After gruelling chemotherapy and radiotherapy, an MRI scan showed the cancer had spread to his brain stem and spine.

Source: https://www.independent.co.uk/life-style/health-and-families/brain-tumour-symptoms-headache-medulloblastoma-b2263137.html

But an MRI (magnetic resonance imaging) scan revealed he had a high-grade glioma, a malignant tumour, on his brain stem and he was given months to live.

Source: https://www.birminghammail.co.uk/news/midlands-news/birmingham-dad-told-chew-gum-27989047

Despite the estate's claims, a medical examiner determined that Sicknick had suffered two devastating strokes in his brain stem, which caused a clot in an artery.

Source: https://www.dailymail.co.uk/news/article-11604961/Estate-Capitol-officer-died-Jan-6-riot-files-wrongful-death-suit-against-Trump.html?ns_mchannel=rss&ns_campaign=1490&ito=1490

'Unfortunately, radiation isn't viable given Hugo's age and his growing brain, and the tumour is still inoperable due to its proximity to the brain stem,' Ollie and Brooke wrote.

Source: https://www.dailymail.co.uk/news/article-11987973/Brooke-Ollie-Carter-reveal-11-week-old-Hugos-ATRT-brain-cancer-diagnosis-brutal-fight.html?ns_mchannel=rss&ns_campaign=1490&ito=1490