Weekly Cisplatin Cycles and Outcomes for Chemoradiation in Head and Neck Cancer

National Comprehensive Cancer Network guidelines recommend weekly cisplatin as an alternative concurrent systemic therapy for definitive chemoradiation in patients with head and neck cancer. However, the impact of different levels of adherence to weekly cisplatin on outcomes stratified by human papillomavirus p16 status remains unclear.

To evaluate the association between the number of weekly cisplatin cycles and outcomes.

This retrospective, observational, single-institution cohort study at The Ohio State Comprehensive Cancer Center included patients with a diagnosis of nonmetastatic head and neck cancer between December 1, 2011, and March 30, 2020, who received chemoradiation. Data analysis was performed between March and May 2024.

A total of 5, 6, or 7 to 8 weekly cisplatin cycles.

The primary outcomes were overall survival (OS), progression-free survival (PFS), locoregional failure (LRF), and distant failure (DF). Cox multivariable analysis was performed for variables associated with OS and PFS, and Fine-Gray multivariable analysis was performed for variables associated with LRF and DF.

A total of 142 patients met the criteria (119 men [83.8%]; median [IQR] age, 59 [54-63] years). Median (IQR) follow-up was 46.8 (40.8-55.6) months. Among 92 patients with reasons for cisplatin interruption reported, the most common reason was low blood counts (42 patients [45.7%]). Those who missed weekly cisplatin cycles had worse OS (adjusted hazard ratio [aHR], 2.22; 95% CI, 1.19-4.17; P = .01) and PFS (aHR, 1.83; 95% CI, 1.06-3.15; P = .03) than those who received 7 to 8 cycles. Cancer control outcomes were comparable between these groups (LRF aHR, 0.53; 95% CI, 0.15-1.93; P = .34; DF aHR, 1.51; 95% CI, 0.60-3.82; P = .38). Patients with p16-negative tumors who missed weekly cisplatin cycles had worse OS (for every missing cisplatin cycle, aHR, 11.34, 1.51-84.94; P = .02) than those treated with 7 to 8 cycles. However, for those with p16-positive tumors, there were no statistically significant differences in OS between those who missed weekly cisplatin cycles vs others who received 7 to 8 cycles (aHR, 1.21; 95% CI, 0.47-3.14; P = .69).

In this cohort study of patients with head and neck cancer who received definitive chemoradiation, those with p16-negative tumors who missed weekly cisplatin cycles had lower OS than those who received 7 to 8 cycles, although OS was comparable between these groups for p16-positive tumors. Cytopenia represented the most common reason for cisplatin interruption.