Prospective study of magnetic resonance imaging (MRI) and multiparameter gene expression assay in ductal carcinoma in situ (DCIS): A trial of the ECOG-ACRIN Cancer Research Group (E4112)

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Background: Prior retrospective studies have evaluated breast MRI in DCIS, and prospective-retrospective biomarker studies have shown that the DCIS Score is prognostic for recurrence after BCS alone. E4112 is a prospective cohort study designed to assess the combined impact of breast MRI and DCIS Score on surgical and RT management. Methods: Women diagnosed with screen-detected DCIS on core biopsy, if BCS eligible, underwent breast MRI. Those remaining so following MRI and related biopsies, with no invasive disease, underwent BCS. If final surgical margins were ≥2 mm, the DCIS lesion was submitted for DCIS Score assay. Women with low DCIS Score (≤39, LS) were advised that RT could be avoided; RT was recommended to those with high/intermediate (H/I) scores. The primary objective was to estimate the fraction converting to mastectomy (Mx) following MRI. Secondary objectives included estimation of re-operation rates after first BCS, and DCIS Score distribution.A sample size of 333 evaluable women would allow estimation of Mx rate of 12% with 95% confidence interval 9-16%. Results: 334 enrolled women had completed surgery; the first surgical procedure was Mx in 54 (16.2%) and BCS in 280 (83.8%), of whom 62 (22.1%) required at least one re-excision, and 11 (3.9%) converted to Mx. DCIS Scores were obtained on 171 patients who completed BCS, of whom 82 were LS and 89 were H/I. Demographics were similar between the two groups, other features will be reported. Only 7/82 (8.5%) of the LS group received RT, whereas 82/89 (92.1%) of the H/I group received RT. Of the 98 BCS patients who did not qualify for DCIS Score-based therapy, 23 had invasive disease, 34 had final surgical margins < 2 mm, and 13 had both. There was insufficient tissue for DCIS Score in 11, and 17 did not complete follow-up. Conclusions: In this study, among DCIS patients who were BCS-eligible following MRI, total mastectomy rate was 19.5%; re-excision rate was 22.1% for women who had BCS. Approximately half had low DCIS Scores, and RT recommendations based on the DCIS Score were acceptable to most women. Clinical trial information: E4112.

Clinical risk factors alone are inadequate for predicting significant coronary artery disease

OBJECTIVE

We sought to derive and validate a model for identifying suspected ACS patients harboring undiagnosed significant coronary artery disease (CAD).

METHODS

This was a secondary analysis of data from a randomized control trial (RCT). Patients randomized to the CTA arm of an RCT examining a CTA-based strategy for ruling-out acute coronary syndrome (ACS) constitute the derivation cohort, which was randomly divided into a training dataset (2/3, used for model derivation) and a test dataset (1/3, used for internal validation (IV)). ED patients from a different center receiving CTA to evaluate for suspected ACS constitute the external validation (EV) cohort. Primary outcome was CTA-assessed significant CAD (stenosis of ≥50% in a major coronary artery).

RESULTS

In the derivation cohort, 11.2% (76/679) of subjects had CTA-assessed significant CAD, and in the EV cohort, 8.2% of subjects (87/1056) had CTA-assessed significant CAD. Age was the strongest predictor of significant CAD among the clinical risk factors examined. Predictor variables included in the derived logistic regression model were: age, sex, tobacco use, diabetes, and race. This model exhibited an area under the receiver operating characteristic curve (ROC AUC) of 0.72 (95% CI: 0.61-0.83) based on IV, and 0.76 (95% CI: 0.70, 0.82) based on EV. The derived random forest model based on clinical risk factors yielded improved but not sufficient discrimination of significant CAD (ROC AUC = 0.76 [95% CI: 0.67-0.85] based on IV). Coronary artery calcium score was a more accurate predictor of significant CAD than any combination of clinical risk factors (ROC AUC = 0.85 [95% CI: 0.76-0.94] based on IV; ROC AUC = 0.92 [95% CI: 0.88-0.95] based on EV).

CONCLUSIONS

Clinical risk factors, either individually or in combination, are insufficient for accurately identifying suspected ACS patients harboring undiagnosed significant coronary artery disease.

PRagmatic trial Of Video Education in Nursing homes: The design and rationale for a pragmatic cluster randomized trial in the nursing home setting

Background/Aims Nursing homes are complex healthcare systems serving an increasingly sick population. Nursing homes must engage patients in advance care planning, but do so inconsistently. Video decision support tools improved advance care planning in small randomized controlled trials. Pragmatic trials are increasingly employed in health services research, although not commonly in the nursing home setting to which they are well-suited. This report presents the design and rationale for a pragmatic cluster randomized controlled trial that evaluated the "real world" application of an Advance Care Planning Video Program in two large US nursing home healthcare systems. Methods PRagmatic trial Of Video Education in Nursing homes was conducted in 360 nursing homes (N = 119 intervention/N = 241 control) owned by two healthcare systems. Over an 18-month implementation period, intervention facilities were instructed to offer the Advance Care Planning Video Program to all patients. Control facilities employed usual advance care planning practices. Patient characteristics and outcomes were ascertained from Medicare Claims, Minimum Data Set assessments, and facility electronic medical record data. Intervention adherence was measured using a Video Status Report embedded into electronic medical record systems. The primary outcome was the number of hospitalizations/person-day alive among long-stay patients with advanced dementia or cardiopulmonary disease. The rationale for the approaches to facility randomization and recruitment, intervention implementation, population selection, data acquisition, regulatory issues, and statistical analyses are discussed. Results The large number of well-characterized candidate facilities enabled several unique design features including stratification on historical hospitalization rates, randomization prior to recruitment, and 2:1 control to intervention facilities ratio. Strong endorsement from corporate leadership made randomization prior to recruitment feasible with 100% participation of facilities randomized to the intervention arm. Critical regulatory issues included minimal risk determination, waiver of informed consent, and determination that nursing home providers were not engaged in human subjects research. Intervention training and implementation were initiated on 5 January 2016 using corporate infrastructures for new program roll-out guided by standardized training elements designed by the research team. Video Status Reports in facilities' electronic medical records permitted "real-time" adherence monitoring and corrective actions. The Centers for Medicare and Medicaid Services Virtual Research Data Center allowed for rapid outcomes ascertainment. Conclusion We must rigorously evaluate interventions to deliver more patient-focused care to an increasingly frail nursing home population. Video decision support is a practical approach to improve advance care planning. PRagmatic trial Of Video Education in Nursing homes has the potential to promote goal-directed care among millions of older Americans in nursing homes and establish a methodology for future pragmatic randomized controlled trials in this complex healthcare setting.

Airflow Limitation and Histology Shift in the National Lung Screening Trial. The NLST-ACRIN Cohort Substudy

RATIONALE

Annual computed tomography (CT) is now widely recommended for lung cancer screening in the United States, although concerns remain regarding the potential harms, including those from overdiagnosis.

OBJECTIVES

To examine the effect of airflow limitation on overdiagnosis by comparing lung cancer incidence, histology, and stage shift in a subgroup of the National Lung Screening Trial (NLST).

METHODS

In an NLST subgroup (n = 18,714), screening participants were randomized to annual computed tomography (CT, n = 9,357) or chest radiograph (n = 9,357) screening and monitored for a mean of 6.1 years. After baseline prebronchodilator spirometry, to identify the presence of airflow limitation, 18,475 subjects (99%) were assigned as having chronic obstructive pulmonary disease (COPD) or no COPD. Lung cancer prevalence, incidence, histology, and stage shift were compared after stratification by COPD.

MEASUREMENTS AND MAIN RESULTS

For screening participants with spirometric COPD (n = 6,436), there was a twofold increase in lung cancer incidence (incident rate ratio, 2.15; P < 0.001) and, when compared according to screening arm, no excess lung cancers and comparable histology. Compared with chest radiography, there was also a trend favoring reduced late-stage and increased early-stage cancers in the CT arm (P = 0.054). For those with normal baseline spirometry (n = 12,039), we found an excess of lung cancers during screening in the CT arm, almost exclusively early-stage adenocarcinoma-related cancers (histology shift and overdiagnosis). After correction for these excess cancers, stage shift was marginal (P = 0.077).

