Young-age onset colorectal cancer: Analysis of incidence, clinical features and outcomes

Abstract

Background: Recent studies suggest an increase in the incidence of colorectal cancer (CRC) in young-age patients. Data concerning clinical behavior, pathologic findings and prognosis are still poorly understood for this age group. The aim of this study is to analyze clinical features and survival of the young-onset CRC population in our institution. Method(s): We retrospectively reviewed records of 5,806 patients diagnosed with CRC between January/2011 and November/2016 in Instituto do Cancer do Estado de Sao Paulo and identified 781 patients aged 50 years or younger Kaplan-Meier method was used to estimate overall survival (OS) and uni/multivariate analysis were carried out to identify factors associated with OS. Result(s): We found an absolute increase in the incidence of CRC in patients <50 years by 1.88% to 2.23% annually (2011-2012: 11.6%; 2013-2014: 13.5%; 2015-2016: 15.7%) with a relative increase of 35.3% between 2011 and 2016. Median age was 42 years (17- 49), 57.4% were female and 20.9% reported family history (FH) of CRC. Mismatch repair (MMR) protein immunohistochemical analysis were performed in 466 patients and 78 (16.7%) hadMMRdeficient CRC. Left-sided tumors were more frequent (left colon 8.2%, sigmoid 33.7% and rectum 31.5%), whereas the incidence of right-sided tumors was 19.4%. Almost all of patients were symptomatic (93.9%) and abdominal pain (39.6%) and rectal bleeding (28.7%) were common. MMR deficiency was associated with better OS (p=0.029). The stage distribution was stage I 2.6%, II 25.8%, III 34.1% and IV 37.5%. The median OS of stage IV was 25 months (CI95% 20.7-29.3) and not reached for I-III (p<0.001). FH of CCR (p=0.021) and adjuvant chemotherapy (p<0.001) were independently associated with better OS in stage IV. For stages I-III, wild-type KRAS (p=0.003), FH of CCR (p=0.024) and absence of lymphovascular invasion (p<0.001) were associated with better OS. Conclusion(s): In our experience, the incidence of early-onset CRC is increasing. Young patients were more likely to be diagnosed with metastatic disease, left-sided/rectumsite and symptoms at presentation. These findings highlight the emerging importance of young-age onset CRC and the need to discuss strategies to early diagnosis.