Detailed Instructions: In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.
Q: Context: We conducted this pooled analysis to assess the prognostic value of pretreatment Quality of Life (QOL) assessments on overall survival (OS) in advanced non-small cell lung cancer (NSCLC).', 'Four hundred twenty patients with advanced NSCLC (stages IIIB with pleural effusion and IV) from six North Central Cancer Treatment Group trials were included in this study. QOL assessments included the single-item Uniscale (355 patients), Lung Cancer Symptom Scale (217 patients), and Functional Assessment of Cancer Therapy-Lung (197 patients). QOL scores were transformed to a 0 to 100 scale with higher scores representing better status and categorized using the sample median or clinically deficient score (CDS, <or=50 versus >50). Cox proportional hazards models stratified by study were used to evaluate the prognostic importance of QOL on OS alone and in the presence of other prognostic factors such as performance status, age, gender, body mass index, and laboratory parameters.', 'Pretreatment QOL accessed by Uniscale was significantly associated with OS univariately (p < 0.0001). Uniscale (p < 0.0001; hazard ratio = 1.6 for the sample median and 2.0 for the CDS categorization) and body mass index were the only significant predictors of OS multivariately. The median survival of patients who had a Uniscale score less than or equal to the CDS (<or=50) was 5.7 versus 11.1 months for the >50 group; and 7.8 versus 13 months for the less than or equal to sample median (<or=83) group and >83 group, respectively. The Lung Cancer Symptom Scale and the Functional Assessment of Cancer Therapy-Lung total scores were not significant predictors of OS.\Question: Is pretreatment quality of life an independent prognostic factor for overall survival in patients with advanced stage non-small cell lung cancer?
A:
Pretreatment QOL measured by Uniscale is a significant and an independent prognostic factor for OS, and QOL should be routinely integrated as a stratification factor in advanced NSCLC trials.