Comparing Breast Screening Protocols: Inserting Catch Trials Does Not Improve Sensitivity over Double Screening

Area of Science:

• Radiology
• Medical Imaging
• Cancer Detection

Background:

• Breast screening is crucial for early breast cancer detection.
• Low tumour prevalence in mammograms can lead to missed diagnoses (prevalence effect).
• A novel catch trial (CT) protocol was developed to improve tumour detection rates.

Purpose of the Study:

• To evaluate if the catch trial (CT) protocol enhances radiologist sensitivity compared to the double screener (DS) protocol.
• To assess if the CT protocol reduces missed tumours without increasing radiologist workload.

Main Methods:

• Two laboratory-based experiments were conducted.
• The catch trial (CT) protocol's sensitivity (d') was compared to the double screener (DS) protocol.
• Experiments used varying stimuli, with the second using more realistic tumour representations.

Main Results:

• The first experiment showed a criterion shift but unclear sensitivity differences between CT and DS protocols.
• The second experiment, using realistic stimuli, found no convincing evidence of increased sensitivity with the CT protocol.
• Both hit and false alarm rates increased in the CT protocol, suggesting similar sensitivity to the DS protocol.

Conclusions:

• The catch trial (CT) protocol is unlikely to improve sensitivity over the current double screener (DS) protocol.
• The study does not recommend the CT protocol for clinical trial implementation.
• Further research may be needed to explore alternative methods for improving breast cancer detection in screening programs.