RESUMO
When induction chemotherapy is used in locally advanced squamous cell cancer of the head and neck (SCCHN), patients often receive cisplatin-5-fluorouracil (PF) followed by radical loco-regional therapy. Phase II studies of docetaxel-cisplatin-5-fluorouracil (TPF) induction therapy, with or without leucovorin (L), have achieved high survival rates versus those reported in phase III PF trials. However, the distribution of prognostic factors may vary between phase II and phase III study populations, making the extrapolation of phase II TPF/L results to phase III PF populations difficult. This study used a patient selection standardization method and Cox model to adjust for potential selection bias. Thus, the survival benefit from adding docetaxel into PF induction regimens in SCCHN could be more accurately assessed. The TPF/L dataset comprised 195 patients from six phase II trials. The PF dataset of 585 patients was derived from five large randomized trials included in the Meta-Analysis of Chemotherapy in Head and Neck Cancer (MACH-NC) database. TPF/L and PF datasets differed significantly concerning the distribution of several prognostic factors. Adjusting for these differences, the relative risk of death in the PF versus TPF/L datasets was 1.85 (95% confidence interval 1.37-2.49), corresponding to a 20% 2-year survival benefit (p < 0.0001). Sensitivity analyses confirmed that this improved 2-year survival rate of TPF/L over PF was robust, irrespective of the distribution of studied prognostic factors between treatment datasets. We conclude that this improved survival might be due either to docetaxel's pharmacologic effect or to uncontrolled prognostic factors.
