Impact of p16 expression on induction taxotere-cisplatin-5 FU (TPF) followed by cetuximab-radiotherapy in N2b-N3 head and neck squamous cell carcinoma (HNSCC): Results of GORTEC 2007-02 phase III randomized trial.

Abstract

6070 Background: TPF is a reference induction chemotherapy regimen in non-operated locally advanced (LA) HNSCC. GORTEC 2007-02 phase III randomized trial was restricted to HNSCC patients with large nodal spread (N2b-N3). Results showed no benefit of 3 cycles of induction TPF followed by cetuximab-radiotherapy (RT), as compared to concurrent chemoradiotherapy (CRT) (Geoffrois et al ASCO 2016). Methods: Patients were randomized to receive concurrent CRT (arm A) or induction TPF followed by cetuximab-RT (arm B). RT was 70 Gy/35F/7 weeks. Concurrent chemotherapy was 3 cycles of carboplatin-5FU as previously described (Calais JNCI 1999). About 2/3 of patients had oropharyngeal cancers (OPC) and HPV status was determined in these patients using p16 expression as a surrogate (immunohistochemistry). Smoking status was also collected. Primary endpoint was progression free survival (PFS). Results: Between May 2009 and Aug 2013, 360 eligible patients were randomized including 231 (64%) OPC. Overall, p16 expression could be assessed in 172 / 231 OPC patients (74%) with 84 in arm A and 88 in arm B. 26 patients were found p16+ in arm A (31%) and 19 in arm B (22%). Only 8 out 45 (18%) p16+ patients were non-smokers showing that the large majority of OPC patients randomized were p16- (127/172) and smokers (117/129). A significant improvement in PFS was found in p16+ compared to p16- OPC (p < 0.0001). The absence of benefit in PFS associated with TPF + cetux-RT compared with CRT was suggested both in p16+ (HR: 0.78, 95% CI: 0.28 – 2.20) and in p16- OPC (HR: 1.28, 95% CI: 0.84 – 1.93), and the interaction between p16 and treatment modality was not significant (p = 0.35). A significant benefit was observed in favor of arm B regarding distant metastasis, but this effect was not different between the p16+ and p16- OPC, while there was no benefit of TPF + cetux-RT compared with CRT for loco-regional control, regardless of p16 status. Conclusions: The OPC p16 subpopulations were small. No benefit of induction TPF chemotherapy followed by cetuximab-RT compared with CRT in OPC patients regardless of p16 status. Clinical trial information: NCT01233843.