Epidemiology, risk factors and impact of cachexia on patient outcome: Results from the Japanese Lung Cancer Registry Study.

Background: Cancer cachexia is a syndrome that does not fully recover with nutritional support and causes appetite loss and body weight loss. It worsens a patient's quality of life and prognosis. In this study, the epidemiology of cachexia in lung cancer, its risk factors and its impact on chemotherapy response rate and prognosis were examined using the national database of the Japan Lung Cancer Society. Understanding these things related to cancer cachexia is important as a starting point in overcoming cancer cachexia in patients with lung cancer.

Methods: In 2012, 12 320 patients from 314 institutions in Japan were registered in a nationwide registry database (Japanese Lung Cancer Registry Study). Of these, data on body weight loss within 6 months were available for 8489 patients. We defined the patients with body weight loss ≥ 5% within 6 months, which is one of the three criteria listed in the 2011 international consensus definition of cancer cachexia, as cachectic in this study.

Results: Approximately 20.4% of the 8489 patients had cancer cachexia. Sex, age, smoking history, emphysema, performance status, superior vena cava syndrome, clinical stage, site of metastasis, histology, epidermal growth factor receptor (EGFR) mutation status, primary treatment method and serum albumin levels were significantly different between patients with and without cachexia. Logistic analyses showed that smoking history, emphysema, clinical stage, site of metastasis, histology, EGFR mutation, serum calcium and albumin levels were significantly associated with cancer cachexia. The response to initial therapy, including chemotherapy, chemoradiotherapy or radiotherapy, was significantly poorer in the patients with cachexia than in those without cachexia (response rate: 49.7% vs. 41.5%, P < 0.001). Overall survival was significantly shorter in the patients with cachexia than in those without cachexia in both univariate and multivariable analyses (1-year survival rate: 60.7% vs. 37.6%, Cox proportional hazards model, hazard ratio: 1.369, 95% confidence interval: 1.274-1.470, P < 0.001).

Conclusions: Cancer cachexia was seen in approximately one fifth of the lung cancer patients and was related to some baseline patient characteristics. It was also associated with a poor response to initial treatment, resulting in poor prognosis. The results of our study may be useful for early identification and intervention in patients with cachexia, which may improve their response to treatment and their prognosis.