Proportion of Thick versus Thin Melanomas as a Benchmarking Tool.

BACKGROUND: The ratio of benign moles excised for each malignant melanoma diagnosed (number-needed-to-excise (NNE)) is a metric used to express the efficiency of diagnostic accuracy of melanoma. The literature suggests a progressive effort to reduce the NNE, thus raising concerns about missing early melanoma because the NNE does not capture the most significant outcome for melanoma prognosis, which is linked to the Breslow thickness. A lower NNE could reduce health costs related to melanoma diagnosis only if doing so does not increase the proportion of thicker melanomas. OBJECTIVES: The diagnostic performance by two tertiary referral centres using the NNE and proportion of thick (Breslow thickness > 1 mm) versus thin (Breslow thickness ≤ 1 mm) excised melanoma (thick/thin ratio: TTR) was compared to determine if a lower NNE is associated with a greater proportion of thicker melanoma. Combining TTR with NNE allows a better estimate of the effectiveness in melanoma diagnosis, assessing both the overall cost for a given pool of excised melanomas and costs due to unnecessary nevi excision at a particular dermatology centre. METHODS: Demographic data and Breslow thickness of excised melanoma were extracted from patient histologic records at two referral centres for melanoma (Parma Dermatology Unit and Ravenna and Meldola Skin Cancer Unit, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori. IRCCS (IRST)) on all skin tumours excised between 2002 and 2011 and diagnosed as melanoma or melanocytic nevus. NNE and TTR were calculated and compared among the considered variables. Logistic regression was used to assess the contribution of each variable in predicting a higher TTR. RESULTS: Data from 16,738 excised lesions were analysed. The IRST Unit reported a mean NNE of 4.6, whereas the Parma Unit excised 10.6 nevi for each melanoma. No statistically significant differences existed in the mean (IRST Unit, 0.56 ± 0.89 mm; Parma Unit, 1.07 ± 2.2 mm) and median (range) Breslow thickness (IRST Unit, 0.4 (9) mm; Parma Unit 0.4 (30) mm). The TTR between centres was significantly different (Parma Unit, 24%; IRST Unit, 12%; p < 0.001). Based on logistic regression, the diagnosing centre was the most powerful factor in determining a thickness of >1 mm among diagnosed melanomas (OR = 1.8; 95% CI, 1.2-2.7; p < 0.01), with all other factors being equal. The NNE decreased at both centres from younger-to-older patients, whereas the TTR increased simultaneously; however, the increase in TTR was non-significantly related to NNE reduction after adjusting for confounders (age, gender, and localization). CONCLUSIONS: A better diagnostic performance is capable of reducing the NNE and TTR, i.e., unnecessary excisions of melanocytic nevi can be reduced without increasing the risk of overlooking melanomas. The TTR, in addition to the NNE, allows stakeholders to better estimate the effectiveness in melanoma diagnosis because both overall costs for a given pool of excised melanomas and costs due for unnecessary nevi excision at a particular dermatology centre can be compared.

Correlation Between Screening Mammography Interpretive Performance on a Test Set and Performance in Clinical Practice.

RATIONALE AND OBJECTIVES: Evidence is inconsistent about whether radiologists' interpretive performance on a screening mammography test set reflects their performance in clinical practice. This study aimed to estimate the correlation between test set and clinical performance and determine if the correlation is influenced by cancer prevalence or lesion difficulty in the test set. MATERIALS AND METHODS: This institutional review board-approved study randomized 83 radiologists from six Breast Cancer Surveillance Consortium registries to assess one of four test sets of 109 screening mammograms each; 48 radiologists completed a fifth test set of 110 mammograms 2 years later. Test sets differed in number of cancer cases and difficulty of lesion detection. Test set sensitivity and specificity were estimated using woman-level and breast-level recall with cancer status and expert opinion as gold standards. Clinical performance was estimated using women-level recall with cancer status as the gold standard. Spearman rank correlations between test set and clinical performance with 95% confidence intervals (CI) were estimated. RESULTS: For test sets with fewer cancers (N = 15) that were more difficult to detect, correlations were weak to moderate for sensitivity (woman level = 0.46, 95% CI = 0.16, 0.69; breast level = 0.35, 95% CI = 0.03, 0.61) and weak for specificity (0.24, 95% CI = 0.01, 0.45) relative to expert recall. Correlations for test sets with more cancers (N = 30) were close to 0 and not statistically significant. CONCLUSIONS: Correlations between screening performance on a test set and performance in clinical practice are not strong. Test set performance more accurately reflects performance in clinical practice if cancer prevalence is low and lesions are challenging to detect.

Radiologists' interpretive skills in screening vs. diagnostic mammography: are they related?

PURPOSE: This study aims to determine whether radiologists who perform well in screening also perform well in interpreting diagnostic mammography. MATERIALS AND METHODS: We evaluated the accuracy of 468 radiologists interpreting 2,234,947 screening and 196,164 diagnostic mammograms. Adjusting for site, radiologist, and patient characteristics, we identified radiologists with performance in the highest tertile and compared to those with lower performance. RESULTS: A moderate correlation was noted for radiologists' accuracy when interpreting screening versus their accuracy on diagnostic examinations: sensitivity (rspearman=0.51, 95% CI: 0.22, 0.80; P=.0006) and specificity (rspearman=0.40, 95% CI: 0.30, 0.49; P<.0001). CONCLUSION: Different educational approaches to screening and diagnostic imaging should be considered.

Improving Breast Ultrasound Interpretation in Uganda Using a Condensed Breast Imaging Reporting and Data System.

RATIONALE AND OBJECTIVES: This study aimed to determine whether a 2-day educational course using a condensed Breast Imaging Reporting and Data System (condensed BI-RADS) improved the accuracy of Ugandan healthcare workers interpreting breast ultrasound. MATERIALS AND METHODS: The target audience of this intervention was Ugandan healthcare workers involved in performing, interpreting, or acting on the results of breast ultrasound. The educational course consisted of a pretest knowledge assessment, a series of lectures on breast imaging interpretation and standardized reporting using a condensed BI-RADS, and a posttest knowledge assessment. Participants interpreted 53 different ultrasound test cases by selecting the finding type, descriptors for masses, and recommendations. We compared the percent correct on the pretest and posttest based on occupation and training level. RESULTS: Sixty-one Ugandan healthcare workers participated in this study, including 13 radiologists, 13 other physicians, 12 technologists, and 23 midlevel providers. Most groups improved in identifying the finding type (P < 0.05). All occupations showed improved use of descriptive terms for the shape and internal echogenicity of masses (P < 0.05). Most groups showed significant improvement in recommendations for normal and benign findings with a corresponding reduction in biopsy recommendations. CONCLUSIONS: Targeted breast ultrasound education using a condensed BI-RADS improved the interpretive performance of healthcare workers and was particularly successful in reducing the frequency of unnecessary biopsies for normal and benign findings. Multimodal educational efforts to improve accuracy and management of breast ultrasound findings may augment breast cancer early detection efforts in resource-limited settings.