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Ambinder EB, Harvey SC, Panigrahi B, Li X, Woods RW. Synthesized Mammography: The New Standard of Care When Screening for Breast Cancer with Digital Breast Tomosynthesis? Acad Radiol 2018; 25:973-976. [PMID: 29395801 DOI: 10.1016/j.acra.2017.12.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 11/10/2017] [Accepted: 12/21/2017] [Indexed: 12/20/2022]
Abstract
RATIONALE AND OBJECTIVES This study aims to evaluate the screening performance of digital breast tomosynthesis (DBT) combined with synthesized mammography (SM) vs combined with full-field digital mammography (FFDM). MATERIALS AND METHODS We retrospectively reviewed all screening studies utilizing FFDM + DBT (n = 7845) and SM + DBT (n = 14,776) between April 1, 2013, and February 15, 2016. Recall rate, biopsy rate, positive predictive value 1 (PPV1), positive predictive value 3 (PPV3), and cancer detection rate (CDR) were compared between the two groups. A generalized linear mixed model specifying the reading radiologist as the random effect and controlling for age was used to compare clinical outcomes between the two groups. RESULTS The overall recall rate was significantly lower in the SM + DBT cohort compared to the FFDM + DBT cohort (7.06% vs 7.63%, P = .04). There was no difference in biopsy rate, PPV1, PPV3, or CDR between the two groups. CONCLUSIONS When DBT is performed for screening, the use of SM rather than acquiring an additional FFDM has no significant effect on biopsy rate, PPV1, PPV3, or CDR. We found a decrease in recall rate in the SM + DBT group, which may be related to the learning curve of interpreting DBT. These findings support the use of SM for patients undergoing screening with DBT.
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Downs BM, Fackler MJ, Mercado-Rodriguez C, Cimino-Mathews A, Chen C, Yuan JP, Berg EVD, Cope LM, Harvey SC, Ali SZ, Tulac S, Kocmond KJ, Lai EW, Rhees B, Bates M, Sukumar S. Abstract LB-220: An automated breast cancer detection assay for screening in the developing world. Cancer Res 2018. [DOI: 10.1158/1538-7445.am2018-lb-220] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Introduction: Breast cancer incidence is rapidly increasing globally with 1.7 million new cases and 600,000 deaths due to the disease annually. Death due to breast cancer is four to six times more frequent in the developing world compared to the USA due to lack of early detection, definitive diagnosis, and limited access to treatment. Ultrasound imaging for early detection and ultrasound guided fine needle aspiration (FNA) of suspicious lesions followed by an automated, cartridge-based analysis of methylated genes could triage malignancies for faster pathology assessment and treatment, thus enabling better use of scarce resources.
Experimental Procedures: To identify a panel of methylated DNA markers to enable sensitive and specific detection of malignant breast lesions, we screened 24 methylated genes (known to be frequently methylated in malignant breast tissue and unmethylated in normal breast tissue) by Quantitative Multiplex Methylation-Specific PCR (QM-MSP) analysis. Formalin-fixed paraffin-embedded (FFPE) sections of biopsies of both benign and malignant breast lesions from the USA, China and South Africa were analyzed. Samples were divided into Training and Test sets. The Training set consisted of 206 tissues [66 invasive ductal carcinoma (IDC), 30 ductal carcinoma in situ (DCIS), 99 benign breast disease (BBD) and 11 normal breast (NB)]. The gene panel selected in the Training set was examined in an independent Test set of tissues (n=204) [65 IDC, 29 DCIS, 99 BBD and 11 NB]. Further, we optimized the technical performance of an automated, prototype breast cancer detection cartridge system for quantitative assessment of gene methylation and tested it in pilot study using FNA samples from breast cancers.
Results: Analysis of the tissues in the Training set (n=206) led to the selection of a panel of 10 genes highly methylated in malignant lesions with little or no methylation in benign lesions. For the 10-gene panel to achieve a sensitivity greater than 90%, a laboratory cutoff of 14.5 cumulative methylation (CM) units (out of a possible 10,000 units) was set. In the Training set, the 10-gene panel achieved a sensitivity of 90% and a specificity of 85% with receiver operating characteristic (ROC) statistics: ROC, AUC= 0.947. In a blinded Test set of tissue samples (n=204), with a laboratory cutoff of 14.5 CM units, the 10-gene panel achieved a sensitivity of 87% and a specificity of 89%, with ROC statistics: p<0.001, AUC= 0.936, and provided significant accuracy for breast cancers from three countries and all molecular subtypes. In a pilot study of FNA samples using the cartridge system, robust methylation in all ten genes was detected in malignant tumors.
