Table 2

Main characteristics, results and quality rating of four studies on mammography screening
Author, Year (ref) Study design, Study period,Population, Readers Index test (I) Reference test Results CI= confidence interval Se= sensitivity Sp=specificity Study quality, Comments
Gilbert et al., 2008 [71] Prospective, multicentre 2006-2007 I.1: single reading + CAD, n=28,204 Biopsy of suspected cases or follow-up (not all, though; number not reported) Cancer detection rate: Moderate
Single reading + CAD: 7.02 /1000.
Population: Double reading: 7.06/1000. Restricted generalisability since results were based on single reading +CAD by experienced radiologists.
Difference not statistically significant (NS).
I.2: double reading, n=28,204.
Initially invited: 68,060 women.
Recall rate: Incomplete follow-up, particularly affecting the estimates of sensitivity.
Investigated: 28,204.
Aged 50-70 years (1 % > 70 years). Single reading + CAD: 3.9 %.
Double reading: 3.4 %. Scanned analogue mammograms.
Difference 0.5 % (95 % CI: 0.3;0.8).
Readers: radiologists (n=17), specially trained staff (n=10).
Accuracy:
Single reading + CAD:
Se= 87.2 %
Sp= 96.9 %
All readers had at least 6 years’ experience and >5000 readings/year Double reading:
Se= 87.7 %
Sp= 97.4 %
Difference in sensitivity:
0.5 % (95 % CI:
-7.4;6.6), (NS).
Difference in specificity 0,5% ( CI not specified but reported NS).
Gromet et al., 2008 [69] Retrospective I.1: Single reading + CAD Biopsy and follow-up Cancer detection rate: Low
Population: Single reading + CAD: 4.2/1000. Retrospective study (controlled for age and time since last screening).
231 221 women Double reading: 4.46/1000 (NS).
2001-05 n=118,808.
I.2: Double reading Follow-up time unclear.
Readers:
Screening situation not applicable to European conditions (i.e. recall rate higher than accepted in Europe).
Single reading + CAD: specialists in mammography.
n=112,413. Recall rate:
Single reading + CAD: 10.6 %.
Double reading: Specialists in mammography + radiology. Double reading:11.9%.
Difference statistically significant (p=0.001).
Invitation procedure and blinded readings unclear.
Accuracy:
Single reading + CAD: Se= 90.4 % Scanned analogue mammograms.
Double reading:
Se=88.0 %.
Difference statistically significant.
Percent of recalled with cancer:
Single reading + CAD: 3.9%.

Double reading: 3.7%

(NS).

Georgian-Smith et al., 2007 [68] Prospective I.1: Single reading + CAD Biopsy and at least 12 months´ follow-up to detect false negatives. Cancer detection rate: Low
Study period: 2001-03 Single reading +CAD: 2.0/1000. Screening situation not applicable to European conditions. Invitation procedure not described.
n=6381. Double reading: 2.4/1000 (NS).
Population: 6381 consecutive screening examinations
I.2: Double reading
Recall rate: Population, selection criteria, withdrawals unclear.
n=6381. Single reading +CAD: 7.87%.
Double reading: 7.93% (NS).
Readers: Not independent double reading but blinded to CAD
Experienced breast radiologists Accuracy:
Sensitivity and specificity not reported. Number of recalls based on all readings.
Single reading + CAD. Scanned analogue radiographs.
Double reading: Not independent reading.
Khoo et al., 2005 [70] Prospective I.1: Single reading +CAD n= 6111. Biopsy Cancer detection rate: Low
Study period: not reported. Not reported Total for double reading + single reading + symptomatic patients:10/1000. A so-called relative sensitivity used since 3-year follow-up not yet achieved.
No follow-up
Population: 6,111 women (45-94 years), screening every 3rd year
Not reported individually for the groups.
Relatively high screening age and long screening intervals.
I.2: Double reading n= 6111.
Recall rate:
Single reading + CAD: 6.1%. Unclear whether the readings were blinded.
Double reading: 5.0 %. Incomplete follow-up.
Readers: Difference statistically significant Scanned analogue radiographs.
Radiologists (n=7) and specially trained staff (n=5).
Accuracy: (relative sensitivity)*
Single reading + CAD: Se= 91.5%.
Double reading: Se= 98.4% (NS).
Double reading not always performed by two radiologists.

* Relative sensitivity= number of detected cancer cases per reader divided by all detected cancer cases (due to lack of follow-up).

Azavedo et al.

Azavedo et al. BMC Medical Imaging 2012 12:22   doi:10.1186/1471-2342-12-22

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