EFFICACY OF BREAST-CANCER SCREENING FOR FEMALE RELATIVES OF BREAST-CANCER-INDEX CASES - TAIWAN MULTICENTER CANCER SCREENING (TAMCAS)

Although the efficacy of mass screening for breast cancer has been est ablished in Western countries, this strategy may be too costly for oth er countries with low incidence rates of breast cancer. We propose an alternative approach to screen female relatives of breast-cancer-index cases from hospitals, as part of the Taiwan multicentre cancer screen ing (TAMCAS) project. In order to assess the efficacy of this programm e, and to estimate how often this high-risk group should be screened, we firstly elucidated the disease natural history from the pre-clinica l screen-detectable phase (PCDP) by estimating the relevant parameters based on Markov chain models. We further predicted the proportion of interval cancers, advanced breast tumours and deaths from breast cance rs by different screening frequencies. Results showed that the estimat e of mean sojourn time (MST) for this high-risk group (1.9 years; 95% CI.1.18-4.86) is shorter than that for females from the general popula tion, Analysis of a surrogate endpoint based on regional lymph-node sp read and tumour size shows that annual screening for this high-risk gr oup is likely to confer a significant 33% reduction in breast-cancer m ortality compared with a non-significant 25 and 20% reduction for 2 ye arly and 3-yearly screening regimes respectively. The above results su ggest that a 1-year interval might be appropriate for this high-risk g roup. A simple cost-effectiveness analysis indicates a cost per year o f life saved for mass screening ($72,480) 15 times that for the high-r isk group ($4,851). Int J. Cancer 78:21-26, 1998, (C) 1998 Wiley-Liss, Inc.