Department of Plastic and Breast Surgery, Peer Michael Christiansen

In collaboration with the Danish Breast Cancer Cooperative Group (DBCG), researchers from the breast unit perform studies on national cohorts of patients:

• BCS vs. mastectomy. International publications from recent years have indicated that breast cancer patients treated by BCS have a better survival than patients treated by mastectomy. Most of the studies were done on registry material lacking important information on tumour biology and oncological treatment and the results can therefore be questioned. In the on-going Danish study, more complete data on the individual patients is available?. The study includes more than 60,000 patents, and the comparison will take the available patient, tumour and treatment characteristics into a multivariate analysis and include an intention to treat analysis.
• The relationship between lymph node status and tumour size in breast cancer. The purpose is on the basis of a large data material from DBCG database to describe the relationship between observed tumour size and occurrence of lymph node metastases in order to develop an algorithm that can predict the occurrence of metastases based on a number of patient and tumour characteristics.

In collaboration with Department of Clinical Epidemiology, AUH, and Emory University, Georgia, USA, and Wake Forest University, North Carolina, USA:

• Tamoxifen-resistance in premenopausal women. Pre-menopausal ERα+ tamoxifen-treated breast cancer patients with inhibited CYP2DG function will have a higher rate of recurrence than those without. On pre-menopausal women diagnosed with breast cancer between 2002 and 2011 (6200 breast cancer patients: 3600 ER+ patients and 2600 ER– patients), data are collected on their genetic and pharmaceutical inhibition of CYP2D6 and other genes involved in tamoxifen metabolism to estimate the association between metabolic inhibition and breast cancer recurrence. Archived formalin-fixed paraffin-embedded tumour specimens have been collected.
• Ptalates and the risk of breast cancer. Phthalates have been shown to stimulate estrogen-responsive pathways and may play a role in elevating breast cancer risk—particularly  hormone receptor-positive disease. Cumulative phthalate exposure from medical prescriptions will be related to the risk of breast cancer in a cohort of Danish women with no prior cancer diagnosis in 1995.
• PD-L1: A molecular epidemiological study of the expression and prognostic importance of programmed cell death ligand 1 (PD-L1) and other immune checkpoint biomarkers in breast cancer in Danish women. A study by immunohistochemistry on tissue microarrays (TMAs) to evaluate immune checkpoint biomarker expression (PD-L1; PD-1; CTLA-4) and numbers of tumour infiltrating lymphocytes (TILs) in breast cancer. The study includes a cohort of 7,700 Danish patients.
• Molecular predictors of late cancer recurrence. A study aiming at identifying biological markers of late cancer recurrence risk in four cohorts of patients with initial non-metastatic breast, prostate, melanoma, and renal cell carcinoma followed for up to 25 years. The aim is to enable risk stratification and development of novel therapeutics to disrupt the processes that lead to late recurrence. Tumour material from cohorts of the four studied cancer types will be collected.