The short answer
Cancer treatment can change desire, arousal, physical function and body image, usually for several reasons at once. This page sets out what NCI and ACS say about each, why fertility has to be raised before treatment starts, and how to open the conversation with your team.
Pelvic radiation, pelvic surgery and hormone therapy can all cause erection problems, while chemotherapy usually does not affect erections.
Fertility preservation is a before-treatment decision, so talk with a fertility specialist before therapy starts.
Some chemotherapy can remain in semen or vaginal secretions, so condoms may be recommended to protect a partner.
Most people can be sexually active during treatment, though abstaining is advised when infection or bleeding risk is raised.
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The full explanation.
Cancer treatment changes sex. Most people find this out on their own, in private. They assume they are the only one. They are not.
The American Cancer Society is direct about the scope. Cancer and its treatments "can affect every part of your sexuality, including your: Sex organs, Sexual desire (sex drive or libido), Sexual function and well-being, Body image." That is a wide net. It means the problem is rarely only one thing.
Why Desire Drops
Low desire during treatment usually has several causes stacked together.
Hormones. The National Cancer Institute notes that chemotherapy and hormone therapy can lower estrogen in women and testosterone in men. It states plainly that chemotherapy "may lower your testosterone levels and libido during the treatment period." It says hormone therapy "can lower testosterone levels and decrease a man's sexual drive."
Everything else treatment does to you. NCI lists fatigue, pain, hair loss, and sadness as things that affect desire. ACS adds nausea, bowel or bladder problems, skin problems, and changes in appearance. Medicines matter too. NCI names opioids and antidepressants as drugs that may "lower your interest in sex."
So treat the fatigue, the pain, or the depression. That is often the most effective thing you can do for desire. It is not a detour from the sexual problem.
Arousal and Physical Function
For women, there are three main physical changes: vaginal dryness, thinning and narrowing of vaginal tissue, and pain with penetration. NCI notes chemotherapy can cause "vaginal dryness, which can make sexual intercourse difficult or painful." It says pelvic radiation causes vaginal stenosis and atrophy. Our separate article on dryness and vaginal pain covers lubricants, moisturizers, vaginal estrogen, and dilators in detail.
For men, the main change is trouble getting or keeping an erection. NCI names radiation to the pelvis, surgery in the pelvis and hormone therapy as treatments that can cause it. And, usefully, "chemotherapy does not usually affect your ability to have an erection." Radiation damage to the prostate can also cause "a dry orgasm," meaning orgasm without ejaculation. Our article on erectile dysfunction after prostate cancer treatment goes through the treatment options.
Fertility Is a Before-Treatment Decision
This one is time-sensitive in a way the rest is not. NCI states: "If having a biological child one day may be important to you, consider talking with your doctor and a fertility specialist before starting cancer treatment."
Several treatments can reduce or end fertility. They include chemotherapy, above all the alkylating agents. They also include radiation to the pelvis or central nervous system, hormone therapy, stem cell transplant, and surgery on reproductive organs. NCI notes that sperm banking is "the most common fertility preservation method for males who have gone through puberty." For women it lists egg freezing, embryo freezing, ovarian tissue freezing, ovarian transposition, ovarian shielding, and radical trachelectomy. Survivors who consult a fertility specialist report less regret afterward.
Can You Have Sex During Treatment?
Usually yes. NCI says most women and most men can be sexually active during treatment. But confirm it with your doctor. There are times when you may be advised to abstain. That applies when you are at increased risk of infection or bleeding.
Two other precautions come from NCI directly. Some types of chemotherapy can remain in semen or vaginal secretions, so condoms may be recommended to prevent your partner's exposure. And contraception may be advised to prevent pregnancy during treatment, and for a period of time afterward.
Body Image
Surgery for gynecologic cancers, mastectomy, and ostomy surgery may change how you see your body. NCI says your health care team should talk with you about what to expect. They should also teach you how to adjust after surgery. ACS notes a partner may worry about how to express love physically after treatment. That is not rejection, though it can feel like it.
Talking About It
With a partner. ACS suggests picking "a low-stress, unrushed time to talk." Let your partner know what gives you pleasure, and what reduces discomfort. And remember that "sexual intimacy involves more than intercourse."