CONCLUSIONS

In the CT arm of the NLST-ACRIN (American College of Radiology Imaging Network) cohort, COPD status was associated with a doubling of lung cancer incidence, no apparent overdiagnosis, and a more favorable stage shift.

Lung cancer incidence and mortality in National Lung Screening Trial participants who underwent low-dose CT prevalence screening: a retrospective cohort analysis of a randomised, multicentre, diagnostic screening trial

BACKGROUND

Annual low-dose CT screening for lung cancer has been recommended for high-risk individuals, but the necessity of yearly low-dose CT in all eligible individuals is uncertain. This study examined rates of lung cancer in National Lung Screening Trial (NLST) participants who had a negative prevalence (initial) low-dose CT screen to explore whether less frequent screening could be justified in some lower-risk subpopulations.

METHODS

We did a retrospective cohort analysis of data from the NLST, a randomised, multicentre screening trial comparing three annual low-dose CT assessments with three annual chest radiographs for the early detection of lung cancer in high-risk, eligible individuals (aged 55-74 years with at least a 30 pack-year history of cigarette smoking, and, if a former smoker, had quit within the past 15 years), recruited from US medical centres between Aug 5, 2002, and April 26, 2004. Participants were followed up for up to 5 years after their last annual screen. For the purposes of this analysis, our cohort consisted of all NLST participants who had received a low-dose CT prevalence (T0) screen. We determined the frequency, stage, histology, study year of diagnosis, and incidence of lung cancer, as well as overall and lung cancer-specific mortality, and whether lung cancers were detected as a result of screening or within 1 year of a negative screen. We also estimated the effect on mortality if the first annual (T1) screen in participants with a negative T0 screen had not been done. The NLST is registered with ClinicalTrials.gov, number NCT00047385.

FINDINGS

Our cohort consisted of 26 231 participants assigned to the low-dose CT screening group who had undergone their T0 screen. The 19 066 participants with a negative T0 screen had a lower incidence of lung cancer than did all 26 231 T0-screened participants (371·88 [95% CI 337·97-408·26] per 100 000 person-years vs 661·23 [622·07-702·21]) and had lower lung cancer-related mortality (185·82 [95% CI 162·17-211·93] per 100 000 person-years vs 277·20 [252·28-303·90]). The yield of lung cancer at the T1 screen among participants with a negative T0 screen was 0·34% (62 screen-detected cancers out of 18 121 screened participants), compared with a yield at the T0 screen among all T0-screened participants of 1·0% (267 of 26 231). We estimated that if the T1 screen had not been done in the T0 negative group, at most, an additional 28 participants in the T0 negative group would have died from lung cancer (a rise in mortality from 185·82 [95% CI 162·17-211·93] per 100 000 person-years to 212·14 [186·80-239·96]) over the course of the trial.

INTERPRETATION

Participants with a negative low-dose CT prevalence screen had a lower incidence of lung cancer and lung cancer-specific mortality than did all participants who underwent a prevalence screen. Because overly frequent screening has associated harms, increasing the interval between screens in participants with a negative low-dose CT prevalence screen might be warranted.

FUNDING

None.

Metrology Standards for Quantitative Imaging Biomarkers

Although investigators in the imaging community have been active in developing and evaluating quantitative imaging biomarkers (QIBs), the development and implementation of QIBs have been hampered by the inconsistent or incorrect use of terminology or methods for technical performance and statistical concepts. Technical performance is an assessment of how a test performs in reference objects or subjects under controlled conditions. In this article, some of the relevant statistical concepts are reviewed, methods that can be used for evaluating and comparing QIBs are described, and some of the technical performance issues related to imaging biomarkers are discussed. More consistent and correct use of terminology and study design principles will improve clinical research, advance regulatory science, and foster better care for patients who undergo imaging studies.

Patient willingness for repeat screening and preference for CT colonography and optical colonoscopy in ACRIN 6664: the National CT Colonography trial

BACKGROUND

Current American Cancer Society recommendations for colon cancer screening include optical colonoscopy every 10 years or computed tomography colonography (CTC) every 5 years. Bowel preparation (BP) is currently required for both screening modalities.

PURPOSE

To compare ACRIN 6664: the National CT Colonography Trial (NCTCT) participant experiences with CTC and optical colonoscopy (OC), procedure preference, and willingness to return for each procedure.

MATERIALS AND METHODS

Participants from fifteen NCTCT sites, who underwent CTC followed by OC under sedation, were invited to complete questionnaires 2 weeks postexam, asking about procedure preference, physical discomfort, and embarrassment experienced and whether that discomfort and embarrassment was better or worse than expected during BP, CTC, and OC, as well as willingness to return for repeat CTC and OC at different time intervals.

RESULTS

A total of 2,310 of 2,600 patients (89%) returned their questionnaires. Of patients reporting a preference, 1,058 (46.6%) preferred CTC, 569 (25.0%) preferred OC, and 626 (27.6%) reported no preference. Participant-reported discomfort worse than expected differed significantly between CTC (32.9%) and OC (5.0%) (P<0.001). About 79.3% were willing to be screened again with CTC in 5 years, and 96.6% with OC in 10 years. Discomfort and embarrassment worse than expected with OC were associated with increased intention to adhere with CTC in the future. Conversely, embarrassment experienced during CTC and discomfort worse than expected on CTC were associated with increased intention to adhere with OC in the future.

CONCLUSION

While a larger proportion of participants indicated that they preferred CTC to OC, willingness to undergo repeat CTC compared to OC was limited by unanticipated exam discomfort and embarrassment and CTC's shorter screening interval.

Quantitative imaging biomarkers: a review of statistical methods for technical performance assessment

Technological developments and greater rigor in the quantitative measurement of biological features in medical images have given rise to an increased interest in using quantitative imaging biomarkers to measure changes in these features. Critical to the performance of a quantitative imaging biomarker in preclinical or clinical settings are three primary metrology areas of interest: measurement linearity and bias, repeatability, and the ability to consistently reproduce equivalent results when conditions change, as would be expected in any clinical trial. Unfortunately, performance studies to date differ greatly in designs, analysis method, and metrics used to assess a quantitative imaging biomarker for clinical use. It is therefore difficult or not possible to integrate results from different studies or to use reported results to design studies. The Radiological Society of North America and the Quantitative Imaging Biomarker Alliance with technical, radiological, and statistical experts developed a set of technical performance analysis methods, metrics, and study designs that provide terminology, metrics, and methods consistent with widely accepted metrological standards. This document provides a consistent framework for the conduct and evaluation of quantitative imaging biomarker performance studies so that results from multiple studies can be compared, contrasted, or combined.

Cost-effectiveness of CT screening in the National Lung Screening Trial

BACKGROUND

The National Lung Screening Trial (NLST) showed that screening with low-dose computed tomography (CT) as compared with chest radiography reduced lung-cancer mortality. We examined the cost-effectiveness of screening with low-dose CT in the NLST.

METHODS

We estimated mean life-years, quality-adjusted life-years (QALYs), costs per person, and incremental cost-effectiveness ratios (ICERs) for three alternative strategies: screening with low-dose CT, screening with radiography, and no screening. Estimations of life-years were based on the number of observed deaths that occurred during the trial and the projected survival of persons who were alive at the end of the trial. Quality adjustments were derived from a subgroup of participants who were selected to complete quality-of-life surveys. Costs were based on utilization rates and Medicare reimbursements. We also performed analyses of subgroups defined according to age, sex, smoking history, and risk of lung cancer and performed sensitivity analyses based on several assumptions.

RESULTS

As compared with no screening, screening with low-dose CT cost an additional $1,631 per person (95% confidence interval [CI], 1,557 to 1,709) and provided an additional 0.0316 life-years per person (95% CI, 0.0154 to 0.0478) and 0.0201 QALYs per person (95% CI, 0.0088 to 0.0314). The corresponding ICERs were $52,000 per life-year gained (95% CI, 34,000 to 106,000) and $81,000 per QALY gained (95% CI, 52,000 to 186,000). However, the ICERs varied widely in subgroup and sensitivity analyses.

