The objectives of this thesis, aimed to reduce overtreatment of ductal carcinoma in situ (DCIS) of the breast, were : 1) to evaluate the risk of underestimation after a diagnosis of DCIS and the... Show moreThe objectives of this thesis, aimed to reduce overtreatment of ductal carcinoma in situ (DCIS) of the breast, were : 1) to evaluate the risk of underestimation after a diagnosis of DCIS and the interrater reliability in the histopathological classification of DCIS, important conditions in order to safely adopt an active surveillance strategy for low-risk DCIS, 2) to investigate associations of clinicopathological factors with the risk of developing ipsilateral invasive breast cancer after treatment of DCIS and 3) to analyze the extent of response of DCIS, adjacent to HER2-positive breast cancer, to neoadjuvant systemic therapy and to investigate associations of clinicopathological factors with DCIS response.We have taken significant steps on the road towards conquering overtreatment of DCIS: by having identified several clinicopathological prognostic factors in pure DCIS, by providing reassuring evidence regarding underestimation in the context of active surveillance, by stressing the need for improvement of interrater reliability in histopathological classification, and by showing that the presence of DCIS adjacent to HER2-positive breast cancer should not preclude the option of breast conserving surgery. Show less
Deken, M.M.; Bos, D.L.; Tummers, W.S.F.J.; March, T.L.; Velde, C.J.H. van de; Rijpkema, M.; Vahrmeijer, A.L. 2019
Background Combining modalities using dual-labeled antibodies may allow preoperative and intraoperative tumor localization and could be used in image-guided surgery to improve complete tumor... Show moreBackground Combining modalities using dual-labeled antibodies may allow preoperative and intraoperative tumor localization and could be used in image-guided surgery to improve complete tumor resection. Trastuzumab is a monoclonal antibody against the human epidermal growth factor-2 (HER2) receptor and dual-labeled trastuzumab with both a fluorophore (IRDye800CW) and a radioactive label (In-111) can be used for multimodal imaging of HER2-positive breast cancer. The aim of this study was to demonstrate the feasibility of HER2-targeted multimodal imaging using [In-111]In-DTPA-trastuzumab-IRDye800CW in an orthotopic breast cancer model. Methods Trastuzumab was conjugated with p-isothiocyanatobenzyl (ITC)-diethylenetriaminepentaacetic acid (DTPA) and IRDye800CW-NHS ester and subsequently labeled with In-111. In a dose escalation study, the biodistribution of 10, 30, and 100 mu g [In-111]In-DTPA-trastuzumab-IRDye800CW was determined 48 h after injection in BALB/c nude mice with orthotopic high HER2-expressing tumors. Also, a biodistribution study was performed in a low HER2-expressing breast cancer model. In addition, multimodal image-guided surgery was performed in each group. Autoradiography, fluorescence microscopy, and immunohistochemically stained slices of the tumors were compared for co-localization of tumor tissue, HER2 expression, fluorescence, and radiosignal. Results Based on the biodistribution data, a 30 mu g dose of dual-labeled trastuzumab (tumor-to-blood ratio 13 +/- 2) was chosen for all subsequent studies. [In-111]In-DTPA-trastuzumab-IRDye800CW specifically accumulated in orthotopic HER2-positive BT474 tumors (101 +/- 7 %IA/g), whereas uptake in orthotopic low HER2-expressing MCF7 tumor was significantly lower (1.2 +/- 0.2 %IA/g, p = 0.007). BT474 tumors could clearly be visualized with both micro-SPECT/CT, fluorescence imaging and subsequently, image-guided resection was performed. Immunohistochemical analyses of BT474 tumors demonstrated correspondence in fluorescence, radiosignal, and high HER2 expression. Conclusions Dual-labeled trastuzumab showed specific accumulation in orthotopic HER2-positive BT474 breast tumors with micro-SPECT/CT and fluorescence imaging and enabled image-guided tumor resection. In the clinical setting, [In-111]In-DTPA-trastuzumab-IRDye800CW could be valuable for preoperative detection of (metastatic) tumors by SPECT/CT imaging, and intraoperative localization by using a gamma probe and fluorescence image-guided surgery to improve radical resection of tumor tissue in patients with HER2-positive tumors. Show less
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