University of Texas Health Science Center at Houston Houston, TX, United States
Caitlin C. Murphy, PhD, MPH1, Sandi L. Pruitt, PhD, MPH2, Himani R. Radadiya aka Patel, MPH2 1University of Texas Health Science Center at Houston, Houston, TX; 2University of Texas Southwestern Medical Center, Dallas, TX
Introduction: Incidence rates of colorectal cancer (CRC) are increasing in younger (age < 50 years) adults, but little is known about mechanisms contributing to this increase. At the same time, the number of persons diagnosed with multiple cancers has increased in the U.S., raising questions about the etiology of multiple cancers and outcomes of this population. We characterized patterns of multiple cancers among persons newly diagnosed with early-onset CRC in a population-based sample.
Methods: We identified persons newly diagnosed with early-onset CRC in 2013-2017 using population-based data from the Surveillance, Epidemiology, and End Results program of cancer registries. We used sequence numbers to determine the order of all reportable cancers in a lifetime and categorized patterns of multiple cancers as: 1) previous CRC; 2) previous cancer of a different type; and 3) both previous CRC and cancer of a different type. For those previously diagnosed with cancer of a different type, we also described common types of and time since previous cancer.
Results: A total of 6,586 persons were newly diagnosed with early-onset CRC in 2013-2107 (mean age 42.3 years, 53.5% men, 58.2% non-Hispanic white). Of these, 50 (0.8%) had a previous CRC, 186 (2.8%) had a previous cancer of a different type, and only 2 (0.03%) had both. Most previous cancers of a different type were diagnosed more than five years prior to early-onset CRC (n=100, 53.8%), and about 10% (n=16) were diagnosed in childhood (age < 18 years). As shown in Figure 1, common types of previous cancers included: breast (15.6%), thyroid (12.9%), testicular (10.8%), uterine (5.9%), and cervical (4.3%) cancer, melanoma (7.0%), and lymphoma (5.9%).
Discussion: Some persons newly diagnosed with early-onset CRC have survived a previous cancer, and most previous cancers were of a different type. Although the proportion is small, patterns of multiple cancer highlight underlying conditions that may be amenable to targeted screening and surveillance, including: genetic predisposition (e.g., previous uterine cancer, related to Lynch syndrome) or late effects of treatment (e.g., previous lymphoma, related to treatment with radiation therapy to the abdomen or pelvis). Shared behavioral and environmental risk factors, such as obesity, may also contribute to observed patterns. Additional research is needed to inform screening and surveillance recommendations for cancer survivors who may have higher risk of early-onset CRC.
Figure: Figure 1. Common types of previous cancers among those newly diagnosed with early-onset colorectal cancer
Caitlin Murphy: Freenome – Consultant.
Sandi Pruitt indicated no relevant financial relationships.
Himani Radadiya aka Patel indicated no relevant financial relationships.
Caitlin C. Murphy, PhD, MPH1, Sandi L. Pruitt, PhD, MPH2, Himani R. Radadiya aka Patel, MPH2. P0148 - Patterns of Multiple Cancers Among Persons Newly Diagnosed With Early-Onset Colorectal Cancer, ACG 2021 Annual Scientific Meeting Abstracts. Las Vegas, Nevada: American College of Gastroenterology.