Full-field digital versus screen-film mammography: comparative accuracy in concurrent screening cohorts.

OBJECTIVE: The purpose of this study was to compare the diagnostic accuracy of digital mammography with that of screen-film mammography in concurrent cohorts participating in the same population-based screening program. MATERIALS AND METHODS: In a retrospective study covering 2004-2005, we compared digital with screen-film mammography in two concurrent screening cohorts of women 50-69 years old participating in a screening program operated from mobile units. Each cohort had 14,385 participants matched by age and interpreting radiologist from all participants consecutively registered. We compared recall and cancer detection rates. RESULTS: The recall rate was higher for digital mammography (4.56% vs 3.96%, p = 0.01), particularly when clustered microcalcifications were the only finding (1.05% vs 0.41%, p = 10(-6)) and for younger women (50-59 vs 60-69 years, 5.12% vs 4.17%, p = 0.009). The higher recall rate for digital mammography was mainly evident at incidence screening. The recall rate due to poor technical quality was lower with digital mammography (0.27% vs 0.50%, p = 0.002), possibly because real-time feedback was available. The detection rate was higher for digital mammography (0.72% vs 0.58%, p = 0.14), particularly for cancers depicted as clustered microcalcifications (0.26% vs 0.12%, p = 0.007), in younger (50-59 years) women (0.63% vs 0.42%, p = 0.09), and in denser breasts (1.09% vs 0.53%, p = 0.24). No significant difference was observed in positive predictive value on recall for digital mammography or screen-film mammography. Early cancer (pTis, pT1mic, pT1a) was more frequent in cancer detected with digital mammography than in that detected with screen-film mammography (41.3% vs 27.3%, p = 0.06). CONCLUSION: Digital mammography may be more effective than screen-film mammography in contemporary screening practice in mobile units. The data indicate that digital mammography depicts more tumors than does screen-film mammography, especially lesions seen as microcalcifications. The potential association with improved outcome warrants further study.

Accuracy and underestimation of malignancy of breast core needle biopsy: the Florence experience of over 4000 consecutive biopsies.

Breast core needle biopsy (CNB) is used for sampling breast lesions in both the screening and diagnostic context. We present the accuracy of breast CNB from a consecutive series of 4035 core biopsies, using methods that minimise selection and verification bias. We calculate accuracy and underestimation of malignancy for both automated (14G) and directional vacuum-assisted (11G) CNB performed under stereotactic or sonographic guidance. Overall sensitivity of CNB is 94.2% (92.9-95.5%) and specificity is 88.1% (86.6-89.6%), positive and negative predictive values are 84.8% (82.9-86.7%) and 95.6% (94.6-96.6%), respectively. In sampling microcalcification, the overall underestimation of malignancy is 26.6% (22.9-30.3%): underestimation is significantly higher for automated CB relative to VAB (chi2 ((df = 1)) = 8.90 , P = 0.002), the absolute difference in underestimation being 14% (5-23%); sensitivity is higher for VAB than automated CB (chi2 ((df = 1)) = 3.28, P = 0.06) but specificity is significantly higher for automated CB (14G) relative to VAB (11G) (chi2 ((df = 1)) = 6.37, P = 0.01), and the overall accuracy of the two methods is similar. Sensitivity of CNB improved with experience (over time and in relation to caseload). Accuracy was not substantially affected by lesion palpability or image-guidance method, and was similar for both masses and calcification but lower for lesions depicted as distortions on mammography. Inadequacy was very low and decreased with greater operator caseload, and was not associated with core gauge or image-guidance method. False negatives occurred in 4.4% (3.4-5.4%) of cases, and where core histology was benign but discordant with (suspicious) imaging and/or clinical findings the likelihood of malignancy was 33.1% (18.5-47.7%), emphasising the importance of correlating all test information in breast diagnosis.

Negligible advantages and excess costs of routine addition of breast ultrasonography to mammography in dense breasts.