Conclusions: QM-MSP of breast lesions led to the selection of a panel of 10 genes methylated for detection of breast cancer. We have validated the technical performance of an automated, prototype cartridge system. The study reveals the potential of methylation markers to provide fast, accurate and automated cancer detection at a low cost in developing regions globally.
Research Use Only. Not for diagnostic tests.
A sponsored research agreement from Cepheid to Dr. Sukumar's Lab at Johns Hopkins University.
Citation Format: Bradley M. Downs, Mary Jo Fackler, Claudia Mercado-Rodriguez, Ashley Cimino-Mathews, Chuang Chen, Jing-Ping Yuan, Eunice van den Berg, Leslie M. Cope, Susan C. Harvey, Syed Z. Ali, Suzana Tulac, Kriszten J. Kocmond, Edwin W. Lai, Brian Rhees, Mike Bates, Saraswati Sukumar. An automated breast cancer detection assay for screening in the developing world [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-220.
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Smith EG, Davis K, Sulsh L, Harvey SC, Fowler KE. Canine recommended breed weight ranges are not a good predictor of an ideal body condition score. J Anim Physiol Anim Nutr (Berl) 2018; 102:1088-1090. [PMID: 29737554 DOI: 10.1111/jpn.12919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 04/13/2018] [Indexed: 11/29/2022]
Abstract
Breed-specific ideal bodyweight range information is widely used by dog owners and breeders as a guideline to ensure animals are within a healthy weight range. Body Condition Scoring, a method used by veterinarians to assess an animal's overall shape with regard to weight is considered to be an excellent method to determine an animal's overall body condition; these values, however, do not always correspond to published weight ranges. Here, the weight, neuter status, age and a nine-point Body Condition Score of a population of 140 purebred dogs were recorded and subsequently analysed to determine whether bodyweight was an effective predictor for Body Condition Scores. This comparison indicated that published recommended, breed-specific body weight ranges are not a good predictor for an ideal BCS and as such, guidelines for owners and breeders need to be systematically reviewed.
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Salas Fragomeni RA, Amir T, Sheikhbahaei S, Harvey SC, Javadi MS, Solnes LB, Kiess AP, Allaf ME, Pomper MG, Gorin MA, Rowe SP. Imaging of Nonprostate Cancers Using PSMA-Targeted Radiotracers: Rationale, Current State of the Field, and a Call to Arms. J Nucl Med 2018; 59:871-877. [PMID: 29545375 DOI: 10.2967/jnumed.117.203570] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 02/23/2018] [Indexed: 11/16/2022] Open
Abstract
Prostate-specific membrane antigen (PSMA) is a type II transmembrane glycoprotein that is highly overexpressed on prostate cancer epithelial cells and for which there is a growing body of literature examining the role of small-molecule and antibody radiotracers targeted against this protein for prostate cancer detection and therapy. Despite its name, PSMA is also expressed, to varying degrees, in the neovasculature of a wide variety of nonprostate cancers; indeed, the pathology literature is replete with promising immunohistochemistry findings. Several groups have begun to correlate those pathology-level results with in vivo imaging and therapy in nonprostate cancers using the same PSMA-targeted agents that have been so successful in prostate cancer. The potential to leverage radiotracers targeted to PSMA beyond prostate cancer is a promising approach for many cancers, and PSMA-targeted agents may be able to supplement or fill gaps left by other agents. However, to date, most of the reported findings with PSMA-targeted radiotracers in nonprostate malignancies have been in case reports and small case series, and the field must adopt a more thorough approach to the design and execution of larger prospective trials to realize the potential of these promising agents outside prostate cancer.
