Defining platinum-ineligible head and neck cancer patients from administrative data

Survival outcomes of head and neck squamous cell carcinoma (HNSCC) remain poor with limited improvement over the past several decades. While the addition of cisplatin to definitive radiotherapy has improved survival in randomized controlled trials (RCT), its significant toxicities limit its use among a population with a high comorbidity burden. The ability to accurately identify a population eligible for cisplatin treatment in large datasets is needed. This study aims to better characterize populations eligible for cisplatin in administrative data by defining specific contraindications.

This retrospective cohort study utilizes SEER-Medicare data (2010-2019) to evaluate adults with locoregionally advanced HNSCC (T3-4 or N1-3, M0) of the pharynx or larynx treated with definitive radiation therapy. Cisplatin contraindications were defined using validated algorithms for comorbidities. General comorbidity burden was assessed using the Elixhauser Comorbidity index. Multivariable logistic regression models determined associations between cisplatin use and comorbidities.

Of 3548 patients, 23.2% received cisplatin and 49.7% received no systemic therapy with an increasing proportion receiving no systemic therapy over time (-2.76%/year; 95% CI [-5.32 - -0.14]). Renal failure, neuropathy and hearing loss were associated with not receiving cisplatin, but on multivariable analysis, only Elixhauser Index (OR 0.95; 95% CI [0.92-0.98]) remained associated.

In real-world practice, few locoregionally advanced HNSCC patients treated with definitive radiation receive cisplatin, and increasingly patients receive no systemic therapy. In this setting, specific contraindications to cisplatin are not associated with cisplatin use after accounting for other factors, likely because real-world practice frequently deviates from guideline recommended care.