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Colorectal cancer (CRC) is the second most common cancer in Aotearoa New Zealand, second only behind prostate cancer in men and breast cancer in woman. It is the second highest cause of cancer death behind lung cancer, with approximately the same death rate as prostate and breast cancer combined.1 In 2019, there were 3,318 colorectal cancers diagnosed in New Zealand1 and, while the overall the rate is slowly declining, early-onset colorectal cancer (EOCRC), defined as CRC in adults under the age of 50, is on the rise.2 From 1995 to 2012, early-onset rectal cancer in New Zealand men increased by 18%, and by 13% in New Zealand women.2 This pattern is not confined to New Zealand, with increases reported in at least 18 other countries; however, New Zealand is seeing the second fastest increase in incidence in the world.3 Moreover, the increase in EOCRC is occurring independently of late-onset CRC (LOCRC)35 and, if current trends continue, it has been estimated that by 2030 1 in 4 rectal cancers diagnosed will be in patients under 50.4
Clinical characteristics
EOCRC usually presents in the distal colon (sigmoid) or rectum and, compared to LOCRC, it has several distinct clinical and pathological characteristics. The vast majority (up to 95%) of EOCRC cases present with symptoms,6 the most common being rectal bleeding, change in bowel habit and abdominal pain. These cancers are thought to show more aggressive histopathologi-cal characteristics with higher rates of mucinous or signet ring histology and poorly differentiated cancers.7 EOCRC patients are more likely to present with advanced (stage 3 or 4) disease.8
Delays to diagnosis are reportedly more common in younger patients, ranging from a median time of 217 to 239 days in USA and New Zealand studies, respectively1112 In contrast, these studies also report a median time from symptom onset to diagnosis in older patients as 29 and 122 days, respectively1112 Moreover, this effect is likely to be larger if under 50s are subdivided out from the under 60s. That young people tend to not seek help when symptoms arise likely contributes to this delay, but another factor is when healthcare professionals do not adequately investigate symptoms in younger patients because they believe they are "too young" to have cancer. This can result in general...