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Table 1 Summaries of included reviews’ characteristics and results

From: Effectiveness of clinical breast examination as a ‘stand-alone’ screening modality: an overview of systematic reviews

Author (year) Number of included studies Focus only on CBE AMSTAR 2b classification Reports on outcomes Conclusions on CBE
  a. RCTs
b. NRSI
c. Systematic reviews
   a. Mortality
b. Downstaging
c. False positive rate
d. Sensitivity | Specificity | Positive predicted value
 
Fletcher SW (1993) [30] a. 2
b. 0
c. 0
No Low a. No difference in mortality rate between MMR + CBE vs CBE
b. Did not report
c. Did not report
d. 46–64% | 99.1–99.7% | 2.9–4%
+ Mammography and CBE detect breast cancer in a complementary manner
+ Careful CBE may be as effective as mammography regarding mortality reduction
Barton MB (1999) [32] a. 4
b. 4
c. 0
Yes Low a. No difference in mortality rate between MMR + CBE vs CBE
b. Did not report
c. Did not report
d. Pooled results: 54.1% | 94% | 10.6%
+ A well-conducted CBE can detect at least 50% of asymptomatic cancers and may contribute to mortality rate reduction in women screened -- > Screening CBE should be conducted
Humphrey LL (2002) [33] a. 4
b. 2
c. 1
No Moderate a. 14–29% mortality reduction in trials of MMR + CBE. Mortality reductions in trials of MMR + CBE were similar to trials of CBE only
b. Did not report
c. 13.4%
d. 40–69% | 88–99% | 4–50%
+ MMR has little additive benefit in the setting of a careful, detailed CBE
+ No direct evidence that CBE decreases mortality
Kosters JP (2003) [31] a. 1
b. 0
c. 0
No High a. Did not report
b. Did not report
c. Did not report
d. Did not report
The only trial investigated CBE vs no screening was discontinued due to poor compliance -- > CBE cannot be recommended
Elmore JG (2005) [37] a. 4
b. 3
c. 2
No Low a. Did not report
b. Did not report
c. 20%
d. 28–54% | 94% | NR
+ CBE detects some cancers missed by MMR
Nelson HD (2009)a [29, 34] a. 4
b. 1
c. 0
No High a. No difference in mortality rate between MMR + CBE vs CBE (RR = 1.02, 95% CI: 0.78–1.33)
b. Did not report
c. Did not report
d. 25.6% | NR | 1%
+ Trials of CBE are ongoing -- > no benefit on mortality has been shown at this point
CTFPHC (2011)a [6, 28] a. 4
b. 2
c. 0
No High a. No evidence was found to show that CBE reduced mortality due to BC or all-cause mortality
b. Did not report
c. Did not report
d. Did not report
No evidence was found to support the benefit of CBE, either alone or in conjunction with mammography
Myers ER (2015)a [27, 35] a. 3
b. 4
c. 0
No Moderate a. No effect of CBE alone on mortality (based on only 1 US case-control study which also found no effect of mammography on mortality)
b. Did not report
c. 0.9–5.7%
d. Did not report
+ Lack of evidence showing benefits of CBE alone or in conjunction with mammography
+ No studies assessing other critical outcomes
Hamashima C (2016) [7] a. 1
b. 6
c. 1
No Moderate a. Based on 1 Japanese case-control study, among asymptomatic women, 1 CBE within 5 years: OR = 0.45 (95% CI: 0.22–0.89)
b. Did not report
c. Did not report
d. 46–63% | 94.3–97.3% | NR
+ CBE is not recommended for population-based screening program due to insufficient evidence
IARC (2016) [36] a. 6
b. 10
c. 1
No Moderate a. No difference in mortality rate between MMR + CBE vs CBE (RR = 0.97, 95% CI: 0.62–1.52)
b. Mumbai trial: Significant shift to a lower stage in the screening arm compared with the control arm (RR, 1.45; 95% CI: 1.09–1.93). Kerala trial: early-stage breast cancer was 43.8% in the intervention group versus 25.4% in the control group (P = 0.023)
c. 5.7%
d. 52–85% | 93.4–96% | 1–4%
+ There is sufficient evidence that screening by CBE alone shifts the stage distribution of tumours detected towards a lower stage
+ There is inadequate evidence that screening by CBE alone reduces breast cancer mortality
Mandrik O (2019) [4] a. 0
b. 0
c. 10
No Moderate a. No solid evidence of mortality reduction
b. Acknowledged but did not summarise the evidence
c. Higher rate of false-positive rates (did not report how higher)
d. 28–36% in the community, 47–69% in RCTs in all except 1 review | > 88% in all reviews | NR
+ The review could not summarise evidence on down-staging but IARC report concluded there are sufficient evidence for this outcome
+ More original research on benefits and harms of CBE is required
+ Lack of research in LMICs -- > evidence cannot be generalized to these settings
  1. CBE Clinical breast examination, MMR Mammography, NR Did not report, NRSI Non-randomized studies of interventions, RCTs Randomised controlled trials
  2. aIncluded results from the full report version (grey literature)
  3. bAMSTAR stands for A MeaSurement Tool to Assess systematic Reviews (https://amstar.ca). The AMSTAR checklist contains 16 items, of which, 7 items are marked as critical. The overall quality rating of four categories “high”, “moderate”, “low”, and “critically low” is based on the weaknesses detected in critical and non-critical items [24]