Arvo building, auditorium F115, address: Lääkärinkatu 1.
Doctoral defence of Lic.Med. Suvi Tuohinen
The field of science of the dissertation is Cardiology.
The opponent is Associate professor Antti Saraste (University of Turku). Professor Kjell Nikus acts as the custos.
The language of the dissertation defence is Finnish.
Radiotherapy-induced early cardiac changes in breast cancer patients
Approximately half of the cancer patients receive radiotherapy (RT)as a part of their cancer treatment. RT is effective and it has low cost. However, RT induces adverse effects on healthy tissue. I the chest region, RT increases the incidence of cardiac morbidity and mortality by 2 to 6-fold with several years of latency.
The RT protocols have been actively improved, and the cardiac radiation exposure has diminished significantly. However, even low doses seem to increase the risk of RT-induced heart diseases (RIHD) without any obvious safe threshold. There is little knowledge of the early cardiac changes and late manifestations of the modern conformal RT. The aims of our study was to explore whether there are early cardiac changes detectable in echocardiography in the early-phase after RT in the early-stage breast cancer patients. RT induced both structural and functional changes in our patients. The heart became thicker with slower filling. The sensitive markers of heart systolic function declined. The cardiac changes were located in the areas of RT fields, while areas outside the RT field were spared from cardiac changes. Furthermore, the changes had an association with the radiation dose, higher dose induced stronger changes in the heart.
Our study shows that the modern conformal RT for breast cancer patients induced cardiac changes that are detectable already in the very early phase after the treatment. Some of our findings are novel and widen the knowledge of the early cardiac changes after RT, while some of the parameters displaying significant changes could be used in the screening of RT-induced changes or in the follow-up of this patient population. The long delay of the clinically significant cardiac changes is problematic concerning the continuous work to improve the safety of the RT protocols. An early subclinical indicator of cardiac manifestation would be better suited to guide this work. Several of our findings could be well suited for this purpose. Furthermore, our results can be used to guide the search of mid-term cardiac changes in the further follow-up of this patient population. However, only the long-term follow-up will reveal whether our results of the early cardiac changes will develop into clinical adverse effects.
The dissertation is published in the publication series of Acta Universitatis Tamperensis; 2273, Tampere University Press, Tampere 2017. The dissertation is also published in the e-series Acta Electronica Universitatis Tamperensis; 1774, Tampere University Press 2017.