Interval cancers in the Dutch breast cancer screening programme

Fracheboud, Jacques; Koning, Harry J. de; Beemsterboer, Petra M. M.; Boer, R. de; Verbeek, A.L.M.; Hendriks, Jan H. C. L.; Ineveld, B. Martin van; Broeders, Mireille J. M.; Bruyn, A. E. De; Maas, P.J. van der

doi:10.1038/sj.bjc.6690786

Cited by 67 publications

(53 citation statements)

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“…Further, discarding DCIS should enhance international comparability of IC by excluding an entity whose classification may differ across pathologists and which is the main contributor to over-diagnosis in screening programmes. On the other hand, inclusion of the DCIS diagnosed in the interscreening interval, which contribute between 2 and 8% of all IC, 7,10,29 implicitly considers opportunistic screening activity as a contributory factor for international differences in IC frequency.…”

Section: Discussionmentioning

confidence: 99%

“…22 The Dutch programme evaluation takes the loss to follow-up into account for women who died or moved away from their region before their next screening examination, and also the exact date of the next screening examination. 10 IC rates are then expressed as the number of IC divided by the number of women-years of follow-up within the corresponding time period. It is important that the numerator and the denominator refer to the same time span when calculating the incidence of IC.…”

Section: Methodsmentioning

confidence: 99%

“…[7][8][9][10][11][12][13][14][15][16] A metaanalysis of population-based programmes showed a 6-fold variation in the level of IC in the first year after mammographic screening. 17 However, several important issues affect the estimation of IC frequency and, consequently, their comparability and interpretation.…”

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confidence: 99%

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Methodological issues in international comparison of interval breast cancers

Bulliard

Sasieni

Klabunde

et al. 2006

Intl Journal of Cancer

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International comparisons of interval cancers (IC) are important to better understand the relationship between programmes' performance and screening practices. In this respect, differences in (i) definition, (ii) identification and (iii) quantification of IC have received little attention. To examine these 3 comparability issues and activities involving IC, an assessment was conducted among member countries of the International Breast Cancer Screening Network, and the impact of accuracy of identification and quantification practices was estimated using 1996-98 data from the Dutch breast cancer screening programme. Information was obtained from 19 screening programmes in 18 countries, 16 of which acknowledged the coexistence of opportunistic screening. IC data were collected to evaluate performance of the screening programme (100% of programmes) and the radiologists (89%); 53% of programmes had a designated review process for IC. Most programmes (84%) agreed with the European Guidelines definition of IC, but a case situation exercise evidenced substantial discrepancy in classification of cancers that occurred after a positive screen. Completeness of identification of IC appears to contribute most to international variation, and cannot be easily controlled for in methodologically rigorous comparisons. Statistically significant differences of about 4% were measured between quantification methods for IC. An operational definition of IC is proposed to enhance international comparability. Valid comparisons of IC are possible with careful attention to the definition but true differences in IC frequency across screening programmes should exceed 10% to be possibly indicative of real differences between programmes. ' 2006 Wiley-Liss, Inc.Key words: mammography; mass screening; interval cancer; international collaboration; comparative study Although mammography is currently the only proven screening method for reducing mortality from breast cancer, 1-3 some breast cancers will inevitably elude screening detection. Interval cancers (IC) are those tumours that are diagnosed in the time period between 2 screening rounds. They occur because of the following: rapid tumour growth leads to cancers that truly develop in the interval after screening, cancers that are present are masked by characteristics of the breast or the cancer, readers miss subtle or minimal signs on the screening mammogram, or further assessment procedures fail to diagnose the cancer radiologically detected. 4,5 From a population-based perspective, IC are a key measure of the quality of the radiology performed and of the early impact of screening programmes. 6 A high incidence of IC adversely affects the ability of a screening programme to reduce mortality from breast cancer. Knowledge of IC is also necessary to determine the sensitivity of the programme and of the radiologists' performance.The frequency of IC has been assessed in randomised studies and in established programmes that provide mammography to a defined target group (service screening), and compa...

