3623 - Prognostic Significance of Dynamics in Pan-Immune-Inflammation Value in Patients with Head and Neck Cancer Treated with Radiotherapy: Results from a Large Cohort Study

H. T. Chen¹, W. K. Yap¹, T. Y. Tsai², N. M. Tsang³, and C. H. Lin¹; ¹Proton and Radiation Therapy Center, Chang Gung Memorial Hospital-Linkou Medical Center, Department of Radiation Oncology, Chang Gung University, Taoyuan City, Taiwan, ²Department of Otorhinolaryngology, Head and Neck Surgery, Chang Gung Memorial Hospital, Medical College of Chang Gung University, Taoyuan City, Taiwan, ³Department of Radiation Oncology, China Medical University Hsinchu Hospital, Zhubei City, Hsinchu County, Taiwan

Purpose/Objective(s): Systemic immune-inflammatory response to therapy can play a crucial role in cancer progression and treatment resistance. Limited research examined the dynamics of a novel biomarker, pan-immune-inflammation value (PIV) during radiotherapy (RT). We sought to comprehensively evaluate the temporal changes of PIV and their prognostic significance in patients with head and neck cancer treated with RT. Materials/

Methods: Between 2005 and 2013, a total of 690 patients with newly-diagnosed head and neck cancer, receiving either RT or concurrent chemoradiotherapy (CCRT), were enrolled. Complete blood counts at baseline as well as at two, four, and six weeks after the initiation of treatment were collected for all patients. The PIV was calculated by multiplying neutrophil, platelet, and monocyte counts, then divided by lymphocyte counts. The paired t-test was used to evaluate PIV changes across different time points of measurement. The optimal cut-off value for PIV was determined by receiver operating characteristic curve. Overall survival (OS), progression-free survival (PFS), locoregional recurrence-free survival (LRRFS), and distant metastasis-free survival (DMFS) were analyzed using the Kaplan-Meier method. Multivariate Cox analyses were applied to identify independent predictors for study outcomes. Subgroup analyses were performed between patients with nasopharyngeal cancer (NPC) (n = 346) and pharyngo-laryngeal cancer (PLC) (n = 344).

Results: The median OS was 11.2 years and median follow up was 8.1 years. The major primary tumor site was NPC (50.1%) and most of the study patients were treated with CCRT (84.9%). The median PIV at baseline (PIV-0), two weeks (PIV-2), four weeks (PIV-4), and six weeks (PIV-6) after the beginning of RT were 217.3, 267.9, 395.0, and 428.6, respectively. A significant ascending trend of PIV was observed during treatment, with the most substantial increase between PIV-6 and PIV-0 (p < 0.001). Compared with patients with high PIV dynamic ratio at six weeks (PIV-6/PIV-0), those with low PIV dynamic ratio had worse outcomes in terms of 5-year OS (75.3% vs. 58.2%, p = 0.003), 5-year PFS (62.2% vs. 59.1%, p = 0.024, and 5-year LRRFS (79.8% vs. 70%, p = 0.026), but not in 5-year DMFS (88.5% vs. 80.0%, p = 0.125). Multivariate analyses identified low PIV-6/PIV-0 as an independent risk factor for OS, PFS, and LRRFS, but not for DMFS. Nevertheless, there was no significant association of PIV ratio at two weeks (PIV-2/PIV-0) or at four weeks (PIV-4/PIV-0) with survival outcomes. Subgroup analysis among patients with NPC revealed consistent results with respect to the PIV dynamics as well as the association between PIV dynamic ratio at six weeks (PIV-6/PIV-0) and survival outcomes, while such trends and prognostic value were absent in the PLC subgroup.

Conclusion: PIV dynamic ratio is a valuable and independent prognostic biomarker for predicting OS and LRRFS in head and neck cancer undergoing RT, especially at six weeks after the start of RT.