The short answer
Hot flashes are sudden warm feelings over the face, neck, or chest and may cause sweating or flushing. Night sweats are hot flashes during sleep. NCI notes they are common in people with cancer and survivors and may be caused by surgery, radiation, hormone therapy, chemotherapy, opioids, steroids, and other medicines.
Hot flashes and night sweats are common in people with cancer and survivors.
Cancer treatment can trigger hormone changes that cause symptoms.
Medicines, sleep disruption, pain, mood, and menopause-related changes may all matter.
Ask which nonhormonal options are safe for your cancer and medicines.
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The full explanation.
The short answer
Hot flashes are sudden warm feelings. They often affect the face, neck, or chest, and may come with sweating or flushing. When they happen during sleep, people call them night sweats. They are common during and after cancer treatment.
Why cancer treatment can cause them
Surgery to remove the ovaries can trigger early menopause. The ovaries stop making estrogen sooner than usual. Surgery or hormone treatment that lowers testosterone, sometimes used for prostate cancer, causes the same kind of symptom in men. Chemotherapy, hormone therapies like tamoxifen and aromatase inhibitors, and radiation can all contribute too. Other medicines, including opioids, some antidepressants, and steroids, can also cause hot flashes.
What to track
Note when your symptoms happen, how often, and whether they wake you at night. Track your medicines, since timing may line up with a dose. Note whether alcohol, spicy food, stress, or a warm room seems to trigger them. This information helps your team figure out the likely cause and the best fix.
Managing symptoms
Loose clothing made of cotton, along with fans or open windows, can help you cool down quickly. Some people cannot use hormone treatment. For them, non-hormonal options include certain antidepressants, anticonvulsants, and a blood pressure medicine called clonidine. Cognitive behavioral therapy and relaxation techniques can also help. They may not stop hot flashes completely, but can reduce how much they bother you.
Why your cancer history matters here
Estrogen replacement can control hot flashes. But many women cannot take it. NCI notes that women who have or had breast cancer often need a drug without estrogen instead. It also notes that hormone therapy combining estrogen with progestin may raise the risk of breast cancer or of breast cancer coming back.
So do not start any hormone product on your own. That includes over-the-counter supplements sold for menopause. NCI advises telling your care team about every dietary supplement and herb you take, since they can interact with your medicines.
When to get help sooner
Night sweats are not always just hot flashes. A sweat can also be the body's response to an infection.
- Call your care team without delay, at any hour, if you have a temperature of 100.4°F (38°C) or higher, chills, or shaking while on cancer treatment. CDC treats this as a medical emergency, because fever may be the only sign of an infection that can become life-threatening. If you cannot get through, go to an emergency department and tell them you are having cancer treatment.
- Call your care team the same day if you feel faint, your heart is racing, or you are too dizzy to stand safely.
- Call your care team within a day or two if night sweats are new, are soaking your bedding, or come with weight loss you did not plan.
- Call your care team within a day or two if a medicine started for hot flashes brings side effects such as bad dizziness, trouble concentrating, or constipation that will not clear.
Do not stop a prescribed cancer medicine on your own because of hot flashes. Tell your team instead. They can often adjust the plan.
What to ask your team
- What is the most likely cause of my hot flashes or night sweats?
- Could any of my medicines be contributing?
- Which non-hormonal treatments are safe for me, given my cancer history?
- When should night sweats be checked for another cause?
Sources
Words to know
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Common questions
Can men have hot flashes during cancer treatment?
Yes. NCI notes that treatment affecting testosterone, such as some prostate cancer treatments, can cause hot flashes and night sweats.
Can breast cancer survivors use hormone therapy for hot flashes?
That depends on the cancer and treatment history. Ask your oncology team before using hormonal products.
Questions to ask your doctor
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Sources last checked: 2026-08-13 what this meansLast updated: 2026-08-13Next planned review: 2027-01-20
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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: Source checked — This page was written with AI assistance and checked line by line against the sources listed on it. That confirms the sources support what the page says. It is not a medical review, and it does not confirm the page is complete or right for your situation.
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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