Rare cancers in Canada, 2006-2016: A population-based surveillance report and comparison of different methods for classifying rare cancers.

•There was an annual average of 154,900 cancer diagnoses among Canadians, 2006−2016.•The proportion of rare cancers ranged 9.7–52.5 % using different definitions of rare.•Estimated burden of rare cancers was stable across cancer classification schemes with a lower incidence threshold.•The probability of having a rare cancer was low when cancers were defined by histology vs site.•The effect of sex on probability of having a rare cancer varied by age.