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Background: Colorectal cancer (CRC) diagnosed at or before age 50 (early-onset) is increasing in the United States. Early-onset CRC is associated with more advanced stage disease at diagnosis compared to CRC diagnosed at or after 50 years of age (late-onset).
Purpose: To compare the occurrence of early-onset and late-onset CRC at our center from 2000 to 2011 and identify characteristics associated with early-onset CRC.
Methods: We retrospectively studied all patients diagnosed with CRC at our center from January 2000 to January 2011 using our cancer registry database. Patients were defined as early-onset or late-onset CRC based on age at diagnosis. Additional variables were recorded including demographic data, personal or family history of CRC or other cancers, alcohol and tobacco use, tumor location by colonic subdivision and tumor stage at diagnosis. Univariate analysis (Pearson's Chi-square or Kendall's tau-b tests) was used to identify factors associated with early onset CRC. Multivariate analysis (Cox proportional hazards regression) determined independent predictors of early-onset CRC.
Results: We identified total 2,147 patients, of these, 1,057(49.2%) were male, 1,898 (88.4%) had late-onset CRC and 249 (11.6%) had early-onset CRC. 1,447 patients (67.4%) were Caucasian, 111 (5.2%) African American, and 589 (25.4%) Asian. Tumor was located in the appendix in 21 (1%), cecum in 275 (12.8%), ascending colon in 207 (9.6%), hepatic flexure in 102 (4.8%), transverse colon in 134 (6.2%), splenic flexure in 79 (3.7%), descending colon in 90(4.2%), sigmoid colon in 431(20.1%), rectosigmoid junction in 166 (7.1%), and rectum in 592 (27.7%). At diagnosis, 170 patients (7.9%) had carcinoma in situ, 553 (25.8%) stage I, 57 (24.1%) stage 2, 489 (22.8%) stage 3, and 291 (13.6%) stage 4. The prevalence of early-onset CRC increased from 11.4% to 16% during the study period (p=0.157). Patients with early-onset CRC had more rectal tumors than patients with late-onset CRC (48.6% vs. 33.3%, p<0.001), higher rate of recurrence (34.7% vs. 23.6%, p<0.001), and more advanced tumor stage at diagnosis (p<0.001). Independent predictors of early-onset CRC included 1st (aOR 1.8 (1.1-2.9), p=0.016) and 2nd (aOR 5.4 (2.9-10.1), p<0.001) degree family history of CRC and receiving chemotherapy (aOR 3.5 (2.44-5.43), P<0.001). History of smoking, cancer in sigmoid colon, and stage 1 and 2 diseases were less associated with early-onset CRC on the multivariate analysis.
Conclusion: Patients with early-onset CRC had more rectal tumors, more advanced stage disease at diagnosis and a higher rate of recurrence. These patients more frequently had a family history of CRC but less frequently had a history of smoking. Early-onset CRC is an aggressive disease that portends a poor prognosis. Further work is merited to identify additional risk factors for this disease.