Clinicopathological characteristics of early onset colorectal cancer

BACKGROUND: The rising incidence of early onset colorectal cancer (EOCRC) might reflect a novel tumour entity. AIMS: To evaluate clinicopathological characteristics of sporadic EOCRC (in patients < 50 years old) and investigate changes over time METHODS: All patients with sporadic EOCRC between 1989 and 2016 were included and divided by age: 20‐29 years (group I), 30‐39 years (group II) and 40‐49 years (group III). RESULTS: We included 6400 patients. The presence of signet‐ring cells and more poorly differentiated tumours were more common in the younger age groups: 5.4% and 3.7% for signet‐ring cells in group I and II vs 1.4% in group III (P < 0.01), and 28.5% and 20.3% for poorly differentiated in group I and II vs 16.6% in group III, (P < 0.01 group I; P = 0.07 group II). Positive lymph nodes were more frequently observed in the younger age groups: 16.2% in group I vs 9.3% in group II (P = 0.01) and 7.9% (P < 0.01) in group III. Over time, a greater proportion of CRCs were diagnosed in women in group I (34.5% < 2004 vs 54.9%>2005, P = 0.09), and a higher percentage of rectal cancer was found in age group III (34.3% < 2004 vs 40.7% > 2005, P < 0.01). Mean overall survival was 6.3 years and improved over time. CONCLUSIONS: EOCRC is not only characterised by age of onset but also by the more frequent presence of signet‐ring cells, more poorly differentiated tumours, and higher risk of lymph node metastases. In the most recent years, a higher proportion of rectal cancer was found from the age of 30 years, and a higher proportion of CRCs were diagnosed in females below the age of 30 years.