Doctoral defence: Laura Roht „Hereditary colorectal cancer syndromes in Estonia“

On December 15th 2023 Laura Roht will defend her thesis „Hereditary colorectal cancer syndromes in Estonia“. 

Supervisors:
Professor Katrin Õunap, University of Tartu
Associate professor Tiina Kahre, University of Tartu
Lecturer Jaan Soplepmann, University of Tartu

Opponent: 
Associate professor Toni Tapani Seppälä, Tampere Univeristy (Finland)

Summary:
Colorectal cancer (CRC) is defined as a cancer that starts from the colon or rectum. Up to 10% of CRC cases are hereditary. In Estonia, CRC is one of the most common cancers as well as a frequent cause of cancer-related death. Until 2012, only a few genetic tests were available for hereditary CRC. MMR (mismatch repair) genes immunohistochemistry (IHC) was another diagnostic method available. Today, sequencing of many genes simultaneously is used for diagnostics: analysis from blood is used to diagnose hereditary CRC syndromes and for treatment-related decisions cancer tissue is used. Furthermore, genetic testing is also important in healthy family members to detect individuals at risk and survey them accordingly to decrease cancer-related death. 

In this study we estimated the diagnostic efficacy of sequencing in the routine clinical setting in CRC patients and found that 22.3% had a disease-causing hereditary gene variant. Birth prevalence of Lynch syndrome (LS) in 1930-2003 in Estonia was 1:8 638 (95% CI: 1:9 859-7 588). In ten years LS prevalence has risen approximately six times, which is probably the result of better diagnostic opportunities and knowledge. Compared to cancer patients, their family members are diagnosed approximately eight years earlier leading to earlier surveillance. Analysing MMR IHC diagnostic efficacy among CRC patients aged >50 years, in more than half of the cases LS was diagnosed. Because of that, we suggest MMR IHC for all CRC patients independent of their age. AXIN2-related oligodontia-colorectal cancer syndrome studies showed that cleft palate might be a new clinical feature of this syndrome. Still, further studies are needed to investigate the phenotype and develop a surveillance plan.

Watch defence via Teams.