"At least since the late 90s, it's been known that in Inuit regions of Canada the rates of lung cancer are amongst the highest in the world," says Dr. Faiz Ahmad Khan, Assistant Professor in the Department of Medicine at McGill University and Director of TB Clinical Services at the Montreal Chest Institute of the MUHC. “But no one ever studied the outcomes of lung cancer treatment of this population.”
Faced with this knowledge gap, Dr. Khan, a respirologist who splits his time working in Montreal and in Nunavik, gathered a team from the MUHC, the Nunavik Regional Board of Health and Social Services, the Ungava Tulattavik Health Center, and the Jewish General Hospital, to study this question. If lung cancer outcomes were different amongst the Inuit, they wanted to know whether the root of the problem was a health system-related issue that they could tackle head on. Their research is supported by the Rossy Cancer Network (RCN)'s Cancer Quality & Innovation (CQI) Fund.
Using data from the lung cancer registry, they compared diagnoses of all Nunavik residents diagnosed with lung cancer between 2005 and 2016 to all patients from Montreal who had been diagnosed and treated at McGill-affiliated cancer centres in the same period.
Their first step was to look for signals that might suggest delays in lung cancer diagnosis were affecting patients in Nunavik. "We had a feeling that it was possible that patients from Nunavik were being diagnosed with lung cancer at later stages compared to other patients," says Dr. Khan. Fortunately this wasn't actually the case. "We found that the stage at diagnosis is quite similar between patients from Nunavik and Montreal."
The team also suspected patients from Nunavik had poorer survival rates than other patients treated in Montreal. Unfortunately, preliminary analyses suggest this may be correct: "We haven’t finished our analyses, but at first glance it looks like there's an increased risk of mortality amongst lung cancer patients from Nunavik as compared to those from Montreal," says Dr. Khan. The team still isn’t sure why.
A deadlier cancer prevalent in the Arctic
A clue could lie in an unexpected finding that emerged from the data analysis. "We were surprised to find that the type of lung cancer that is the most common in Nunavik is different from the most common type in Montreal," says Dr. Khan.
In Nunavik, the most common subtype of cancer is squamous cell cancer, accounting for 41.8% of cases. In Montreal only 18.3% were squamous. By contrast, in Montreal adenocarcinoma is the most common subtype, making up 46.7% of cases. In Nunavik, 17.6% of cases were adenocarcinoma.
Given that patients with squamous cell cancer are known to have poorer survival rates than those with adenocarcinoma, could these subtype differences explain the lung cancer anomalies in Nunavik? "It's really tough to speculate," says Dr. Khan, adding that the Nunavik-Montreal team has embarked on a follow-up study that matches each Nunavik lung cancer patient's data against those of two same-aged Montreal patients diagnosed the same year to get to the bottom of it.
d"The ultimate goal is for our health centres to work together with regional health authorities in Nunavik to ensure every Nunavimmiut with lung cancer is getting the same quality of lung cancer care as someone living in Montreal," says Dr. Khan. "There is no reason why we can’t strive for the best outcomes for our patients from Nunavik, even though they're living over a thousand kilometres away."