On the rising trends of incidence and prognosis for breast cancer patients diagnosed 1975-2004: A long-term population-based study in southeastern Netherlands
Background: Much progress has been made in the early diagnosis and treatment of breast cancer. We have assessed the changing burden of this disease, by means of a comprehensive description of trends in incidence, survival, and mortality. Methods: Data on breast cancer patients diagnosed between 1975 and 2004 (n = 26,464) registered in the population-based Eindhoven Cancer Registry were investigated. Results: Incidence for patients aged below 40 and 40-49 has increased by 2.1% and 2.4% annually, since 1995 (p = 0.08 and p = 0.001, respectively). Mortality decreased in all age groups, but most markedly among women aged 50-69 (-1.5% yearly since 1985, p = 0.14). The proportion of stage I tumors increased from 25% to 39%, that of advanced stages (III & IV) decreased from 30% (1975-1984) to 13% in 1995-2004, and the proportion of in situ tumors increased from 1.5% to 10%. Adjuvant systemic treatment was administered to 15% of patients in 1975-1984 vs. 49% in 1995-2004. Relative 10-year survival rates for women aged 50-69 (period analysis) increased from 53% to 75% between 1975 and 2004. The best prognosis was observed for women aged 45-54. Women younger than 35 had a particularly poor prognosis. Conclusion: The observed improvement in survival of breast cancer patients during the last three decades is impressive. The peak in breast cancer incidence is not yet in sight considering the recent trends in exposure to known risk factors and improved diagnosis. The combination of increasing incidence and improved survival rates implies that the number of prevalent cases will continue to increase considerably in the next 10 years.