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Purpose The aim of this study is to identify the prognostic factors of distant metastasis (DM) after induction chemotherapy (IC) followed by concurrent chemoradiotherapy (CRT) for locoregionally advanced head and neck cancer (HNC). Materials and Methods A total of 321 patients with HNC who underwent IC followed by CRT treated between January 2005 and December 2010 were analyzed retrospectively. IC consisted of three courses of docetaxel (70 mg/m2) and cisplatin (75 mg/m2) every three weeks, followed by radiotherapy of 66-70 Gy/2 Gy per fraction/5 fractions per week concurrent with weekly cisplatin (40 mg/m2). Tumor/nodal stage, primary site, tumor differentiation, lower neck node involvement (level IV, VB, and supraclavicular regions), number of concurrent chemotherapy cycles, overall duration of radiotherapy, and response to IC were assessed as potential prognostic factors influencing DM and survival outcome. Results The five-year loco-regional recurrence and DM rates were 23.6% and 18.2%. N stage, overall duration of radiotherapy, lower neck node involvement, and response to IC were significant factors for DM. With a median follow-up period of 52 months (range, 4 to 83 months), the 5-year progression-free, DM-free, and overall survival rates were 41.2%, 50.7%, and 55.1%, respectively. Lower neck node involvement (p=0.008) and poor response to IC (p < 0.001) showed an association with significantly inferior DM-free survival. Conclusion Even with the addition of IC, the DM rate and survival outcome were poor when metastatic lower neck lymph nodes were present or when patients failed to respond after receiving IC.

Platelet retention in columns packed with glass beads has been theoretically analyzed in a manner similar to that commonly used to describe the behavior of fixed-bed adsorbers. Combining the results of this analysis with experimental observations has confirmed that the process of platelet deposition from whole blood onto glass bead surfaces is entirely adsorption controlled. In contrast to this finding, a theory often used to predict the performance of a wide range of filtration processes has been utilized to show that platelet deposition from PRP is dominated not by the adsorption step, but by resistances to platelet transport which are confined to the plasma phase. Furthermore, a direct relationship between platelet retention in glass bead columns and hematocrit has been observed using whole blood and ghost cell suspensions. These results, which are in accord with observations made by Zuckeret al. (1972), strongly suggest that ADP released from red cells cannot account for the increased retention with increased hematocrit. This behavior can be explained, however, by recognizing that the efective platelet diffusivity is considerably enhanced by increasing the hematocrit of red cell or ghost cell suspensions and consequently the frequency of cell-cell interactions. As confirmed experimentally, these physical interactions, as opposed to biochemical factors, are primarily responsible for determining the observed changes in platelet retention when the suspending medium is gradually changed from PRP (0% hct) to normal hematocrit values. Furthermore, theoretical and experimental techniques are described which permit, for the first time, a quantitative measure of platelet retention in columns packed with glass beads which is independent of both hemodynamic factors and column geometry. This new measure of platelet retention is shown to relate directly to the affinity of platelets for one another and for solid surfacesin vitro, thereby offering the possibility of using glass bead columns as highly sensitive diagnostic tools for the detection of hemorrhagic disorders.