Former U.S. Sen. Ben Sasse, R-Neb., said he has undergone successful surgery on his liver as part of his ongoing battle with stage-four pancreatic cancer, but doctors discovered that the tumors were more advanced than previously understood.

Sasse, who served in the Senate from 2015 to 2023, announced the latest development as he continues treatment for cancer that has spread beyond his pancreas, including to his liver and other parts of his body. He has previously described his diagnosis as metastatic pancreatic cancer and said doctors initially gave him only a few months to live.

Earlier this year, Sasse reported that an experimental treatment had produced a substantial reduction in his overall tumor volume. He said in an April interview that his tumors had shrunk by 76% over four months while he was receiving daraxonrasib through a clinical trial.

The treatment has attracted significant attention because daraxonrasib targets the KRAS pathway, which is involved in a large share of pancreatic cancers. Clinical-trial results reported in 2026 found a median overall survival of 13.1 months among patients receiving the drug after prior treatment, although the medication also produced significant side effects in some patients.

Sasse will now begin a new and more aggressive chemotherapy regimen following the findings during surgery. The former senator has continued to publicly discuss his treatment and prognosis while remaining active in public appearances, including a scheduled keynote address at Nebraska Gov. Jim Pillen's Governor's Summit later this month.

The latest development comes as Sasse continues treatment for an advanced disease that doctors initially considered terminal. His new chemotherapy regimen will form the next phase of his treatment following the liver surgery.