Northridge Hospital Medical Center plans to add 18,500 square feet of new facilities, including a cancer center, surgery center and radiation therapy service.
Ground was broken Thursday for the cancer and surgery centers, which have already received $3.7 million in pledges.
The expansion plans include four new operating rooms, five outpatient treatment stations, a 25 million-electron-volt accelerator, a laser room and a data center for information on cancer care.
The 433-bed nonprofit hospital at 18300 Roscoe Blvd. near Reseda Boulevard, founded in 1955, is affiliated with UniHealth America.