Role of Prognostic Nutritional Index in Postoperative Radiotherapy for Non-Small Cell Lung Cancer
Hye-Jo Ryu,
Korea Republic of
PO-1241
Abstract
Role of Prognostic Nutritional Index in Postoperative Radiotherapy for Non-Small Cell Lung Cancer
Authors: Hye-Jo Ryu1, Changhoon Song2, Jae Sung Kim3, Jae Hyun Jeon4, Sukki Cho5, Kwhanmien Kim6, Sanghoon Jheon6, Se Hyun Kim7, Yu Jung Kim7, Jong Seok Lee8
1Seoul National University Hospital, Radiation Oncology, Seoul , Korea Republic of; 2 Seoul National University Bundang Hospital , Department of Radiation Oncology, Bundang, Korea Republic of; 3Seoul National University Bundang Hospital, Department of Radiation Oncology , Bundang, Korea Republic of; 4Seoul National University Bundang Hospital, Department of Thoracic and Cardiovascular Surgery, Bundang, Korea Republic of; 5Seoul National University Bundang Hospital, Department of Thoracic and Cardiovascular Surgery , Bundang , Korea Republic of; 6Seoul National University Bundang Hospital, Department of Thoracic and Cardiovascular Surgery , Bundang, Korea Republic of; 7Seoul National University Bundang Hospital, Department of Internal Medicine, Bundang, Korea Republic of; 8Seoul National University Bundang Hospital, Department of Internal Medicine , Bundang, Korea Republic of
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Purpose or Objective
Prognostic Nutritional index (PNI) is known to be correlated with clinical outcomes in non-small cell lung cancer (NSCLC) patients after surgical resection. However, prognostic role of PNI has not been studied yet in patients underwent postoperative radiotherapy (PORT), which may also lower PNI values by suppressing immune function or by causing poor oral intake. Therefore, the purpose of this study was to investigate the relationship between PNI and survival and recurrence in patients with PORT.
Material and Methods
We reviewed 97 Stage I-III NSCLC patients who underwent radical resection followed by PORT between January, 2004 and December, 2020 at our institution. We obtained PNI values for both pre-RT and post-RT (within 2 months after RT) by using the following formula: 10 x serum albumin (g/dL) + 0.005 X absolute lymphocyte count (cells/mm3). A cutoff value for PNI was determined by the time-dependent receiver operating characteristic curve (ROC). Pearson’s chi-square test was used to analyze the relationship between PNI and clinicopathologic parameters. The Kaplan-Meier method and the Log Rank test were performed to analyze overall survival (OS) and disease free survival (DFS). The Cox hazard model was applied for univariate and multivariate analysis. The median follow-up period was 52.8 month.
Results
The ROC curve of post-RT PNI exhibited higher area under the curve (AUC 0.68, cut-off: 47) than that of pre-RT PNI (AUC 0.55, cut-off: 51), and therefore the group was divided into high post-RT PNI (> 47) and low post-RT PNI (≤ 47). The 5-year OS was 41.8% in the low post-RT PNI group, compared to 66.2% in the high post-RT PNI group (p=0.018). The patients with both “low pre-RT and low post-RT PNI” had the worst survival outcome (5-yr OS : 31.1%). A multivariate analysis revealed that low post-RT PNI (HR 1.99, 95% CI 1.02-3.85, p=0.046) was one of the independent risk factors for mortality along with age and male sex. On the contrary, there was no significant difference in 5-year DFS between low and high post-RT PNI groups (13.2% vs 35.8%, p=0.23). Extranodal extension was the only significant factor for disease recurrence in a multivariate analysis (HR 2.12, 95% CI 1.21-4.14, p=0.008).
Conclusion
Low PNI status after PORT was significantly associated with unfavorable survival, but not the disease recurrence. This finding suggests that PNI can be used as a prognostic marker and any kind of intervention to maintain optimal PNI might improve survival. Further study with a larger population is required to validate the role of PNI in PORT setting.