Can sex cause cancer?

For most cancers, there is no link between a person's sex life and the risk of developing cancer. Nor does having sex after cancer treatment increase the chances of cancer coming back or getting out of control. And cancer cannot be passed from one person to another through sex.

A few kinds of cancer can be caused by viruses that are passed from one person to another through sexual contact. The roles of these viruses are not fully understood, but some can cause changes in the DNA of the cell.

The cancers that may be linked to these viruses include squamous cell carcinoma of the cervix, vulva, vagina, penis, mouth and throat, vagina, or anus. They also include Kaposi sarcoma or other cancers in people with acquired immunodeficiency syndrome (AIDS). Hepatitis B and hepatitis C viruses, which can be passed from one person to another during sex, can increase the risk for liver cancer. Epstein-Barr virus, which causes mononucleosis (also called mono or the "kissing disease"), seems to increase the risk of certain other types of cancer, too.

These cancers are not caused by having sex itself, but by viruses that can be picked up during sexual activity with someone who already has the virus. News stories about viruses and cancer can be confusing. Keep in mind that most people who get these viruses never develop cancer.

Human papilloma virus: Nearly all women with cervical cancer have been infected with human papilloma virus (HPV), which is recognized as the main cause of cervical cancer. In addition, HPV can cause cancers of the mouth and throat, anus, penis, vulva, and vagina. HPV is the most common sexually transmitted infection in the United States. HPV is passed from one person to another during skin-to-skin contact. HPV can be spread during sex -- including vaginal intercourse, anal intercourse, and even during oral sex. Most adults who have had sex will at some point get HPV. But HPV does not cause cancer in most people who get it. Some people with HPV may be more at risk of getting cancer because of their age, poor health, family history, or past experience with other cancer-causing agents. Women who smoke cigarettes, for example, have an increased risk of cervical cancer. Men who are not circumcised are more likely to develop cancer of the penis.

Human herpes virus type 8 (HHV-8): This virus causes Kaposi sarcoma in people with HIV infection. HHV-8 is different from the herpes virus that causes sores on the mouth or genitals. It is thought to be shared through intimate contact, although there may be other ways to get it. Avoiding the cancer linked to HHV-8 would include the same measures as HIV prevention.

Hepatitis B and hepatitis C: Some cases of liver cancer in the United States may be related to hepatitis B and hepatitis C, which can both be contracted through unprotected sex.

Again, most people who get these viruses never develop cancer. For more information about viruses and cancer, see our document, Infectious Agents and Cancer.

Can sex harm a patient or partner?

Some people with cancer stop having sex because they fear that it will make the cancer worse. Sometimes the worries are vague, coming from the image of sex and cancer as both somehow unclean. A few people believe that cancer is a punishment for past sins. They try to bargain with God, promising to give up sex in return for a cancer cure. If you have had such thoughts, a talk with your minister, priest, or rabbi may comfort you. Few religions support such a harsh view of illness. From a scientific point of view, there is no evidence that sex causes cancer to return, makes it worse, or gives it to a partner.

There are a couple of safety issues during and shortly after chemotherapy and certain types of radiation. A man who is having "seed implants" (brachytherapy) for prostate cancer should check with his doctor about safety precautions, such as using condoms because sometimes the seeds can migrate. And small amounts of a few chemo drugs can be found in semen for awhile after you get them. Ask your doctor whether you should use condoms around the time you get chemo.

Men who are getting chemo should avoid causing pregnancy during and for some time after treatment because chemo may harm the DNA in sperm cells. This could lead to birth defects. Ask your doctor about birth control if your partner might get pregnant. You will also want to know when you can stop using birth control for this reason.

Although sexual activity is usually safe for your partner during your cancer treatment, some couples just stop having sex, without checking out their fears with the health care team. If you have been cleared medically to resume sex, but are still unsure, perhaps you just need more time. Think about your feelings. Are there times when you feel a stirring of sexual desire?

Be sure to let your partner know that you will want to have sex as soon as you feel better. Give your partner some ideas on helping you feel more sexual again, such as, "Let's try being affectionate in a relaxed way," or "I'd like to know that you still find me attractive."

You may also need to reassure your partner that your cancer treatment does not make sexual activity dangerous. Cancer cannot be caught from another person. If you have external radiation treatments, having sex with you does not expose your partner to radiation.

When should a person with cancer not have sex?

Ask your doctor if sex would cause a problem with treatment. Each person with cancer must be treated as an individual. Here are some general guidelines to think about:

During recovery from surgery, sex can cause bleeding or strain the incision. Sex may also raise your chance of an infection. The time between surgery and resuming your sex life varies. This depends on the type of operation and your rate of healing. Your surgeon can tell you when it would be safe to try sex again.

Some types of cancer, such as cancer of the bladder, may cause bleeding in the genital area or urinary tract. If this bleeding is worse after sex, talk with your doctor about it. You may need to stop having sex until the bleeding has stopped and the area has healed.

During chemotherapy, a person with an infusion catheter sometimes worries that sexual activity will harm it. As long as you keep the dressing dry and take care not to rub against it, sex should not be a problem.

When you are being treated for cancer, there are often times when the immune system is not working as well as it should. This may happen during radiation or chemotherapy. At such times, it may be easier for you to get all kinds of infections. Again, ask your doctor for advice on whether sexual contact poses too much threat of infection. Most doctors say that if you are well enough to be out in public, you are well enough to have sex. If you are in the hospital because of weak immunity, ask your doctor's advice on kissing, cuddling, or sexual touching.

Bacteria that can start infections in the urinary tract or genital area may wash away if you urinate a few minutes after sex. You might even want to drink a glass of water before you make love, so it will be easier to urinate afterwards.