CONCLUSIONS

We estimated that screening for lung cancer with low-dose CT would cost $81,000 per QALY gained, but we also determined that modest changes in our assumptions would greatly alter this figure. The determination of whether screening outside the trial will be cost-effective will depend on how screening is implemented. (Funded by the National Cancer Institute; NLST ClinicalTrials.gov number, NCT00047385.).

Impact of lung cancer screening results on participant health-related quality of life and state anxiety in the National Lung Screening Trial

BACKGROUND

Low-dose computed tomography (LDCT) lung screening has been associated with a 20% reduction in lung cancer mortality. A major barrier to the adoption of lung screening is the potential negative psychological impact of a false-positive (FP) screen, occurring in 20% to 50% of those screened. The objective of this study was to assess the impact of abnormal findings on health-related quality of life (HRQoL) and anxiety in the American College of Radiology (ACRIN)/National Lung Screening Trial (NLST).

METHODS

The NLST was a randomized screening trial comparing LDCT with chest X-ray screening (CXR). This study was part of the original protocol. A total of 2812 participants at 16 of 23 ACRIN sites who had baseline HRQoL assessments were asked to complete the Short Form-36 and the State Trait Anxiety Inventory (form Y-1) questionnaires to assess short-term (1 month) and long-term (6 months) effects of screening. FP were lung cancer-free at 1 year, and true-positives (TP) were not.

RESULTS

Of the total participants, 1024 (36.4%) participants were FP, 63 (2.2%) were TP, 344 (12.2%) had significant incidental findings (SIFs), and 1381 (49.1%) had negative screens. Participants had been randomized to LDCT (n = 1947) and CXR (n = 865). Short-term and long-term HRQoL and state anxiety did not differ across participants with FP, SIF, or negative screens. Short-term and long-term HRQoL were lower and anxiety was higher for TP participants compared to participants with FP, SIF, and negative screens.

CONCLUSIONS

In a large multicenter lung screening trial, participants receiving a false-positive or SIF screen result experienced no significant difference in HRQoL or state anxiety at 1 or at 6 months after screening relative to those receiving a negative result.

Contralateral prophylactic mastectomy in the American College of Radiology Imaging Network 6667 trial: effect of breast MR imaging assessments and patient characteristics

PURPOSE

To assess which patient and magnetic resonance (MR) imaging factors are associated with the likelihood of contralateral prophylactic mastectomy (CPM) in patients with newly diagnosed breast cancer.

MATERIALS AND METHODS

The American College of Radiology Imaging Network 6667 trial was compliant with HIPAA; institutional review board approval was obtained at each site. All patients provided written informed consent. This study was a retrospective review of data from 934 women enrolled in the trial who did not have a known contralateral breast cancer at the time of surgical planning. The authors assessed age, menopausal status, index breast cancer histologic results, contralateral breast histologic results, breast density, family history, race and/or ethnicity, MR imaging Breast Imaging Reporting and Data System (BI-RADS) assessment, and number of MR imaging lesions for association with CPM by using the Fisher exact test, exact χ(2) test, and multivariate logistic regression analyses.

RESULTS

Eighty-six of the 934 (9.2%) women underwent CPM and were more likely to be younger (mean age, 48 years [range, 27-78 years] vs mean age, 54 years [range, 25-86 years]; P < .0001), be premenopausal (55 of 86 [64%] vs 349 of 845 [41%], P < .0001), have ductal carcinoma in situ (DCIS) in the index breast (31% [27 of 86] vs 19% [164 of 848], P = .02), have greater breast density (71 of 86 [83%] vs 572 of 848 [68%], P = .004), and have a family history of breast cancer (44 of 86 [30%] vs 150 of 488 [18%], P = .01) than those who did not undergo CPM. Distributions of race and/or ethnicity, contralateral lesion pathologic results, and number of MR imaging lesions were similar in both groups. With multivariate modeling, younger age, greater breast density, DCIS index cancer, and family history remained significant, whereas menopausal status did not. Positive MR imaging assessments were not significantly more frequent in the CPM group than in the group of women who did not undergo CPM (14 of 86 [16.3%] vs 113 of 848 [13.3%], P = .43).

CONCLUSION

In patients with newly diagnosed breast cancer who underwent breast MR imaging at which a contralateral breast cancer was not identified, patient factors and not breast MR imaging BI-RADS scores were chief determinants in decisions regarding CPM. Online supplemental material is available for this article.

Overdiagnosis in low-dose computed tomography screening for lung cancer

IMPORTANCE

Screening for lung cancer has the potential to reduce mortality, but in addition to detecting aggressive tumors, screening will also detect indolent tumors that otherwise may not cause clinical symptoms. These overdiagnosis cases represent an important potential harm of screening because they incur additional cost, anxiety, and morbidity associated with cancer treatment.

OBJECTIVE

To estimate overdiagnosis in the National Lung Screening Trial (NLST).

DESIGN, SETTING, AND PARTICIPANTS

We used data from the NLST, a randomized trial comparing screening using low-dose computed tomography (LDCT) vs chest radiography (CXR) among 53 452 persons at high risk for lung cancer observed for 6.4 years, to estimate the excess number of lung cancers in the LDCT arm of the NLST compared with the CXR arm.

MAIN OUTCOMES AND MEASURES

We calculated 2 measures of overdiagnosis: the probability that a lung cancer detected by screening with LDCT is an overdiagnosis (PS), defined as the excess lung cancers detected by LDCT divided by all lung cancers detected by screening in the LDCT arm; and the number of cases that were considered overdiagnosis relative to the number of persons needed to screen to prevent 1 death from lung cancer.

RESULTS

During follow-up, 1089 lung cancers were reported in the LDCT arm and 969 in the CXR arm of the NLST. The probability is 18.5% (95% CI, 5.4%-30.6%) that any lung cancer detected by screening with LDCT was an overdiagnosis, 22.5% (95% CI, 9.7%-34.3%) that a non-small cell lung cancer detected by LDCT was an overdiagnosis, and 78.9% (95% CI, 62.2%-93.5%) that a bronchioalveolar lung cancer detected by LDCT was an overdiagnosis. The number of cases of overdiagnosis found among the 320 participants who would need to be screened in the NLST to prevent 1 death from lung cancer was 1.38.

CONCLUSIONS AND RELEVANCE

More than 18% of all lung cancers detected by LDCT in the NLST seem to be indolent, and overdiagnosis should be considered when describing the risks of LDCT screening for lung cancer.

Positron emission tomography/computed tomography identification of clear cell renal cell carcinoma: results from the REDECT trial

PURPOSE

A clinical study to characterize renal masses with positron emission tomography/computed tomography (PET/CT) was undertaken.

PATIENTS AND METHODS

This was an open-label multicenter study of iodine-124 ((124)I) -girentuximab PET/CT in patients with renal masses who were scheduled for resection. PET/CT and contrast-enhanced CT (CECT) of the abdomen were performed 2 to 6 days after intravenous (124)I-girentuximab administration and before resection of the renal mass(es). Images were interpreted centrally by three blinded readers for each imaging modality. Tumor histology was determined by a blinded central pathologist. The primary end points-average sensitivity and specificity for clear cell renal cell carcinoma (ccRCC)-were compared between the two modalities. Agreement between and within readers was assessed.

RESULTS

(124)I-girentuximab was well tolerated. In all, 195 patients had complete data sets (histopathologic diagnosis and PET/CT and CECT results) available. The average sensitivity was 86.2% (95% CI, 75.3% to 97.1%) for PET/CT and 75.5% (95% CI, 62.6% to 88.4%) for CECT (P = .023). The average specificity was 85.9% (95% CI, 69.4% to 99.9%) for PET/CT and 46.8% (95% CI, 18.8% to 74.7%) for CECT (P = .005). Inter-reader agreement was high (κ range, 0.87 to 0.92 for PET/CT; 0.67 to 0.76 for CECT), as was intrareader agreement (range, 87% to 100% for PET/CT; 73.7% to 91.3% for CECT).

CONCLUSION

This study represents (to the best of our knowledge) the first clinical validation of a molecular imaging biomarker for malignancy. (124)I-girentuximab PET/CT can accurately and noninvasively identify ccRCC, with potential utility for designing best management approaches for patients with renal masses.

