Unintentional Weight Loss as a Marker of Malignancy Across Body Weight Categories

Weight loss has long been known to be associated with multiple chronic conditions, including heart failure, COPD, depression, and cancer. Recent reports have suggested that unintentional weight loss (UWL) could be leveraged as an early marker of malignancy. Most studies use standardized cutoff values of ≥5% weight loss to define UWL; however, this threshold has not been validated in different body weight classifications (underweight, overweight, etc.). The purpose of this review was to describe the association between a patient’s weight category, the severity of UWL prior to cancer diagnosis, cancer stage at diagnosis, and cancer-specific mortality. Obesity has been identified as a risk factor for many malignancies. Current data are conflicting about whether patients with obesity are more or less likely to experience UWL prior to diagnosis of a malignancy. Similarly, data analyzing the association between baseline BMI and cancer stage at diagnosis or cancer-specific mortality are mixed. UWL has been associated with an increased risk of all-cause mortality, independent of baseline BMI. Unfortunately, reliable body weight measurements are infrequently obtained, decreasing the likelihood that UWL would be detected clinically. Weight loss, when unintentional, is a serious condition which requires prompt clinical evaluation. Future studies are needed to objectively quantify UWL among patients with varying baseline BMI.