The majority of radiologists (63.4%) reported usually or always using clinical history when interpreting screening mammography (), 29.2% reported using it only when they identified an abnormality, and 7.4% reported never or rarely using it. The majority of radiologists were male, age 50 or older, working full time in radiology, not affiliated with an academic medical center, not fellowship trained and with more than 10 years' experience interpreting mammography (). Only one radiologist characteristic was associated with use of clinical history: full-time radiologists reported being more likely to use clinical history routinely (e.g., mostly or always) compared to part-time radiologists.
Radiologists Demographics/Characteristics by How They Use Available Clinical History When Interpreting Screening Mammography Exams.
outlines the characteristics of women who underwent screening mammography interpreted by study radiologists, including the number of mammograms and the number of cancers detected. Cancer detection rates increased with increasing patient age, increasing breast density, longer time since last mammogram, having a family history of breast cancer, having a prior breast biopsy, and increasing summary score for clinical history factors. Cancer detection rates were lower among radiologists who interpreted more than 20 years, but were not associated with any other characteristic of the radiologists including the use of clinical history.
Characteristics of Women Obtaining Screening Mammography Exams in 7 U.S. States Included in the Study
shows performance indices (sensitivity, false-positive rate, and positive predictive value) by women's characteristics with all patients combined and then according to use of the clinical history by the interpreting radiologist and shows odds ratios from oneway interaction analyses comparing performance by women's characteristics and radiologist's use of clinical history. We found no significant associations between use of clinical history and recall (p=0.72), sensitivity (p=0.37), false-positive (p=0.70), or PPV (p=0.29). However, we found that use of clinical history changed the magnitude of the associations between performance measures and numerous women-level risk factors.
Interpretive Performance by Women's Characteristics (All Patients Combined) and Clinical History Use Categories
Odds Ratios and 95% Confidence Intervals from Conditional Logistic Regression Models on Use of Clinical History, Accuracy Indices and Characteristics of Women.
Overall, regardless of whether the radiologist used the clinical history, younger women were more likely to be recalled (p<0.001) with lower sensitivity (p<0.001), higher false positive rate (p<0.001), and lower PPV (p<0.001) compared to older women (). Among women without cancer, the decrease in false-positive rates observed with increasing patient age was stronger among radiologists who use the clinical history compared to those who never or rarely use it, but this interaction was only borderline significant (p=0.07). This resulted in a higher false-positive rate for women aged 40–49 (10.7 and 10.1 vs. 9.7) and a lower false-positive rate for women older than 70 (6.5 and 6.5 vs. 6.9) when mammograms were interpreted by radiologists who mostly/always or only if abnormality used clinical history compared to radiologists who did not use clinical history (Adjusted odds ratio by use of clinical history: never/rarely 0.66 (95% confidence intervals: 0.60, 0.73) compared to abnormality only 0.60 (95% CI: 0.58, 0.63); p=0.079 and mostly/always 0.60 (95% CI: 0.58, 0.61); p=0.37) ( and ).
As expected, women with denser breasts were recalled more often (p<0.001) and had a lower sensitivity (p<0.001), higher false-positive rate (p<0.001), and lower PPV (p<0.001). The increase in false-positive rates observed with increasing breast density was stronger for radiologists who use clinical history compared to those who never or rarely use it. This resulted in more women being recalled without cancer who had heterogeneously or extremely dense breasts by radiologists who used clinical history compared to those who never use clinical history (Adjusted OR by use of clinical history: heterogeneously dense vs. scattered fibroglandular tissue: [never/rarely use clinical history 1.32 (95% confidence intervals: 1.23, 1.42) compared to use history only if an abnormality is noted 1.48 (95% CI: 1.44, 1.53); p=0.003 and mostly/always use the history 1.47 (95% CI: 1.44, 1.50); p=0.006] and extremely dense vs. scattered fibroglandular tissue: [never/rarely 1.13 (95% confidence intervals: 1.00, 1.29) compared to abnormality only 1.32 (95% CI: 1.25, 1.39); p=0.030 and mostly/always 1.33 (95% CI: 1.28, 1.38); p=0.017])
Overall, radiologists recalled more women with a longer time since last mammogram (p<0.001) with a higher sensitivity (p<0.001), higher false-positive rate (p<0.001), and a higher PPV (p=0.002) compared to women with shorter times since last mammogram. The increase in false-positive rate with increasing screening interval length was stronger for radiologists who used the clinical history. Radiologists who used clinical history recalled a higher proportion of women without cancer with at least 3 years since their last mammogram relative to women with ≤2 years since their last mammogram compared to radiologists who never use clinical history (Adjusted OR by use of clinical history: 3–4 yrs vs. ≤2yrs since last mammogram: [never/rarely 1.15 compared to abnormality only 1.22; p=0.15 and mostly/always 1.26; p=0.03] and ≥ 5yrs vs. ≤2yra since last mammogram: [never/rarely 1.46 compared to abnormality only 1.78; p=0.004 and mostly/always 1.74; p=0.010]) (). This interaction between clinical history use and time since last mammogram resulted in higher observed false-positive rates among women who had not been screened in the prior 5 years (12.5 vs. 10.5) for radiologists who always used clinical history compared to those who did not ().
Current HT use was associated with higher recall (p<0.001) and false-positive rates (p<0.001), but not associated overall with sensitivity (p=0.29) or PPV (p=0.43). The associations were not as strong for radiologists who use clinical history compared to those who never use it. As a result, among HT users, fewer false-positive exams (9.2 vs. 9.8) and a corresponding, non-significant lower sensitivity (79.2 vs. 85.2) occurred for mammograms interpreted by radiologists who used clinical information compared to those who rarely or never used it ().
Women with a family history of breast cancer had significantly higher recall (p<0.001), false-positive rate (p=0.002), and PPV (p<0.001) compared to those without a family history, but there was no significant difference in sensitivity (p=0.12) ). Similarly, women with a previous benign breast biopsy had a significantly higher recall rate (p<0.001), false-positive rate (p<0.001) and PPV (p<0.001), and a significantly lower sensitivity (p=0.028) compared to women without a previous benign biopsy. A radiologist's use of clinical history had no significant effect on the relationship between any of the performance measures and family history of breast cancer or a previous biopsy. Women with more clinical risk factors (current HT use, family history, and benign breast biopsy) had a higher recall rate (p<0.001), lower sensitivity (p= 0.005), higher false-positive rate (p<0.001), and higher PPV (p<0.001) compared to women with no clinical risk factors. Reported use of clinical history by the radiologist did not change these associations.
All results from the multivariable analyses that adjusted for the other patient risk factors were similar to the bi-variable results except that use of clinical history no longer significantly changed the magnitude of the effect of patient age on recall or false-positive rate (data not shown).