Subsequently he trained in Medical Oncology at the Oncology Department of Ioannina University Hospital, Greece (2010-2013) where he gained experience in the diagnostic and therapeutic approach of solid tumours, working for Prof Nicholas Pavlidis.
Dr Boussios was awarded European School of Oncology (ESO) and Hellenic Society of Medical Oncology (HeSMO) fellowships for clinical and laboratory research at the Royal Marsden Hospital, London, United Kingdom (2014-2015). He specialised in ovarian cancer under the supervision of Dr Susana Banerjee.
Returning to Greece in 2015, he continued to work on his PhD thesis on circulating cancer cells and cancer cells with blastic phonotype and epithelial mesenchymal transition in peripheral blood of patients with Carcinomas of Unknown Primary site (CUP) and successfully defended the thesis in 2016. He was awarded the HeSMO second award for his research on CUP in the 2016 National Congress. He worked as a locum Consultant Medical Oncologist at the Department of Medical Oncology, University Hospital of Ioannina, Greece, until 2017. Dr Boussios was selected by the European Society of Medical Oncology (ESMO) Fellowship and Award Committee to be part of the ESMO Leaders Generation Programme in 2017.
His research interests include individualisation of patient treatment and targeted therapies in gynaecological cancers, CUP, urological cancers, new drug development and cancer diagnosed in pregnancy.