“Patients with cancer who are cachexic by the conventional criterion (involuntary weight loss) and by two additional criteria (muscle depletion and low muscle attenuation) share a poor prognosis, regardless of overall body weight,” concluded a study in the Journal of Clinical Oncology.
Researchers assessed 1,473 patients with lung or gastrointestinal cancers at presentation for weight loss history, lumbar skeletal muscle index, and mean muscle attenuation by computed tomography. By body mass index distribution, 36% were normal weight, 35% were overweight, 17% were obese, and 12% were underweight.
“Patients in all [body mass index] categories varied widely in weight loss, muscle index, and muscle attenuation. Thresholds defining associations between these three variables and survival were determined using optimal stratification. High weight loss, low muscle index, and low muscle attenuation were independently prognostic of survival,” the investigators explained.
“Patients who possessed all three of these poor prognostic variables survived 8.4 months [95% CI = 6.5–10.3], regardless of whether they presented as obese, overweight, normal weight, or underweight, in contrast to patients who had none of these features, who survived 28.4 months [95% CI = 24.2–32.6; P < .001],” the researchers reported.
The authors noted that while the conventional view of cancer cachexia was patients who appear thin or wasted, “patients in our cohort were more commonly overweight or obese, but they often harbored occult, severe pre-existing muscle depletion.” Diagnostic imaging is important in revealing this depletion. “We feel this is of increasing importance as the world prevalence of overweight/obesity continues to climb; these patients have a survival no longer than patients who are frankly cachectic if they have simultaneous weight loss, sarcopenia, and low [muscle attenuation],” the authors wrote. ■