Low BMI Linked to Poorer Survival in Colorectal Cancer

Though a high body mass index (BMI) is a risk factor for colorectal cancer, a new study has found that in patients diagnosed with metastatic colorectal cancer, a low BMI could be a poor prognostic factor. Among a group of patients with metastatic colorectal cancer, those with the lowest BMI had a shorter median survival, according to the results of a pooled analysis (abstract LBA-01) presented at the European Society for Medical Oncology (ESMO) 17th World Congress on Gastrointestinal Cancer in Barcelona.

These results were taken from a group of 6,128 patients from the prospective BEAT, BRiTE, AWB, CONCERT, and ARIES studies, which looked at patients with previously untreated metastatic colorectal cancer who received treatment with bevacizumab and chemotherapy.

“There is good evidence that obesity increases the risk of getting colorectal cancer and that it increases the risk of colorectal cancer recurrence after curative therapy,” said lead study author Yousuf Zafar, MD, associate professor of medicine at Duke Cancer Institute, in a prepared statement. “What we did not know prior to these results is whether there is a relationship between obesity and survival in patients with metastatic colorectal cancer.”

In the study, Zafar and colleagues classified patients according to a BMI of < 25, 25 to < 30, 30 to 35, and 35 or greater. The median BMI for all patients was 25.3 kg/m².

Those patients with the lowest BMI (< 25) had a median overall survival of 21.1 months compared with 23.5 months for a BMI of 25 to < 30, 24 months for 30 to 35, and 23.7 months for patients with a BMI of 35 or higher.

Commenting on the data, ESMO spokesperson Roberto Labianca, MD, director of the Cancer Centre, Ospedale Giovanni XXIII in Bergamo, Italy, said: “This study is important because we can now consider BMI as a prognostic factor for patients with metastatic colorectal cancer. The clinical implication could be that patients with low BMI should be considered similar to patients with more aggressive cancer and probably they should be given more active treatment.”

The researchers found that progression-free survival was similar across all of the groups.

“It’s possible that the lowest-weight patients may receive adequate first-line treatment but then are too sick to receive subsequent lines of therapy,” said Zafar. “That may be where we can focus more attention on improving their outcomes.”