The short answer
A panic attack and a blood clot in the lung feel almost identical from the inside. This guide covers getting assessed first, what NCI says causes and treats anxiety in cancer, and what helps in the moment.
New chest pain or new breathlessness needs a medical assessment first. Do not decide for yourself that it is panic — CDC's list of pulmonary embolism signs is nearly the same list.
NCI describes a panic attack as a sudden wave of intense fear, usually lasting 10 to 20 minutes, and reports that almost half of people with cancer feel some anxiety.
Before settling on panic, NCI's treatable causes are worth excluding: steroids and other medicines, withdrawal, sepsis, low blood oxygen, heart failure, electrolyte imbalance, uncontrolled pain, and certain tumors.
NCI lists cognitive behavior therapy, relaxation training, counseling and medicine, and says people having trouble adjusting to cancer should try counseling before medicine.
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The full explanation.
When to get help sooner
A panic attack and a serious medical emergency can feel exactly the same from the inside. Racing heart. Air that will not go deep enough. Chest pain. Sweating. Doom.
During cancer treatment, that overlap is dangerous. New chest pain or new breathlessness needs a medical assessment first. Do not decide for yourself that it is panic.
- Call 911 or go to an emergency department if you have chest pain, difficulty breathing, a cough that brings up blood, or a heartbeat that is fast or irregular — especially if the chest pain is worse when you breathe in or cough. Those are the signs of a blood clot in the lung.
- Phone your oncology team at once, at any hour, if your temperature reaches 100.4°F (38°C) or higher and you are on chemotherapy; if you cannot reach them quickly, go to an emergency department and say at the desk that you are on chemotherapy. CDC calls a fever during chemotherapy a medical emergency, because your body may have too few white cells to fight the infection behind it. Do not sit on it until morning. If your current treatment does not lower your blood counts, a same-day call is enough — ask your team which applies to you.
- Call your care team the same day if you had an episode of chest pain or breathlessness that has now passed, or one leg is swollen, painful, warm, or discoloured.
- Call your care team within a day or two if the attacks keep coming, you are avoiding scans or appointments because of them, or you are rating your distress at 4 or higher out of 10.
This is not caution for its own sake. The Centers for Disease Control and Prevention states that having cancer, and some of its treatments, increases the risk of a blood clot. Hospital stays, surgery, chemotherapy, hormone therapy, and catheters all raise it. A clot that travels to the lungs is called a pulmonary embolism, and CDC lists its signs as difficulty breathing, chest pain that gets worse with a deep breath or a cough, coughing, coughing up blood, and a fast or irregular heartbeat.
Read that list again. It is nearly the same list as panic.
Review hold: This safety-sensitive draft is excluded from public search until an appropriate qualified reviewer checks the wording.
The National Cancer Institute makes the same point about anxiety generally. It notes that anxiety may be a warning sign of a change in metabolism such as low blood sugar, a heart attack, a severe infection, pneumonia, or a blood clot in the lung.
Nobody at the clinic will think less of you for calling and being told it was anxiety. That is a good outcome, not a wasted trip.
What a panic attack actually is
A panic attack is a sudden wave of intense fear with strong physical symptoms. NCI describes shortness of breath, a fast heartbeat, sweating, and nausea. It usually lasts 10 to 20 minutes. The fear of the next one can last much longer, and for many people that is the harder part.
Panic attacks are not dangerous in themselves. They are not a sign that you are losing your mind. They feel enormous because your body has fired an alarm designed for real danger.
Anxiety in cancer is common. NCI reports that almost half of people with cancer feel some anxiety, and about a quarter feel a great deal of it.
Other things that cause these symptoms
Before settling on panic, it is worth ruling out the treatable causes NCI lists.
- Medicines. Corticosteroids, thyroxine, bronchodilators, and antihistamines can all cause restlessness, agitation, or anxiety.
- Withdrawal. Stopping alcohol, nicotine, opioids, or antidepressants can cause agitation or anxiety.
- Body chemistry and illness. Sepsis, low blood oxygen, heart failure, and electrolyte imbalance all produce anxious symptoms.
- Certain tumors. NCI notes that tumors of the adrenal gland, pituitary gland, pancreas, or thyroid can cause anxiety and panic attacks.
- Pain. NCI puts it directly: people with uncontrolled pain feel anxious, and anxiety can increase pain.
Bring your full medicine list, including anything you were given for nausea, and anything you have stopped or run out of.
Getting through one
Once your team has assessed you and knows what is happening, these help in the moment.
- Slow the out-breath. Breathe out for longer than you breathe in. Long exhale, short pause, repeat. This is the fastest lever you have.
- Name it. "This is panic. It peaks and it passes." Saying it interrupts the loop where fear feeds fear.
- Ground yourself in the room. Name five things you can see, four you can touch, three you can hear. It gives your attention somewhere else to go.