Efficiency of study designs in diagnostic randomized clinical trials

From the patients' management perspective, a good diagnostic test should contribute to both reflecting the true disease status and improving clinical outcomes. The diagnostic randomized clinical trial is designed to combine both diagnostic tests and therapeutic interventions. Evaluation of diagnostic tests is carried out with therapeutic outcomes as the primary endpoint rather than test accuracy. We lay out the probability framework for evaluating such trials. We compare two commonly referred designs-the two-arm design and the paired design-in a formal statistical hypothesis testing setup and identify the causal connection between the two tests. The paired design is shown to be more efficient than the two-arm design. The efficiency gains vary depending on the discordant rates of test results. We derive sample size formulas for both binary and continuous endpoints. We derive estimation of important quantities under the paired design and also conduct simulation studies to verify the theoretical results. We illustrate the method with an example of designing a randomized study on preoperative staging of bladder cancer.

Dynamic Optimal Strategy for Monitoring Disease Recurrence

Surveillance to detect cancer recurrence is an important part of care for cancer survivors. In this paper we discuss the design of optimal strategies for early detection of disease recurrence based on each patient's distinct biomarker trajectory and periodically updated risk estimated in the setting of a prospective cohort study. We adopt a latent class joint model which considers a longitudinal biomarker process and an event process jointly, to address heterogeneity of patients and disease, to discover distinct biomarker trajectory patterns, to classify patients into different risk groups, and to predict the risk of disease recurrence. The model is used to develop a monitoring strategy that dynamically modifies the monitoring intervals according to patients' current risk derived from periodically updated biomarker measurements and other indicators of disease spread. The optimal biomarker assessment time is derived using a utility function. We develop an algorithm to apply the proposed strategy to monitoring of new patients after initial treatment. We illustrate the models and the derivation of the optimal strategy using simulated data from monitoring prostate cancer recurrence over a 5-year period.

On ROC analysis with nonbinary reference standard

Statistical methods for the evaluation of the accuracy of diagnostic tests usually assume a binary true disease status. However, this assumption may not be realistic in practical settings in which "disease" is defined by dichotomizing continuous or ordinal categorical measures using a pre-specified threshold value. In this paper, we focus on the analysis of studies in which both the diagnostic test and the reference standard are reported as continuous measures. We propose a semiparametric model for estimating the sensitivity, specificity, and the ROC curve as functions of reference standard thresholds. Under suitable order restrictions on the mean of the test result variable, fitting is done via two alternative approaches: isotonic regression and monotone smoothing splines. The model provides the basis to assess the effect of varying reference standard threshold on the performance of a diagnostic test. An example to evaluate the ability of the maximal SUV-lean (standardized uptake value normalized to lean body mass) in predicting axillary node involvement in women diagnosed with breast cancer is presented.

Positive predictive value of BI-RADS MR imaging

PURPOSE

To evaluate the positive predictive values (PPVs) of Breast Imaging and Reporting Data Systems (BI-RADS) assessment categories for breast magnetic resonance (MR) imaging and to identify the BI-RADS MR imaging lesion features most predictive of cancer.

MATERIALS AND METHODS

This institutional review board-approved HIPAA-compliant prospective multicenter study was performed with written informed consent. Breast MR imaging studies of the contralateral breast in women with a recent diagnosis of breast cancer were prospectively evaluated. Contralateral breast MR imaging BI-RADS assessment categories, morphologic descriptors for foci, masses, non-masslike enhancement (NMLE), and kinetic features were assessed for predictive values for malignancy. PPV of each imaging characteristic of interest was estimated, and logistic regression analysis was used to examine the predictive ability of combinations of characteristics.

RESULTS

Of 969 participants, 71.3% had a BI-RADS category 1 or 2 assessment; 10.9%, a BI-RADS category 3 assessment; 10.0%, a BI-RADS category 4 or 5 assessment; and 7.7%, a BI-RADS category 0 assessment on the basis of initial MR images. Thirty-one cancers were detected with MR imaging. Overall PPV for BI-RADS category 4 and 5 lesions was 0.278, with 17 cancers in patients with a BI-RADS category 4 lesion (PPV, 0.205) and 10 cancers in patients with a BI-RADS category 5 lesion (PPV, 0.714). Of the cancers, one was a focus, 17 were masses, and 13 were NMLEs. For masses, irregular shape, irregular margins, spiculated margins, and marked internal enhancement were most predictive of malignancy. For NMLEs, ductal, clumped, and reticular or dendritic enhancement were the features most frequently seen with malignancy. Kinetic enhancement features were less predictive of malignancy than were morphologic features.

CONCLUSION

Standardized terminology of the BI-RADS lexicon enables quantification of the likelihood of malignancy for MR imaging-detected lesions through careful evaluation of lesion features. In particular, BI-RADS assessment categories and morphologic descriptors for masses and NMLE were useful in estimating the probability of cancer.

Annual screening strategies in BRCA1 and BRCA2 gene mutation carriers: a comparative effectiveness analysis

BACKGROUND

Although breast cancer screening with mammography and magnetic resonance imaging (MRI) is recommended for breast cancer-susceptibility gene (BRCA) mutation carriers, there is no current consensus on the optimal screening regimen.

METHODS

The authors used a computer simulation model to compare 6 annual screening strategies (film mammography [FM], digital mammography [DM], FM and magnetic resonance imaging [MRI] or DM and MRI contemporaneously, and alternating FM/MRI or DM/MRI at 6-month intervals) beginning at ages 25 years, 30 years, 35 years, and 40 years, and 2 strategies of annual MRI with delayed alternating DM/FM versus clinical surveillance alone. Strategies were evaluated without and with mammography-induced breast cancer risk using 2 models of excess relative risk. Input parameters were obtained from the medical literature, publicly available databases, and calibration.

RESULTS

Without radiation risk effects, alternating DM/MRI starting at age 25 years provided the highest life expectancy (BRCA1, 72.52 years, BRCA2, 77.63 years). When radiation risk was included, a small proportion of diagnosed cancers was attributable to radiation exposure (BRCA1, <2%; BRCA2, <4%). With radiation risk, alternating DM/MRI at age 25 years or annual MRI at age 25 years/delayed alternating DM at age 30 years was the most effective, depending on the radiation risk model used. Alternating DM/MRI starting at age 25 years also produced the highest number of false-positive screens per woman (BRCA1, 4.5 BRCA2, 8.1).

CONCLUSIONS

Annual MRI at age 25 years/delayed alternating DM at age 30 years is probably the most effective screening strategy in BRCA mutation carriers. Screening benefits, associated risks, and personal acceptance of false-positive results should be considered in choosing the optimal screening strategy for individual women.

CT angiography for safe discharge of patients with possible acute coronary syndromes

BACKGROUND

Admission rates among patients presenting to emergency departments with possible acute coronary syndromes are high, although for most of these patients, the symptoms are ultimately found not to have a cardiac cause. Coronary computed tomographic angiography (CCTA) has a very high negative predictive value for the detection of coronary disease, but its usefulness in determining whether discharge of patients from the emergency department is safe is not well established.

METHODS

We randomly assigned low-to-intermediate-risk patients presenting with possible acute coronary syndromes, in a 2:1 ratio, to undergo CCTA or to receive traditional care. Patients were enrolled at five centers in the United States. Patients older than 30 years of age with a Thrombolysis in Myocardial Infarction risk score of 0 to 2 and signs or symptoms warranting admission or testing were eligible. The primary outcome was safety, assessed in the subgroup of patients with a negative CCTA examination, with safety defined as the absence of myocardial infarction and cardiac death during the first 30 days after presentation.

RESULTS

We enrolled 1370 subjects: 908 in the CCTA group and 462 in the group receiving traditional care. The baseline characteristics were similar in the two groups. Of 640 patients with a negative CCTA examination, none died or had a myocardial infarction within 30 days (0%; 95% confidence interval [CI], 0 to 0.57). As compared with patients receiving traditional care, patients in the CCTA group had a higher rate of discharge from the emergency department (49.6% vs. 22.7%; difference, 26.8 percentage points; 95% CI, 21.4 to 32.2), a shorter length of stay (median, 18.0 hours vs. 24.8 hours; P<0.001), and a higher rate of detection of coronary disease (9.0% vs. 3.5%; difference, 5.6 percentage points; 95% CI, 0 to 11.2). There was one serious adverse event in each group.

