A tanned but frail looking Jack Layton said Monday morning he will temporarily step down as New Democrat leader because he is suffering a new form of cancer.

The 61-year-old made the surprise announcement in Toronto, with his wife Olivia Chow by his side. Sounding hoarse, it appeared Layton had lost weight.

Layton said his battle against prostate cancer was "going very well," but test results indicate he has a new cancer that requires immediate treatment.

He did not specify what type of cancer he is now battling.

"On the advice of my doctors, I am going to focus on treatment and recovery," Layton told reporters. "I'm going to fight this cancer now, so I can be back to fight for families when Parliament resumes."

Layton was diagnosed with prostate cancer in February last year. He underwent hip surgery in March, just weeks before the beginning of the federal election campaign.

His party went on capture official Opposition status for the first time in its 50-year history.

The "orange tide" made particularly large gains in British Columbia.

Layton said he is feeling upbeat about his medical treatment and expects to resume his duties on Sept. 19, the first time Parliament meets after the summer break.

"I am hopeful and optimistic about the personal battle that lies before me in the weeks to come," he said.

Well-wishes

Layton has decided not to disclose the specifics of his disease, unlike when he was diagnosed with prostate cancer.

"I think he told us what we need to know," NDP President Brian Topp told CTV News Channel. "He is aware of the influence that an important national figure has to people when he talks about his health."

Layton's announcement was met with well-wishes from his opponents in Ottawa.

"I salute the courage (Jack Layton) continues to show in his fight against cancer. I wish Jack a successful recovery," Prime Minister Stephen Harper said on his Twitter account.

Liberal interim leader Bob Rae said he was "deeply saddened by the news.

"All we can say is we wish him the very best for his recovery and I guess on a personal level I think he is making the right decision to take a complete break from politics," he told CTV News Channel. "Obviously, this has got to be is focus."

Serious consequences

Layton's absence will have serious implications for a party that has just cemented its position as the official opposition, says SFU public policy professor Doug McArthur.

"This is a real shock for the NDP nationally and I think a considerable blow. They've just come through with a substantial election result and he was the one who really carried that whole effort," McArthur told ctvbc.ca in a telephone interview.

With a party full of young and inexperienced caucus members, the NDP needs Layton's experienced leadership, he added.

"This takes them off of their game, to show in the fall that they've earned this position. Without Jack at the helm this is going to be a very rough ride," McArthur said.

A new interim leader will likely be announced on Thursday. Layton is recommending that rookie Quebec MP Nycole Turmel fills in during his absence, saying she is an experienced MP who is also bi-lingual. The former leader of the Public Service Alliance of Canada has only sat in Parliament for less than three months.  However, she does have years of experience working in various positions within the federal government. 

McArthur said that if his leave extends beyond September the party would be wise to bring in a more experienced candidate.

"All of this is very disorienting to a political party," he said, adding that Layton has overcome substantial health problems in the past, often to the amazement of his detractors.

"He's a fighter, but you have to wonder how much one man can do."