The changing epidemiology of colorectal cancer and its relevance for adapting screening guidelines and methods.

In many countries at risk for colorectal cancer (CRC), screening guidelines provide average-risk screening for patients aged between the ages of 50 and 75 years. However, an earlier onset of CRC, an increasing life span and an incidence of right-sided CRC have been noted, which could require changes in age guidelines and screening methodology, especially for the elderly. We examined this in our Jewish populations using Israel Cancer Registry data, 1980-2008, computed by age groups, sex, ethnic groups, cancer site, and cancer stage. In patients who were below 50 years of age, there was no significant increase in incidence except for men born in Israel (P=0.05). In patients aged between 50 and 74 or more than 75 years there was an increased incidence (P<0.001 for both). However, the percentage for CRC patients aged between 50 and 74 years decreased but those who were aged more than 75 years increased (P<0.001 for both). Therefore, 45.3% of patients (39.1% aged ≥ 75 years) would not be electively screened. In addition, there was an increased trend (P<0.001) for right-sided (from cecum to and including the splenic flexure) CRC in patients both 50-74 and more than 75 years old. During 1999-2008, as compared with patients aged between 50 and 74 years, those below 50 years were less likely to be diagnosed with stage 1 or 2 CRC and more likely have stage 3 or 4 CRC (P<0.01 for all), whereas those aged more than 75 years were less likely to have stage 3 CRC (P<0.01). These results should influence CRC screening age guidelines, especially for 'healthy' individuals aged 75 years or more, and their need for noninvasive, but sensitive and specific pre-colonoscopy screening methodologies. In addition, the more advanced cancer stage in the patients aged below 50 years needs to make the treating physicians more aware of the fact that CRC can occur even at this age.