machado: survival predictions are based on math, science and past experience — but they aren't always accurate

when i was diagnosed with the same cancer, my doctor told me that i had a better chance of dying from being hit by a bus than dying from the cancer. it sounded promising at first, but if i thought about it too much, i became unclear of what it actually meant for me. after all, as random as being mowed down by a bus seems, it could happen. for example, in the u.k., roughly two people for every million will die in an accident involving a bus — there’s one chance in 305,644 for people living in the united states. not wildly likely, but not impossible either. so while the analogy was supposed to illustrate the low risk of dying from cml and thus ease my worry, it was such a random and obscure comparison that it didn’t give me a sense of prognosis-confidence that i could hang my hat on.

for sure, doctors do the best they can when it comes to guessing the chances of survival. it’s a skilful combination of math and science and what happened the last time they treated someone like you. using tools that help predict outcomes, research and clinical experience — probably a bit of instinct too — to inform their rhyming-off of percentages, they take somewhat educated guesses on whether your outcome will be roses and rainbows, or not. but there are other things too that can determine how much time you have, things that are difficult to include in these “guesses,” including health history, age, the stage of your disease, the effectiveness of your medication, frequency of monitoring and the quality of care you receive. even where you get care matters: research has shown that people who are treated at cancer centres live longer . add in the possible influence of a positive attitude, social support and coping abilities on slowing progression of disease and improving outcomes, and well, determining the odds of living or dying can seem like a bit of a, well, crapshoot.

certainly, you probably wouldn’t bet on a horse that had just a 10 per cent chance of winning the race, or hire a contractor who had a 90 per cent failure rate, but when it comes to whether or not your life ends, hell ya, even a one per cent chance can feel like a decent shot. and since there are so many things that influence how the game plays out for each of us, it makes perfect sense that we try, regardless of the “odds.” consider scientist stephen hawking , who lived for more than 50 years with amyotrophic lateral sclerosis (als), a devastating progressive disease that has no cure and usually kills people within two years of diagnosis or ontario-based denis raymond who has been living with glioblastoma — the same deadly brain cancer that killed the tragically hip’s gord downie — for six years, after doctors gave him little over one year to live. people do beat the “odds.” we don’t know who will, and maybe not even why they do — hopefully it’s you and i, and everyone we care about.