AIM: To assess the role of breast ultrasonography as a complement to negative mammography in radiologically dense breasts. MATERIAL AND METHODS: Out of a total series of 49,044 consecutive mammograms reported as negative in asymptomatic women, 25,665 (52.3%) were coded as dense (BI-RADS D3-4) and ultrasonography was recommended. Due to organizational problems, ultrasonography was performed immediately or within 1 month only in 5,227 cases, representing the study series. RESULTS: Two cancers were detected at immediate ultrasonography (0.03%). The cancer detection rate in women aged 40-49 and 50-69 years was 0.002% and 0.07%, respectively. The benign biopsy rate was 0.5% for core biopsies and 0.02% for surgical biopsies. The cost per ultrasonography-assessed woman was Euro 56.05, whereas the cost per additional mammographically occult but ultrasonography-detected cancer was Euro 146,496.53. The mammograms of the 2 cancer cases underwent blind review by an expert reader and were confirmed as negative. DISCUSSION: Our findings show a low cancer detection rate, substantially lower compared to other clinical studies of ultrasonography in dense breasts, though in accordance with preliminary evidence from an Italian randomized clinical trial within a population-based screening program. The policy of adding ultrasonography to negative mammography in dense breasts seems to have very limited cost-effectiveness, and should not be adopted in routine practice before results of ongoing clinical trials are available.

Conventional versus digital mammography in the analysis of screen-detected lesions with low positive predictive value.

PURPOSE: To compare the performance of screen-film and digital mammography in the assessment of screen-detected breast lesions. MATERIALS AND METHODS: A series of 100 consecutive mammographic screen-detected lesions (65 masses, 6 architectural distortions, 29 microcalcifications) deserving diagnostic assessment and judged to have a low positive predictive value underwent screen-film mammography (SFM) and digital mammography by a Fuji computed radiography system (FCR) (double exposure, same view, without removing compression) of the corresponding breast. Three sets of images (SFM, hard copy and soft copy FCR) were read, blind of assessment outcome, by three experienced radiologists. For the three different imaging modalities a contrast-detail analysis, dose evaluation and diagnostic accuracy by means of ROC analysis were performed. At the end of the diagnostic workup all suspicious cases (20) underwent surgical biopsy and were histologically confirmed as cancers and the cases which were negative or benign at assessment (80) were followed up for a period of 12-20 months. During the follow-up period two more cases proved to be cancers at subsequent examinations. RESULTS: Contrast-detail analysis gives better image quality for FCR compared to SFM at the same delivered dose, whilst in ROC analysis the SFM (AUC 0.7158), hard copy FCR (AUC 0.7404) and soft copy FCR (AUC 0.7501) (chi(2)=1.30, p=0.5220) are equivalent. CONCLUSION: FCR has a diagnostic performance equivalent to SFM in the assessment of screen-detected lesions with a low positive predictive value for cancer and it may be safely included in routine screening practice.

Determining overdiagnosis by screening with DRE/TRUS or PSA (Florence pilot studies, 1991-1994).

The rate of overdiagnosis of prostate carcinoma was assessed by following 6890 participants in pilot screening studies from 1991 to 1994. Observed/expected incidence and mortality were determined using data from the Cancer and Mortality Registry. The cancer detection rate (1.75%) and observed/expected ratio (12.5:1) were high at the first screening, and substantially lower at the second screening (0.65% or 4.10:1). According to the registry follow-up, prostate cancer occurred in 225 subjects in the whole study cohort, while 178.2 were expected with 50652 men/years at risk. The standardised incidence rate was 1.66 in the screened (95%CI=1.4-2.0), 0.97 in the non-responders (95%CI=0.8-1.2) and 1.23 in subjects excluded from invitation due to previous cancer or major illness (95%CI=0.8-1.5). A 66% excess incidence rate was observed in the screened subjects over a 9-year period, confirming previous estimates of overdiagnosis.

Role of ultrasound-guided fine needle cytology of axillary lymph nodes in breast carcinoma staging.