CONCLUSIONS

A CCTA-based strategy for low-to-intermediate-risk patients presenting with a possible acute coronary syndrome appears to allow the safe, expedited discharge from the emergency department of many patients who would otherwise be admitted. (Funded by the Commonwealth of Pennsylvania Department of Health and the American College of Radiology Imaging Network Foundation; ClinicalTrials.gov number, NCT00933400.).

Abstract 99: Beta-Blocker Monotherapy is Inferior to Treatment with Angiotensin-Converting-Enzyme Inhibitor/Angiotensin-Receptor Blocker or Combined Therapy after Hospital Discharge among Patients with Acute Decompensated Heart Failure with Reduced Ejection Fraction

Introduction AHA/ACC guidelines recommend combination therapy with an angiotensin-converting-enzyme inhibitor (ACEI) or angiotensin-receptor blocker (ARB) and a beta-blocker (BB) at discharge for patients hospitalized for heart failure (HF) with reduced ejection fraction. However, there is little information available to compare outcomes associated with these three treatment options at discharge, and the optimal monotherapy with either an ACEI/ARB or BB for patients who cannot tolerate combination therapy is unknown.

Hypothesis We hypothesized that: 1) patients receiving ACEI/ARB or BB monotherapy would have higher rates of mortality and HF re-hospitalization than patients receiving combination therapy; and 2) patients receiving ACEI/ARB monotherapy would experience similar rates of mortality and lower rates of HF re-hospitalization when compared with patients receiving BB monotherapy.

Methods We studied 21,849 patients with left ventricular ejection fraction < 40% hospitalized for HF at 144 VA hospitals nationwide and who were assessed for HF quality measures between 2003 and 2007. Patients who received any of the three therapies (n=19,303) were 1:1:1 propensity score matched. We evaluated the association between treatment at hospital discharge and outcomes using the Kaplan-Meier method, pair-wise log-rank tests to test for significant differences in event-free survival, and hazard ratios (HR) and 95% confidence intervals (CI) from Cox proportional hazards regression models.

Results Among 4,995 patients in our matched sample, BB monotherapy at discharge was associated with increased 30-day mortality compared with ACEI/ARB monotherapy (HR: 1.62; 95% CI: 1.15, 2.29; log-rank P=0.009), which was not observed at six months (HR: 1.08; 95% CI: 0.91, 1.27; log-rank P=1.00). BB monotherapy at discharge was associated with increased mortality risk when compared with combination therapy at 30 days (HR: 1.67; 95% CI: 1.19, 2.36; log-rank P=0.009) and at six months (HR: 1.28; 95% CI: 1.08, 1.52; log-rank P=0.030). No significant differences in mortality between patients receiving ACEI/ARB monotherapy and combination therapy were observed. No significant association between HF therapy at discharge and risk of HF re-hospitalization was found.

Conclusions In this cohort of veterans hospitalized with decompensated HF and reduced ejection fraction, receipt of BB monotherapy at hospital discharge was associated with an elevated risk of mortality when compared with ACEI/ARB monotherapy and combination therapy.

ACRIN 6665/RTOG 0132 phase II trial of neoadjuvant imatinib mesylate for operable malignant gastrointestinal stromal tumor: monitoring with 18F-FDG PET and correlation with genotype and GLUT4 expression

We investigated the correlation between metabolic response by (18)F-FDG PET and objective response, glucose transporter type 4 (GLUT4) expression, and KIT/PDGFRA mutation status in patients with gastrointestinal stromal tumor undergoing neoadjuvant imatinib mesylate therapy.

METHODS

(18)F-FDG PET was performed at baseline, 1-7 d, and 4 or 8 wk after imatinib mesylate initiation. Best objective response was defined by version 1.0 of the Response Evaluation Criteria in Solid Tumors (RECIST). Mutational analysis and tumor GLUT4 expression by immunohistochemistry were done on tissue obtained at baseline or surgery.

RESULTS

(18)F-FDG PET showed high baseline tumor glycolytic activity (mean SUV(max), 14.2; range, 1.3-53.2), decreasing after 1 wk of imatinib mesylate (mean, 5.5; range, -0.5-47.7, P < 0.001, n = 44), and again before surgery (mean, 3.0; range, -0.5-36.1, P < 0.001, n = 40). At week 1, there were 3 patients with complete metabolic response (CMR), 33 with partial metabolic response (PMR), 6 with stable metabolic disease (SMD), and 2 with progressive metabolic disease (PMD). Before surgery, there were 3 with CMR, 33 with PMR, 4 with SMD, and none with PMD. The best response according to RECIST was 2 with partial response, 36 with stable disease, and 1 with progressive disease (n = 39). Of the patients with a posttreatment decrease in GLUT4 expression, 1 had CMR, 15 had PMR, 2 had SMD, and 1 had PMD at week 1, whereas before surgery 1 patient had CMR, 16 had PMR, 2 had SMD, and none had PMD. Among 27 patients with KIT exon 11 mutations, 1 had CMR, 22 had PMR, 3 had SMD, and 1 had PMD at week 1, whereas 1 had CMR, 22 had PMR, 2 had SMD, and 2 were unknown before surgery; among 4 patients with a wild-type genotype, 2 had PMR and 2 SMD at week 1, whereas 1 had CMR, 2 had PMR, and 1 had SMD before surgery.

CONCLUSION

After imatinib mesylate initiation, metabolic response by (18)F-FDG PET was documented earlier (1-7 d) and was of much greater magnitude (36/44) than that documented by RECIST (2/39). Immunohistochemistry data suggest that GLUT4 may play a role in (18)F-FDG uptake in gastrointestinal stromal tumor, GLUT4 levels decrease after imatinib mesylate therapy in most patients with PMR, and the biologic action of imatinib mesylate interacts with glycolysis and GLUT4 expression. A greater than 85% metabolic response was observed as early as days 1-7 in patients with exon 11 mutations.

OT2-05-04: ACRIN PA 4006: Comparison of Full-Field Digital Mammography with Digital Breast Tomosynthesis Image Acquisition in Relation to Screening Call-Back Rate

Background

With competing parameters of specificity and sensitivity, breast cancer screening must limit both missed cancers and false-positive call-backs (with potential to biopsy) to reduce cost and unnecessary anxiety to patients. Full-field digital mammography (FFDM) has been shown to provide improved sensitivity over analog mammography in the detection of breast cancers, particularly in women with dense breasts. Unfortunately, call-back rates for both digital and analog screening mammography have similar, elevated rates of approximately 10% (E. Pisano et al, NEJM, 2005). Incorporation of digital breast tomosynthesis (DBT), a novel 3-D reconstruction of multiple low-dose digital mammographic images, may reduce the number of call-back visits needed by providing many of the benefits of diagnostic imaging at screening. This study will assess variations in DBT image acquisition while limiting radiation dose to women with varying breast sizes and densities, to define parameters to be used in a larger national screening tomosynthesis trial.

Eligibility: Asymptomatic women 25 years and older with no breast cancer history are eligible for Group A or B (see below). Pregnant women, women unable to tolerate compression of the breast associated with mammography, women with implants, and women with breasts too large for DBT are excluded from participation.

Trial design/target accrual: This multicenter trial uses Hologic digital mammography units at two institutions in Philadelphia, Pennsylvania. The timing of the study-related imaging visits are segregated into two cohorts, screening (Group A) and diagnostic (Group B). Group A comprises 500 women who will undergo both FFDM and DBT at screening. Initial independent interpretations of the FFDM and DBT from local readers will determine call back. Enriched Group B comprises 50 women who have been informed of abnormal findings from a FFDM screening within 30 days of enrollment. They will be recruited prior to their diagnostic imaging and consent to DBT of both breasts as part of their diagnostic imaging. Participants from both Groups will be followed or biopsied as recommended by their treating physician. Follow up includes medical record review and images collection at approximately 1-year. Follow-up data may be collected up to 18 months.

Specific aims and statistical methods: ACRIN PA 4006 will evaluate the specificity of 2-D FFDM versus a combination of 2-D and 3-D tomosynthesis imaging in breast cancer screening. Specificity will be measured by the participant call-back rate by each modality. Sensitivity and specificity by lesion-type characteristics, especially focused on DBT assessment of calcifications, will be compared.

