Younger patients with advanced colon cancer don't live longer than older patients, but it's unclear why, researchers say.
The authors of the new study said they were surprised by the findings, which come as colon cancer rates are on the rise among young Americans.
"As a group, younger patients are more physically active and have higher performance status and are better able to perform the activities of daily living than older patients. They also tend to be treated with higher doses of therapy and have less severe side effects," said study senior author Dr. Kimmie Ng. She is director of the Dana-Farber Cancer Institute's Young-Onset Colorectal Cancer Center, in Boston.
"This is the first study to compare survival in younger versus older patients participating in a clinical trial of treatment for metastatic colorectal cancer," Ng said in an institute news release.
For the study, the researchers compared the survival times of more than 500 patients younger than 50 and more than 1,800 patients older than 50 who took part in a clinical trial that assessed a combination of chemotherapy and biologic therapy in patients with advanced (metastatic) colon cancer.
Study co-author Dr. Marla Lipsyc-Sharf said, "We found no significant difference in overall survival between the two groups."
Median overall survival was 27.07 months among the younger patients and 26.12 months among the older patients, the findings showed. Progression-free survival -- how long patients lived before the cancer worsened -- was 10.87 months for the younger patients and 10.55 months for the older ones.
The researchers also found that patients younger than 35 had the shortest median overall survival of any age group: 21.95 months versus 26.12 months in older patients.
The study included relatively few patients younger than 35, so the difference is not considered statistically significant. Still, the findings match previous research suggesting that very young patients have worse outcomes, according to the authors.
The report was published Oct. 27 in the Journal of the National Cancer Institute.
The findings suggest that colon cancer may be more aggressive at an earlier age, but further research is needed to confirm that.
Learning more about colon cancer in younger people is important because cases in Americans younger than 50 rose from 6% in 1990 to 11% in 2013, even as overall incidence fell, according to the American Cancer Society.
"If current trends hold, colorectal cancer is projected to be the second leading cancer and leading cause of cancer death in patients ages 20 to 49 by the year 2040," Lipsyc-Sharf said. "It is important to understand survival in this population in order to develop tailored treatments."
The American Cancer Society has more on colon cancer.
SOURCE: Dana-Farber Cancer Institute, news release, Oct. 27, 2021