Pancreatic cancer is the seventh leading cause of cancer related mortalities worldwide and incidences are increasing. The prognosis remains poor as the 5-year survival rate is below 10%. This can be partly explained by the silent progression of disease as most patients present with advanced disease at time of diagnosis. In turn, surgical resection, the only potential curative measure, is not possible in nearly 80% of cases due to the occurrence of distant metastasis and/or infiltration of major vessels in close proximity to the pancreas. In patients with localized but advanced disease, resectability can be achieved in some cases by initiation of a neoCTx. However, as neoCTx is commonly conducted by administering multi-drug treatments, severe side effects occur frequently, which require an adaption of drug doses administered.
In this study, we revealed the negative impact of these drug dose changes during neoCTx on the patients´ treatment outcome. R0 resections were significantly less frequently observed, and the N-status significantly impacted by the tumor regression grade, which in turn trended towards minor response in the cohort of patients that did not sustain full dose course prior surgery. In turn, treatment of LA PDAC could be improved by increasing the proportion of patients that undergo neoCTx without any changes of the treatment schedule. Patient-derived PDAC organoid could serve as an avatar of patients´ tumor disease on which optimal treatment protocols could be tested.
In this study, a large living PDAC PDO biobank successfully has been established from surgical resection specimens as well as EUS guided FNA samples. Subsequently, a new protocol for molecular subtyping of PDAC on organoids was established by assessing the expression level of KRT81 and CFTR, as a replacement for HNF1a, using IF staining. Strikingly, we observed identical PDAC subtypes in PDOs and their respective tissue of origin in nearly all cases. This observation allowed the assumption that PDOs could indeed be used as patient-individual avatars to identify treatment sensitivities and resistances, as they share fundamental molecular properties with the tissue they have been initiated from.
Extensive pharmacotyping was performed for many PDO lines by testing the response behavior to the multi-drug regimens FOLFIRINOX and Gem/Pac, as well as their respective single drug compounds. As a result, we observed diverse response patterns for each PDAC PDO line. A poor response to FOLFIRINOX did not necessarily imply a resistance to Gem/Pac. PDO pharmacotyping could guide treatment decision making in the foreseeable future. Moreover, when the non-efficient drug was removed, no changes of overall efficacy of treatment in PDOs was observed, implying that additional therapy improvements could be possible using this ex vivo model. This observation was true for both commonly used chemotherapy protocols, FOLFIRINOX and Gem/Pac and could result in less drug mediated side effects under (neo)adjuvant CTx without impacting treatment efficacy.
Yet, the main goal of this study was to assess if PDAC PDOs can be used to predict the neoCTx outcome of PDAC patients. All methods required to address this issue in a prospective clinical trial have been established as a protocol for PDAC PDOs initiation from minimal starting material has been established and subsequently improved resulting in take rates of up to 80%. To support this study, we successfully secured patient enrollment from a second clinical center, which will increase the number of recruited patients in the future. Unfortunately, at the time of writing this thesis, patient numbers were not sufficient to answer the question of the predictive value of PDAC PDOs in regard to the current standard of care.
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:82941 |
| Date | 16 January 2023 |
| Creators | Hennig, Alexander |
| Contributors | Dahmann, Christian, Reichert, Maximilian, Technische Universität Dresden |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, doc-type:doctoralThesis, info:eu-repo/semantics/doctoralThesis, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | 10.1155/2019/1024614, 10.1002/path.5906, 10.1172/jci.insight.137809, 10.3791/60704, 10.1053/j.gastro.2019.09.026, 10.1002/jcb.26675 |
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