Proving Causality in Cancer

Review from the Office of the Ombudsman | English Services

The complainant, Steve Hrudey, professor emeritus at University of Alberta in the Department of Laboratory Medicine and Pathology under the Faculty of Medicine and Dentistry, was chair of a Royal Society of Canada panel that examined the environmental and health effects of Canada's oil sands industry.

The panel's 438-page report in 2010 dealt with an array of issues, among them the impact on downstream communities from oil sands development, including Fort Chipewyan, a northern Albertan community of 1,200. Among its findings, the Royal Society study concluded there was “no credible evidence to support the commonly repeated media accounts of excess cancer in Fort Chipewyan being caused by contaminants released by oil sands operations.”

The panel report noted that the College of Physicians and Surgeons of Alberta later found the controversial 2006 diagnosis of cancer in high levels at Fort Chipewyan by a local physician, Dr. John O'Connor, inaccurate and untruthful. Of six suspected cases of a relatively rare cancer, cholangiaocarcinoma, only two were confirmed, three were other cancers and one was not cancer. A later review of that study concluded that there was “not evidence that an environmental exposure is a cause.”

The Royal Society panel said that community concerns and stress were “understandable” in part because of the number of claims about toxic pollution from oil sands emissions. Still, “evidence to document environmental contaminant exposures sufficient to pose measurable health effects in these communities has yet to be reported.”

It welcomed a plan by the Alberta government to further study local health. “More monitoring focused on human contaminant exposures is needed to address First Nation and community concerns.”

The panel also hoped that such work would not raise unachievable expectations because “black and white answers are unlikely to be found” in assessing such a small population.

A segment January 3, 2011 on CBC Radio's The Current concerned the challenge of proving causality of cancer. The segment was part of a wide-ranging campaign across radio, television and online called LiveRightNow to encourage greater public awareness on personal health.

The program featured a discussion of nearly a half-hour with two guests on the causality issue. To establish the theme, it featured short clips from Hrudey and O'Connor on the situation in Fort Chipewyan, and scripted material.

It began by paraphrasing the panel finding in saying it “came to the conclusion there is no evidence of a link between the oil sands and cancer rates in Fort Chipewyan.”

Hrudey was quoted once: “If you're going to attribute cases of cancer to contaminant exposure, you surely have to find evidence of these exposures.” But in reviewing the air and water quality studies over the years, he said, the panel didn't “find anything like the levels that would be necessary to explain elevated cancer rates in a community that size.”

The program went on to say that the Royal Society panel had “however” called for more study on human exposure to potential carcinogens coming from the oil sands.

It said that was a frustrating conclusion for Dr. John O'Connor. He was the physician who made the controversial 2006 diagnosis later found flawed. The program didn't identify him in that way. It described him as a physician working closely with the community in Fort Chipewyan.

O'Connor questioned the Royal Society panel: “They've said repeatedly that they have limited data, yet they can conclusively say that they can find no link between tars and toxins and elevated cancer” in the community.

The program then examined the challenge of demonstrating causality. It featured two guests: Gideon Forman, executive director of the Canadian Association of Physicians for the Environment, and Mario Chevrette, a McGill University cancer researcher and president of the Cancer Research Society.

Forman started the discussion by saying he was “very sympathetic” with O'Connor's frustrations. Forman noted O'Connor was working with First Nations communities and seeing cancer first-hand.“ If he is finding rare cancers in clusters in these communities, we would do well to listen and not to ignore his results,” Forman said.

The program didn't pursue the Fort Chipewyan community issue further, though; the thrust of the discussion was on the difficulty in proving causality in an array of instances.

The complainant wrote a program producer January 5 that The Current had erred in stating that his panel called for further studies. He said the editing of the clips and the script created a “false dichotomy” between him and O'Connor, whose behaviour on the local health issue had been criticized by the Alberta College.

“Through the editing and the set up of this piece, CBC is furthering a myth that has no basis in fact and which is needlessly scaring the innocent residents of Fort Chipewyan,” Hrudey wrote. “This is not only wrong, it is unethical!”

