The 26-year-old Koivu was diagnosed with intra-abdominal lymphoma on Sept. 12 after undergoing a series of comprehensive tests at Montreal General Hospital.
"Five months ago we sat in this same room and we were all a little shocked," Koivu said Thursday during a news conference at Molson Centre. "This good news is such a great relief. I cannot say enough about the support I received here and in Finland.
"And if not for my fiancee Hannah, I'm not sure I could have gone through all these months without her support. To her I say just thank you."
Koivu has a cleanly shaven head as a result of the chemotherapy, and appeared healthy and happy at Thursday's news conference.
Team doctors David Mulder and Vincent Lacroix said they were amazed by Koivu's progress.
"Saku attacks this disease as he plays," Dr. Mulder said. "He will continue to undergo testing as a method of monitoring progress in his rehabilitation. But his progress to this point has been remarkable."
"There were no traces of lymphoma, but Saku will require periodic evaluations and continue his chemotheraphy," Dr. Lacroix said.
This season was to have been Koivu's seventh with the Canadiens. The center tied for the team lead in scoring last season with 47 points in 54 games, missing 28 contests with a torn left MCL.
The 5-10, 183-pound Koivu missed 58 games with knee and shoulder injuries in 1999-2000. Over the previous four seasons, he missed a total of 120 games due to injuries.
Koivu is Montreal's top playmaker and was expected to play for Finland in the 2002 Olympics. But he has played just one injury-free season in the NHL and has never scored more than 20 goals.