Long-Term Update of a Phase 3 Randomized Study Comparing Once-a-Week Versus Once-Every-3-Weeks Cisplatin Along With Radiation in Head and Neck Cancer.

Purpose: In the weekly-3-weekly study, cisplatin at 100 mg/m² once-every-3-weeks led to superior locoregional control compared with cisplatin 30 mg/m² once-a-week in combination with radical radiation for locally advanced head and neck squamous cell carcinoma (LAHNSCC). We report the updated analysis of the study.

Methods and materials: In this phase 3 open-label noninferiority study conducted between 2013 and 2017, 300 patients with LAHNSCC were randomly assigned to receive cisplatin 100 mg/m² once-in-every-weeks or cisplatin 30 mg/m² once-a-week, concurrently with radiation. The primary endpoint was locoregional control. Secondary outcomes were overall survival, progression-free survival, and late adverse events.

Results: The median follow-up was 6.91 years (95% CI, 6.12-7.36). The updated 2-year and 5-year locoregional control rates for the once-a-week cisplatin arm were 58.75% (95% CI, 51.08-67.58) and 48.09% (95% CI, 40.26-57.43), whereas for the once-every-3-weeks, cisplatin arm were 73.95% (95% CI, 66.93-81.70) and 56.76% (95% CI, 48.46-66.48), respectively, hazard ratio = 1.44 (95% CI, 1.03-2.03), P = .034. The 5-year overall survival was 43.60% (95% CI, 36.29-52.37) in the once-a-week cisplatin arm and 50.55% (95% CI, 43.06-59.35) in the once-every-3-weeks cisplatin arm; P = .19. There was no difference in any grade or grade ≥3 late adverse events between the 2 arms, except for hearing dysfunction, which was significantly more common in patients who received high-dose cisplatin.

Conclusions: Long-term follow-up confirms that cisplatin at 100 mg/m² administered once-every-3-weeks concurrently with radical radiation for LAHNSCC leads to superior locoregional control compared with cisplatin 30 mg/m² once-a-week and should remain one of the standard treatment options.