesses. First, up to now we have not implemented double reading as recommended in the EU guidelines. Interestingly, performance parameters and especially interval cancer rate showed that also without double reading an acceptable quality level was achieved. One reason could be the extensive use of additional US, about three of four women underwent additional US. The real benefit of US in a population-based mammography screening program is currently under discussion and has to be further evaluated [16, 17]. Calculation of the interval cancer rate is reliant on the completeness of the Cancer Registry of Tyrol, which covers the target population. Completeness of incidence data in general has been shown to be very good [3, 18]. In order to be able to analyse interval cancer rates for the screening program the timeliness of registration of breast cancer was improved, and linkage between cancer registry data and screening data is based on pseudonymising the social insurance number, which is read electronically. In the meantime, we have also assessed interval cancer in the time window 12 to 23 months for the pilot phase of the Tyrol program, see , and found five interval cancer cases in age group 40-49 (55% of BIR) and seven interval cancer cases in age group 50-69 (33% of BIR), data not shown.
Second, the average number of screens read by a radiologist in Tyrol per year (about 3200) does not meet the EU recommendation of 5000. A recent publication  showed that annual numbers below 5000 can still provide good sensitivity and acceptable false-positive rates.
Third, we used BI-RADS categories instead of a single yes/no rule for recall for further assessment. Some radiologists still use BI-RADS 0 (meaning unclear result) in a small number of cases (0.2% of all screens), and 15 per 1000 screens were invited to an intermediate screening test six months following a BI-RADS 3 screening result. Due to this inconsistency, the current program includes the following modifications: BI-RADS 0 is no longer allowed and BI-RADS 3 is strictly associated with recall for further assessment.
Many countries have run a mammography screening program for decades or for a shorter time. On the other hand, there are still some countries with no organised breast cancer screening program. For those countries thinking of or already in the process of introducing a mammography screening program, our manner of introducing an organised program can serve as one how-to example. In our opinion, the greatest difference between our approach and other approaches, especially compared to Germany, is the smooth transition made from an existing spontaneous program to an organised population-based screening. We made use of the network of screening and assessment units that had already been set up during spontaneous screening and added an invitation system covering the entire population of Tyrol, a screening database that allows quality indices to be monitored and a well-defined training program for both screening and assessment units. With this strategy we were able to meet most EU quality indices within a very short time.
In Tyrol, Austria, an organised mammography screening system realised in a smooth transition from an existing spontaneous screening system was rolled out in a short time. The high level of performance already observed in the pilot phase has not changed after the first year of complete rollout. Improvements suggested during the pilot phase were affirmed after rollout: it will be necessary to concentrate on efforts to improve the participation rate, introduce double reading, change the rule for BI-RADS 3, and reduce the number of additional ultrasound exams.
List Of Abbreviations
ultrasound, ÖRG: Austrian Radiology Association, ACR: American College of Radiology, MRI: magnetic resonance imaging, BIR: background incidence rate, PPV: posivite predictive value.
We thank Patricia Gscheidlinger for secretarial support.
Mammography Screening Project Tyrol Working Group:
Radiologists: B. Bischof, Innsbruck; J. Bliem, Wörgl; M. Daniaux, Innsbruck; A. Dessl, Zams; G. Egender, Hall/Tirol; W. Hönlinger, Innsbruck; W. Kastlunger, Schwaz; R. Knapp, Kufstein; A. Lederer, Lienz; C. Lottersberger, Schwaz; D. Lungenschmid, Innsbruck; A. Oberhauser, Innsbruck; E. Partl, Kitzbühel; T. Penz, Innsbruck; C. Rapf, Lienz; E. Schmaranzer, St. Johann; G. Schön, Telfs; R. Schöpf, Landeck; F. Weber, Hall in Tirol; K. Wicke, Innsbruck; C. Wolf, Reutte
Project Team: W. Buchberger, M. Daniaux, C. Greil-Thum, R. Knapp, G. Nestler, W. Oberaigner, B. Schreiner, K. Wicke
This work was supported by the ONCOTYROL Center for Personal Cancer Medicine. ONCOTYROL is a COMET Center funded by the Austrian Federal Ministry of Transport, Innovation and Technology (BMVIT) and the Austrian Federal Ministry of Economics, Family and Youth (BMWFJ), the Tyrolean Future Foundation (TZS) and the State of Styria represented by the Styrian Business Promotion Agency (SFG) and supported by UMIT - University for Health Sciences, Medical Informatics and Technology, Innsbruck Medical University, Tyrolean Health Insurance Fund and Tyrolean Health Company.
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