Purpose: There is no established diagnostic approach to rule out cancer in patients who present with involuntary weight loss in the absence of other symptoms (isolated involuntary weight loss). We sought to evaluate the efficiency of various diagnostic studies used in these patients.
Methods: We studied 306 patients referred to an urban tertiary care teaching hospital for isolated involuntary weight loss, 276 of whom were followed for at least 1 year or until a final diagnosis was reached. We collected data about the diagnostic approach, the causes of unintentional weight loss, and survival.
Results: Of the 276 patients, 104 (38%) had cancer, mainly of the digestive system (54%, n = 56). The first diagnostic clue usually came from routine blood tests (complete blood count, erythrocyte sedimentation rate, and a biochemical profile), which led to a more targeted diagnostic procedure, such as abdominal ultrasonography, computed tomography, and gastrointestinal endoscopy. Only 2 patients with cancer had normal results in all of these tests. Nine of the patients with cancer were not detected during the initial evaluation. Median survival was 2 months among patients with cancer, and only 9 survived longer than 1 year.
Conclusion: These results suggest that a clinical approach, including routine laboratory tests (complete blood count, erythrocyte sedimentation rate, and serum albumin, aminotransferases, gamma-glutamyl transpeptidase, alkaline phosphatase, and lactate dehydrogenase levels) and abdominal ultrasonography, seems to be appropriate for detecting the majority of cases of cancer among patients with isolated involuntary weight loss.