Chung-Yuan Hu

IMPORTANCE: The overall incidence of colorectal cancer (CRC) has been decreasing since 1998 but there has been an apparent increase 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, SETTING, AND PATIENTS: 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 years. SEER*Stat was used to obtain the annual cancer incidence rates, annual percentage change, and corresponding P values for the secular trends. Data were obtained from the National Cancer Institute's SEER registry for all patients diagnosed as having colon or rectal cancer from January 1, 1975, through December 31, 2010 (N = 393 241). MAIN OUTCOME AND MEASURE: Difference in CRC incidence by age. RESULTS: The overall age-adjusted CRC incidence rate decreased by 0.92% (95% CI, -1.14 to -0.70) 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, the incidence rates of localized, regional, and distant colon and rectal cancers have increased. An increasing incidence rate was also observed for patients with rectal cancer aged 35 to 49 years. Based on current trends, in 2030, the incidence rates for colon and rectal cancers will increase by 90.0% and 124.2%, respectively, for patients 20 to 34 years and by 27.7% and 46.0%, respectively, for patients 35 to 49 years. CONCLUSIONS 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.

PURPOSE: Neoadjuvant chemoradiotherapy for rectal cancer is associated with improved local control and may result in complete tumor response. Associations between tumor response and disease control following radical resection should be established before tumor response is used to evaluate treatment strategies. The purpose of this study was to assess and compare oncologic outcomes associated with the degree of pathologic response after chemoradiotherapy. PATIENTS AND METHODS: All patients with locally advanced (cT3-4 or cN+ by endorectal ultrasonography, computed tomography, or magnetic resonance imaging) rectal carcinoma diagnosed from 1993 to 2008 at our institution and treated with preoperative chemoradiotherapy and radical resection were identified, and their records were retrospectively reviewed. The median radiation dose was 50.4 Gy with concurrent chemotherapy. Recurrence-free survival (RFS), distant metastasis (DM), and local recurrence (LR) rates were compared among patients with complete (ypT0N0), intermediate (ypT1-2N0), or poor (ypT3-4 or N+) response by using Kaplan-Meier survival analysis and multivariate Cox proportional hazards regression. RESULTS: In all, 725 patients were classified by tumor response: complete (131; 18.1%), intermediate (210; 29.0%), and poor (384; 53.0%). Age, sex, cN stage, and tumor location were not related to tumor response. Tumor response (complete v intermediate v poor) was associated with 5-year RFS (90.5% v 78.7% v 58.5%; P < .001), 5-year DM rates (7.0% v 10.1% v 26.5%; P < .001), and 5-year LR only rates (0% v 1.4% v 4.4%; P = .002). CONCLUSION: 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.

IMPORTANCE: Colon cancer is increasing among adults younger than 50 years. However, the prognosis of young-onset colon cancer remains poorly defined given significant age-related demographic, disease, and treatment differences. OBJECTIVE: To define stage-specific treatments and prognosis of colon cancer diagnosed in young adults (ages 18-49 years) vs older adults (ages 65-75 years) outside of the clinical trial setting while accounting for real-world age-related variations in patient, tumor, and treatment factors. DESIGN, SETTING, AND PARTICIPANTS: A nationwide cohort study was conducted among US hospitals accredited by the American College of Surgeons Commission on Cancer. Participants were 13 102 patients diagnosed as having young-onset colon adenocarcinoma aged 18 to 49 years and 37 007 patients diagnosed as having later-onset colon adenocarcinoma aged 65 to 75 years treated between January 1, 2003, and December 31, 2005, and reported to the National Cancer Data Base. EXPOSURES: Patients who underwent surgical resection and postoperative systemic chemotherapy of curative intent. MAIN OUTCOMES AND MEASURES: The primary end point was stage-specific relative survival, an objective measure of survival among patients with cancer, adjusting for baseline mortality rates and independent of the data on cause of death. The secondary end point was stage-specific likelihood of receiving postoperative systemic chemotherapy. RESULTS: Most young-onset colon cancer was initially seen at advanced stages (61.8% had stage III or IV). After adjusting for patient-related and tumor-related factors, young patients were more likely to receive systemic chemotherapy, particularly multiagent regimens, at all stages relative to those with later-onset disease. These odds ratios were 2.88 (95% CI, 2.21-3.77) for stage I, 3.93 (95% CI, 3.58-4.31) for stage II, 2.42 (95% CI, 2.18-2.68) for stage III, and 2.74 (95% CI, 2.44-3.07) for stage IV. The significantly more intense treatments received by younger patients were unmatched by any survival gain, which was nil for stage II (relative risk, 0.90; 95% CI, 0.69-1.17) and marginal for stage III (relative risk, 0.89; 95% CI, 0.81-0.97) and stage IV (relative risk, 0.84; 95% CI, 0.79-0.90). CONCLUSIONS AND RELEVANCE: 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.