People who are overweight or obese are at risk of developing colorectal cancer, but according to a new study, high body mass index (BMI) can actually help prolong the survival in patients who develop the deadly disease.
The study conducted by researchers at Duke University found that overweight and obese patients lived an average of 2.5 months longer than thinner patients.
Researchers expected obese patients with colorectal cancer to respond more poorly to treatments for advanced colorectal cancer due to their increased risk of developing the disease.
Lead researcher Dr Yousuf Zafar, associate professor of medicine at Duke University, said, "Contrary to our hypothesis, patients who had the lowest BMI [body mass index] were at risk for having the shortest survival. In this case, patients with the lowest body weight — people who had metastatic colon cancer and a BMI of less than 25 — were at the highest risk."
The study involved 6,128 patients with colorectal cancer. All the participants received the anti-cancer drug Avastin along with chemotherapy in their treatment and were tracked for two years.
Patients with a BMI between 20 to 24.9, which would be considered a normal weight, survived an average of 21.1 months after starting the treatment.
Patients with a BMI range between 25 to 29, considered overweight, survived an average of 23.5 months.
Patients with BMI between 30 to 35, considered obese, survived an average of 24 months, while those with BMI of 35.1 and higher survived an average of 23.7 months.
"There may be a relationship between having a lower BMI and how much treatment patients can tolerate. I would hypothesize that the lowest weight patients in our analysis received or tolerated less treatment, or received adequate treatment at first, but became too sick to receive additional therapy. That may be where we can focus more attention on improving their outcomes," said Zafar.
The study was presented at the European Society for Medical Oncology World Congress on Gastrointestinal Cancer.