Elizabeth Edwards (search), the wife of former Democratic vice presidential candidate John Edwards, is making progress in her treatment for breast cancer (search), the family says.

She underwent surgery Monday at Massachusetts General Hospital in Boston to remove a cancerous growth following four months of chemotherapy to shrink the half-dollar-size mass.

"She is resting comfortably, and our doctors believe that the surgery was a success," John Edwards (search), a former senator from North Carolina, said in an e-mail to friends and supporters. "The prognosis continues to be very positive."

Family spokeswoman Kim Rubey called the chemotherapy successful as well.

"The size was reduced dramatically," Rubey said.

Edwards, 55, will undergo five to six weeks of radiation treatment starting in early April, Rubey said.