Breast cancer screening with digital breast tomosynthesis - 4 year experience and comparison with national data.

BACKGROUND: To determine if mammography combined with digital breast tomosynthesis (DBT), leads to superior performance in screening for breast cancer compared to digital mammography (DM) alone. METHODS: We retrospectively collected data from A) the results of population-based mammography-screening provided by the National Cancer Registry in Taiwan, and B) the results from all screening mammography performed with DBT from 2012 through 2015 at Kaohsiung Veterans General Hospital (VGHKS) since the institution of DBT at the end of 2011. This was compared data from 3 years with DM performed prior to DBT implementation. We calculated the results of medical audit of VGHKS and compared this with national data. Fisher's exact test is applied. RESULTS: VGHKS data demonstrated a higher cancer detection rate (CDR) and positive predictive value 1 (PPV 1) than the national average. Most prominently in the year 2014, our CDR was 120% better than that of the national average. CDR ranged from 6.3 to 8.1‰ prior to the introduction of DBT, and following DBT implementation this improved to 8.5-11.4‰, reflecting a mean increase of 32.2%. Early cancer detection was 50% higher and node negative rate was 25% higher than the national average of latest year. A 17.8% reduction in recall rate (RR) was achieved due to a decrease in unnecessary recall. CONCLUSION: There was a 32.2% increase in CDR and a 17.8% decrease in RR when DBT was used as an adjunct to DM, as compared to DM alone. CDRs were approximately twofold better than national average data. DBT was more effective at detecting cancer in ductal carcinoma in situ and stage 1.

The outcome of a quality-controlled mammography screening program: experience from a population-based study in Taiwan.

BACKGROUND: A greater policy of emphasis on the early detection and treatment of breast cancer is prevalent among developed countries. To raise the screening performance with a potentially decreased mortality rate, it is crucial to evaluate and analyze the screening outcome after implementation. We report the clinical outcome of an 8-year nationwide mammography screening in Taiwan to help share our statistical information on breast screening worldwide, especially in Asia. METHODS: Taiwan has provided nationwide, free, biennial mammographic screening since 2004. A total of 2,392,789 consecutive screening mammography examinations were performed during this study period for women aged 50-69 years (2006-2009) and 45-69 years (from December 2009 onwards). The screening covers 33.2% of the target population in the most recent 2 years. The workload of every screening radiologist, the overall recall rate, positive predictive value (PPV1), cancer detection rate (CDR), cancer incidence rate (CIR) from the screening, 1-year interval cancer, sensitivity, and specificity of the screening mammography are calculated, and compared with the American College of Radiology (ACR) recommendation level and/or those of other screening mammographic series. RESULTS: The CDRs (%) and CIRs (%) increased from 3.94-4.08 and 4.80-5.04 to 4.71-5.04 and 5.71 after 2009, implying a high occurrence of breast cancer in the younger age group of 45-49 years. The recall rates (9.3-10.0%) in this review are within the ACR recommendation range (<10%) and the PPV1 has also reached the ACR recommended level (>5%) in the most recent 2 years. The improvement of the screening performance may be attributed to our peer auditing review and education program. The sensitivity of our screening mammography is slightly lower than that of the ACR recommended level (>85%), which is still comparable to the results of the Vermont area in the USA. Although the workload (screenees/screeners) for every radiologist each year has increased from 150 in 2004 to 1360 in 2012, it does not seem to worsen the quality outcome of this screening program. CONCLUSION: From the outcome review of this national mammography screening, there is still room to ameliorate our performance through comprehensive and continued education, to improve the competence of cancer detection and decrease false negative (FN) cases.

Monitoring sedation for bronchoscopy in mechanically ventilated patients by using the Ramsay sedation scale versus auditory-evoked potentials.

