Professor McLaren is a consultant clinical oncologist specialising in Prostate and Bladder Cancer. He established the prostate low dose rate ‘seed’ brachytherapy service in 2001 which offers this treatment to men across Scotland. He has expertise both in radiotherapy, chemotherapy, and immunotherapy for these diseases. He was clinical lead for Genito-Urinary Trials for many years as local principal investigator, member of the trial management group or independent data monitoring committee for practice changing GU cancer trials.
He leads the Edinburgh Radiation Research Group with a focus on personalisation of radiotherapy to maximise tumour response and minimise toxicity. The group has expertise in analysing big data sets with artificial intelligence to predict a patient's response to treatment. Other techniques include radiomic analysis of diagnostic and radiotherapy treatment scans to predict tumour and normal tissue response in combination with groundbreaking laboratory research investigating the release of volatile organic compounds in the breath and normal tissue and cell free DNA into the bloodstream to predict an individual patient's response to their treatment.