MINNEAPOLIS (WCCO) — Doctors at the Mayo Clinic are trying a new treatment for mesothelioma, a rare and deadly form of cancer.

The first patient enrolled in the study was Mary Kuntz, a 68-year-old grandmother diagnosed with the disease last summer.

Doctors sprayed liquid nitrogen to freeze Mary’s tumor. Two weeks later, surgeons removed it.

The goal is to trigger Mary’s immune system to fight any remaining cancer cells.