Due to copyright issues, an electronic copy of the thesis must be ordered from the faculty. For the faculty to have time to process the order, the order must be received by the faculty at the latest 2 days before the public defence. Orders received later than 2 days before the defence will not be processed. After the public defence, please address any inquiries regarding the thesis to the candidate.
Trial Lecture – time and place
See Trial Lecture.
Adjudication committee
- First opponent: Associate Professor Jana de Boniface, Karolinska Institute, Stockholm, Sweden
- Second opponent: Associate Professor Monica Engstrøm, Norwegian University of Science and Technology, Trondheim
- Third member and chair of the evaluation committee: Professor II Kristian Bjøro, University of Oslo
Chair of the Defence
Professor Emeritus Torill Sauer, University of Oslo
Principal Supervisor
Kristine Kleivi Sahlberg, Vestre Viken Hospital Trust
Summary
The primary aim of treatment of Ductal carcinomas in situ (DCIS) is to reduce the risk of invasive local recurrence. In the 1980s and 1990s, the surgical options for treating DCIS were limited to mastectomy or wide local excision. In the 2000s, breast surgery changed to include oncoplastic breast-conserving procedures and primary breast reconstructions. Most patients keep their breast. Breast surgery aim to provide the best possible surgery with the least potential harm to the patient. Safety is paramount when introducing new surgical techniques, as an invasive recurrence can be fatal. There is limited scientific knowledge about the long-term outcomes of oncoplastic breast-conserving surgery and primary reconstructions in DCIS, and increased evidence is needed. This thesis aimed to provide insight into the long-term results of surgical procedures for Norwegian patients diagnosed with DCIS. The studies are population-based on a retrospective cohort design. In three studies, we analysed data from the Cancer Registry of Norway and the Norwegian Cause of Death Registry, which consisted of clinical, pathological, and survival data after surgery. We confirmed that the surgical treatment of DCIS has changed from 37.8 % breast-conserving surgery in 1996 to 84.5 % in 2018. The main reasons are the change in treatment recommendations and the implementation of oncoplastic techniques with precision surgery. Furthermore, we confirmed that skin-sparing mastectomies and oncoplastic breast-conserving surgery are safe alternatives to standard breast-conserving techniques and simple mastectomy as the survival is similar. However, patients must be informed that the risk of recurrence is greater with breast-conserving techniques than with mastectomy and that there is a balance between the risk of relapse and quality of life. To determine the best treatment option, it is necessary to consider the patient's values, such as cosmetic results, availability of medical follow-up and anxiety of local relapse.
Additional information
Contact the research support staff.