Current accrual: Currently, the trial accrual has reached 259 of 550.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr OT2-05-04.

OT2-05-06: ACOSOG Z11101/ACRIN 6694: Effect of Preoperative Breast MRI on Surgical Outcomes, Costs and Quality of Life of Women with Breast Cancer

Background

Surgical planning and local-regional treatment of breast cancer relies on accurate assessment of disease extent including the primary tumor size and the presence/absence of multiple tumor foci. As a staging modality for breast cancer, MRI has shown high sensitivity for detection of additional foci of diseases within the index breast. However, the impact of preoperative breast MRI on reducing re-excision rates and improving local control is less clear. Data from the COMICE trial in the UK suggested that routine use of pre-operative breast MRI did not alter rates of re-excision; however issues have been raised about the lack of quality standards for the MR imaging that may have resulted in the negative results of this trial. Retrospective data suggest that local recurrence is not impacted by use of breast MRI. In concert with data showing no improvement in clinical outcomes of breast cancer patients, concerns have been raised that routine use of preoperative breast MRI is associated with increased rates of mastectomy and delays to surgery. Therefore, the application of MRI for preoperative surgical staging remains controversial. In order to address this ongoing controversy, a joint effort has been launched by ACOSOG and ACRIN for a prospective clinical trial focused on evaluating the impact of preoperative breast MRI on clinically relevant patient outcomes. An important part of this collaboration is implementation of standards of how MRI findings should be clinically managed and used to direct localization methods and surgical planning, thereby creating guidelines for subsequent patient intervention.

Trial design/eligibility criteria: A prospective multicenter trial will include women eligible for BCT by standard criteria and randomized between current standard of care, clinical examination and mammography (+/− ultrasound) and the same plus preoperative breast MRI. The study will focus on women at the highest risk of local recurrence: ER/PR/HER-2 negative (triple negative) and HER-2 amplified breast cancers.

Specific aims: To compare the rates of local recurrence following breast conserving therapy in a cohort randomized to preoperative staging with mammography or mammography plus breast MRI. Additionally, a comparison of rates of re-operation, time to local recurrence, survival outcomes, contralateral breast cancer rates, rates of multicentric disease and other secondary aims will be performed. Costs and quality of life measures will also be investigated.

Statistical methods: A stratified logrank test and Cox partial likelihood score test will be used to assess whether the distribution of LR times differs with respect to diagnostic work-up approach having adjusted for tumor stage. Cox modeling with the Cox partial likelihood score test will be used to examine the strength of association between these time to event distributions and such additional potential prognostic factors as menopausal status, chemotherapy, radiation therapy, ER, PR, number of positive lymph nodes, HER-2/neu expression, Nottingham grade, and Ki-67 expression.

Target Accrual: 556 patients

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr OT2-05-06.

Reduced lung-cancer mortality with low-dose computed tomographic screening

BACKGROUND

The aggressive and heterogeneous nature of lung cancer has thwarted efforts to reduce mortality from this cancer through the use of screening. The advent of low-dose helical computed tomography (CT) altered the landscape of lung-cancer screening, with studies indicating that low-dose CT detects many tumors at early stages. The National Lung Screening Trial (NLST) was conducted to determine whether screening with low-dose CT could reduce mortality from lung cancer.

METHODS

From August 2002 through April 2004, we enrolled 53,454 persons at high risk for lung cancer at 33 U.S. medical centers. Participants were randomly assigned to undergo three annual screenings with either low-dose CT (26,722 participants) or single-view posteroanterior chest radiography (26,732). Data were collected on cases of lung cancer and deaths from lung cancer that occurred through December 31, 2009.

RESULTS

The rate of adherence to screening was more than 90%. The rate of positive screening tests was 24.2% with low-dose CT and 6.9% with radiography over all three rounds. A total of 96.4% of the positive screening results in the low-dose CT group and 94.5% in the radiography group were false positive results. The incidence of lung cancer was 645 cases per 100,000 person-years (1060 cancers) in the low-dose CT group, as compared with 572 cases per 100,000 person-years (941 cancers) in the radiography group (rate ratio, 1.13; 95% confidence interval [CI], 1.03 to 1.23). There were 247 deaths from lung cancer per 100,000 person-years in the low-dose CT group and 309 deaths per 100,000 person-years in the radiography group, representing a relative reduction in mortality from lung cancer with low-dose CT screening of 20.0% (95% CI, 6.8 to 26.7; P=0.004). The rate of death from any cause was reduced in the low-dose CT group, as compared with the radiography group, by 6.7% (95% CI, 1.2 to 13.6; P=0.02).

CONCLUSIONS

Screening with the use of low-dose CT reduces mortality from lung cancer. (Funded by the National Cancer Institute; National Lung Screening Trial ClinicalTrials.gov number, NCT00047385.).

Quantitative imaging test approval and biomarker qualification: interrelated but distinct activities

Quantitative imaging biomarkers could speed the development of new treatments for unmet medical needs and improve routine clinical care. However, it is not clear how the various regulatory and nonregulatory (eg, reimbursement) processes (often referred to as pathways) relate, nor is it clear which data need to be collected to support these different pathways most efficiently, given the time- and cost-intensive nature of doing so. The purpose of this article is to describe current thinking regarding these pathways emerging from diverse stakeholders interested and active in the definition, validation, and qualification of quantitative imaging biomarkers and to propose processes to facilitate the development and use of quantitative imaging biomarkers. A flexible framework is described that may be adapted for each imaging application, providing mechanisms that can be used to develop, assess, and evaluate relevant biomarkers. From this framework, processes can be mapped that would be applicable to both imaging product development and to quantitative imaging biomarker development aimed at increasing the effectiveness and availability of quantitative imaging.

SUPPLEMENTAL MATERIAL

http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.10100800/-/DC1.

The promise and realities of comparative effectiveness research

Comparative Effectiveness Research (CER) has been given a broad and ambitious mandate. Will it be able to deliver the multifaceted and granular comparative information that it has been tasked with developing? After a discussion of the general conditions for the feasibility of CER, we focus our attention on one of the most challenging areas: the evaluation of diagnostic tests and biomarkers.

The National Lung Screening Trial: overview and study design

The National Lung Screening Trial (NLST) is a randomized multicenter study comparing low-dose helical computed tomography (CT) with chest radiography in the screening of older current and former heavy smokers for early detection of lung cancer, which is the leading cause of cancer-related death in the United States. Five-year survival rates approach 70% with surgical resection of stage IA disease; however, more than 75% of individuals have incurable locally advanced or metastatic disease, the latter having a 5-year survival of less than 5%. It is plausible that treatment should be more effective and the likelihood of death decreased if asymptomatic lung cancer is detected through screening early enough in its preclinical phase. For these reasons, there is intense interest and intuitive appeal in lung cancer screening with low-dose CT. The use of survival as the determinant of screening effectiveness is, however, confounded by the well-described biases of lead time, length, and overdiagnosis. Despite previous attempts, no test has been shown to reduce lung cancer mortality, an endpoint that circumvents screening biases and provides a definitive measure of benefit when assessed in a randomized controlled trial that enables comparison of mortality rates between screened individuals and a control group that does not undergo the screening intervention of interest. The NLST is such a trial. The rationale for and design of the NLST are presented.

Frequency of malignancy seen in probably benign lesions at contrast-enhanced breast MR imaging: findings from ACRIN 6667

PURPOSE

To determine the frequency of malignancy in probably benign lesions seen at magnetic resonance (MR) screening of the contralateral breast in patients with known breast cancer enrolled in American College of Radiology Imaging Network (ACRIN) protocol 6667.

MATERIALS AND METHODS

ACRIN conducted a prospective multi-institutional MR imaging screening trial of the contralateral breast in women in whom breast cancer had been diagnosed recently. Each participating institution obtained institutional review board approval before patient accrual and was compliant with HIPAA. Informed consent was obtained from the patients. At enrollment, all women had negative clinical breast examination results and negative mammograms of the study breast. At image interpretation, radiologists scored lesions by using the Breast Imaging and Reporting and Data System (BI-RADS) lexicon. Of the 969 women who comprised the final study group, 106 were classified as having a BI-RADS category 3 lesion as their highest scoring lesion at MR imaging. There were 145 BI-RADS category 3 lesions in 106 patients.

