Survival and prognostic factor analyses
The Kaplan–Meier survival curve method provided a 2-year survival rate
of 77.2%, a 3-year survival rate of 61.6% and a 5-year survival rate
of 47.4%. Univariate analysis was carried out in accordance with the
general data, tumour characteristics and TNM stage of the patients. The
results of log-rank test showed that sex, age, history of smoking and
alcohol, degree of tumour differentiation, primary site, clinical stage
and preservation of laryngeal function were all P>0.05,
which indicates no statistical significance (Table 2). However,
significant differences in survival were found between stages T1–T2 and
T3–T4 (χ2=3.959, P=0.047) and amongst N0–N3
(χ2=17.767, P<0.001; Fig.3). The Cox
regression analysis of tumour differentiation based on primary site,
clinical stage, T and N stages and preservation of laryngeal function
revealed that N stage is an independent risk factor of pyriform sinus
carcinoma resected via the paraglottic space approach (P=0.042, Fig.3).