Study provides new guidelines for assessing severity of oral cavity cancers
LOS ANGELES, U.S.: Since current head and neck cancer staging systems include lymph node size and laterality, but focus less on the total number of positive metastatic nodes, researchers at the Cedars-Sinai Medical Center, took it upon themselves to reassess the existing classification rules. In the study, the independent impact of numerical metastatic lymph node burden on survival was investigated and the results were applied to establish new and improved guidelines.
For decades, doctors have determined the stage and predicted the progression of head and neck cancers based primarily on nodal size, location and how far the cancer has spread beyond the lymph nodes, but they have attached less importance to the number of cancerous nodes. As a result, staging and treatment recommendations, based on current national guidelines, "are the same whether a patient has two or 20 positive lymph nodes," said Dr. Zachary Zumsteg, assistant professor at the Radiation Oncology Department at Cedars-Sinai and the study's senior author.
The study, which involved reviewing data of 14,554 U.S. patients identified in the National Cancer Database who were treated for squamous cell carcinoma of the oral cavity (mouth, gum and tongue) between 2004 and 2013, found that an increased risk of death was associated with each additional cancerous lymph node found. The investigators concluded that the number of cancerous lymph nodes is a predominant, independent factor associated with death in those patients.
With the new system, based on the number of cancerous lymph nodes, patients are separated into similarly sized groups with distinct outcomes, Zumsteg said. "Our study demonstrated a better way to assess cancer severity, which will improve our ability to predict outcomes and give patients more personalized treatment."
"Although considering the number of cancerous lymph nodes in staging is a simple concept that many head and neck cancer specialists have assumed to be true for years, data has been limited until now," Zumsteg said. The study’s authors said they hope that, based on the new data, the number of positive nodes in staging will now be incorporated into clinical practice.
"The greater the number of malignant lymph nodes, the less favorable the patients' chances of survival," said Dr. Allen Ho, director of the Head and Neck Program at the Samuel Oschin Comprehensive Cancer Institute at Cedars-Sinai and lead author of the study. "This new approach could dramatically simplify staging systems," he added.
The number of metastatic nodes is a critical predictor of oral cavity cancer mortality, eclipsing other features such as lymph node size and contralaterality when it comes to prognosis. More robust incorporation of numerical metastatic lymph node burden may augment staging and better inform adjuvant treatment decisions.
The study, titled “Metastatic lymph node burden and survival in oral cavity cancer,” was published in the Journal of Clinical Oncology in November 2017.