Risk of non-sentinel node metastases in patients with symptomatic cancers compared to screen-detected breast cancers.

BACKGROUND: Symptomatic breast cancers may be more aggressive as compared to screen-detected breast cancers. This could favor axillary lymph node dissection (ALND) in patients with symptomatic breast cancer and positive sentinel nodes. METHOD: We identified 955 patients registered in the Danish Breast Cancer Cooperative Group (DBCG) Database in 2008 - 2010 with micrometastases (773) or isolated tumor cells (ITC) (182) in the sentinel node. Patients were cross-checked in the Danish Quality Database of Mammography Screening and 481 patients were identified as screen-detected cancers. The remaining 474 patients were considered as having symptomatic cancers. Multivariate analyses of the risk of non-sentinel node metastases were performed including known risk factors for non-sentinel node metastases as well as method of detection. RESULTS: 18% of the patients had metastases in non-sentinel nodes. This was evenly distributed between patients with symptomatic and screen-detected cancers; 18.5% vs 17.5% (OR 1.07; 95% CI 0.77-1.49; p = 0.69). In patients with micrometastases 21% had non-sentinel node metastases in the group with symptomatic cancers compared to 19% of patients with screen-detected cancers. This difference was not significant (OR 1.16; 95% CI 0.81-1.65, p = 0.43). Neither the multivariate analysis showed an increased risk of non-sentinel node metastases in patients with symptomatic cancers compared to screen-detected cancers (OR 1.12, CI 0.77-1.62, p = 0.55). In patients with ITCs 8% of patients with symptomatic cancers had non-sentinel node metastases compared to 13% of patients with screen-detected cancers. This difference was not significant (OR 0.58; 95% CI 0.22-1.54, p = 0.27). In the multivariate analysis, the risk of non-sentinel node metastases was still not significantly increased in patients with symptomatic cancers compared to screen-detected cancers (OR 0.45; 95% CI 0.16-1.27, p = 0.13). CONCLUSION: We did not find any clinically relevant difference in the risk of non-sentinel node metastases between patients with symptomatic and screen-detected cancers with micrometastases or ITC in the sentinel node.

Existing data sources for clinical epidemiology: the Danish Quality Database of Mammography Screening.

The Danish Quality Database of Mammography Screening (DKMS) was established in 2007, when screening was implemented on a nationwide basis and offered biennially to all Danish women aged 50-69 years. The primary aims of the database are to monitor and evaluate the quality of the screening program and - after years of follow-up - to evaluate the effect of nationwide screening on breast cancer-specific mortality. Here, we describe the database and present results for quality assurance from the first round of national screening. The steering committee for the DKMS defined eleven organizational and clinical quality indicators and standards to monitor the Danish breast cancer screening program. We calculated the relevant proportions and ratios with 95% confidence intervals for each quality indicator. All indicators were assessed on a national and regional level. Of 670,039 women invited for mammography, 518,823 (77.4%) participated. Seventy-one percent of the women received the result of their mammography examination within 10 days of screening, and 3% of the participants were recalled for further investigation. Among all detected cancers, 86% were invasive cancers, and the proportion of women with node negative cancer was 67%. There were 36% women with small cancers, and the ratio of surgery for benign lesions to malignant lesions was 1:6.3. A total of 80% of women with invasive cancers were treated with breast conserving therapy. Screening interval and interval cancers were not relevant in the first round, and data regarding radiation dose were not available at the time of evaluation. Overall, the quality indicators showed satisfactory quality in the first round of national breast cancer screening in Denmark. The DKMS is a potentially valuable tool for improving quality and conducting research in the field of breast cancer screening.

Stage and survival in breast cancer patients in screened and non-screened Danish and Swedish populations.

Comparisons between the Danish and Swedish Cancer Registry revealed a 9% difference in 5-year survival for breast cancer patients diagnosed between 1983 and 1989. The purpose of this study was to determine whether previous differences in survival and stage still exist or whether the Danish figures approach those of the Swedish registry. Complete population-based cohorts of patients with breast cancer in the years 1996-1997 from well-defined areas in Denmark and Sweden were compared. The study regions were a Danish (Funen) and a Swedish (Malmö) county with mammography screening and two Danish counties without screening. No difference in extent of disease or survival was observed between screening areas regardless of country. However, there were significant differences in stage distribution and survival between screening populations and Danish non-screening populations, to the benefit of populations provided with a screening programme. Five-year survival was 5-6%, higher in screening populations than in Danish non-screening counties. Corresponding disease-specific survival enhanced the difference. In a multivariate analysis increasing age, tumour size and stage decreased survival. Adjusting for these factors eliminated differences in survival according to country/county. Survival difference could be attributed to early diagnosis and favourable stage in populations offered mammography screening and was not related to nation. Denmark may, through early detection, approach the beneficial stage distribution and survival observed in Sweden.