Leiden University Scholarly Publications

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Seijen, M. van (2021)

Ductal carcinoma in situ and invasive breast cancer: diagnostic accuracy and prognosis

Doctoral Thesis
The studies in this thesis contribute to more accurate risk assessment and prognosis prediction for DCIS and to better response evaluation of IBC treatment.
For the Ductal Carcinoma In Situ (DCIS) studies, unbiased cohorts were used within the international Grand Challenge PRECISION consortium, funded by Cancer Research UK and KWF Dutch Cancer Society. DCIS is graded as low-, intermediate-, or high-grade depending on how abnormal the DCIS-cells look like. However, we showed that pathologists often disagree on grade. To overcome this limitation, we found that almost all DCIS scored as non-high-grade by the majority of pathologists express the estrogen receptor (ER) and are negative for the growth factor receptor HER2, whereas high-grade DCIS is mixed in expression for ER and HER2. We also provided insights in the recurrence risks of DCIS after treatment. See also https://cancergrandchallenges.org/teams/precision....Show moreThe studies in this thesis contribute to more accurate risk assessment and prognosis prediction for DCIS and to better response evaluation of IBC treatment.
For the Ductal Carcinoma In Situ (DCIS) studies, unbiased cohorts were used within the international Grand Challenge PRECISION consortium, funded by Cancer Research UK and KWF Dutch Cancer Society. DCIS is graded as low-, intermediate-, or high-grade depending on how abnormal the DCIS-cells look like. However, we showed that pathologists often disagree on grade. To overcome this limitation, we found that almost all DCIS scored as non-high-grade by the majority of pathologists express the estrogen receptor (ER) and are negative for the growth factor receptor HER2, whereas high-grade DCIS is mixed in expression for ER and HER2. We also provided insights in the recurrence risks of DCIS after treatment. See also https://cancergrandchallenges.org/teams/precision.
The studies on Invasive Breast Cancer (IBC) were performed on a hospital-based cohort. We found for example substantial variation in tumour response evaluation for HER2-positive IBC after pre-operative chemotherapy due to different guidelines used. For accurate outcome analysis, reducing such variation is mandatory. Therefore, we are working on reaching international consensus of response evaluation.
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Ductal carcinoma in situ
Interobserver variability
Radiotherapy
Surgery
Prognosis
Breast cancer
Neo-adjuvant systemic therapy
Response evaluation
All authors
Seijen, M. van
Supervisor
Wesseling, J.
Co-supervisor
Lips, E.H.; Schaapveld, M.
Committee
Schmidt, M.K.; Smit, V.T.H.B.M.; Rutger, E.J.T.; Vijver, M.J. van der; Portielje, J.E.A.
Qualification
Doctor (dr.)
Awarding Institution
Faculty of Medicine, Leiden University Medical Center [LUMC], Leiden University
Date
2021-09-09
ISBN (print)
9789464191684

Funding

Sponsorship
The Netherlands Cancer Institute-Antoni van Leeuwenhoek Ziekenhuis The Netherlands Comprehensive organisation (IKNL)