CALCA and breast cancer: Receiver Operating Characteristic analysis, performed to assess the diagnostic accuracy of PCT values to predict SF and BC results, showed an area under the curve for SF of 0.927 (95% confidence interval: 0.899–0.955, p<0.0001) and for BC of 0.820 (95% confidence interval: 0.769–0.870, p<0.0001) (Figure 1).