Tsongas was diagnosed with non-Hodgkin lymphoma in 1983 and retired in 1984. He returned to politics after undergoing a successful bone marrow transplant. He experienced early success in the 1992 Democratic presidential primaries, winning the New Hampshire primary, but withdrew from the race in March 1992 and endorsed Clinton.
Tsongas died in Lowell, Massachusetts on January 18, 1997 of complications from pneumonia and non-Hodgkin lymphoma at the age of 55.[1]