Canadians are living longer after a diagnosis of cancer, a new report from Statistics Canada suggests, with the survival rates for most types of cancer up since the 1990s -- sometimes by a big margin.
The conclusions were reached by looking at something called the "relative survival ratio." The authors calculate that the overall five-year survival rate of Canadians diagnosed with cancer between 2004 and 2006 is 62 per cent of that of identical Canadians without cancer.
So, compared with someone of the same age without cancer, someone with cancer has about three-fifths the probability of surviving the next five years, on average.
The overall 10-year relative survival ratio is nearly as high, at 58 per cent.
"The most important message to take from this is that cancer survival is improving, and for some cancers, appreciably so," study co-author Larry Ellison told Â鶹´«Ã½ Wednesday.
The survival odds for some cancers are also rising faster than others. For example, the relative survival ratio for non-Hodgkin lymphoma is at 63 per cent, up from 51 per cent in 1992-1994. The ratio for leukemia has risen 10 points, from 44 per cent to 54 per cent.
And the survival ratio for liver cancer has nearly doubled in the same timeframe, from 9 per cent to 17 per cent, an improvement, but still, a relatively low survival rate.
The study authors note that the two factors greatly influence cancer survival rates: the type of cancer; and the age at diagnosis.
"Generally, relative survival is greater when cancer is diagnosed in early rather than later adulthood, but for some of the most common cancers, survival is less affected by age," the report notes.
For example, five-year relative survival for brain cancer is 58 per cent for young patients between the ages of 15 and 44, but only 9 per cent between ages 65 and 74, and 4 per cent for those over 75.
The chances of surviving five years are high for some cancers (again, compared to other people without the disease):
- thyroid cancer (98 per cent)
- prostate (96 per cent)
- testicular (95 per cent)
- melanoma (89 per cent)
- breast cancer (88 per cent).
Gillian Bromfield of the Canadian Cancer Society said for the cancers with higher survival rates, "we see those kinds of changes or those kinds of improvements due generally to earlier detection and more effective treatments."
But the relative five-year survival is low for other cancers:
- esophageal cancer (13 per cent)
- lung and bronchial (16 per cent)
For cancers with poor long-term prognoses, the probability of dying is typically highest shortly after diagnosis. For example, the one-year relative survival ratio for pancreatic cancer was 21 per cent. The three-year ratio was 8 per cent, while the 10-year ratio was 6 per cent.
Study author Ellison says it's important to note that prognosis is different for each cancer patient.
"These cancer stats that we are presenting today are an average of many different people diagnosed with cancer and they don't necessarily reflect an individual's chances. So a person should always consult and talk with their own doctor or oncologist about their own particular situation," he said.
With a report from CTV's medical specialist Avis Favaro