BACKGROUND: Appropriate sedation benefits patients by reducing the stress response, but it requires an appropriate method of assessment to adjust the dosage of sedatives. The aim of this study was to compare the difference in the sedation of mechanically ventilated patients undergoing flexible bronchoscopy (FB) monitored by auditory-evoked potentials (AEPs) or the Ramsay sedation scale (RSS). METHODS: In a prospective, randomized, controlled study, all patients who underwent FB with propofol sedation were monitored and their sedation adjusted. During FB, one group was monitored by AEP and another group was monitored by RSS. The propofol dosage was adjusted by the nursing staff during examination to maintain the Alaris AEP index (AAI) value between 25 and 40 in the AEP group and the RSS at 5 or 6 in the RSS group. Before FB and during FB, the AAI, heart rate (HR), and mean arterial pressure (MAP) were recorded every 5 min. The percentages of time at the sedation target and the propofol dosages were calculated. RESULTS: Nineteen patients received AEP monitoring and 18 patients received RSS monitoring. The percentage of time at the sedation target during FB was significantly higher in the AEP monitoring group (51.3%; interquartile range [IQR], 47.0-63.5%) than in the RSS group (15.4%; IQR, 9.5-23.4%), (P < 0.001). During FB, the RSS group had a significantly higher AAI (P = 0.011), HR (P < 0.001), and MAP (P < 0.001) than the AEP group. CONCLUSIONS: In mechanically ventilated patients undergoing FB, AEP monitoring resulted in less variation in AAI, HR, and MAP, and a higher percentage of time at the sedation target than RSS monitoring.

Forward selection two sample binomial test.

Fisher's exact test (FET) is a conditional method that is frequently used to analyze data in a 2 × 2 table for small samples. This test is conservative and attempts have been made to modify the test to make it less conservative. For example, Crans and Shuster (2008) proposed adding more points in the rejection region to make the test more powerful. We provide another way to modify the test to make it less conservative by using two independent binomial distributions as the reference distribution for the test statistic. We compare our new test with several methods and show that our test has advantages over existing methods in terms of control of the type 1 and type 2 errors. We reanalyze results from an oncology trial using our proposed method and our software which is freely available to the reader.

Peer reviewing of screening mammography in Taiwan: its reliability and the improvement.

BACKGROUND: Early detection with screening mammography can potentially reduce breast cancer mortality rates. To achieve an efficient screening, a peer review system provides a compensatory double-check reviewing, will hopefully to prevent the omission of detectable lesions and reduce unnecessary recall. METHODS: In 2009, 4643 initial mammographic screenings reported by 74 screening radiologists had negative results with a recall rate of less than 5%. In the same year, 2538 initial positives screened by 18 screening radiologists had a recall rate higher than 15%. Those 7181 randomized screenings were evenly distributed for reassessment by 39 reviewing radiologists. The disagreement of assessments between the reviewers and screening radiologists was recorded. The differential rate was defined as the number of the disagreements divided by the number of audited films reviewed by a screening radiologist. The equality of the differential rates for each screening radiologists with negative and positive assessments was compared by a Chi-square test. The performance of the 39 auditors was measured by the Kendall's tau statistic. P values less than 0.05 were considered statistically significant. RESULTS: The mean differential rate for screening radiologists of negative assessments was 6.7% (P = 0.588), while 35.0% for positive assessments were significant (P < 0.001). The result indicated that most of the initial negative assessments reported by the screening radiologists were generally accepted by the reviewers but not the positive assessments. With respect to the 39 reviewers, there was no significant evidence for the association of the difference rates between negative and positive assessments. Nine reviewers were found to have their differential rate for negative and positive assessments larger than the average of the population. Eleven reviewers were found to have their differential rates smaller than the average for both. Thirteen reviewers had their differential rates smaller than the average for negative assessments but larger than the average for positive assessments. The opposite condition was found for six reviewers. The Kendall's tau statistic was 0.038 (P = 0.735). CONCLUSIONS: Reviewers usually agreed with the opinion of the initial screening doctors who reported negative findings. Therefore, a 5% recall rate as the lower range of reviewing negatives may be still too high. The recall rate of more than 15% was significantly related to improper interpretation, especially when the differential rate is 25% or higher, a warning to the underperforming screening radiologist is recommended. An ideal reviewer should interpret films independently. Reviewers with tendencies to be followers or contrarians should not be enrolled in the reviewing system.

Can missed breast cancer be recognized by regular peer auditing on screening mammography?

