The Prognostic Value Of Lymph Node Ratio In Patients With N2 Stage Lung Squamous Cell Carcinoma: A Nomogram And Heat Map Approach
Received 21 May 2019
Accepted for publication 28 September 2019
Published 6 November 2019 Volume 2019:11 Pages 9427—9437
Checked for plagiarism Yes
Review by Single-blind
Peer reviewers approved by Dr Melinda Thomas
Peer reviewer comments 2
Editor who approved publication: Dr Antonella D'Anneo
Guoshu Bi,* Tao Lu,* Guangyu Yao, Yunyi Bian, Mengnan Zhao, Yiwei Huang, Yi Zhang, Liang Xue, Cheng Zhan, Hong Fan
Department of Thoracic Surgery, Zhongshan Hospital, Fudan University, Shanghai 200032, People’s Republic of China
*These authors contributed equally to this work
Correspondence: Hong Fan; Cheng Zhan
Zhongshan Hospital, No. 180 Fenglin Road, Xuhui District, Shanghai 200032, People’s Republic of China
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Background: Lymph node ratio (LNR), defined as the ratio of the number of positive lymph nodes to the total of all resected nodes, has been reported to be a predictor of survival of patients with several types of cancer. However, the prognostic value of LNR and other factors in patients with resected N2 stage lung squamous cell carcinoma has never been considered.
Methods: Data from 1778 patients with resected N2 stage lung squamous cell carcinoma were obtained from the Surveillance, Epidemiology, and End Results (SEER) database. The optimal cutoff value of LNR was identified by X-tile. A multivariable Cox model and corresponding nomogram were constructed to predict overall survival (OS) and cancer-specific survival (CSS). Both the cutoff value of LNR and the model were further validated in 146 similar patients treated in Zhongshan Hospital. Heat maps were created to visualize the distribution of LNR and the number of positive lymph nodes with the predicted survival probabilities.
Results: The optimal cutoff value for LNR was identified as 0.42. Multivariable analysis showed that age, sex, tumor laterality, type of surgery, T stage, chemotherapy and LNR were independently correlated with OS. Harrell’s C-index of the nomogram (0.64) was significantly higher than the index of the T stage-based model (0.54). Calibration curves showed good agreement between predicted and observed survival probabilities. The robustness of the model was also demonstrated by external validation.
Conclusion: LNR less than 0.42 was associated with improved OS and CSS for patients with resected N2 stage lung squamous cell carcinoma.
Keywords: lymph node ratio, N2 stage lung squamous cell carcinoma, prognostic model, nomogram, heatmap
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