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Methodological issues in international comparison of interval breast cancers

Bulliard

Sasieni

Klabunde

et al. 2006

Intl Journal of Cancer

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“…18,19 Early assessment after an unclear screening result is discouraged in the Norwegian Breast Cancer Screening Program's quality manual. Women who [15][16][17] However, when the interval was split in 2 periods, comparison of observed/expected ratios revealed that whereas our rate in the first year was in accordance with the reported proportionate incidences, our estimate of the second year (0.75) was higher than the corresponding figures from other programs (0.59 in East Anglia, 14 0.52 in Holland, 15 0.52 in North West England 16 and 0.54 in Victoria, Australia 17 ). In the last 6-month period, the observed/expected ratio approached 1, which indicated that the incidence of interval cancers approached the expected incidence without screening.…”

Section: Frequency Of Invasive Interval Cancersmentioning

confidence: 99%

“…The results were in agreement with results reported from other mammography screening programs with a 2-year screening interval. 15,22 Two Norwegian clinical breast cancer materials from the prescreening period are published. 23,24 The proportion of pT1 (Յ20 mm) tumors and the proportion of patients with affected axillary lymph in these materials were about 40%.…”

Section: Characteristics Of the Interval Cancersmentioning

confidence: 99%

Interval cancers in the Norwegian breast cancer screening program: Frequency, characteristics and use of HRT

et al. 2001

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Key words: mammography screening; interval cancer; breast density; HRTAs a result of the mortality reduction found in several randomized controlled clinical trials, 1,2 breast cancer screening programs have been implemented in several western countries. 3 The Norwegian Breast Cancer Screening Program is a population-based program that offers women aged 50 -69 years biannual mammography screening. The program started as a pilot project in 4 counties in 1996, and the results from the first screening round were reported earlier. 4 Interval cancers can be defined as breast cancer diagnosed in screened women during the interval between 2 screening rounds, where the diagnosis does not follow from the screening examination. 5 The benefit of attending a screening program is reduced for women diagnosed with interval cancer. Thus the effect of a screening program in terms of mortality reduction can diminish if the frequency of interval cancer is high. This frequency depends, among other factors, on sensitivity of the test and length of the screening interval.Most interval cancers are diagnosed because of symptoms, hence interval and screening-detected cancers might be expected to have different characteristics. High breast density and use of hormone replacement therapy (HRT) have been discussed as possible contributors to reduction of screening sensitivity, and this may be related to occurrence of interval cancers. 6 -11 The purpose of our study was to quantify the interval cancers in the pilot project and to explore characteristics and factors that may be associated with interval cancer. To study the relations between use of HRT, breast density and interval cancer, data from a blinded review (breast density) and a questionnaire (use of HRT) were linked. MATERIAL AND METHODS Screening populationThe Norwegian Breast Cancer Screening Program is population based and covers women aged 50 -69 years. The screening population is identified through the Central Population Register, in which each inhabitant in Norway has a unique 11-digit number. Women are invited into the Norwegian Breast Cancer Screening Program irrespective of previous breast cancer history. The screening interval is 2 years. Two-view mammograms and independent double reading are standard. The pilot project included 4 counties with about 40% of the Norwegian female population aged 50 -69 years. During the first round (1996-97), 159,887 women born from 1927-46 were invited and 127,064 women were examined (79.5%). 4 Study subjectsWomen who had their first screening examination within the pilot project after July 31, 1998 (n ϭ 411) and women who experienced recurrence in the same breast as a previous lesion (n ϭ 6) were excluded from the study. Women who received a cancer diagnosis in the first screening round (n ϭ 854) were not included as being at risk of interval cancer. However, women who were screen-positive but cleared after assessment were included. This left 125,793 women at risk of developing interval cancer. The women were followed until the date an in...

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Spontaneous Regression of Cancerous Tumors Detected by Mammography Screening

2004

JAMA

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Interval cancers in the Dutch breast cancer screening programme

Cited by 67 publications

References 21 publications

Methodological issues in international comparison of interval breast cancers

Methodological issues in international comparison of interval breast cancers

Interval cancers in the Norwegian breast cancer screening program: Frequency, characteristics and use of HRT

Spontaneous Regression of Cancerous Tumors Detected by Mammography Screening

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