Comorbidity and Karnofksy performance score are independent prognostic factors in stage III non-small-cell lung cancer: an institutional analysis of patients treated on four RTOG studies. Radiation Therapy Oncology Group.

Abstract

To determine the prognostic role of comorbidity in Stage III non-small cell lung cancer (NSCLC) treated definitively with radiotherapy alone. A total of 112 patients with clinical Stage III NSCLC (American Joint Commission on Cancer 1997) enrolled in four Radiation Therapy Oncology Group studies (83-11, 84-03, 84-07, and 88-08 nonchemotherapy arms) at a single institution were analyzed retrospectively for overall survival (OS) and comorbidity. Of the 112 patients, 105 (94%) completed their assigned radiotherapy. The median assigned dose was 50.4 Gy to the lymphatics (range 45-50.4 Gy) and 70.2 Gy to the primary tumor (range 60-79.2 Gy). Comorbidity was rated retrospectively using the Cumulative Illness Rating Scale for Geriatrics (CIRS-G) and Charlson scales. Karnofsky performance scores (KPSs) and weight loss were prospectively recorded. Because only 8 patients had a KPS of <70, these patients were combined with patients who had a KPS of 70. The OS of this group was compared with that of the patients with better KPSs (>70). The median survival was 10.39 months (range 7.87-12.91). The 2-, 3-, and 5-year OS rate was 20.5%, 12.5%, and 7.1%, respectively. On univariate analysis, clinical stage (IIIA vs. IIIB) was found to be a statistically significant factor influencing OS (p = 0.026), and the histologic features, grade, tumor size as measured on CT scans, age, tobacco use, weight loss >or=5%, and total dose delivered to the primary tumor were not. A KPS of <or=70 (p = 0.001), the presence of a CIRS-G score of 4 (extremely severe; p = 0.0002), and a severity index of >2 (p <0.0001) were associated with statistically significant inferior OS. Multivariate analysis with clinical stage, KPS, and comorbidity (severity index) of all patients showed that a KPS <or=70 and severity index >2 were independently associated with inferior OS; clinical tumor stage was not found to be an independent prognostic factor. KPS and comorbidity are important independent prognostic factors in Stage III NSCLC. Comorbidity should be included in protocols studying advanced stage NSCLC and used for stratification.