RESULTS

In the 106 patients with at least one BI-RADS category 3 lesion, there were 37 masses (25.5%), 59 areas of nonmass enhancement (40.7%), and 47 foci of enhancement (32.4%). In two (1.4%) of these patients, no findings were reported. Eighty-three (78.3%) of the 106 patients had no evidence of malignancy in the study breast after 2 years of follow-up; the remaining 23 (21.7%) received a tissue diagnosis. Seventeen (16.0%) of the 106 patients elected to undergo biopsy. Biopsy was recommended in the remaining six patients (5.7%) on the basis of follow-up imaging findings. The biopsy results were benign in 18 (78%) of the 23 patients, whereas they showed atypical hyperplasia in two (9%). One (4%) of the 23 patients had ductal carcinoma in situ. Overall, malignancy was diagnosed in one (0.9%) of the 106 patients.

CONCLUSION

In a multi-institutional study, the frequency of malignancy in MR-detected BI-RADS category 3 lesions was 0.9% (95% confidence interval: 0.02%, 5.14%).

Cancer cases from ACRIN digital mammographic imaging screening trial: radiologist analysis with use of a logistic regression model

PURPOSE

To determine which factors contributed to the Digital Mammographic Imaging Screening Trial (DMIST) cancer detection results.

MATERIALS AND METHODS

This project was HIPAA compliant and institutional review board approved. Seven radiologist readers reviewed the film hard-copy (screen-film) and digital mammograms in DMIST cancer cases and assessed the factors that contributed to lesion visibility on both types of images. Two multinomial logistic regression models were used to analyze the combined and condensed visibility ratings assigned by the readers to the paired digital and screen-film images.

RESULTS

Readers most frequently attributed differences in DMIST cancer visibility to variations in image contrast--not differences in positioning or compression--between digital and screen-film mammography. The odds of a cancer being more visible on a digital mammogram--rather than being equally visible on digital and screen-film mammograms--were significantly greater for women with dense breasts than for women with nondense breasts, even with the data adjusted for patient age, lesion type, and mammography system (odds ratio, 2.28; P < .0001). The odds of a cancer being more visible at digital mammography--rather than being equally visible at digital and screen-film mammography--were significantly greater for lesions imaged with the General Electric digital mammography system than for lesions imaged with the Fischer (P = .0070) and Fuji (P = .0070) devices.

CONCLUSION

The significantly better diagnostic accuracy of digital mammography, as compared with screen-film mammography, in women with dense breasts demonstrated in the DMIST was most likely attributable to differences in image contrast, which were most likely due to the inherent system performance improvements that are available with digital mammography. The authors conclude that the DMIST results were attributable primarily to differences in the display and acquisition characteristics of the mammography devices rather than to reader variability.

ACRIN 6665/RTOG 0132 phase II trial of neoadjuvant imatinib mesylate (IM) for primary and recurrent operable malignant GIST: Imaging findings and correlation with genotype and GLUT4 expression

10552

Background: IM has improved the treatment of GIST patients (pts), but few achieve objective response despite significant clinical benefit. Imaging of tumor metabolism may provide earlier assessment of therapeutic response. In this study, FDG-PET metabolic response (MR) was compared with RECIST, GLUT4 expression, and KIT/PDGFRA mutation status. Methods: FDG-PET was done at baseline, 1–7 days, and 4 or 8 weeks (wk) after IM initiation. Best objective response was defined by RECIST. Immunohistochemical (IHC) tumor GLUT4 expression and mutation analyses were done at baseline and/or surgery. Background-subtracted SUVmax was measured in all lesions and summed; MR based on EORTC criteria was compared to RECIST, GLUT4 expression, and KIT/PDGFRA mutation status. Results: FDG-PET showed high tumor glycolytic activity at baseline (mean SUVmax = 14.2, range: 1.3–53.2), decreasing after 1 wk of IM (5.5, range: 0.5–47.7, p < 0.001, n = 44), and again prior to surgery (3.0, range: 0.5–36.1, p < 0.001, n = 40). FDG-PET response at wk 1 was 3 complete MR (CMR), 33 partial MR (PMR), 6 stable metabolic disease (SMD), and 2 progressive metabolic disease (PMD). Prior to surgery, FDG-PET response was 3 CMR, 33 PMR, 4 SMD, and no PMD. For 39 pts, RECIST best response was 2 PR, 36 SD, and 1 PD. GLUT4 expression decreased in 19 pts with PMR, and 3 with SMD. Among 12 pts with exon 11 mutation, 11 had PMR, 1 SMD; among 5 pts with wild-type genotype, 4 had PMR, and 1 SMD. Conclusions: After IM initiation, MR by FDG-PET was documented earlier (1–7 days), and was of much greater magnitude (36/40) than that documented by RECIST (2/39). IHC data suggest that: (1) GLUT4 plays a role in FDG uptake in GIST; (2) GLUT4 decreases in most pts with PMR; and, (3) the biologic action of IM interacts with glycolysis and GLUT4 expression. No difference in PMR was seen in pts with exon 11 vs. wild type mutations.

[Table: see text]

MRI tumor volume for predicting response to neoadjuvant chemotherapy in locally advanced breast cancer: Findings from ACRIN 6657/CALGB 150007

529

Background: American College of Radiology Imaging Network (ACRIN) trial 6657, the imaging component of the I-SPY trial (CALGB 150007/150012), is testing MRI for predicting response to treatment and stratifying risk-of-recurrence in patients with locally-advanced breast cancer. We report preliminary results evaluating MRI for prediction of pathologic response. Methods: Women with ≥3 cm invasive breast cancer receiving neoadjuvant chemotherapy (NACT) with anthracycline-cyclophosphamide (AC) followed by a taxane (T) were enrolled from May 2002 to March 2006. MRI was performed prior to NACT (t1), after 1 cycle AC (t2), between AC and T (t3), and following T prior to surgery (t4). MRI tumor size assessments included longest diameter (MRLD) and tumor volume (MRVol). Clinical size (clinsize) and mammographic longest diameter (MGLD) were also recorded. Linear dimension was measured by the radiologist for MGLD and MRLD; MRVol was calculated by computer using signal enhancement ratio (SER) thresholds. Change in clinical and MRI variables at t2 were compared for ability to predict pathologic complete response (pCR). Results: 237 patients were enrolled at 9 institutions. 216 patients with complete imaging were analyzed. Of tumor size measurements at t4, MRVol showed the strongest correlation with pathsize among clinsize (r = 0.44), MGLD (ns), MRLD (r = 0.28) and MRVol (r = 0.61). Early change in MRVol measured at t2 was the only variable predictive of pCR among clinsize (p = 0.14, 0.15), MRLD (p = 0.40, 0.07), MRVol (p = 0.02, 0.01) and peak SER (p = 0.53, 0.72) in univariate and multivariate logistic regression, respectively. Conclusions: Tumor response measured volumetrically by MRI is a stronger and earlier predictor of pathologic response after NACT than clinical exam or tumor diameter. This work is funded by NIH/ACRIN U01 CA79778; CALGB CA31946, CA33601; NCI SPORE CA58207.

[Table: see text]

ACRIN 6664: Patient acceptance and preferance of CT colonography compared to optical colonoscopy for colon cancer screening

4034

Background: Colorectal cancer screening must be repeated on a regular basis. Understanding patient perceptions and willingness to be rescreened will help to determine future compliance rates. The purpose of this study was to compare National CT Colonography Trial (NCTCT) screening participant experiences with CT colonography (CTC) and optical colonoscopy (OC), willingness to return for each procedure, and procedure preference. Methods: NCTCT participants underwent a single bowel preparation (BP). Participants were scheduled to receive CTC, followed by sedation and OC. Participants were asked to complete a questionnaire two weeks post-exam on physical discomfort and embarrassment during BP, CTC and OC and willingness to repeat CTC and OC (with or without BP) at different time intervals. McNemar's Test and logistic regression were used for statistical analysis. Results: 2310 of 2600 patients (89%) responded (1224 women, 1086 men). Mean age was 58.39 years (range 50–86). The participant population was 85% Caucasian, 11% African American and 4% other. Severe discomfort was reported by 7.1% participants with BP, 6.3% with CTC, and 2.2% with OC. Severe embarrassment was reported by 1.6% participants with BP, 1.3% with CTC, and 0.7% with OC. Forty-six percent of participants preferred CTC, 27.4% reported no preference, and 24.9% preferred OC (p<0.001). Repeat screening with CTC is currently recommended every 5 years and with OC every 10 years. 80.5% of the participants were willing to be screened again with CTC in 5 years and 97.5 % were willing to be screened again with OC in 10 years (p<0.001). If the screening interval for CTC were extended to ten years, 93.7% of participants were willing to return for screening (p<0.001). If BP were unnecessary, 91.0% were willing to be rescreened with CTC in 5 years and 97.5% were willing to be rescreened with OC in 10 years (p<0.001). Conclusions: NCTCT participants preferred CTC to OC, but their willingness to undergo repeat CTC was limited by the shorter interval between screenings currently recommended for CTC as opposed to OC. Improvements in technology that would eliminate the need for bowel preparation or extend the recommended screening interval would likely improve adherence to recommended repeat screening.

