Obesity and weight loss at presentation of lung cancer are associated with opposite effects on survival.

BACKGROUND

Lung cancer is the second most common neoplasm and the leading cause of cancer deaths in the United States. In cancer, weight loss and obesity are associated with reduced survival. However, the effect of obesity or weight loss at presentation on lung cancer survival has not been well studied.

MATERIALS AND METHODS

Using an extensive cancer dataset, we identified 76,086 patients diagnosed with lung cancer during the period of 1998-2002, of which 14,751 patients presented with obesity and/or weight loss. We examined the relationship between survival and weight loss or obesity at diagnosis using univariate and multivariate analysis.

RESULTS

Median survival time (MST) for all lung cancer patients was 8.7 mo. Patients presenting with weight loss (15.8%) had shorter MST versus those who did not (6.4 versus 9.2 mo, P < 0.001) and patients with weight loss had significantly shortened MST for all stages and histologic subtypes. In contrast, obese patients at presentation (5.4%) had longer MST relative to non-obese patients (13.0 versus 8.6 mo, P < 0.001), which was significant across all stages and histologic subtypes. Multivariate analysis revealed that the absence of weight loss was an independent, positive predictor of improved survival (HR = 0.087, P < 0.001), while the absence of obesity was an independent predictor of worsened survival in lung cancer (HR = 1.16, P < 0.001).

CONCLUSIONS

Our results demonstrate an inverse relationship between survival and weight loss at presentation and a potentially protective effect of obesity in lung cancer survival, which could be due to greater physiologic reserves, thereby prolonging life by slowing the progress of cancer cachexia.