When Ride delivered a speech at the National Science Teachers Association Conference in San Francisco on March 10, 2011, O'Shaughnessy and a friend noted that she looked ill. Alarmed, O'Shaughnessy had her book a doctor's appointment for the following day. A medical ultrasound revealed a tumor the size of a golf ball in her abdomen. A follow-up CT scan at UCSD confirmed a diagnosis of pancreatic cancer. She underwent chemotherapy and radiation therapy to reduce the size of the tumor. Ride had ensured that O'Shaughnessy would inherit her estate when she drew up her will in 1992. They registered their domestic partnership on August 15, 2011. On October 27, surgeons removed part of Ride's pancreas, bile duct, stomach and intestine, along with her gallbladder.