Weekly Cisplatin Shows No Toxicity Advantage in Advanced Head and Neck Cancer

For patients with advanced head and neck cancer, the choice of how to deliver chemotherapy has long been a clinical guessing game. Doctors could give a larger dose of cisplatin every three weeks alongside radiation, or spread smaller doses across weekly treatments. Both approaches aimed to kill cancer while keeping side effects manageable. But which actually worked better—and for whom—remained largely unanswered until now.

The NRG-HN009 trial set out to settle this question for a particularly vulnerable population: patients with p16-negative head and neck cancer, a group often burdened by other health conditions and less able to tolerate aggressive treatment. Researchers enrolled 234 eligible patients with p16-negative squamous cell carcinoma and randomly assigned them to one of two paths. One group received 70 Gray of radiation paired with 100 milligrams per square meter of cisplatin every three weeks. The other received the same radiation dose but with 40 milligrams per square meter of cisplatin given weekly. The trial stratified patients by performance status, smoking history, tumor stage, and age to ensure balanced comparison.

The primary question was straightforward: which regimen produced fewer serious side effects? Researchers measured this using a T-score—a count of all grade 3 or 4 adverse events occurring during treatment or within six months after. The results, presented at the 2026 American Society for Radiation Oncology Annual Meeting in Boston, delivered an unexpected answer: there was essentially no difference. The three-weekly arm had a mean T-score of 2.23, while the weekly arm scored 2.48. The ratio between them was 1.11, with a confidence bound that crossed the threshold the trial had set as meaningful. The study did not meet its predefined criteria for reduced toxicity with weekly dosing, which meant the p16-negative cohort would not advance to a larger Phase III trial.

Yet the two regimens did not produce identical harm. They simply harmed patients in different ways. The three-weekly schedule drove higher rates of nausea, dehydration, and acute kidney injury—the concentrated dose taking a heavier toll on the body's systems. The weekly approach instead elevated blood count decreases and magnesium depletion, the cumulative effect of repeated smaller exposures. Ninety-one percent of enrolled patients completed six-month follow-up, providing solid data on what actually happened to them.

One finding stood out with potential clinical weight: locoregional failure rates—the cancer returning in the treated area—differed between arms. The three-weekly group saw recurrence in 4.6 percent of patients, while the weekly group experienced it in 9.6 percent. That five-percentage-point gap, though modest, suggested the more intensive schedule might offer better cancer control, at least in this population. Paul Harari, the lead author from the University of Wisconsin, acknowledged the complexity. Weekly cisplatin did not deliver the toxicity advantage researchers had hoped for, but the two approaches created distinct side-effect profiles. The findings, he stated, underscored the need for future research to develop more tailored treatment strategies—ones that could reduce harm while preserving the ability to control disease.

The trial's failure to meet its primary endpoint closed one door but opened questions about what comes next. For p16-negative patients with advanced head and neck cancer, neither standard regimen emerged as clearly superior on safety grounds. The choice between them now rests on other factors: which specific toxicities a given patient might tolerate better, what their kidney function allows, whether blood counts or magnesium levels are already compromised. The study did not provide an easy answer, but it did provide clarity—and sometimes that is what evidence does.