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. |