Clinicopathological Features and Survival Outcomes of Colorectal Cancer in Young Versus Elderly
The incidence of colorectal cancer (CRC) in young adults is rising. We aimed to analyze the clinicopathological characteristics and survival outcomes of young versus elderly CRC patients. All patients diagnosed with CRC in the Surveillance, Epidemiology, and End Results program data (1988–2011) from the United States were evaluated. They were divided into 3 groups by age at diagnosis: group 1 (20–40 years old), group 2 (41–50 years old), and group 3 (>50 years old). The clinicopathological characteristics and CRC-specific survival (CRC-SS) were evaluated and compared among the 3 groups. A total of 279,623 CRC patients were included: 6700 (2.4%) in group 1, 19,385 (6.9%) in group 2, and 253,538 (90.7%) in group 3. Young CRC patients had more tumors located in rectum, fewer cases with multiple tumors, later stage, more mucinous carcinoma and signet ring-cell carcinoma, more poor differentiated tumors, and more lymph nodes (no. 12) examined. The 5-year CRC-SS rates of patients in groups 1, 2, and 3 were 65.1%, 67.1%, and 62.8%, respectively (group 1 vs group 2, P1⁄4 0.001; group 1 vs group 3, P< 0.001; group 2 vs group 3, P< 0.001). Multivariate analysis revealed older (>50 years old) age was an independent predictor of poor prognosis (hazard ratio, 1.545; 95% confidence interval, 1.456–1.639; P< 0.001). Young CRC patients had later stage presentation and more aggressive pathological features, but better survival. CRC patients aged 41 to 50 years had best CRC-SS in contrast to patients in another 2 age groups. (Medicine 94(35):e1402) Abbreviations: CI = confidence intervals, CRC = colorectal , MD, PhD, and Jie Ping, PhD INTRODUCTION C olorectal cancer (CRC) is the third most common cancer in the United States and a major health burden worldwide. The American Cancer Society estimated that 142,820 new CRC cases and 50,830 CRC deaths occurred in 2013. In spite of these sobering epidemiological data, the annual report of 2010 cancer current status highlighted that CRC incidence rates in the United States had been dropping off. This steady decline has largely been attributed to increases in the use of CRC screening in older population. It allows for the detection and removal of colorectal polyps before they progress to cancer. As a disease predominantly affecting older individuals, 90% of all CRC have been diagnosed in patients >50 years of age. However, recent evidences suggest a constantly rising incidence of CRC in young individuals, a population not receiving routine screening. The CRC incidence per 100,000 individuals for young individuals were 0.85 (ages 20–24 years) to 28.8 (ages 45–49 years) in the United States. Consequently, the percentage of young patients in total CRC patients had been reported to range from 0.4% to as high as 35.6% in another literature review. The limited studies reveal a wide range of reported clinicopathological characteristics and prognosis for young CRC patients. Some studies have demonstrated that young CRC patients presented poor pathological features and advanced stage compared with older patients. Nonetheless, others have found no difference when tumor stage and pathological features were compared with the older population. As regards survival of young CRC patients, there is also a controversy. These controversies are partly caused by no accepted clear definition of young CRC patient. Although most studies reported on young CRC patient as one 40 years old or less, some studies used the cutoff age of 50 years old. Furthermore, the biases associated with single-institution experiences or limit sample sizes may make the published data vary markedly. In this study, we used population-based data from the Surveillance, Epidemiology and End Results (SEER) program of the National Cancer Institute in the United States to compare aracteristics, prognostic factors, and overall survival among 3 age groups (20–40, 41–50, and >50 years) of CRC patients. MATERIALS AND METHODS