PURPOSE: To evaluate the efficacy of cytology on axillary lymph node ultrasound-guided aspiration biopsy in the reduction of inappropriate surgery, such as the sentinel node (SN) procedure if positive, or axillary dissection if negative. MATERIALS AND METHODS: Cytology was performed on 159 consecutive cases, on the ultrasonographically most suspicious lymph node. Lymph node histology was used as a reference standard to determine accuracy. Four different scenarios were simulated: routine axillary ultrasonography with cytology of the lymph nodes visible at ultrasonography (A), or of only the lymph nodes suspicious at ultrasonography (B), with ultrasonography limited to clinically negative axillae and cytology of the lymph nodes visible at ultrasonography (C), or only of the lymph nodes suspicious at ultrasonography only (D). RESULTS: Cytologic sensitivity was 58.6%, specificity 100%. Immediate axillary dissection only in the case of positive cytology would have avoided 6/6 inappropriate axillary dissections and 5/34 (14.7%) inappropriate SN, compared to routine practice (immediate dissection for palpable adenopathy, SN in the remaining cases). Each of the simulated scenarios saved inappropriate surgical procedures (A: 6 dissections, 5 SNs; B: 6 dissections, 3 SNs; C: 13 SNs; D: 11 SNs) at no expense (A and B) or limited expense (C: Euro 348, D: Euro 232 for each inappropriate surgical procedure saved). CONCLUSIONS: Axillary lymph node cytology can save axillary dissections or sentinel node procedures and is recommended as routine practice. Routine axillary ultrasonography, with cytology of sonographically visible lymph nodes, followed by immediate axillary dissection only in case of positive cytology proved to be the best approach in terms of cost-benefit ratio.

Comparison of two commercial systems for computer-assisted detection (CAD) as an aid to interpreting screening mammograms.

PURPOSE: To compare the diagnostic accuracy of two commercial CAD systems (CADx and R2) and their impact as an aid to conventional reading of screening mammograms. MATERIALS AND METHODS: The image set considered consisted of 120 mammograms, 89 confirmed negative and 31 with subsequent interval cancers (11 classified as false negatives (FN), 20 as "minimal signs" (MS)). The set was digitised and processed with CAD, and printouts obtained of the mammograms with indications of the areas warranting review. Six expert radiologists read the mammograms three times, once using conventional reading and twice using CAD reading with CADx and R2, respectively. The two CAD systems were compared in terms of diagnostic accuracy of the marks and the impact of CAD reading compared to conventional reading and to the use of independent second reading simulated by combining pairs of single conventional readings. RESULTS: R2 highlighted more calcifications (218 vs 132, +65%) and CADx highlighted more masses (208 vs 105, +98%). CADx and R2 marked 15 and 17 out of 31 cancers, respectively (sensitivity 48.3% vs 54.8%, chi squared=6.4, p=0.79), 10 and 6 out of 11 FN (90.9% vs 54.5%, chi squared=2.0, p=0.15), respectively, and 5 and 11 out of 20 MS (25.0% vs 55.0%, chi squared=2.6, p=0.10), respectively. As for specificity, the false positive markings for masses were on average (per case) 1.60 for CADx and 0.75 for R2, those for calcifications were 1.08 for CADx and 1.77 for R2 and the total false positive markings were 2.68 for CADx and 2.52 for R2. CADx and R2 marked 73 and 63 of 89 negative controls (specificity = 0.18 vs 0.29, chi squared=2.52, p=0.11), respectively. All the radiologists showed greater sensitivity with CAD reading compared to conventional reading. On average, sensitivity with conventional reading was 58.6% (109/186), as against 70.9% (132/186) for CADx or R2 (chi squared=5.71, p=0.016). Sensitivity for FN cases was 71.2% (47/66) with conventional reading, 84.8% (56/66) with CADx (chi squared=2.82, p=0.09) and 80.3% (53/66) for R2 (chi squared=1.03, p=0.30) (CADx vs R2, chi squared=0.21, p=0.64). Sensitivity for MS cases was 51.6% (62/120) for conventional reading, 63.3% (76/120) for CADx (chi squared=2.88, p=0.08) and 65.8% (79/120) for R2 (chi squared=4.40, p=0.03) (CADx vs R2, chi squared=0.07, p=0.78). The recall rates were 18.1% (97/534) for conventional reading, 29.7% (159/534) for CADx (chi squared=5.72, p=0.01) and 24.3% (130/534) for R2 (chi squared=10.11, p=10-5) (CADx vs R2, chi squared=3.71, p=0.05). Double reading was significantly more sensitive than conventional reading (chi squared=29.6, p=10-6), CADx (chi squared=5.33, p=0.02) and R2 (chi squared=5.33, p=0.02). The recall rate for double reading was significantly higher than for conventional reading (chi squared=21.5, p=10-6) whereas no significant difference was detected when compared to CADx (chi squared=0.16, p=0.68) or R2 (chi squared=3.4, p=0.06). CONCLUSIONS: Despite using different algorithms, the two CAD systems exhibit comparable levels of diagnostic accuracy and a similar positive impact on sensitivity when used as an aid to conventional reading. Single reading with either CAD system is as specific but not as sensitive to double independent reading: its use as an alternative to double reading cannot be recommended and should be investigated further by means of controlled prospective studies.

