The interaction of sex, age and ethnicity has a significant impact on overall survival in metastatic colorectal cancer (MCRC) patients, a study led by researchers at the University of Southern California (USC) and USC/Norris Comprehensive Cancer Center suggests.
While age and ethnicity are well-established factors that impact survival in colorectal cancer, the study found that gender also plays an important role in overall survival, says Andrew Hendifar, M.D., MPH, fellow in the division of hematology/oncology at the Keck School of Medicine of USC and lead author of the study. Researchers found that pre-menopausal women with metastatic colorectal cancer (18-44 years old) lived longer than younger men, while older women (75 and older) had significantly worse overall survival than older men.
The results of the study will be presented at a poster discussion Sunday, June 1, at the 2008 annual meeting of the American Society of Clinical Oncology (ASCO) held at McCormick Place in Chicago.
The study adds to the growing evidence that female hormones are protective for colon cancer, researchers say.
"This study provides further evidence that estrogen may play an important role not only in colon cancer development but also progression of the disease, and may impact how we develop therapies for women and men with colon cancer," says Heinz-Josef Lenz, M.D., professor of medicine at the Keck School of Medicine and a senior investigator on the study.
Researchers screened 56,598 patients with metastatic colorectal cancer from 1988 to 2003, using the Surveillance, Epidemiology and End Results (SEER) registry. Models were created using the patients' age at diagnosis, sex, ethnicity and overall survival.
Independent of age, there were no survival differences between men and women with MCRC. However, when age was added to the model, sex became significantly associated with survival across all ethnicities.
Researchers also found that certain ethnicities had better overall survival than others. Namely, Hispanics and Asians have better outcomes than Caucasians and African-Americans. Further studies in this area should look at how certain diets or specific surroundings contribute to the development of colorectal cancer, Hendifar notes.
"The data warrant further studies to determine the role of estrogen and ethnicity in colorectal cancer development," he says. "In the future, we may tailor different treatments for men and women."