Cancer: The six-letter word everyone dreads to hear

Today is World Cancer Day—not the type of date most people would have circled on their calendar.

After all, over two in five Canadians (43%) are expected to be diagnosed with cancer in their lifetime, and cancer remains the leading cause of death in Canada.

Just over 80,000, or almost one-quarter, of the 307,000 Canadians who passed away in 2020 died of cancer. This was over 25,000 more deaths than from heart disease and five times as many as from COVID-19.

While cancer remains a health concern, we are making progress, and Canadians diagnosed with cancer today have on average better odds of living longer than those diagnosed a decade earlier.

This is true for both children and adults. Since the early 1990s, five-year childhood cancer survival increased from 77% to 85%, while five-year cancer survival among adults rose from 55% to 64%.

Current survival for some types of cancer is relatively high. For example, five-year net survival for those diagnosed with thyroid cancer or testicular cancer is 97%. Five-year net survival is also high for prostate cancer (91%), breast cancer (89%) and melanomas of the skin (89%). The relatively favourable prognoses for these cancers are encouraging, especially considering some of them are among the most commonly diagnosed cancers.

Cancer staging—the extent of the disease in the body—is a recognized way of describing and classifying a cancer when it is diagnosed. Generally, a cancer that is diagnosed at an earlier stage is easier to treat, and patients have a higher chance of survival than those diagnosed when a cancer has progressed further.

In 2017, over half of all cases of cervical cancer (54%) were diagnosed at stage I, and more than 8 in 10 breast cancer cases (82%) were diagnosed at either stage I or II. Similar trends were observed for prostate cancer, where slightly more than 7 in 10 cases (71%) were diagnosed at stage I or stage II.

Lung cancer was more likely to be diagnosed at a later stage, with over two-thirds of cases (67%) diagnosed at either stage III or IV. However, this reflects an improvement. While lung cancer was still typically diagnosed at a later stage than other cancers, in 2017, a larger proportion of cases were diagnosed at stage I (23%) than in 2011 (17%), and a smaller proportion of cases were diagnosed at stage IV (47%) than in 2011 (53%).

One recent concern is that many cancer screening programs and follow-up tests were temporarily suspended at various times throughout the COVID-19 pandemic. A recent study, which projected the future impact of interruptions in colorectal cancer screening, suggests that among the 540,000 Canadians who might have missed their colorectal cancer screening between April 1 and June 30, 2020, nearly 440 could die because of colorectal cancer in the long term if there is no catch-up in screening (that is, if they have to wait until their next scheduled screening, typically every two years).

Although cancer remains the number one cause of death in Canada, the overall cancer death rate has decreased substantially over the past few decades, especially in recent years.

Now that is something worth celebrating.