- Do not fight the feeling. Trying to force it away tends to extend it. Letting it rise and fall shortens it.
- Stay put if you can. Leaving the infusion chair or the scanner teaches your brain that the room was the threat. That makes next time harder.
Treatment that lasts
NCI lists several treatments for anxiety in cancer:
- Cognitive behavior therapy. This teaches you to catch and change the thoughts that fuel the alarm.
- Relaxation training, including hypnosis, meditation, guided imagery, and biofeedback.
- Counseling, one-to-one or in a group.
- Medicine. Anti-anxiety medicines can be used alone or with therapy, and NCI notes that studies show antidepressants are useful for anxiety disorders.
NCI adds an important sequencing point: people having trouble adjusting to cancer should try counseling before medicine.
Ask your cancer center whether it has psycho-oncology, meaning mental health care built around cancer. Ask social work too. Both usually know who to send you to.
Panic tied to scans and procedures
Many people find panic is not random. It arrives in the scanner, in the waiting room, or on the drive in.
NCI describes how this happens. Neutral things such as smells, sounds, and sights become linked to a distressing experience, and later set off the same reaction on their own. For people with earlier trauma, being inside an MRI or CT scanner can restart older symptoms.
That is treatable too, and it is worth naming to the team. Options may include a different appointment time, a talk-through of the scan beforehand, someone with you, or medicine before the scan.
Getting it taken seriously
Cancer centers screen for distress, often with a simple 0 to 10 rating. In research on that scale, a score of 4 or higher was the point that best identified people who needed follow-up.
If you are asked, answer honestly. If nobody asks, say it anyway. Useful ways to open:
- "I had an episode of chest pain and breathlessness on Tuesday. I need it checked, and I also want to talk about anxiety."
- "I have had four of these in two weeks. What should I do when one starts?"
- "The scanner is the trigger. Can we plan the next one differently?"
Keep a short log: when it started, how long it lasted, what you felt, what you had taken, and what helped. It turns a vague complaint into something a clinician can act on.
Sources
- Adjustment to Cancer: Anxiety and Distress (PDQ) — National Cancer Institute
- Adjustment to Cancer: Anxiety and Distress (PDQ), Health Professional Version — National Cancer Institute
- Understanding Your Risk for Blood Clots with Cancer — Centers for Disease Control and Prevention
- Cancer-Related Post-Traumatic Stress (PDQ) — National Cancer Institute
- Infections and Neutropenia During Cancer Treatment — National Cancer Institute
- Watch Out for Fever — Centers for Disease Control and Prevention
Words to know
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Common questions
How do I tell a panic attack from something dangerous?
From the inside, often you cannot, and during cancer treatment that overlap is dangerous. New chest pain or new breathlessness needs a medical assessment first. CDC notes that cancer and some treatments raise the risk of a blood clot, and the signs of a pulmonary embolism are nearly the same list as panic. Nobody will think less of you for calling and being told it was anxiety.
How long does a panic attack last?
NCI describes a sudden wave of intense fear with shortness of breath, a fast heartbeat, sweating, and nausea, usually lasting 10 to 20 minutes. The fear of the next one can last much longer, and for many people that is the harder part. Panic attacks are not dangerous in themselves and are not a sign that you are losing your mind.
Could something other than anxiety be causing this?
Yes, and NCI lists causes worth ruling out first. Corticosteroids, thyroxine, bronchodilators, and antihistamines can cause restlessness or anxiety. So can withdrawal from alcohol, nicotine, opioids, or antidepressants. Sepsis, low blood oxygen, heart failure, electrolyte imbalance, and uncontrolled pain all produce anxious symptoms, and tumors of the adrenal gland, pituitary gland, pancreas, or thyroid can cause panic attacks.
What helps while one is happening?
Once your team has assessed you, breathe out for longer than you breathe in, which is the fastest lever you have. Name it: this is panic, it peaks and it passes. Ground yourself by naming five things you can see, four you can touch, and three you can hear. Do not fight the feeling, and stay put if you can, because leaving the infusion chair teaches your brain that the room was the threat.
What treatment works beyond the moment?
NCI lists cognitive behavior therapy, relaxation training including hypnosis, meditation, guided imagery, and biofeedback, counseling one-to-one or in a group, and medicine. Anti-anxiety medicines can be used alone or with therapy, and studies show antidepressants are useful for anxiety disorders. NCI adds that people having trouble adjusting to cancer should try counseling before medicine.
Questions to ask your doctor
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Sources last checked: 2026-08-13 what this meansLast updated: 2026-08-18Next planned review: 2027-01-22
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How this page was created
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes. We do not employ clinicians and do not intend to — our work is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Editorial review complete — This page completed Cancer Explained's editorial checks (sources, safety, plain language, duplication). It has not been reviewed by a physician or other healthcare professional.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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