BACKGROUND: This study was conducted to investigate whether detectable missed breast cancers could be distinguished from truly false negative images in a mammographic screening by a regular peer auditing. METHODS: Between 2004 and 2007, a total of 311,193 free nationwide biennial mammographic screenings were performed for 50- to 69-year-old women in Taiwan. Retrospectively comparing the records in Taiwan's Cancer registry, 1283 cancers were detected (4.1 per 1000). Of the total, 176 (0.6 per 1000) initial mammographic negative assessments were reported to have cancers (128 traditional films and 48 laser-printed digital images). We selected 186 true negative films (138 traditional films and 48 laser-printed ones) as control group. These were seeded into 4815 films of 2008 images to be audited in 2009. Thirty-four auditors interpreted all the films in a single-blind, randomized, pair-control study. The performance of 34 auditors was analyzed by chi-square test. A p value of < 0.05 was considered significant. RESULTS: Eight (6 traditional and 2 digital films) of the 176 false negative films were not reported by the auditors (missing rate of 4.5%). Of this total, 87 false negatives were reassessed as positive, while 29 of the 186 true negatives were reassessed as positive, making the overall performance of the 34 auditors in interpreting the false negatives and true negatives a specificity of 84.4% and sensitivity of 51.8%. The specificity and sensitivity in traditional films and laser-printed films were 98.6% versus 43.8% and 41.8% versus 78.3%, respectively. Almost 42% of the traditional false negative films had positive reassessment by the auditors, showing a significant difference from the initial screeners (p < 0.001). The specificity of their reinterpretation of laser-printed films was obviously low. CONCLUSION: Almost 42% of the false negative traditional films were judged as missed cancers in this study. A peer auditing should reduce the probability of missed cancers.

Moderate glucose control results in less negative nitrogen balances in medical intensive care unit patients: a randomized, controlled study.

INTRODUCTION: Hyperglycemia and protein loss are common in critically ill patients. Insulin can be used to lower blood glucose and inhibit proteolysis. The impact of moderate insulin therapy on protein metabolism in critically ill patients has not been evaluated. We compared urinary nitrogen excretion, nitrogen balance, serum albumin concentrations, prealbumin concentrations, and clinical outcomes between patients receiving moderate insulin therapy (MIT) and conventional insulin therapy (CIT) in a medical ICU. METHODS: Patients were randomly divided into groups and treated with MIT (glucose target 120 to 140 mg/dl) or CIT (glucose target 180 to 200 mg/dl). Calories and protein intake were recorded each day. On days 3, 7 and 14, the 24-hour urinary nitrogen excretion, nitrogen balance, and serum albumin and prealbumin concentrations were measured. Clinical outcomes data were collected. RESULTS: A total of 112 medical ICU patients were included, with 55 patients randomized to the MIT group and 57 patients randomized to the CIT group. Patients treated with MIT showed a trend towards increased nitrogen balance (P = 0.070), significantly lower urinary nitrogen excretion (P = 0.027), and higher serum albumin (P = 0.047) and prealbumin (P = 0.001) concentrations than patients treated with CIT. The differences between the two groups were most significant on day 3, when all factors showed significant differences (P < 0.05). CONCLUSIONS: Moderate glucose control results in less negative nitrogen balances in medical ICU patients. Differences are more significant in the early stages compared with the late stages of critical illness. TRIAL REGISTRATION: ClinicalTrial.Gov NCT 01227148.

Impact of disease severity on gastric residual volume in critical patients.

AIM: To investigate whether illness severity has an impact on gastric residual volume (GRV) in medical critically ill patients. METHODS: Medical intensive care unit (ICU) patients requiring nasogastric feeding were enrolled. Sequential Organ Failure Assessment (SOFA) score was assessed immediately preceding the start of the study. Acute Physiology and Chronic Health Evaluation (APACHE) II scores were recorded on the first, fourth, seventh, and fourteenth day of the study period. GRV was measured every 4 h during enteral feeding. The relationship between mean daily GRV and SOFA scores and the correlation between mean daily GRV and mean APACHE II score of all patients were evaluated and compared. RESULTS: Of the 61 patients, 43 patients were survivors and 18 patients were non-survivors. The mean daily GRV increased as SOFA scores increased (P < 0.001, analysis of variance). Mean APACHE II scores of all patients correlated with mean daily GRV (P = 0.011, Pearson correlation) during the study period. Patients with decreasing GRV in the first 2 d had better survival than patients without decreasing GRV (P = 0.017, log rank test). CONCLUSION: GRV is higher in more severely ill medical ICU patients. Patients with decreasing GRV had lower ICU mortality than patients without decreasing GRV.

Estimating HIV hazard rates from cross-sectional HIV prevalence data.

We propose a method of estimating the HIV hazard rate in a population when only cross-sectional data measuring HIV-prevalence are available. In a cross-sectional study, individuals who test positive are left-censored since we know only that the transition time is smaller than the monitoring time. Individuals who test negative are right-censored since we know only that the transition time is greater than the monitoring time. The transition time is not observed directly. For our method, we assume the hazard rate is well-defined after the time we start screening. We assume further the mortality rates for HIV-positive and HIV-negative individuals are known. The method is illustrated using HIV-prevalence data collected over four years among women in Cape Town, South Africa.