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Mullen LA, Panigrahi B, Hollada J, Panigrahi B, Falomo ET, Harvey SC. Strategies for Decreasing Screening Mammography Recall Rates While Maintaining Performance Metrics. Acad Radiol 2017; 24:1556-1560. [PMID: 28760363 DOI: 10.1016/j.acra.2017.06.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 04/14/2017] [Accepted: 06/08/2017] [Indexed: 01/09/2023]
Abstract
RATIONALE AND OBJECTIVE This study aimed to determine the impact of interventions designed to reduce screening mammography recall rates on screening performance metrics. MATERIALS AND METHODS We assessed baseline performance for full-field digital mammography (FFDM) and digital breast tomosynthesis mammography (DBT) for a 3-year period before intervention. The first intervention sought to increase awareness of recalls from screening mammography. Breast imagers discussed their perceptions regarding screening recalls and were required to review their own recalled cases, including outcomes of diagnostic evaluation and biopsy. The second intervention implemented consensus double reading of all recalls, requiring two radiologists to agree if recall was necessary. Recall rates, cancer detection rates, and positive predictive value 1 (PPV1) were compared before and after each intervention. RESULTS The baseline recall rate, cancer detection rate, and PPV1 were 11.1%, 3.8/1000, and 3.4%, respectively, for FFDM, and 7.6%, 4.8/1000, and 6.0%, respectively, for DBT. Recall rates decreased significantly to 9.2% for FFDM and to 6.6% for DBT after the first intervention promoting awareness, as well as to 9.9% for FFDM after the second intervention implementing group consensus. PPV1 increased significantly to 5.7% for FFDM and to 9.0% for DBT after the second intervention. Cancer detection rate did not significantly change with the implementation of these interventions. An average of 2.3 minutes was spent consulting for each recall. CONCLUSION Reduction in recall rates is desirable, provided performance metrics remain favorable. Our interventions improved performance and could be implemented in other breast imaging settings.
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Dickerson LK, Rositch AF, Lucas S, Harvey SC. Pilot Educational Intervention and Feasibility Assessment of Breast Ultrasound in Rural South Africa. J Glob Oncol 2017; 3:502-508. [PMID: 29094089 PMCID: PMC5646899 DOI: 10.1200/jgo.2016.008086] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
PURPOSE Breast cancer is the leading cause of cancer death in women worldwide, with high mortality in low- and middle-income countries because of a lack of detection, diagnosis, and treatment. With mammography unavailable, ultrasound offers an alternative for downstaging. The literature reports successful training in various domains, but a focus on the breast is novel. We assessed the feasibility (knowledge acquisition, perceived usefulness, and self-efficacy) of breast ultrasound training for nonphysician providers. METHODS Training was implemented for 12 providers at Hlokomela Clinic in Hoedspruit, South Africa, over 3 weeks. Didactic presentations and example cases were followed by a presurvey and test (n = 12). All providers received hands-on training with nurses as models; five providers trained with patients. A post-test (n = 12) assessed knowledge acquisition and a postsurvey (n = 10) assessed perceived program usefulness and provider self-efficacy. RESULTS The pre- to post-test averages improved by 68% in total and in four competencies (foundational knowledge, descriptive categories, benign v malignant, and lesion identification). On the postsurvey, providers expressed that ultrasound could significantly influence breast cancer detection (9.1 out of 10), treatment (7.9 out of 10), and survival (8.7 out of 10) in their community and endorsed moderate confidence in their scanning (6.3 out of 10) and interpreting abilities (5.6 out of 10). CONCLUSION Our research supports the feasibility of breast ultrasound training as part of a breast education program in low- and middle-income countries. Pre- and post-test results and observed proficiency indicate that training nonphysician providers is achievable; postsurvey responses indicate program acceptance, community-based ownership, and provider self-efficacy with ultrasound. Future work may show that breast ultrasound is viable for early detection where mammography is unavailable.