If you notice a strange sore on your partner's genitals, or any unusual fluids or discharge, you should ask for an explanation of the symptom before having sex. But you should not expect to be able to screen your partner for STDs before having sex. Most STDs are hard to spot. The only way to detect most of them is to go to the doctor and ask to be tested for them.

Remember that STDs like HIV, HPV, or chlamydia almost never have signs or symptoms you can see. Often the person with an STD does not even know he or she has it. You can reduce your chances of getting an STD if you wear a latex condom for oral, vaginal, or anal sex.

Is cancer contagious through sex? What about AIDS?

Cancer cannot be passed from one person to another, even through contact as close as kissing, sex, or oral sex. But many patients and their partners worry that cancer is contagious. News stories about viruses and cancer can also be confusing. Contrary to the myths, a cancer cell from one person's body cannot transfer during sex and take root and grow in someone else. Not only are all cells fragile, needing the proper setting to survive, but the partner's immune system knows the cancer cell is foreign and destroys it. Cancer itself is not contagious.

The human immunodeficiency virus (HIV) causes AIDS. HIV can be passed to someone by an exchange of blood, semen, or vaginal fluids through oral (mouth), vaginal, and anal (entering or being entered through the anus) sex. This virus is passed on by sexual contact, by sharing an infected person's needle or equipment during injection (IV) drug use, or from a mother to her baby during pregnancy or breast-feeding. In rare cases, the virus can be passed on by other contacts with an infected person's blood, such as during a blood transfusion or during medical treatment. Unless you know for sure that neither you nor your partner carries HIV, you should practice safer sex. If you are in a trusting relationship, and both of you have been tested and don't have the virus, unprotected sex may be safe. But both partners must stay faithful in order to protect themselves from HIV.

If you don't know for sure about your partner's (or your own) HIV status, the safest sex is mutual genital-hand touching. Oral sex can be made safer if you wear a latex condom or if you use a latex dental dam or sheet of plastic kitchen wrap that fits over the woman's vulva during oral sex. A person should never taste or swallow semen or vaginal secretions without knowing that person's HIV status first. Vaginal, oral, and anal intercourse can be made safer if you wear a latex condom. For this to be effective, condoms must be used correctly, from start to finish, every time. Water-based lubricants such as K-Y® or Astroglide® should be used with latex condoms. Oil-based lotions and petroleum products (such as petroleum jelly or Vaseline®) can cause latex to weaken or break. Using water-based lubricants can actually help keep condoms from breaking by reducing friction.

Spermicides (sperm-killing chemicals often used to prevent pregnancy) are not a good idea if you are trying to protect yourself from HIV. The sperm-killing chemicals in contraceptives were once thought helpful in fighting bacteria and some viruses. But some studies have suggested a higher risk of getting HIV infection in people who used nonoxynol-9 (N-9), a popular ingredient in foam, film, and gel contraceptives. N-9 can harm both vaginal and rectal tissues. Some lubricated condoms also have N-9, so you may want to check the label before you use them. Talk with your doctor about what methods might best meet your needs for preventing STDs or pregnancy.

We know that people with HIV infection develop certain cancers at a much higher rate than people who are uninfected. For example, non-Hodgkin lymphoma and Kaposi sarcoma are more common in people with HIV infection.

Talk to an HIV counselor at your local health department if you have questions about HIV transmission, or see the "Additional resources" section at the end of this document for more information.

What if I already have HIV?

If you have HIV, safer sex is important to avoid sexually transmitted diseases (STDs). You will also want to protect your sex partner from HIV. Even if your partner has HIV too, either of you could become infected with a second strain of the virus. Researchers have discovered, for example, that people who were first infected with a type of HIV that could be treated with anti-viral drugs have gotten drug-resistant HIV through unprotected sex. Latex condoms, if properly used, can keep HIV from being transmitted through sex. (See our document, HIV Infection and AIDS for more information.)

Do other people with cancer feel shame or guilt?

Even if a cancer treatment has not left obvious scars, many people still feel ashamed of having cancer. Some people feel that the person with cancer may be unclean or somehow to blame for the disease. These ideas are not true. Feelings of guilt or blame can only take away from the efforts you make toward solving sexual problems.

My partner is acting different since we talked about my cancer. How do I handle that?

People who know little about cancer often assume it is always fatal. In a nation where one out of every 2 to 3 people will have cancer in his or her lifetime, and where survival rates are steadily going up for those with cancer, this belief is unfounded and harmful. Still, it can affect the way others relate to you.

Keeping your partner informed about your diagnosis and treatment as it unfolds may be helpful to both of you. Fear of the unknown can interfere with intimacy. Your partner may be afraid of losing you but afraid to say so, and sometimes it helps if you can bring that up. You may have some other concerns you would like to share, too.

Sit down in a quiet, private place. Offer a chance to talk, but don't force the issue if your partner is unable to open up with you at first. Try to be available if your partner wants to talk later. If that doesn't happen, you may want to try again. If it continues to be a problem, you may want to think about counseling. If your partner doesn't want to seek help, it's OK to go by yourself. (See the "Professional help" section.)

How do I deal with sexuality if my cancer is advanced?

A very ill person is not often seen as a sexual person, but sexual feelings exist in everyone, even in times of very poor health. When cancer is advanced, a person's needs for affection, sharing of feelings, and touch may become even stronger. Partners of patients with advanced cancer can help by remembering how important physical closeness is, even when intercourse might be too much for the person with cancer.

You probably have many other questions that haven't been addressed here. Don't be afraid or embarrassed to discuss them with your doctor or other members of your health care team. Write them down now so you'll remember to ask them at your next visit.

Last Medical Review: 02/02/2009
Last Revised: 02/02/2009