215 - Prognostic Nutritional Index as a Prognostic Factor in Stage IV Lung Cancer Patients Receiving Palliative Radiation Therapy

Purpose/Objective(s): The Prognostic Nutritional Index (PNI), calculated from serum albumin and total lymphocyte count, is used to predict postoperative complications. Recent studies have demonstrated its utility as a prognostic factor in patients undergoing surgery or chemotherapy for cancer. However, there are relatively few reports on whether PNI can predict prognosis in patients who have undergone radiation therapy (RT). We evaluated the potential of PNI as a prognostic factor in stage IV lung cancer patients who received palliative RT.

Materials/Methods: A total of 147 patients with stage IV lung cancer (111 males and 36 females) who received palliative RT were enrolled. The median age was 70 years, and the median BMI was 21.36. Histology included adenocarcinoma in 75 patients, squamous cell carcinoma in 24, large cell carcinoma in 2, pleomorphic carcinoma in 1, NSCLC, NOS in 7, carcinoma, NOS in 1, small cell lung cancer in 33, and LCNEC in 4. The performance status (PS) was 0 in 25 patients, 1 in 69, 2 in 31, 3 in 18, and 4 in 4. The median BED was 39.0 Gy (range, 14.4-72.0 Gy). The irradiated sites were bone in 75 patients, brain in 46, and others in 26. One hundred and six patients (72.1%) received chemotherapy (CTx) after RT. PNI was calculated using the following formula: PNI = 10 × albumin + 0.005 × lymphocyte count. Cox proportional hazards model was used to identify prognostic factors for overall survival (OS). Cut-off values for BMI and PNI were determined using the ROC curve analysis. Multivariate analysis was performed using parameters with a p-value less than 0.10 in univariate analysis. Kaplan-Meier method was used to estimate the survival time.

Results: The median follow-up period was 5 (range, 1-57) months. Ninety-one patients died during the follow-up period. The cut-off values for BMI and PNI were 17.35 and 35.5, respectively. Univariate analysis revealed that PNI (p < 0.001) and CTx administration (p < 0.001) were significant factors for OS. BMI (p = 0.078) and PS (p = 0.058) showed a trend towards significance. Multivariate analysis including these four factors demonstrated that PNI (p = 0.011) and CTx administration (p < 0.001) remained significant factors (Table). The median survival time was 13 months for the high PNI group and 4 months for the low PNI group.