Importance The overall incidence of colorectal cancer (CRC) has been decreasing since 1998, but there has been an apparent rise in the incidence of CRC in young adults. Objective To evaluate age-related disparities in secular trends in CRC incidence in the United States. Design A retrospective cohort study using the Surveillance, Epidemiology, and End Results (SEER) CRC registry. Age at diagnosis was analyzed in 15-year intervals starting at the age of 20. SEER*Stat was used to obtain the annual cancer incidence rates, annual percent change (APC), and corresponding p-values for the secular trends. Setting Data was obtained from the National Cancer Institute’s SEER registry. Patients All patients diagnosed with colon or rectal cancer from January 1, 1975 through December 31, 2010 (N = 393,241). Main Outcome Difference in CRC incidence by age. Results Overall age-adjusted CRC incidence rate decreased by 0.92% between 1975 and 2010. There has been a steady decline in the incidence of CRC in patients age 50 years or older, but the opposite trend has been observed for young adults. For patients 20 to 34 years of age, the incidence rate of localized, regional and distant colon and rectal cancer has increased. Increasing incidence rate was also observed for rectal cancer patients aged 35 to 49. Based on current trends, in 2030 the incidence rate for colon and rectal cancer will increase by 90.0% and 124.2% for patients 20 to 34 years of age and by 27.7% and 46.0% for patients 35 to 49 years of age. Conclusion and Relevance There has been a significant increase in the incidence of CRC diagnosed in young adults, with a decline in older patients. Further studies are needed to determine the cause for these trends and identify potential preventive and early detection strategies.

Treatment response to neoadjuvant chemoradiotherapy among patients with locally advanced rectal cancer undergoing radical resection is an early surrogate marker and correlate to oncologic outcomes. These data provide guidance with response-stratified oncologic benchmarks for comparisons of novel treatment strategies.

Purpose We evaluated clinical features and survival outcomes among patients with signet ring and mucinous histologies of colorectal adenocarcinoma using data from the National Cancer Data Base (NCDB). Methods Patients aged 18–90 years with colorectal adenocarcinoma diagnosed between 1998 and 2002 were identified from the NCDB. Site-stratified (colon vs rectum) survival analysis was performed using multivariate relative survival adjusted for multiple clinicopathologic and treatment variables. Results The study included 244,794 patients: 25,546 (10%) with mucinous, 2,260 (1%) with signet ring, and 216,988 (89%) with nonmucinous, non–signet ring adenocarcinoma. Mucinous and signet ring cancers were more frequently right-sided (60% and 62%, respectively) than were nonmucinous, non–signet ring adenocarcinomas (42%, P < .001). Signet ring histology was associated with a higher stage (P < .001), and 77.2% of signet ring tumors were high-grade lesions, compared with 20% of mucinous and 17% of non–signet ring, nonmucinous adenocarcinomas (P < .001). After adjustment for covariates, signet ring histology was independently associated with higher risk of death (HR 1.42, 95% confidence interval [CI] 1.33-1.51, and HR 1.57, CI 1.38-1.77, for tumors located in the colon and rectum, respectively). Mucinous tumors of the rectum (HR 1.22, CI 1.16-1.29), but not the colon (HR 1.03, CI 1.00-1.06), were associated with increased risk of death. Conclusion Signet ring cell adenocarcinomas of the colon and rectum and mucinous adenocarcinomas of the rectum are associated with poorer survival. These aggressive histologic variants of colorectal adenocarcinoma should be targeted for research initiatives to improve outcomes.

BACKGROUND: The objective of the current study was to examine the impact of adherence to guidelines on stage‐specific survival outcomes in patients with stage III and high‐risk stage II colon cancer. The National Comprehensive Cancer Network (NCCN) has established working, expert consensus, and evidence‐based guidelines for organ‐specific cancer care, including care of patients with colon cancer. METHODS: Patients who were diagnosed with colon adenocarcinoma between 1998 and 2002 were selected from within the National Cancer Data Base. The cohort was limited to patients who received their first course of treatment at the reporting facility. Pathologic variables, including tumor depth, lymph node status, and evidence of metastatic disease, were used to restage patients, and the patients were divided into low‐risk and high‐risk categories on the basis of criteria defined by the NCCN. Relative survival rates were calculated for the entire cohort, stratified according to adherence versus nonadherence to NCCN treatment guidelines. RESULTS: In univariate analysis of treatment adherence patterns for both patient subgroups (high‐risk stage II and stage III), several factors were associated with a higher rate of nonadherence in both groups, including older age (P < .001); Medicaid, Medicare, or uninsured status versus private insurance (P < .001); and subsequent treatment at a facility other than the facility at which the cancer was first diagnosed (P < .001). In multivariate analysis, multiple factors were associated with differences in relative survival, although analyses that included the year of diagnosis did not demonstrate significant differences over time. CONCLUSIONS: The current study documented practice patterns in a heterogeneous population of patients with colon cancer and demonstrated a survival benefit for patients with stage III and high‐risk stage II colon cancer who received treatment that adhered to NCCN guidelines. These data validate the current NCCN practice guidelines for colon cancer and support the concept of guideline‐based metrics that can be compared across institutions to assess the quality of cancer care and to compare the quality of cancer care among institutions. Cancer 2013. © 2012 American Cancer Society.

Young adults with colon cancer received significantly more postoperative systemic chemotherapy at all stages, but they experienced only minimal gain in adjusted survival compared with their older counterparts who received less treatment. This mismatch suggests that attention should be given to long-term cancer survivorship in young adults with colon cancer because they likely face survivorship needs that are distinct from those of their older counterparts.