This is no longer to be proven, overweight and obesity are risk factors for many cancers, including colorectal cancer. However, and this is an astonishing paradox, excess weight would be rather beneficial for the survival of patients with this cancer.
A new American study presented at the international congress of the European Society for Medical Oncology on gastrointestinal cancer reveals that thin patients with colorectal cancer have a lower survival rate than obese patients.
To arrive at this paradoxical conclusion, researchers at Duke University (North Carolina, United States) followed 6,128 patients treated for metastatic colorectal cancer, at body mass index (BMI)mean 25.3 (slightly overweight) at the start of treatment. All patients received the same chemotherapy.
Scientists divided the patients into three categories based on BMI and measured their survival rate as well as the time it takes for their tumors to stop growing.
Result: the patients with the lowest BMI (between 20 and 24.9 kg / m²) – and therefore a priori with the most favorable BMI – had the shortest survival rate, with 21.1 months after the start of treatment. Patients with a BMI between 25 and 29 (corresponding to a overweight) had a survival rate of 23.5 months on average, compared to 24 months for patients with a BMI between 30 and 35 (moderate obesity). Finally, patients with a BMI greater than 35.1 had a survival rate of 23.7 months. In the end, the thinnest patients had a survival rate of at least two and a half months lower than overweight or obese patients.
However, the study does not say that being overweight is a good way to survive for cancer patients. According to the authors, the results rather suggest that there is a biological factor that would disadvantage the thinnest patients.
“There may be a link between having a lower BMI and the way you respond to treatment,” suggests Professor Yousuf Zafar, co-author of the study. “I would hypothesize that the lower-weight patients in our experiment tolerated the treatment less well, or received adequate treatment initially, and then became ill with additional treatment. This is undoubtedly what we must focus our efforts on to improve their results. “
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