Diane Allen is not releasing details of her illness.
Allen issued a statement Monday saying she is exploring treatment options with a world-class team of physicians. She says she expects to undergo surgery as early as this week and hopes to return to the state Senate soon.
Allen has represented parts of Burlington and Camden counties since 1996, the past 11 years in the Senate.
As a senator, she has focused on issues involving child care, health care, education, housing and tax relief.