Disputas – Cand.med. Olga Vikhammer Gran “Venous thromboembolism and cancer”


Cand.med. Olga Vikhammer Gran  disputerer for ph.d.-graden i helsevitenskap og vil offentlig forsvare avhandlingen:

Venous thromboembolism and cancer”

Kort sammendrag av avhandlingen:
Venous thromboembolism (VTE) is a collective term for deep vein thrombosis and pulmonary embolism. VTE is a common cause of mortality and morbidity in patients with cancer, and may also be the first sign of an underlying cancer. The first aim of this thesis was to investigate the risk of incident and recurrent VTE in active cancer compared to a cancer-free reference population and to explore the influence of genetic risk factors on cancer-related VTE. Secondly, we aimed to investigate the association between plasma D-dimer levels at VTE and the subsequent risk of cancer. All four papers in this thesis use the Tromsø Study. The Tromsø Study was started in 1974 and, thus far, 7 surveys have been completed. Our study populations were recruited from the Tromsø 4 and 6 surveys for Paper I, and Tromsø 1 to 6 surveys for Papers III and IV. Participants were followed from 1994, when the VTE registry was established in Tromsø, throughout 2012. Paper II was based on the Scandinavian Thrombosis and Cancer cohort, which is comprised of data from the Tromsø 4 survey, the second Nord-Trøndelag Health Study and the Danish Diet, Cancer and Health Study. Validated VTE events and cancer diagnoses were registered from inclusion (1993-1997) to the end of follow-up (2007-2012). We found a joint effect between two single nucleotide polymorphisms (SNPs) in the F5 gene (F5 rs6025 and F5 rs4524) and active cancer on the risk of VTE. The incidence of cancer-related VTE increased considerably in the 6 months after a cancer diagnosis, and especially so in patients with risk alleles at these SNPs. Further, cancer-related factors consistently demonstrated a strong influence on incident and recurrent VTE. In traditional analysis, the risk of VTE was highest in the first 6 months after cancer diagnosis and the risk declined markedly thereafter. However, when mortality was taken into account, the risk of VTE was equal in the 6 months before and after a cancer diagnosis, which suggests that cancer itself is a major contributor to the VTE risk. The risk of VTE by cancer sites was greatly influenced by mortality and the time since cancer diagnosis. We found that patients with an occult cancer-related incident VTE had a higher rate of VTE recurrence than those with overt cancer and those cancer-free. Patients with occult cancer-related incident VTE who experienced a VTE recurrence more often had prothrombotic and advanced cancers at the time of cancer diagnosis. The majority of VTE recurrences were not related to cancer treatment as they occurred prior to cancer diagnosis. Finally, we found that plasma D-dimer levels above 5000 ng/ml at incident VTE were associated with an increased risk of cancer at one and two years. Patients with higher D-dimer levels at incident VTE had more advanced cancers at the time of diagnosis and mortality was greater among these patients.
(Avhandlingen er tilgjengelig for utlån hos Seksjon for utdanningstjenester frem til disputasdato)

Veiledere
Hovedveileder professor John-Bjarne Hansen, Institutt for klinisk medisin, UiT - Norges arktiske universitet
Biveileder førsteamanuensis Sigrid Brækkan, Institutt for klinisk medisin, UiT - Norges arktiske universitet

Bedømmelseskomiteen
Førsteamanuensis Paolo Bucciarelli, Department of Internal Medicine, University of Milan, Italia– 1. opponent
Førsteamanuensis Anders Erik Astrup Dahm, Universitetet i Oslo, Akershus universitetssykehus– 2. opponent
Professor Anne Elise Eggen, Institutt for samfunnsmedisin, UiT – Norges Arktiske Universitet – leder av komiteen

Disputasleder
Førsteamanuensis Khaled Meknas, Institutt for klinisk medisin, UiT – Norges arktiske universitet, Universitetssykehuset Nord-Norge

Prøveforelesning over oppgitt emne holdes kl. 10.15, samme sted: “Who needs long-term anticoagulation for venous thrombosis?

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Informasjon
     
Når:
27.06.17 kl. 12:15 - 15:00
Hvor:
Aud 7, Medisin- og helsefagbygget
Studiested:
Tromsø
Målgruppe:
Alle
Ansvarlig:
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