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Holz K, Harvey SC, Alvin MD, Beach MC, Pisano K, Woods R. Communication in Breast Imaging: Lessons Learned at Diagnostic Evaluation. J Am Coll Radiol 2017; 14:665-667. [DOI: 10.1016/j.jacr.2016.10.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Revised: 10/16/2016] [Accepted: 10/19/2016] [Indexed: 11/28/2022]
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Trupe LA, Rositch A, Dickerson L, Lucas S, Harvey SC. Knowledge and Attitudes About Breast Cancer in Limpopo, South Africa. J Glob Oncol 2017; 3:509-514. [PMID: 29094090 PMCID: PMC5646900 DOI: 10.1200/jgo.2016.008102] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Purpose Breast cancer survival is unacceptably low in many low-resource settings, including rural South Africa, where access to screening and treatment services is limited. To describe the context for implementing an early detection program, we assessed knowledge and attitudes toward breast cancer risk, early detection, and treatment. Methods We conducted a cross-sectional survey among 243 women presenting to Hlokomela Clinic in Hoedspruit, South Africa, during April and May 2016. We used quantitative and qualitative analyses to determine levels of knowledge of risk factors, symptoms, and treatment of breast cancer, as well as experience with and attitudes toward detection and treatment methods. Results Thirty-one percent of women correctly identified at least six of 12 risk factors for breast cancer, and 53.1% identified breast lumps as an important symptom. Although > 97% of women stated that self–breast examination and early detection were highly important and that they would seek care for changes in their breasts, only 33.3% of women reported performing self–breast examination, and only 24.3% reported receiving a clinical breast examination. Age and education were not associated with knowledge, and level of knowledge did not predict care-seeking behaviors or attitudes. Conclusion Although women demonstrated moderate levels of knowledge of breast cancer symptoms and risk factors and the importance of early detection, few women reported seeking services. These data demonstrate sufficient levels of knowledge and positive attitudes toward care seeking and suggest both a need and readiness for increased access to cost-effective services to facilitate early diagnosis and improved outcomes.
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Narayan AK, Harvey SC, Durand DJ. Impact of Medicare Shared Savings Program Accountable Care Organizations at Screening Mammography: A Retrospective Cohort Study. Radiology 2017; 282:437-448. [DOI: 10.1148/radiol.2016160554] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Harvey SC, Di Carlo PA, Lee B, Obadina E, Sippo D, Mullen L. An Abbreviated Protocol for High-Risk Screening Breast MRI Saves Time and Resources. J Am Coll Radiol 2016; 13:R74-R80. [DOI: 10.1016/j.jacr.2016.09.031] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Narayan AK, Visvanathan K, Harvey SC. Comparative effectiveness of breast MRI and mammography in screening young women with elevated risk of developing breast cancer: a retrospective cohort study. Breast Cancer Res Treat 2016; 158:583-9. [PMID: 27444927 DOI: 10.1007/s10549-016-3912-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 07/13/2016] [Indexed: 11/25/2022]
Abstract
Screening guidelines recommend that women with 20 % or greater lifetime risk of breast cancer undergo annual breast MRI screening to supplement mammography, irrespective of age. In patients less than 40 years, mammography is often avoided due to concerns about radiation and decreased performance. However, prior studies have been limited by large percentages of women above 40 with decreased breast density. Our purpose was to test whether adding mammography to breast MRI screening compared to breast MRI screening alone in women below 40 increases cancer detection rates. After obtaining IRB approval, chart review identified patients aged 25-40 years undergoing breast MR screening (2005-2014). Demographics, risk factors, BI-RADS assessments, background parenchymal enhancement, and mammographic breast tissue density were recorded. Cancer detection rates, short-term follow-up (BIRADS 3), image-guided biopsy (BIRADS 4,5), and PPV1-3 were calculated. 342 breast MRI exams were identified (average age was 33, 37 % were nulliparous, and 64 % had prior benign biopsy), 226 (66 %) of which underwent concurrent mammography. Risk factors included 64 % with breast cancer in first-degree relative(s), 90 % had heterogeneous or extremely dense breast tissue on mammography, and 16 % were BRCA carriers. Four invasive cancers were detected by MRI (11.7 cancers/1000 examinations, 95 % CI 8.3, 15.1). None of these was detected by mammography, and no cancers were independently identified by mammography. Breast MRI screening in high-risk women under 40 yielded elevated cancer detection rates (11.7/1000). The cancer detection rate for mammography was 0 %, suggesting that MRI alone may be useful in screening high-risk women under 40.