The producer wrote back that the program would clarify the matter on the next program.

The next day, in its weekly segment that examines listener mail, The Current carried an excerpt of a statement from Hrudey that said the panel had “ample evidence” to support its view and that it didn't need further study to buttress its findings. He said the panel welcomed further study to fortify “community confidence.”

Hrudey wrote January 6 to say the program producers “have knowingly skewed the message of this story to fit their invalid and unsubstantiated view of the circumstances surrounding the existence of an unusual cancer cluster in the largely aboriginal community of Fort Chipewyan which they would attribute to oil sands contaminants.”

He added: “What The Current chose to do was to simply read an extract from my email,” He said CBC didn't show “even a hint of admission that my complaint was based on the CBC's selective editing. There is no signal of any accountability by CBC for its action in how this has been handled.”

On January 11, Linda Groen, director of CBC Radio Current Affairs, wrote Hrudey: “I agree that the program misstated your position and subsequently should have offered a forthright, clear and timely correction. It did not. On both counts I offer my sincere apologies.”

But she said any error was inadvertent, noting that the report itself had implied more study on contaminant effects was needed.

“The program does not hold an opinion on this or any other issue,” Groen wrote. “Indeed, CBC is prohibited by regulation and policy from advocating or supporting any point of view on a controversial matter. It is CBC's responsibility to ensure that Canadians are given the opportunity and the information they need to make up their own minds.”

She said: “I recognize we impaired their ability to do that.”

Groen further said that the program “could have done better; and we should have” with a correction the next day and not later that week. “And yes, we should have acknowledged the error and included an appropriate expression of our regret.”

Groen said she recognized Hrudey was dissatisfied with the clarification, but believed that revisiting the matter 10 days later would add little clarity to the matter. She said the program would continue to follow the story.

Hrudey asked for a review January 13. He appreciated Groen's acknowledgment and apology, but asserted that it was “not credible” to conclude that the error was inadvertent.

He said the purpose of the discussion “would not have been fulfilled by an accurate representation of my interview or my report” and implied that the clip and paraphrase of the report were aimed at fitting into a preconceived story's framework.

CBC Journalistic Standards and Practices identify several elements relevant to this complaint, including the need for accuracy, balance, fairness and integrity.

On matters involving scientific research, the policy states: “We take care to understand properly and reflect the true implications of medical or scientific study results that we obtain, especially those involving statistical data.”

It further states: “In matters of human health we will take particular care to avoid arousing unfounded hopes or fears in persons living with or close to those living with serious illnesses. We will also avoid suggesting unproven benefits or risks to health related to changes in habits of consumption of food or pharmaceutical products.”

On editing interviews: “Whatever editing we do, we present what the interviewee said fairly and without distortion.”

On the issue of setting the record straight, the policy says “we do not hesitate to correct any mistake when necessary nor to follow-up a story when a situation changes significantly.”


The inaccuracy about the panel's views on the need for further studies did not meet CBC standards and practices, nor did the on-air treatment of the complaint. The correspondence with the complainant acknowledged that with a fulsome personal apology. Of course, there is also a wider obligation to the audience.

The audience would have benefited from background on the College of Physicians and Surgeons of Alberta's findings about O'Connor's controversial 2006 diagnoses. As it stood, the statement of Hrudey and not O'Connor was challenged.

It also would have been more helpful to the audience if, in the second broadcast, the program clearly identified the earlier information concerning further studies as inaccurate.

The Current has a strong tradition of thoughtful, varied and challenging discussions that seek diverse opinions and demonstrate consistent, impartial curiosity. In recent times it has featured extensive interviews with the Alberta premier and environment minister, the president of the Association of Canadian Petroleum Producers, the chief executive officer of Suncor, the chief energy economist of ARC Financial, and entrepreneur T. Boone Pickens on matters concerning the oil sands. Indeed, the discussion that followed the complainant's audio clip articulated the scientific challenge of causality.

Kirk LaPointe
CBC Ombudsman