5511 Background: Sequential chemoradiotherapy using induction chemotherapy (IC) followed by chemoradiotherapy (CRT) is often used in patients with SCCHN. Two recent large phase III studies have shown that adding a taxane to standard PF induction regimen improves outcome and is better tolerated than PF (Hitt et al ASCO 2003, Vermorken et al. ASCO 2004). It is our standard practice to biopsy the primary site after IC before CRT. We report the rate of complete pathological response (pCR) after IC with TPF. Material and Methods: All patients received three cycles of IC with TPF followed by CRT. Chemoradiotherapy consisted of weekly carboplatin/ paclitaxel or docetaxel with standard or concomitant boost XRT. All patients were biopsied after IC, before starting CRT. Neck dissection (ND) was performed 6–12 weeks after CRT for N3 patients and incomplete responders to CRT. Results: Between June 1999 and May 2004, 72 patients underwent biopsy of the primary site after IC. Stage IV: 95%, Oropharynx 75%: Biopsy was n...