From today's issue of Friendly Neighborhood Spider-Man #1
Peter can tell something is wrong, so he tries to follow Aunt May on her journey through the city to get to the bottom of things. However, a couple of school bullies distract him from his primary objective of privacy snooping. We do see Aunt May head to the McCarthy Medical Insitute, where inside the hospital walls we learn the startling news that Aunt May found a lump, meaning she could potentially have breast cancer.
https://www.cbr.com/friendly-neighborhood-spider-man-aunt-may-breast-cancer/