ASCO 2015: Colorectal Cancer Genetically Different in Older and Younger Patients
Although the overall rate of colorectal cancer is declining, colorectal cancer specifically among young patients is increasing. Previous studies have shown that colorectal cancer in patients younger than 50 years old tends to be more aggressive than in older patients. A University of Colorado (CU) Cancer Center study presented at the ASCO 2015 Annual Meeting (Abstract e14627) offers early evidence of genetic differences between colorectal cancer in young and old patients, possibly pointing toward different treatments and strategies in combating the disease in younger patients.
“We saw differences in two important gene-signaling pathways, PPAR and IGF1R, which are involved in regulating cell development, metabolism, and growth,” said Christopher Lieu, MD, Investigator at the CU Cancer Center and Assistant Professor of Medical Oncology at the University of Colorado School of Medicine.
Alterations in these signaling pathways have been implicated in the development of several types of cancer.
Study Findings
The study compared the genetics of five colorectal cancer tumors from younger patients (median age 31) with six tumors from older patients (median age, 73), sequencing 45 million “reads” from each tumor. The group then explored the data for significant differences between groups. In addition to the pathways PPAR and IGF1R, the study showed that younger patients’ colorectal cancer tumor samples were enriched for pathways responsible for metabolizing drugs.
“Chemotherapies challenge cancer cells, and younger people may metabolize these chemotherapies differently than older patients. This may explain why our traditional chemotherapy treatments may be less effective for younger patients with metastatic colorectal cancer,” said Todd Pitts, MS, Research Instructor in the Developmental Therapeutics Program at the CU Cancer Center, and the study's lead author.
The group plans to validate the finding of these differences in a larger patient population. Then, if PPAR and/or IGF1R prove to be important drivers of colorectal cancer in young patients, the group hopes to explore trials of drugs targeting these potential tumor drivers. Toward this goal, the group has gathered the important resource of tumor samples grown from the tissues of young colorectal cancer patients, allowing further preclinical genetic and drug testing.
“I would say that our end goal is to be able to offer better treatments for this population of young colorectal cancer patients that seems to be at higher risk from the disease,” Dr. Lieu said.
For full disclosures of the study authors, view the study abstract at abstract.asco.org.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
