Comparison of 1- and 2-year screening intervals for women undergoing screening mammography

Abstract

We compared the long-term impact of 1-and 2-year screening mammography intervals using prognostic, screening, and outcome information for women aged 50 -74 years obtained from the Screening Mammography Program of British Columbia in two time periods, prior to 1997 (policy of annual mammography) and after 1997 (biennial mammography). Survival was estimated for both periods using a prognostic model and the expected rate of interval and screen-detected cancers. The likelihood of a screen-detected cancer with annual screening was 2.32 per thousand screens and with biennial screening was 3.32 per thousand screens. The prognostic profile of screen-detected cancers was better than that of interval cancers. Among both screen-detected and interval cancers, the prognostic profiles with annual and biennial screening were similar. The estimated breast cancer-specific survival rates for women undergoing annual and biennial screening mammography were 95.2 and 94.6% at 5 years, and 90.4 and 89.2% at 10 years, respectively. Annual compared to biennial mammography was associated with a 1.2% increase in the estimated 10-year breast cancer-specific survival for women aged 50 -74 years, diagnosed with invasive breast cancer after screening programme attendance.

Taxa de sobrevida na mulher com câncer de mama: estudo de revisão

“…However, comparing the results of annual and biannual screening over ten years, it was observed that there was an decrease of 1.2% in the specific survival of the women screened biannually. 23 It is noteworthy that this integrative review investigated five-year survival, during which there is a higher tendency for survival. The investigation of survival at ten years or more would probably demonstrate lower rates.…”

“…The publications originated from 20 countries: Korea (six studies), [8][9][10][11][12][13] Japan (five studies), [14][15][16][17][18] Brazil (four studies), 3,[19][20][21] Canada (three studies), [22][23][24] United States (three studies), [25][26][27] Italy (three studies), [28][29][30] Switzerland (three studies), [31][32][33] France (two studies), 34,35 China (one study), 36 Singapore and Sweden (one study, study performed in both countries), 37 Scotland (one study), 38 Spain (one study), 39 Finland (one study), 40 India (one study), 41 England (two studies), 42,45 Mexico (one study), 43 Poland (one study), 44 and the Netherlands (one study). 46 From the aim established for this study, the variables to be investigated were defined: the study design, study site/country, number of subjects, age of the subjects, five year survival rate, disease-free five year survival rate, factors that contribute to the increase in survival rates.…”

Impact of changing from annual to biennial mammographic screening on breast cancer outcomes in women aged 50–79 in British Columbia

“…22 The predictive model used was similar to one used previously 31 and was calibrated to the observed impact of prognostic factors on survival in BC. The predicted reduction in breast cancer death in that analysis resulted primarily from the difference in outcomes between screen-detected and interval cancers and the reduction in the proportion of interval cancers in women screened annually.…”

Number and characteristics of breast cancer cases diagnosed in four periods in the screening interval of a biennial population-based screening programme

“…9,10 However, these studies are small, and turned down by recent studies showing almost similar prognostic characteristics in tumours diagnosed in annual and biennial screening. 11,12 Furthermore, the effect of the screening interval on the mortality from the disease is somewhat unclear. 11,[13][14][15] No randomized trials have compared the effect of annual versus biennial screening intervals, and observational studies on the topic have been limited by small sample sizes and varying definitions of interval cancer.…”

“…11,12 Furthermore, the effect of the screening interval on the mortality from the disease is somewhat unclear. 11,[13][14][15] No randomized trials have compared the effect of annual versus biennial screening intervals, and observational studies on the topic have been limited by small sample sizes and varying definitions of interval cancer. 9,10,16,17 The costs of annual versus biennial screening will be higher, due to twice as many examinations during the same time period, additional biopsies and a higher number of women probably undergoing emotional distress as a result of false-positive recalls.…”