Background Previous prospective phase II study conducted by our research group at the National Cancer Centre Singapore had shown the efficacy of combined induction chemotherapy followed by cytotoxic T-lymphocyte (CTL) immunotherapy as a first-line treatment for advance nasopharyngeal carcinoma (NPC) – i.e. median survival for patients treated with combined therapy was 29.9 months, compared to 17.7 months for patients who received only standard chemotherapy.1 Using the same data set, we further investigate the correlation between various patient factors (Eastern Cooperative Oncology Group (ECOG) score, gender, age, initial stage of cancer, neutrophil-to-lymphocyte ratio (NLR), initial EBV-DNA titre) on overall survival (OS). This is to further validate our hypothesis that the improved OS is due to an effect of treatment and not due to intrinsic patient factors.
Materials and Methods Survival distribution curves were estimated using the Kaplan-Meier method and differences were compared statistically using log-rank test. IBM SPSS statistics software package (v. 22) was used for the purpose of statistical analysis. Overall survival was defined as time from diagnosis to date of event (date of death/date of last follow-up). For analysis of overall survival, data for patients who were alive or who were lost to follow-up were censored at the end of study period.
Results It was revealed that lower ECOG score, a scale used to assess the physical condition of patients, correlated with longer OS while other characteristics such as gender, age, initial stage of cancer, NLR, and initial EBV-DNA titre did not correlate with survival outcomes. ECOG0 patients had a median survival of 146.7 weeks, compared to ECOG1 patients, which had a median survival of 86.6 weeks (hazard ratio: 0.35; 95% CI: 0.14-0.84; P = 0.033).
Conclusions Even though ECOG performance status is found to be statistically associated with survival outcome of patients with advance stage NPC. This result is unsurprising as the prognostic value of ECOG has been well documented in literature, albeit in other cancer types. Other patient parameters such as gender, age, initial stage of cancer, NLR, and initial EBV titre, did not yield significance and did not prognosticate for survival outcome. This finding supports our hypothesis that the improved survival outcomes observed in advance NPC patients treated with chemotherapy followed by EBV CTL-immunotherapy is due to effects of treatment and not because of intrinsic patient factors.
Chia WK, Teo M, Wang WW, Lee B, Ang SF, Tai WM, Chee CL, Ng J, Kan R, Lim WT, Tan SH, Ong WS, Cheung YB, Tan EH, Connolly JE, Gottschalk S, Toh HC. Adoptive T-cell transfer and chemotherapy in the first-line treatment of metastatic and/or locally recurrent nasopharyngeal carcinoma. Mol Ther 2014 Jan;22(1):132–9.
Disclosure Information A. Chu: None. S. Han: None. H. Toh: None.
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