Differences in biological behaviors between young and elderly patients with colorectal cancer.

Abstract

We investigated the differences in biological behaviors of sporadic colorectal cancer (CRC) between young and elderly patients. CRC is a common cancer, with a mean age at onset of > 65 years. However, recent reports indicate increasing rates in younger populations. The biological behaviors of sporadic CRC in elderly patients could differ from those in young patients. Between September 2007 and August 2012, we selected 723 CRC patients from our institution. The patients were divided into Group Y (n = 127, aged ≤50 years) and Group O (n = 596, aged >50 years). The clinicopathologic and oncologic outcomes in the two groups were compared. Group Y tumors were characterized by higher incidences of mucin production (13.4% vs. 6.7%; P = 0.017), high microsatellite instability (MSI-H) (19.8% vs. 5.2%; P < 0.001), and N2 stage (32.3% vs. 22.1%; P = 0.020) than those in Group O. The recurrence rates were similar in both groups (14.9% vs. 17.3%; P = 0.665). The 5-year overall survival and disease-free survival did not differ. Multivariate analysis indicated that cellular differentiation and pathologic stage were significant prognostic factors for 5-year overall survival. Although age was not a prognostic factor for overall survival and young patients did not show a worse prognosis, there were differences in mucin production, MSI-H, and N2 stage between the two groups. Further studies are needed to clarify the clinical and biological characteristics of CRC, improve its treatment strategies, and promote better outcomes in young patients.