Comparison of standard reading and computer aided detection (CAD) on a national proficiency test of screening mammography.

OBJECTIVE: To evaluate the role of computer aided detection (CAD) in improving the interpretation of screening mammograms MATERIAL AND METHODS: Ten radiologists underwent a proficiency test of screening mammography first by conventional reading and then with the help of CAD. Radiologists were blinded to test results for the whole study duration. Results of conventional and CAD reading were compared in terms of sensitivity and recall rate. Double reading was simulated combining conventional readings of four expert radiologists and compared with CAD reading. RESULTS: Considering all ten readings, cancer was identified in 146 or 153 of 170 cases (85.8 vs. 90.0%; chi(2)=0.99, df=1, P=0.31) and recalls were 106 or 152 of 1330 cases (7.9 vs. 11.4%; chi(2)=8.69, df=1, P=0.003) at conventional or CAD reading, respectively. CAD reading was essentially the same (sensitivity 97.0 vs. 96.0%; chi(2)=7.1, df=1, P=0.93; recall rate 10.7 vs. 10.6%; chi(2)=1.5, df=1, P=0.96) as compared with simulated conventional double reading. CONCLUSION: CAD reading seems to improve the sensitivity of conventional reading while reducing specificity, both effects being of limited size. CAD reading had almost the same performance of simulated conventional double reading, suggesting a possible use of CAD which needs to be confirmed by further studies inclusive of cost-effective analysis.

Determining the sensitivity of transrectal ultrasonography on a consecutive series of prostate cancers in a clinical and screening setting.

PURPOSE: To evaluate the sensitivity at transrectal ultrasonography (TRUS) for prostate cancer. MATERIAL: A consecutive series of 170 prostate cancers identified by matching local cancer registry and TRUS archives at the Centro per lo Studio e la Prevenzione Oncologica of Florence. METHOD: TRUS sensitivity was determined as the ratio of TRUS positive to total prostate cancers occurring at different intervals from TRUS date. Univariate and multivariate analyses of sensitivity determinants were performed. RESULTS: Sensitivity at 6 months, 1, 2 and 3 years after the test was 94.1% (95% CI, 90-98), 89.8% (95% CI, 85-95), 80.4% (95% CI, 74-87) and 74.1% (95% CI, 68-81%), respectively. A higher sensitivity (statistically significant) of TRUS was observed only if digital rectal examination was suspicious, whereas no association to sensitivity was observed for age, prostate-specific antigen or prostate-specific antigen density. CONCLUSIONS: The study provided a reliable estimate of TRUS sensitivity, particularly reliable being checked against a cancer registry: observed sensitivity was high, at least of the same magnitude of other cancer screening tests. TRUS, which is known to allow for considerable diagnostic anticipation and is more specific than prostate-specific antigen, might still be considered for its contribution to a screening approach.