Publications by authors named "Nancy Tappenden"
Background: It has been observed that screen-detected breast cancers have a better prognosis than symptomatic tumors, even after taking pathological tumor attributes into account. This has led to the hypothesis that screen-detected tumors are substantially biologically different from symptomatic cancers.
Methods: The pathology and survival by detection mode was investigated in 21,382 breast cancers diagnosed in women aged 50-64 years in the West Midlands, United Kingdom, between 1988 and 2004.
Objectives: To examine variations in screening status category with time for 20,862 invasive breast cancers diagnosed in the West Midlands between 1989 and 2006, and to provide 10-year relative survival rates for each category.
Method: Population-based breast screening was introduced in the West Midlands from 1988. Primary invasive breast cancers diagnosed from 1 April 1989 to 31 March 2006 in women eligible for breast screening were identified from the West Midlands Cancer Intelligence Unit's cancer registration database.
Background: Evidence of the impact of breast screening is limited by biases inherent in non-randomised studies and often by lack of complete population data. We address this by estimating the effect of screen detection on cause-specific fatality in breast cancer, corrected for all potential biases, using population cancer registry data.
Methods: Subjects (N = 26,766) comprised all breast cancers notified to the West Midlands Cancer Intelligence Unit and diagnosed in women aged 50-74, from 1988 to 2004.
Determination of survival time among persons with screen-detected cancer is subject to lead time and length biases. The authors propose a simple correction for lead time, assuming an exponential distribution of the preclinical screen-detectable period. Assuming two latent categories of tumors, one of which is more prone to screen detection and correspondingly less prone to death from the cancer in question, the authors have developed a strategy of sensitivity analysis for various magnitudes of length bias.
View Article and Find Full Text PDFObjectives: To illustrate the ability of the West Midlands breast screening status algorithm to assign a screening status to women with malignant breast cancer, and its uses as a quality assurance and audit tool.
Methods: Breast cancers diagnosed between the introduction of the National Health Service [NHS] Breast Screening Programme and 31 March 2001 were obtained from the West Midlands Cancer Intelligence Unit (WMCIU). Screen-detected tumours were identified via breast screening units, and the remaining cancers were assigned to one of eight screening status categories.