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Mobbs LM, Jannicky EAS, Weaver DL, Harvey SC. The Accuracy of Sonography in Detecting Abnormal Axillary Lymph Nodes When Breast Cancer Is Present. JOURNAL OF DIAGNOSTIC MEDICAL SONOGRAPHY 2016. [DOI: 10.1177/8756479305278268] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This study evaluated the accuracy of sonography in detecting abnormal ipsilateral axillary lymph nodes in women with breast cancer. The authors retrospectively reviewed the sonographic findings and surgical pathology reports of 71 women who were diagnosed with breast cancer by ultrasound-guided biopsies. Results found in 71 cases that the sonographic specificity was 82%, whereas the sensitivity was only 40%. In 8 of the 17 cases (47%), sonography was suspicious for cancer, and the final surgical pathology was malignant. In 42 of 54 cases (77%), sonography of the axilla was not suspicious, and the final axillary node surgical pathology was negative. In 12 cases, sonographic images of the lymph nodes appeared normal, whereas the surgical pathology of the axillary nodes demonstrated malignancy. Ultrasound imaging has a high specificity when evaluating axillary lymph nodes and can be recommended when a suspicious finding is detected in the breast during diagnostic breast sonographic examination.
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Hodgson R, Heywang-Köbrunner SH, Harvey SC, Edwards M, Shaikh J, Arber M, Glanville J. Systematic review of 3D mammography for breast cancer screening. Breast 2016; 27:52-61. [DOI: 10.1016/j.breast.2016.01.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 12/23/2015] [Accepted: 01/06/2016] [Indexed: 10/22/2022] Open
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Harvey SC, Wolff AC. Does a Picture Make a Difference? Ultrasound Guidance in the Management of the Axilla After Neoadjuvant Chemotherapy. J Clin Oncol 2015; 33:3367-9. [DOI: 10.1200/jco.2014.60.1112] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Sippo DA, Kulkarni K, Carlo PD, Lee B, Eisner D, Cimino-Mathews A, Harvey SC. Metastatic Disease to the Breast From Extramammary Malignancies: A Multimodality Pictorial Review. Curr Probl Diagn Radiol 2015; 45:225-32. [PMID: 26293973 DOI: 10.1067/j.cpradiol.2015.07.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 07/02/2015] [Indexed: 11/22/2022]
Abstract
This pictorial review demonstrates imaging features of extramammary malignancies metastatic to the breast seen with multiple modalities, including mammography, ultrasound, computed tomography (CT), positron emission tomography, and magnetic resonance imaging. Although rare, metastases to the breast may have a distinct imaging appearance from the appearance of primary breast cancers. They are important to identify because they can mimic benign breast disease and their treatment differs from that of primary breast cancer. Metastatic disease to the breast most commonly appears as a single round or oval mass with circumscribed margins. Sonographically it is usually hypoechoic, and with CT or magnetic resonance imaging it usually enhances. In contrast with primary breast cancer, breast metastases do not demonstrate spiculated margins and rarely have associated calcifications. A variety of clinical presentations of breast metastases are reviewed, including presentation with a palpable mass, detection at screening mammography, and detection with CT or positron emission tomography.
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Harvey SC, Vegesna A, Mass S, Clarke J, Skoufalos A. Understanding patient options, utilization patterns, and burdens associated with breast cancer screening. J Womens Health (Larchmt) 2014; 23 Suppl 1:S3-9. [PMID: 25247383 DOI: 10.1089/jwh.2014.1510] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Despite ongoing awareness, educational campaigns, and advances in technology, breast cancer screening remains a complex topic for women and for the health care system. Lack of consensus among organizations developing screening guidelines has caused confusion for patients and providers. The psychosocial factors related to breast cancer screening are not well understood. The prevailing algorithm for screening results in significant rates of patient recall for further diagnostic imaging or procedures, the majority of which rule out breast cancer rather than confirming it. For women, the consequences of the status quo range from unnecessary stress to additional out-of-pocket expenses to indirect costs that are more difficult to quantify. A more thoughtful approach to breast cancer screening, coupled with a research agenda that recognizes the indirect and intangible costs that women bear, is needed to improve cost and quality outcomes in this area.
