Allen Ho, Director of the Head and Neck Cancer Program at Cedars-Sinai, believes we have a staging problem when it comes to oral cancers: “Current staging does not distinguish between multiplicity of metastatic lymph nodes. In other words, staging did not distinguish between a patient having two or 20 metastatic lymph nodes.” But, according to Ho, such knowledge is vital. After he and his colleagues noticed that patients with a higher number of metastatic lymph nodes seemed to have poorer outcomes, they applied statistical models to data from over 14,000 patients from cancer databases spanning almost a decade in the US. Those models showed that mortality risk increased with the number of metastatic lymph nodes – with no upper limit to risk (1). “We found that, in fact, there is a near stepwise escalation in mortality risk with each additional metastatic lymph node found,” says Ho.
“This is a constantly evolving field with many factors that can impact a patient’s prognosis. However, based on this nationwide data, the magnitude of lymph node burden is so high that it’s difficult to ignore. It is an overlooked component of our staging system,” says Ho. Notably, the research also found that many other features thought to be important in staging cancer are relatively insignificant when compared with the impact of including the number of metastatic lymph nodes – and that the association between metastatic lymph node burden and mortality remains largely intact even after adjusting for those other features. In response to this discovery, Ho and his lab at Cedars-Sinai developed guidelines that may help predict more accurate survival odds for patients with oral cavity cancers. The researchers proposed a tumor staging template for oral cavity cancers that includes the number of metastatic lymph nodes, along with other factors. “ We hope our results will help streamline the current staging system and better reflect the impact of quantitative metastatic lymph node burden.” The researchers are now further investigating the implications of their work. “There are numerous implications for metastatic lymph node burden,” says Ho. “We are studying whether patients with high numbers of metastatic lymph nodes may benefit from treatment intensification – for instance, whether adding chemotherapy is appropriate and helps improve survival. Biologically, we also wonder why some patients metastasize quickly, whereas others grow large primary tumors without any metastatic lymph nodes.”
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References
- AS Ho at al., “Metastatic lymph node burden and survival in oral cavity cancer”, J Clin Oncol, 35, 3601–3609 (2017). PMID: 28880746.