With your team. ACS is blunt: "Don't assume your doctor or nurse will ask you about sex or intimacy problems. You might have to start the conversation." It offers a script if you need one: "I was reading about (surgery/treatment) and that it might cause sexual problems. Can you explain that to me?"
NCI suggests some questions. What sexual problems are common with this treatment? When might changes occur? How long might they last, and will any be permanent? How can they be prevented or managed? What specialists should I talk with? Teams can refer you to a sex educator, counselor, or therapist.
Where the Evidence Is Thin
These sources describe what happens and what to try. But they do not give recovery rates. They do not give timelines for desire returning. And they do not compare treatments for sexual problems after cancer head to head. Anyone quoting a firm percentage should be able to show you the study.
When to get help sooner
- Call 911 or go to an emergency department if an erection turns painful or goes on beyond 4 hours after a dose of an erection medicine such as sildenafil.
- Call your care team the same day if you notice vaginal bleeding outside a period, or bleeding after sex that does not stop after a few minutes.
- Call your care team within a day or two if pain with penetration keeps getting worse, or the lubricant, moisturizer, or dilator plan you were given is not helping.
Sources
- MedlinePlus (National Library of Medicine): Sildenafil. https://medlineplus.gov/druginfo/meds/a699015.html
- National Cancer Institute: Bleeding and Bruising (Thrombocytopenia). https://www.cancer.gov/about-cancer/treatment/side-effects/bleeding-bruising
- American Cancer Society: Cancer, Sex, and Intimacy. https://www.cancer.org/cancer/managing-cancer/side-effects/sexual-side-effects/how-cancer-affects-sexuality.html
- National Cancer Institute: Sexual Health Issues in Women and Cancer Treatment. https://www.cancer.gov/about-cancer/treatment/side-effects/sexuality-women
- National Cancer Institute: Sexual Health Issues in Men and Cancer Treatment. https://www.cancer.gov/about-cancer/treatment/side-effects/sexuality-men
- National Cancer Institute: Fertility Issues in Girls and Women with Cancer. https://www.cancer.gov/about-cancer/treatment/side-effects/fertility-women
- National Cancer Institute: Fertility Issues in Boys and Men with Cancer. https://www.cancer.gov/about-cancer/treatment/side-effects/fertility-men
Words to know
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Common questions
Why does desire drop during treatment?
Usually several causes stacked together. NCI notes that chemotherapy and hormone therapy can lower estrogen in women and testosterone in men. Fatigue, pain, hair loss and sadness affect desire, as do nausea, bowel or bladder problems and changes in appearance, and NCI names opioids and antidepressants as medicines that may lower interest in sex. Treating the fatigue, the pain or the depression is often the most effective thing you can do for desire.
What physical changes are common for women?
Three main ones: vaginal dryness, thinning and narrowing of vaginal tissue, and pain with penetration. NCI notes that chemotherapy can cause vaginal dryness that makes intercourse difficult or painful, and that pelvic radiation causes vaginal stenosis and atrophy.
What physical changes are common for men?
Mainly trouble getting or keeping an erection. NCI says radiation to the pelvis, surgery in the pelvis and hormone therapy can all make it hard to get or keep an erection, and that chemotherapy does not usually affect the ability to have an erection. Radiation damage to the prostate can also cause a dry orgasm, meaning orgasm without ejaculation.
Can I have sex during treatment?
Usually yes. NCI says most women and most men can be sexually active during treatment, but confirm it with your doctor, because you may be advised to abstain when you are at increased risk of infection or bleeding. Some types of chemotherapy can remain in semen or vaginal secretions, so condoms may be recommended, and contraception may be advised during treatment and for a period afterward.
When do I need to raise fertility?
Before treatment starts. NCI says that if having a biological child one day may be important to you, consider talking with your doctor and a fertility specialist before starting cancer treatment. Chemotherapy, above all the alkylating agents, plus radiation to the pelvis or central nervous system, hormone therapy, stem cell transplant and surgery on reproductive organs can all reduce or end fertility. Survivors who consult a fertility specialist report less regret afterward.
Questions to ask your doctor
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Written by: Cancer ExplainedSources last checked: 2026-08-11 what this meansLast updated: 2026-08-13Next planned review: 2027-01-28
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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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