title: Posterior cervical lymph node metastasis as the valuable prognostic factor for stage IVA/IVB nasopharyngeal carcinoma treated with induction chemotherapy followed by concurrent chemo-radiotherapy.
abstract: OBJECTIVE
  To evaluate the prognostic properties of retropharyngeal lymph node (RP), posterior cervical lymph node (PCN), and supraclavicular lymph node (SPC), in stage IVA/IVB nasopharyngeal carcinoma (NPC) patients in setting of induction chemotherapy.
  
  
  METHODS
  We performed a retrospective study including 43 patients with stage IVA/IVB NPC (7th AJCC) treated with induction chemotherapy followed by concurrent chemo-radiotherapy. We analyzed prognosis with the multivariate Cox regression model and p-value from the Wald's test, using the backward elimination method (by likelihood ratio test and percent change of coefficient factors).
  
  
  RESULTS
  Overall, 24 patients (55.8%) were in stage IVA and 19 (44.2%) in stage IVB. After a median follow-up time of 30 months, the 2-year overall survival (OS) was 79.1%, while the 2-year progression free survival (PFS) and distant metastasis free survival (DMFS) were 59.8% and 69.1%, respectively. In multivariate analysis for predicting DMFS, SPC involvement was not statistically significant (HR 3.39; 95% CI 0.76-15.07; p=0.1), whereas RP involvement was statistically significant (HR 5.81; 95% CI 1.08-31.16; p=0.04). Moreover, and more importantly, PCN involvement was the only nodal factor to predict all of DMFS, PFS, and OS (respectively HR 5.57, 95% CI 1.12-27.71, p=0.036; HR 16.05, 95% CI 1.93-133.65, p=0.01; and HR 28.02, 95% CI 2.74-286.22, p=0.005).
  
  
  CONCLUSIONS
  PCN involvement is the only independent prognostic factor of stage IVA/IVB NPC patients treated by induction chemotherapy that predicts DMFS and turns this effect to PFS and OS. PCN involvement is a highly accurate predictor for failure of conventional chemo-radiotherapy. Therefore, patients with PCN involvement should be defined at high-risk, as to be investigated for a new staging system.
authors.affiliation: Division of Radiation Oncology, Department of Radiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok - Thailand.
authors.forename: Kullathorn
authors.initials: K
authors.lastname: Thephamongkhol
authors.forename: Jiraporn
authors.initials: J
authors.lastname: Setakornnukul
authors.forename: Sunanta
authors.initials: S
authors.lastname: Rojwatkarnjana
authors.forename: Yaowalak
authors.initials: Y
authors.lastname: Chansilpa
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D002277:Carcinoma; D002574:Cervical Vertebrae / Q000473:pathology*; D059248:Chemoradiotherapy; D003131:Combined Modality Therapy; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D060828:Induction Chemotherapy; D008198:Lymph Nodes / Q000473:pathology*; D008206:Lymphatic Diseases / Q000473:pathology; D008207:Lymphatic Metastasis / Q000175:diagnosis / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology*; D009367:Neoplasm Staging; D012189:Retrospective Studies