Abstract 2364: Clinical characteristics and outcomes of colorectal cancer in the ColoCare Study: Differences by age of onset (2020)

Abstract PURPOSE: The ColoCare Study is an international cohort of men and women (&amp;gt;18 years age) newly diagnosed with stage I-IV colorectal cancer from seven centers in the United States and Germany. Study enrollment is currently ongoing. Here, we describe the clinical and demographic characteristics of this large cohort of prospectively followed colorectal cancer patients and describe differences in demographic, lifestyle, and clinical characteristics by age of onset and tumor site. METHODS: Data on demographics (sex, age, race, ethnicity) and lifestyle factors (smoking, body mass index) collected at baseline are included in this analysis, in addition to information on tumor characteristics (tumor stage and site), treatment (neoadjuvant and adjuvant therapy), and clinical outcomes (vital status, recurrence). Patients were categorized into early- (&amp;lt;50 years) vs. late-onset (≥50 years) cancers. Tumor site was categorized into colon and rectal cancers. Frequencies and percentages for categorical variables, and mean and standard deviations for continuous variables were calculated and compared by age of onset and tumor site. Notable differences are described here. RESULTS: Data on 1,933 stage I-IV colorectal cancer cases were included in this study, 19% of which were deceased at the time of this analysis. On average, patients were 60 years old, had a BMI of 29 kg/m2, and were predominantly diagnosed with stage II (25%) and stage III (33%) colorectal cancer. Fifty three percent of cases were diagnosed with colon cancer, while 47% were rectal cancer cases. Twenty percent (n=364) of patients were diagnosed before age 50 (i.e. early-onset cases). The early-onset group presented with a higher percentage of rectal cancer (52%) and more advanced disease (64% stage III-IV cancer) compared to late-onset cases (46% and 48%, respectively). Percentages of ever smokers were higher among late-onset compared to early-onset patients (51% vs. 38%), independent of tumor site. Early-onset cancers were more likely to originate in the rectum compared to colon, particularly among women (61% vs. 51%). Early-onset rectal cancer cases were more likely to be female as compared to late-onset rectal cancer cases (61% vs. 36%). Corresponding with national trends, early-onset cases received more aggressive adjuvant therapy after surgical resection compared to late-onset patients (54% vs. 40%). DISCUSSION: Within this large international multi-center cohort, patients with early-onset colorectal cancer were more likely to be diagnosed with rectal cancer and advanced stage disease. The majority of early-onset cases in the ColoCare Study were non-smokers. As expected, more aggressive treatment modalities were used in patients with early-onset disease. Citation Format: Caroline Himbert, Jane Figueiredo, Lyen Huang, Biljana Gigic, Courtney L. Scaife, Bartley Pickron, Laura Lambert, Jessica Cohan, Mary Bronner, Jolanta Jedrzkiewicz, Esther Herpel, Matthias Kloor, Johanna Nattenmueller, Hans-Ulrich Kauczor, Alexis Ulrich, Seth Felder, Julian Sanchez, Sophie Dessureault, Nathan Hinkle, Justin Monroe, Matthew Mutch, Cory Bernadt, Deyali Chatterjee, Mika Sinanan, Stacey Cohen, Ulrik Wallin, Deepti Reddi, Mukta Krane, Afshin E. Gabayan, David M. Hoffman, Yosef Y. Nasseri, Robert W. Decker, Karen Zaghiyan, Zuri A. Murrell, Andrew E. Hendifar, Jun Gong, Eiman Firoozmand, Alexandra Gangi, Beth A. Moore, Kyle G. Cologne, Maryliza El-Masry, William Grady, Martin Schneider, Stephanie L. Schmit, Erin Siegel, David Shibata, Adetunji Toriola, Christopher Li, Cornelia Ulrich, Sheetal Hardikar. Clinical characteristics and outcomes of colorectal cancer in the ColoCare Study: Differences by age of onset [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2364.