[Table: see text]

Comparison of soft-copy and hard-copy reading for full-field digital mammography

PURPOSE

To compare radiologists' performance in detecting breast cancer when reading full-field digital mammographic (FFDM) images either displayed on monitors or printed on film.

MATERIALS AND METHODS

This study received investigational review board approval and was HIPAA compliant, with waiver of informed consent. A reader study was conducted in which 26 radiologists read screening FFDM images displayed on high-resolution monitors (soft-copy digital) and printed on film (hard-copy digital). Three hundred thirty-three cases were selected from the Digital Mammography Image Screening Trial screening study (n = 49,528). Of these, 117 were from patients who received a diagnosis of breast cancer within 15 months of undergoing screening mammography. The digital mammograms were displayed on mammographic workstations and printed on film according to the manufacturer's specifications. Readers read both hard-copy and soft-copy images 6 weeks apart. Each radiologist read a subset of the total images. Twenty-two readers were assigned to evaluate images from one of three FFDM systems, and four readers were assigned to evaluate images from two mammographic systems. Each radiologist assigned a malignancy score on the basis of overall impression by using a seven-point scale, where 1 = definitely not malignant and 7 = definitely malignant.

RESULTS

There were no significant differences in the areas under the receiver operating characteristic curves (AUCs) for the primary comparison. The AUCs for soft-copy and hard-copy were 0.75 and 0.76, respectively (95% confidence interval: -0.04, 0.01; P = .36). Secondary analyses showed no significant differences in AUCs on the basis of manufacturer type, lesion type, or breast density.

CONCLUSION

Soft-copy reading does not provide an advantage in the interpretation of digital mammograms. However, the display formats were not optimized and display software remains an evolving process, particularly for soft-copy reading.

Validation of novel imaging methodologies for use as cancer clinical trial end-points

The success or failure of a clinical trial, of any phase, depends critically on the choice of an appropriate primary end-point. In the setting of phases II and III cancer clinical trials, imaging end-points have historically, and continue presently to play a major role in determining therapeutic efficacy. The primary goal of this paper is to discuss the validation of imaging-based markers as end-points for phase II clinical trials of cancer therapy. Specifically, we outline the issues that must be considered, and the criteria that would need to be satisfied, for an imaging end-point to supplement or potentially replace RECIST- defined tumour status as a phase II clinical trial end-point. The key criteria proposed to judge the utility of a new end-point primarily relate to its ability to accurately and reproducibly predict the eventual phase III end-point for treatment effect, which is usually assessed by a difference between two arms on progression free or overall survival, both at the patient and more importantly at the trial level. As will be demonstrated, the level of evidence required to formally and fully validate a new imaging marker as an appropriate end-point for phase II trials is substantial. In many cases, this level of evidence will only become available by conducting a series of coordinated prospectively designed multicentre clinical trials culminating in a formal meta-analysis. We also include a discussion of situations where flexibility may be required, relative to the ideal rigorous evaluation, to accommodate inevitable real-world feasibility constraints.

Systematic reviews of diagnostic test accuracy

More and more systematic reviews of diagnostic test accuracy studies are being published, but they can be methodologically challenging. In this paper, the authors present some of the recent developments in the methodology for conducting systematic reviews of diagnostic test accuracy studies. Restrictive electronic search filters are discouraged, as is the use of summary quality scores. Methods for meta-analysis should take into account the paired nature of the estimates and their dependence on threshold. Authors of these reviews are advised to use the hierarchical summary receiver-operating characteristic or the bivariate model for the data analysis. Challenges that remain are the poor reporting of original diagnostic test accuracy studies and difficulties with the interpretation of the results of diagnostic test accuracy research.

The American College Of Radiology Imaging Network--clinical trials of diagnostic imaging and image-guided treatment

The American College of Radiology Imaging Network (ACRIN) is the youngest of the National Cancer Institute (NCI) cooperative groups. ACRIN trials are directed towards evaluating the applications of diagnostic imaging and image-guided treatment to cancer. As ACRIN begins its third funding cycle, the organization is increasingly emphasizing several themes: linking imaging surveillance to pre-imaging testing for disease to improve the efficiency of cancer screening; the evaluation of imaging tests as biomarkers for molecular and physiologic processes in cancer; the standardization and validation of imaging tests to predict and monitor response to treatment; improved characterization of the extent and biology of cancer; and the translation of new emerging technologies from first-in-human testing to multicenter trials. ACRIN is poised to pursue its own research agenda, collaborate with other research entities to address key issues in cancer care, and place at the service of the other cooperative groups its electronic infrastructure to improve imaging in therapeutic trials. ACRIN's pursuit of its unique mission as the sole cooperative group directed principally toward diagnosis has made the network an integral part of the cancer research community.

Comparing patient-reported hospital adverse events with medical record review: do patients know something that hospitals do not?

BACKGROUND

Hospitals routinely survey patients about the quality of care they receive, but little is known about whether patient interviews can detect adverse events that medical record reviews do not.

OBJECTIVE

To compare adverse events reported in postdischarge patient interviews with adverse events detected by medical record review.

DESIGN

Random sample survey.

SETTING

Massachusetts, 2003.

PATIENTS

Recently hospitalized adults.

MEASUREMENTS

By using parallel methods, physicians reviewed postdischarge interviews and medical records to classify hospital adverse events.

RESULTS

Among 998 study patients, 23% had at least 1 adverse event detected by an interview and 11% had at least 1 adverse event identified by record review. The kappa statistic showed relatively poor agreement between interviews and medical records for occurrence of any type of adverse event (kappa = 0.20 [95% CI, 0.03 to 0.27]) and somewhat better agreement between interviews and medical records for life-threatening or serious events (kappa = 0.33 [CI, 0.20 to 0.45]). Record review identified 11 serious, preventable events (1.1% of patients). Interviews identified an additional 21 serious and preventable events that were not documented in the medical record, including 12 predischarge events and 9 postdischarge events, in which symptoms occurred after the patient left the hospital.

LIMITATIONS

Patients had to be healthy enough to be interviewed. Delay in reaching patients (6 to 12 months after discharge) may have resulted in poor recall of events during the hospital stay.

CONCLUSION

Patients report many events that are not documented in the medical record; some are serious and preventable. Hospitals should consider monitoring patient safety by adding questions about adverse events to postdischarge interviews.

The predictive receiver operating characteristic curve for the joint assessment of the positive and negative predictive values

Binary test outcomes typically result from dichotomizing a continuous test variable, observable or latent. The effect of the threshold for test positivity on test sensitivity and specificity has been studied extensively in receiver operating characteristic (ROC) analysis. However, considerably less attention has been given to the study of the effect of the positivity threshold on the predictive value of a test. In this paper we present methods for the joint study of the positive (PPV) and negative predictive values (NPV) of diagnostic tests. We define the predictive receiver operating characteristic (PROC) curve that consists of all possible pairs of PPV and NPV as the threshold for test positivity varies. Unlike the simple trade-off between sensitivity and specificity exhibited in the ROC curve, the PROC curve displays what is often a complex interplay between PPV and NPV as the positivity threshold changes. We study the monotonicity and other geometric properties of the PROC curve and propose summary measures for the predictive performance of tests. We also formulate and discuss regression models for the estimation of the effects of covariates.