A case–control study of patients with squamous cell carcinoma of the oral cavity and oropharynx treated with pulsed-dose-rate brachytherapy

International audiencePURPOSE:Pulsed-dose-rate (PDR) brachytherapy is thought to mimic the radiobiological benefits of continuous low-dose-rate (cLDR) delivery but is safer for medical personnel. We set out to evaluate the outcomes of this technique in patients with head and neck squamous cell carcinoma.METHODS AND MATERIALS:A total of 36 consecutive patients treated with PDR brachytherapy were randomly matched to 72 cLDR controls according to T-stage, tumor site, and management strategy. Local recurrence and late complications were compared between the two groups.RESULTS:Baseline characteristics were similar in both groups. Oral cavity cancers predominated at 81%, and 89% had T1/T2 tumors. Seventy-five percent of patients underwent surgery before radiation treatment. Median followup was 59 and 30 months for cLDR and PDR patients, respectively. Three-year actuarial local recurrence-free survival was 97% and 94% for cLDR and PDR patients, respectively (p = 0.77). Three-year cumulative risk of Grade ≥2 complications was 45% and 32% for cLDR and PDR patients, respectively (p = 0.2). For cLDR, a dose rate exceeding 68 cGy/h resulted in more complications (RR 5.3, p < 0.05). Similarly, PDR patients receiving ≥75 cGy/pulse were at higher risk.CONCLUSIONS:PDR brachytherapy in head and neck squamous cell carcinoma yields comparable results to cLDR treatment. Dose rate was correlated with the risk of late complications, regardless of technique