Mass screening

About: Mass screening is a research topic. Over the lifetime, 34508 publications have been published within this topic receiving 1365148 citations.

The New Era in Breast Cancer: Invasion, Size, and Nodal Involvement Dramatically Decreasing as a Result of Mammographic Screening

Abstract: Objective: To describe the magnitude of changes and opportunities that may arise for simplified surgical procedures for women with breast cancer because of the decreasing size and lymph node involvement in invasive breast cancer and earlier presentation of noninvasive and invasive breast cancer. Design and Main Outcome Assessment: Cases (N=1001) of breast cancer from a tertiary and a community hospital between 1989 and 1993 were analyzed for invasion, size, nodal status, and change over time. Results: Ductal carcinoma in situ constituted 14% and 18% of the cancers at the two hospitals. At the tertiary and community hospitals, the mean maximum diameters were 2.1 and 2.0 cm, respectively, and the median maximum diameters were 1.5 and 1.7 cm, respectively, for invasive breast cancer. Twenty-nine percent and 28%, respectively, were 1 cm or less in diameter. Axillary nodal metastases occurred in only 31% of the invasive cancers (tertiary hospital); only 10% had more than three nodal metastases. In the T1a and Tib cases, nodal metastases occurred in only 10%, and 43% of the positive nodes were solitary; only 16% had more than three nodal metastases. The proportion of ductal carcinoma in situ, T1a and T1b, and node-negative cases increased significantly over time. Conclusions: Within the next decade, the proportion of all breast cancers that are ductal carcinoma in situ will approach 33%, and invasive cancers will approach 1 cm in median maximum diameter. Therapy simplification will be logical because of very small size, low risk of recurrence after breast conservation, and excellent prognosis, and might include increased breast conservation, avoidance of axillary nodal dissection, and omission of radiation therapy to conserved breasts. Adjuvant therapy will be based on the prognostic features of the primary cancer and findings from careful histologic examination of the sentinel lymph nodes. (Arch Surg. 1996;131:301-308)

The Proportion of SARS-CoV-2 Infections That Are Asymptomatic : A Systematic Review.

Abstract: BACKGROUND: Asymptomatic infection seems to be a notable feature of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the pathogen that causes coronavirus disease 2019 (COVID-19), but the prevalence is uncertain. PURPOSE: To estimate the proportion of persons infected with SARS-CoV-2 who never develop symptoms. DATA SOURCES: Searches of Google News, Google Scholar, medRxiv, and PubMed using the keywords antibodies, asymptomatic, coronavirus, COVID-19, PCR, seroprevalence, and SARS-CoV-2. STUDY SELECTION: Observational, descriptive studies and reports of mass screening for SARS-CoV-2 that were either cross-sectional or longitudinal in design; were published through 17 November 2020; and involved SARS-CoV-2 nucleic acid or antibody testing of a target population, regardless of current symptomatic status, over a defined period. DATA EXTRACTION: The authors collaboratively extracted data on the study design, type of testing performed, number of participants, criteria for determining symptomatic status, testing results, and setting. DATA SYNTHESIS: Sixty-one eligible studies and reports were identified, of which 43 used polymerase chain reaction (PCR) testing of nasopharyngeal swabs to detect current SARS-CoV-2 infection and 18 used antibody testing to detect current or prior infection. In the 14 studies with longitudinal data that reported information on the evolution of symptomatic status, nearly three quarters of persons who tested positive but had no symptoms at the time of testing remained asymptomatic. The highest-quality evidence comes from nationwide, representative serosurveys of England (n = 365 104) and Spain (n = 61 075), which suggest that at least one third of SARS-CoV-2 infections are asymptomatic. LIMITATION: For PCR-based studies, data are limited to distinguish presymptomatic from asymptomatic infection. Heterogeneity precluded formal quantitative syntheses. CONCLUSION: Available data suggest that at least one third of SARS-CoV-2 infections are asymptomatic. Longitudinal studies suggest that nearly three quarters of persons who receive a positive PCR test result but have no symptoms at the time of testing will remain asymptomatic. Control strategies for COVID-19 should be altered, taking into account the prevalence and transmission risk of asymptomatic SARS-CoV-2 infection. PRIMARY FUNDING SOURCE: National Institutes of Health.

Screening for prostate cancer--the controversy that refuses to die.

Abstract: In the United States, most men over the age of 50 years have had a prostate-specific–antigen (PSA) test,1 despite the absence of evidence from large, randomized trials of a net benefit. Moreover, about 95% of male urologists and 78% of primary care physicians who are 50 years of age or older report that they have had a PSA test themselves,2 a finding that suggests they are practicing what they preach. And indeed, U.S. death rates from prostate cancer have fallen about 4% per year since 1992, five years after the introduction of PSA testing.3 Perhaps the answer to the PSA . . .