Laura Bush had worked in public schools in Texas from 1968 to 1977, the year she married the future president.
Doctors treated Heinz Kerry for breast cancer in late 2009.
She previously has said she found in September 2009 that she had cancer in her left breast after having her annual mammogram.
A month later, she underwent lumpectomies on both breasts at a Washington hospital after doctors also discovered what they thought was a benign growth on her right breast.
That diagnosis was initially confirmed in postoperative pathology, but two other doctors later found it to be malignant.
In November 2009, Heinz Kerry had another pair of lumpectomies performed at Massachusetts General Hospital.
Before Sunday's emergency, John Kerry had been at the Nantucket home since returning from a nearly two-week, around-the-world diplomatic trip to the Mideast and Southeast Asia in the pre-dawn hours of July 3.
Before his wife's medical problem, he had planned to return to Washington on Monday and then co-host with Treasury Secretary Jack Lew high-level strategic and economic talks with senior Chinese officials on Wednesday and Thursday.
Kerry had also spoken of his desire to make his sixth trip to Israel as secretary starting at the end of the week. State Department officials said Kerry's schedule may now change pending developments with his wife's health.
Associated Press writer Matthew Lee reported from Washington.