Key Takeaway:
- First-Time adult seizures in adults may be an early warning sign of brain cancer or other cancers.
- Immediate medical evaluation after a seizure can help detect serious illness earlier.
- Seizures have many causes, but experts advise treating the first episode as urgent.
A new international study finds that first-time seizures in adults may serve as an early warning sign of brain cancer and other malignancies, urging doctors to treat such events as serious medical emergencies requiring immediate evaluation.
Study Links Adult Seizures To Increased Cancer Risk
An international research team reports that seizures occurring for the first time in adulthood could signal an underlying cancer diagnosis, including brain tumors, according to findings published Monday in JAMA Neurology.
The study analyzed nearly 49,900 Danish adults who experienced seizures at an average age of 50. Researchers found that First-Time adult Seizures were associated with a higher risk of developing cancer within one year and a slightly elevated long-term risk.
Brain cancer remains among the deadliest diseases, making early detection critical for improving survival outcomes. While symptoms such as severe headaches or dizziness are widely recognized, seizures may appear before other warning signs.
About one in 10 adults in the United States experiences a seizure at some point in life, though experts stress that seizures do not automatically indicate cancer.
“I think the seizure is the smoke, not necessarily the fire,” said Dr. Randy D’Amico, director of the Brain and Spine Metastasis Program at Northwell Lenox Hill Hospital. “The fire is probably already ongoing within the brain.”
Brain Anatomy Helps Explain Seizure Warning Signs
Researchers say the connection between seizures and brain cancer is consistent with how tumors affect brain function. Growths located in the brain cortex or swelling caused by tumors can disrupt normal electrical signals.
“When tumors or swelling increase pressure in the brain, they can provoke seizures,” D’Amico said.
Abnormal electrical activity may therefore become one of the earliest detectable signs of disease, sometimes appearing before imaging or physical symptoms reveal a tumor.
The study also identified links between First-Time adult Seizures and cancers outside the nervous system. Elevated risks were observed for lung, bronchial, and tracheal cancers, suggesting seizures may reflect broader systemic disease.
According to D’Amico, cancers elsewhere in the body can spread to the brain without obvious early symptoms.
“You may not know that you have cancer, but small metastatic disease to the brain can already be developing,” he said. “Lung cancer loves to go to the brain.”
Doctors Urge Urgent Evaluation, Not Panic
Medical experts emphasize that many conditions unrelated to cancer can cause seizures. Factors include inflammation, oxygen deprivation, blood sugar fluctuations, breathing changes, or electrolyte imbalances such as sodium disturbances.
Still, physicians advise treating seizures in adulthood as a medical emergency rather than dismissing it as an isolated event. Early testing may help identify serious illness sooner and improve treatment outcomes.
“The first seizure may be telling you that something serious is happening,” D’Amico said. “If you miss that early window of opportunity, diagnosis can be delayed.”
Researchers say the findings highlight the importance of immediate neurological evaluation, imaging, and follow-up care after an unexplained seizure.
Health specialists caution against panic but encourage awareness, noting that prompt medical attention offers the best chance of identifying underlying causes — whether neurological, systemic, or benign.
The study’s authors say further research is needed to better understand why seizures sometimes precede cancer diagnoses and how screening protocols should change for adults experiencing their first seizure.
