Background and purpose: To study pre-treatment cell kinetics and their clinical correlations in nasopharyngeal carcinoma (NPC).
Materials and methods: Ninety newly diagnosed NPC patients were studied using in vivo Bromodeoxyuridine (BrdU) labeling and flow cytometric analysis. Immunohistochemical staining for BrdU and Ki 67 was also performed.
Results: The median S-phase duration (Ts) was 6.2 h (range 3.5-18.7 h), median flow cytometric labeling index (FCM-LI) was 7.4% (1.3-37.6%), and median potential doubling time (Tpot) was 3.6 days (0.5-19.9 days). The median histologic labeling index (H-LI) was 12.4% (1.2-43.3%), and median histologic Tpot (H-Tpot) was 2.1 days (0.5-33.3 days). FCM-LI and H-LI were both positively correlated with Ki67 whereas Tpot and H-Tpot were both negatively correlated with Ki67 and N-stage. In univariate analysis, Tpot and H-Tpot showed a trend for progression free survival. Tpot was significantly associated with local relapse free survival, but lost its significance in multivariate analysis. N-stage was the only significant prognostic factor for all radiotherapy outcomes in both univariate and multivariate analyses.
Conclusions: Tpot was the only pre-treatment cell kinetic parameter for which some evidence was found for an association with survival in NPC patients. Future studies should aim to combine cell kinetic parameters together with other biological markers and clinical parameters to provide more useful prognostic information to guide individual patient's therapy.