Jack Layton has left an optimistic message for Canadians facing cancer.

The former NDP Leader who led the Official Opposition died on Monday.

Layton's death comes less than a month after he announced to the country that he was fighting a new form of cancer and was taking time off for treatment.

Layton, 61, had been diagnosed with prostate cancer last year and underwent treatment for it. He continued working throughout that time and also battled a broken hip earlier this year.  His cause of death has not been released.

"To other Canadians who are on journeys to defeat cancer and to live their lives, I say this: please don't be discouraged that my own journey hasn't gone as well as I had hoped," Layton wrote in a letter to Canadians dated August 20 and released by his partner Olivia Chow.

 "You must not lose your own hope. Treatments and therapies have never been better in the face of this disease. You have every reason to be optimistic, determined, and focused on the future. My only other advice is to cherish every moment with those you love at every stage of your journey, as I have done this summer."

Defender of medicare

Layton told the public he was diagnosed with prostate cancer in February 2010. In July, he announced he was taking a leave of absence to deal with another type of cancer.

Peter Goodhand, president and CEO of the Canadian Cancer Society, said the society will always be grateful for Layton's "passionate efforts to improve the health of Canadians and to raise awareness and funds for our organization to help us in our mission to eradicate cancer and assist those living with the disease."

At their annual general meeting in St. John's, members of the Canadian Medical Association expressed their condolences to Chow and Layton's family, friends and colleagues.

"Mr. Layton was a tireless defender of medicare and a principled voice for the disadvantaged in our society. He was a decent man, deeply committed to social justice, who stayed true to his values," CMA President Dr. Jeff Turnbull said in a statement.

"On a personal note, he and I shared a similar perspective on the need to respect the rights of the homeless and other vulnerable people in our society. I thought he was a wonderful man and we have suffered a great loss."

At the CMA meeting, MP Carolyn Bennett told reporters that members of Layton's family used to come to her family practice in Toronto.

Doctors "don't have magic wands," Bennett said, adding that "this street fighter lost this big fight."

Awareness message

At a cancer centre in Toronto, there was admiration for Layton's energy and spirit.

"I have gone through chemotherapy, radiation, two operations, and I know how weakened the body is," said Alvin King. "I really admire him."

"I was maybe too optimistic about Mr. Layton's chances of survival," said Susan Gordon. "But I think like everyone I thought if anyone could beat cancer, Jack Layton could."

The fact that Layton's cancer was fatal very quickly is difficult news for cancer researchers and all Canadians, said Dr. Tom Hudson, president and scientific director of the Ontario Institute for Cancer Research.

"It's a very honourable message and it's also a very true message," Hudson said from Kingston, where he announced funding for cancer clinical trials.

"There is a reduction in deaths for multiple types of cancers including breast cancer and others that we've seen over 20 years. It's a hard road. Cancer is a difficult enemy. But there is progress happening in specific types of cancers, one at a time. It's important for people to keep hope."

Whenever a prominent person succumbs, it's a great opportunity to remind men, who typically ignore their health, to speak to their family doctor about prostate cancer, screening and the pros and cons of the PSA test, said Dr. Neil Fleshner, head of the urology division at Toronto's Princess Margaret Hospital.

"When you are diagnosed with prostate cancer at an early stage, meaning it's still confined to the prostate, we can cure the vast majority of those men," Fleshner said.

"There are still, unfortunately, a small subgroup of men whose cancer is so aggressive, that even the best way to detect it, using the best available methods today is still not good enough."

Layton's unspecified second cancer left lingering questions for Aaron Bacher, who survived prostate cancer and now runs the Toronto Man to Man Prostate Cancer Support Group in Toronto.

"Nobody is telling you exactly what it was that he died from," said Bacher. "If you make the assumption that it's prostate cancer, you can raise fear in that community."

Prostate Cancer Canada called Layton a friend and supporter for raising awareness .

With files from CBC's Kelly Crowe