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Harvey SC. The charge and the challenges of breast cancer screening. J Womens Health (Larchmt) 2014; 23 Suppl 1:S1-2. [PMID: 25247381 DOI: 10.1089/jwh.2014.1509] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Green JWM, Snoek LB, Kammenga JE, Harvey SC. Genetic mapping of variation in dauer larvae development in growing populations of Caenorhabditis elegans. Heredity (Edinb) 2013; 111:306-13. [PMID: 23715016 PMCID: PMC3807260 DOI: 10.1038/hdy.2013.50] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 04/15/2013] [Accepted: 04/22/2013] [Indexed: 11/09/2022] Open
Abstract
In the nematode Caenorhabditis elegans, the appropriate induction of dauer larvae development within growing populations is likely to be a primary determinant of genotypic fitness. The underlying genetic architecture of natural genetic variation in dauer formation has, however, not been thoroughly investigated. Here, we report extensive natural genetic variation in dauer larvae development within growing populations across multiple wild isolates. Moreover, bin mapping of introgression lines (ILs) derived from the genetically divergent isolates N2 and CB4856 reveals 10 quantitative trait loci (QTLs) affecting dauer formation. Comparison of individual ILs to N2 identifies an additional eight QTLs, and sequential IL analysis reveals six more QTLs. Our results also show that a behavioural, laboratory-derived, mutation controlled by the neuropeptide Y receptor homolog npr-1 can affect dauer larvae development in growing populations. These findings illustrate the complex genetic architecture of variation in dauer larvae formation in C. elegans and may help to understand how the control of variation in dauer larvae development has evolved.
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Harvey SC, Cheung HC. Computer simulation of fluorescence depolarization due to brownian motion. Proc Natl Acad Sci U S A 2010; 69:3670-2. [PMID: 16592039 PMCID: PMC389845 DOI: 10.1073/pnas.69.12.3670] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A computer program has been written to simulate the Brownian motion of rigid fluorescent molecules. The time dependence of the fluorescence polarization anisotropy as generated by this simulation is in agreement with that predicted by the recent theoretical treatment of Belford, Belford, and Weber (Proc. Nat. Acad. Sci. USA (1972) 69, 1392-1393). The program thus serves as a verification of their equation. It is being generalized to cover the case of nonrigid molecules.
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Howes EL, Harvey SC. THE AGE FACTOR IN THE VELOCITY OF THE GROWTH OF FIBROBLASTS IN THE HEALING WOUND. ACTA ACUST UNITED AC 2010; 55:577-90. [PMID: 19870014 PMCID: PMC2132122 DOI: 10.1084/jem.55.4.577] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The velocity curve of fibroplasia in the healing of wounds in young rats reached its end-point 3 days ahead of a similar curve for adults. Strength and fibroplasia were manifest 1 day sooner than in the adults. A study of the increments of the curve showed that the rate of fibroplasia during the accelerated phase was less in the young and that it lasted longer. Correspondingly, retardation appeared later and was less in amount than in the curve for the adult rats. The amount of retardation was even less than in the curve obtained for adults on a high protein diet, in spite of the fact that in this latter curve there was a definite increase in the rate of fibroplasia. Healing in the young, therefore, is more rapid than in adults because fibroplasia begins earlier and is less retarded, not because the rate of fibroplasia is greater. Growth of the young is not hindered by the process of wound healing.
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Stewart HA, Harvey SC. THE VASODILATOR AND VASOCONSTRICTOR PROPERTIES OF BLOOD SERUM AND PLASMA. ACTA ACUST UNITED AC 2010; 16:103-25. [PMID: 19867557 PMCID: PMC2125252 DOI: 10.1084/jem.16.2.103] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
1. In plasma there exists a vasodilator substance specific for the vessels of the kidney. 2. This substance is a proteid of the albumin class and is precipitated by boiling and by alcohol. 3. It is present also in the serum. 4. It acts directly on the muscle coats of the arteries. 5. The process of clotting of the blood liberates a constrictor substance that acts on the renal vessels and also on the vessels of the limb. 6. This constrictor substance is not a proteid; it resists boiling, is soluble in alcohol, and acts directly on the muscle coat.
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Hogan KA, Harvey SC, Conway WF, DeRosimo JF, Gross RH. Superior vena cava compression during posterior spinal fusion for idiopathic scoliosis. A case report. J Bone Joint Surg Am 2009; 91:696-700. [PMID: 19255233 DOI: 10.2106/jbjs.h.00208] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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