Concurrent hyperfractionated chemoradiotherapy for head and neck squamous cell carcinoma: the prognostic impact of the overall treatment time and completion rates of chemotherapy

The purpose of this study was to investigate whether the overall treatment time and completion rates of chemotherapy were predictive factors for the survival rates in patients with squamous cell carcinoma of the head and neck (SCCHN) who were treated with concurrent chemoradiotherapy (CCRT) using hyperfractionated radiotherapy (RT) and daily carboplatin. The number of intermission days of RT were as follows; 0 (n = 37), 1-5 (n = 8), 6-10 (n = 12) and ≥11 (n = 12), and the days of RT without carboplatin; 0 (n = 27), 1-5 (n = 13), 6-10 (n = 13) and ≥7 (n = 16). The overall treatment time (≤48 vs ≥49 days) was a significant prognostic factor for the local control, disease-free survival and overall survival rates. The completion rate of chemotherapy, as the number of days of RT without carboplatin, was not a significant factor affecting any of the survival rates. In discussion, the strengths of the present study contain that all the patients were treated with 72 Gy delivered as 1.2 Gy twice daily, and received concurrent chemotherapy comprising daily carboplatin as a radio-sensitizer. Based on the results, the completion rate of chemotherapy may have a lower impact on the local control rate in comparison with the overall treatment time. We believe that when a treatment interruption is needed because of the acute toxicities, hyperfractionated RT should be resumed as soon as possible independently while continuing the break of daily carboplatin. The overall treatment time influenced the clinical outcomes in SCCHN patients treated with hyperfractionated CCRT using carboplatin, while the impact of the completion rates of daily carboplatin was limited. Sixty-nine consecutive patients with SCCHN were initially treated with definitive CCRT and were retrospectively analyzed. All 69 patients were treated with CCRT using hyperfractionated RT of 72 Gy in 60 fractions and daily carboplatin (25 mg/m(2)). The patients treated with other chemotherapeutic regimens or induction chemotherapy were excluded. On the intermission days of the RT, carboplatin was not prescribed. After the intermission, CCRT using RT plus daily carboplatin or RT alone was resumed.