Improvements in breast cancer survival between 1995 and 2012 in Denmark: The importance of earlier diagnosis and adjuvant treatment

Abstract

Background Breast cancer mortality has declined from 1995 through 2012 which may be attributed to earlier diagnosis, changes in lifestyle risk factors, and improved treatments. To a large extent the relative contribution of these modalities are unknown. Mammography screening was introduced late in Denmark; in 1995 around 20% of the Danish female population aged 50-69 was covered by population-based screening, and this was in 2008 extended to the entire population. Breast conserving surgery gradually replaced mastectomy, and sentinel node biopsy was introduced. In the same period adjuvant treatment was extended considerable. Methods A population-based study of 68 842 breast cancer patients registered in the clinical database of the Danish Breast Cancer Cooperative Group in 1995-2012. Comprehensive data on prognostic factors, comorbidity and treatment together with complete follow-up for survival were used to evaluate improvements in mortality and standardized mortality rate in successive time periods. Results The results from this study demonstrated a significant improvement in prognosis in successive time periods covering 1995-2012. Apart from patients with a high Charlson Comorbidity Index (CCI) improvements were seen in all subgroups of patients. Prognostic factors were more favorable in the latest time period accordingly to the introduction of nationwide screening. In the study period adjuvant treatment was extended considerable. Conclusion The impact of screening was by nature of limited magnitude. The modified treatment strategies implemented by the use of nationwide guidelines seemed to have a major impact on the substantial survival improvements.

Failure pattern and survival after breast conserving therapy. Long-term results of the Danish Breast Cancer Group (DBCG) 89 TM cohort

“…At the time of diagnosis and treatment in the DBCG 89 program, approximately 50% of the patients with early stage breast cancer received adjuvant systemic treatment, compared to more than 90% of the patients today [10]. In a review from 2009 among others based on data from an EBCTCG meta-analysis [39,40] it was emphasized that the treatment with endocrine therapy reduced the five-year risk of LR with 50%.…”

“…In the DBCG, data from the clinical trials are processed and converted into national guidelines as soon as the trial results are available. And owed to the fact that the guidelines have the same high degree of adherence, nationally, high quality data on par with the data originating from clinical trials are provided from the DBCG programs outside the trials [10,45].…”

“…Thus, both nationally and internationally, BCT was found to be a safe procedure and has consequently been implemented into Danish guidelines as a routine procedure since 1989. Today BCT constitutes more than 70% of all local treatments for primary breast cancer in Denmark [10].…”

The clinical database and implementation of treatment guidelines by the Danish Breast Cancer Cooperative Group in 2007–2016

“…These initiatives have improved the quality of diagnostic procedures and all aspects of breast cancer treatment in Denmark. Furthermore, continued development and standardization of procedure and treatment strategies have significantly contributed to an improvement of the prognosis in breast cancer and has become a model for the construction of multidisciplinary cancer groups [3,4]. Improvement in the quality of care by clinical guidelines has been shown repeatedly but it is less clear how effectively guidelines are maintained and how long time it takes to implement modifications [5].…”

Surgical breast cancer patient pathway: Experiences of patients and relatives and their unmet needs

“…In Denmark, approximately one in every nine women gets breast cancer, and most of them are between 50 and 70 years old . The survival rate has increased in recent decades and is 97% after 1 year and 87% after 5 years . The Danish health authorities stipulate cancer patient pathways (CPP)s for cancer treatment .…”