Former hospital chief and accused fraudster Arthur Porter is dying from cancer inside a Panama prison with just "weeks to live," according to his doctor.

Meanwhile, a UN report has found that Panama has violated the rights of the former Montreal hospital executive during his 22-month detention there while awaiting extradition to Canada.

"I've never left here to go into the city. I have no idea what a courtroom looks like in Panama, Canada, Bahamas or anywhere," Porter told CBC News, speaking in a weak sounding voice in a telephone interview from La Joya prison in Panama.

He also said he is buoyed by UN watchdog findings earlier this month, which backs his formal complaint that he was arrested illegally and is being held in deplorable conditions without proper medical care.

His long-time friend and doctor, Karol Sikora, told CBC News that unless Porter is brought to hospital soon for tests and new drugs, he will likely die in prison within six to eight weeks. Sikora is based in the U.K. and hasn't examined Porter in over a year.

But he said in a telephone interview that "judging from his emails, I think he's got very widespread cancer in his chest, in his liver and in his spine. Unless he receives some form of therapy, and indeed a scan to assess what's going on, I suspect he's only got a few weeks to go."

22-month detention, no hearing

Porter was arrested May 27, 2013 at the airport in Panama City while flying from the Bahamas to St. Kitts. He was taken into custody based on a Canadian arrest warrant alleging he accepted $22.5 million in bribes in exchange for rigging the construction contract for the proposed McGill University super-hospital in favour of engineering giant SNC-Lavalin.

Canada requested his "preventative detention," pending extradition.

But Porter is fighting the extradition, alleging his arrest was illegal given that he was travelling on a diplomatic passport at the time, as a special ambassador to Sierra Leone, his birthplace. He has also insisted that Panama and Canada are purposely dragging out the process.

"Canada is slowly but surely killing him with this case," said Porter's lawyer John Jones in a telephone interview from London. "Canada didn't present the extradition papers within the 60 days required by the extradition treaty with Panama. And my impression is Canada is happy for him to die in Panama."

An official from Canada's Justice Department said in a statement "The matter of Mr. Porter’s extradition remains before the courts in Panama, and his challenge will be processed according to their laws and procedures."

Panamanian officials issued a detailed statement stating Porter's rights have not been violated, and that there is no requirement he appear in person before a judge to resolve his extradition.

In addition, Panama says Porter's time in prison has been prolonged due to the four separate habeas corpus applications he has filed.

The UN special rapporteur on torture, Juan Mendez, earlier this month reported Panama failed to respond to UN inquiries and concluded there is "substance" to Porter's allegations. The UN report states that barring any explanation from Panama, officials have kept Porter in inhumane and degrading conditions, denied him medical treatment and "violated his right to not be tortured nor submitted to cruel, inhumane treatment."

Panama disputes the findings, and says officials have now supplied the UN Special Rapporteur on Torture with additional information.

It also said, in a statement to CBC News: "Mr. Porter has repeatedly refused, verbally and/or in writing, to be transferred to a public hospital so that Panamanian health professionals can perform the required tests to diagnose the condition that he may suffer and prescribe treatment for it. He has also refused to allow doctors from the Correctional Centre to provide him primary care."

Lung cancer

Porter, beyond being a hospital executive, is a highly qualified oncologist himself. He left Montreal amid growing controversy in late 2012 to return to his home in the Bahamas where he runs a number of cancer clinics. It was there that he first diagnosed himself in December 2012 and sought confirmation of lung cancer from colleagues and friends.

He told CBC News that he believed until recently his cancer was in remission with help from drugs brought to him in prison by his family.

Arthur Porter is being held at La Joya Prison near Panama City, Panama. (John Nicol/CBC)

But now he feels it is advancing and becoming more aggressive.

Professor Sikora, who has worked with Porter and been a close friend for 35 years, discounts the speculation Porter may be faking his illness to evade prosecution.

"He has got lung cancer," Sikora said, insisting he directly oversaw testing and analysis of X-rays in the Bahamas and visited Porter a year ago in Panama. "We've got pathology reports from London, pathology reports from Nassau in the Bahamas.

"I know that there's some suggestions he's sort of faking it. But I can assure you he's not."

Sikora believes Porter needs to be brought to a hospital and put on a new drug regime, given the emailed description of his new symptoms.

"His prognosis is not good, whatever we do," Sikora said. "But if we do absolutely nothing, then I would have said six to eight weeks — that sort of length of survival."

Sikora has come under scrutiny before over his cancer diagnosis of the Lockerbie bomber, Libyan Abdelbaset al-Megrahi. A U.S. Senate committee questioned the medical diagnosis of Sikora and five other cancer specialists whose opinions paved the way for al-Megrahi's early "compassionate release" from a Scottish prison in 2009.

Said to have only a few months to live, al-Megrahi survived for another, almost three years back in Libya.

Porter's case has other ties to Libya, in particular that his co-accused in Canada, ex-SNC-Lavalin executive Riadh Ben Aïssa was convicted of bribery and money laundering for members of the Gadhafi regime.

What's more, Porter's current lawyer, John Jones, was appointed by the International Criminal Court to defend one of Libya's ex-dictator's former sons, Saif Gaddhafi.

Sikora laughed when presented with the list of coincidences, and insisted there was no "fix" with the medical team that assessed the Lockerbie bomber.

"The public may not want to believe it, but there was no underhand business," he said. "There was no bribery. The report wasn't written for me or anything. All sorts of conspiracy theories here as you can imagine."

CBC News asked Porter why he doesn't simply agree to return to Canada to face the hospital bribery allegations, especially if his health is so dire and his prolonged detention so unbearable.

Porter says given the legal abuses he's already endured, and the alleged indifference of Canadian officials to his legal and medical plight, he believes he can not get a fair trial in Canada and so will continue to oppose his extradition.

"If you look at the articles that have been written," he said. "If you look at the process that has been done, I think you won't say that that is a fair due process for someone who is supposed to be innocent until proven guilty."

If you have information you would like to share on this story, please contact the CBC's Dave Seglins.