Initial surgery may be associated with lower risk of stroke in head and neck cancer patients

PHILADELPHIA – Radiation therapy and chemotherapy for head and neck cancer may be associated with a significantly increased risk of stroke compared to initial surgery, suggests a new study from researchers at the Perelman School of Medicine at the University of Pennsylvania†

The researchers analyzed health records of more than 10,000 U.S. veterans who had been diagnosed with non-metastatic oropharyngeal squamous cell carcinoma (OPSCC) in the period 2000-2020. They found that patients in this cohort who received initial surgery, rather than radiation or chemotherapy with radiation, had a 23 percent lower risk of stroke over the next 10 years.

The results will be presented (Abstract #6057) at the 2022 American Society of Clinical Oncology (ASCO) annual meeting taking place June 3-7, 2022 in Chicago.

“We should consider taking this difference in stroke risk into account in patient counseling and treatment, and to further investigate cardiovascular events in this high-risk population,” said lead author. Lova L. Sun MD, MSCE, an assistant professor of Hematology-Oncology. “There is a significant subset of oropharyngeal squamous cell carcinoma patients for whom it is reasonable to offer surgery or radiation beforehand, and for these patients the potential increase in stroke risk should be an additional risk-benefit consideration.”

More than 50,000 people in the US are diagnosed each year oropharyngeal cancers, and more than 10,000 of them die. Standard treatment includes surgery or radiation therapy and chemotherapy. In recent years, however, researchers have begun to find evidence that radiation and chemotherapy for these cancers can increase the risk of stroke, possibly by damaging arteries that serve the brain.

Sun and her colleagues in their study added to this evidence base by analyzing data from a cohort of a U.S. veteran — a total of 10,436 individuals who were diagnosed with non-metastatic OPSCC. These individuals, approximately 99 percent of them males, were treated with radiotherapy with or without chemotherapy and without surgery (7,719 individuals), or prior surgery with or without chemotherapy and radiotherapy (2,717 individuals).

The results showed that 12.5 percent of the total group, or one in eight, experienced a stroke in the follow-up period up to 10 years after treatment, making them generally a high-risk group. By comparison, the average 65-year-old American man would have a 10-year risk of stroke of about 7 percent.

The analysis also found that patients undergoing surgery had a 23 percent lower risk of stroke after taking into account differences between patients undergoing surgery and non-surgical treatment using propensity score weighting methods, which include: estimate the likelihood of receiving treatment and help isolate the effect of a treatment from other differences that may exist between treatment and comparison groups.

These patients had shorter courses of radiation and chemotherapy on average compared to the no-surgery group, suggesting that the reduced exposure to these sources of tissue damage may have been a factor in the reduced risk of stroke. In addition, the association between surgery and a lower risk of stroke was seen in different age groups, and in groups with and without hypertension, high cholesterol and diabetes, implying that differences in these other risk factors cannot fully explain the lower number of strokes in the surgery group. . †

Sun and her colleagues suggest more research needs to be done to further clarify the effect of radiation and chemotherapy on the risk of stroke and other cardiovascular events, but in the meantime, doctors and patients should consider the possibility of a lower risk of a stroke. stroke with prior surgery when considering OPSCC treatment options.

This work was supported by a faculty pilot grant from the Penn ENT Department.