Left-sided early onset colorectal carcinomas: A sporadic neoplasm with aggressive behavior

Background Early onset (≤50y) colorectal carcinomas (EO-CRCs) are increasing in incidence according to epidemiological data. We investigated clinical-pathological, molecular features and outcomes of 62 left sided EO-CRCs (EOLS-CRCs) and compared them to a group of late onset (≥65) LS-CRCs (LOLS-CRCs). Materials and methods Samples were evaluated for pathological features and microsatellite instability (MSI). Overall survival (OS), disease free survival (DFS) and disease specific survival were evaluated in both groups. Results Five out 62 (8%) EOLS-CRCs showed MSI phenotype. Interestingly these cases were aged 26–39y. Most EOLS-CRCs present at advanced stage and this was statistically significant when compared to LOLS-CRCs. OS was better in EOLS-CRCs whilst DFS showed a worst profile in EOLS-CRCs either in low and high stages even though young patients were treated more often with adjuvant chemotherapy compared to older ones at the same disease stage. Conclusions Most EOLS-CRCs are sporadic non Lynch, microsatellite stable (MSS) CRCs. Our data show that when compared with LOLS-CRCs the early group represents an aggressive disease with worst outcome underlining a possible different carcinogenic pathway.