Frequently asked questions about sex and cancer

Can sex cause cancer?

For most cancers, there’s no link between a person’s sex life and the risk of cancer. Nor does having sex after cancer treatment increase the chances of cancer coming back or getting out of control. But viruses passed from one person to another through sexual contact have been linked to some cancers, including squamous cell carcinoma of the cervix, vulva, vagina, penis, or rectum, and Kaposi sarcoma. Hepatitis B and hepatitis C viruses, which can be passed from person to person during sex, can increase the risk for liver cancer. Epstein-Barr virus, which causes mononucleosis (also called 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. The roles of these viruses are not fully understood, but some can cause changes in the DNA of the cell. Most people who get these viruses never develop cancer. You can get more information about viruses and cancer in our document called Infectious Agents and Cancer. (See the “To learn more” section.)

There are other risk factors involved in cancer development, even in those cancers that are promoted by viruses. Women who smoke cigarettes, for example, have a higher risk of cervical cancer. Women who start having sex before age 18 also seem at higher risk for cancer of the cervix.

Many patients and their partners worry that cancer is contagious — that cancer itself can be passed from one person to another during sex. Despite this myth, a cancer cell from one person’s body simply cannot take root and grow in someone else. Not only are all cells fragile, needing the proper environment to survive, but the partner’s immune system would detect the cancer cell and destroy it. Cancer is not contagious.

Safer sex

Unless you know for sure that neither you nor your sexual partner has any disease, and that both of you are careful to avoid infection, you should practice safer sex. Examples of safer sex include:

• Touching each other’s genitals with the hands
• Oral sex with a man if he wears a condom from start to finish. A woman should never taste or swallow a man’s semen if she suspects he might have a sexually transmitted disease (STD).
• Oral sex with a woman if a “dental dam” is used. A dental dam is a rubber sheet that is used to cover the woman’s vulva during oral sex. Or a sheet of plastic kitchen wrap that keeps the woman’s sexual fluids contained can be used instead.
• Vaginal intercourse or anal intercourse wearing a condom. Condoms only work if they are used correctly, every time, from start to finish. Lots of water-based lubricant can help reduce the risk of the condom breaking. Never use lotion, oils, or petroleum jelly, which weaken latex condoms.

Can sex during treatment be harmful to a patient or partner?

A few chemotherapy drugs can be present in small amounts in semen or vaginal fluids. You may want to use condoms while you are getting chemotherapy and for about 2 weeks afterward. Some types of radiation treatment require special precautions for a certain amount of time, too. Talk to your doctor or nurse if you have questions or concerns.

Keep in mind that some cancer treatments may cause harm to the fetus if you get pregnant, and precautions must be taken to be sure this doesn’t happen. Talk with your doctor about what kind of birth control will work best for you, and how long you will need to use it after treatment.

When should a person with cancer not have sex?

Ask your doctor if sexual activity may be a problem at any time during or after your treatment. Here are some general guidelines:

• When recovering from surgery, intercourse can cause bleeding or strain the incision (cut). Sex may also increase your chance of infection. The time between your surgery and when it’s safe to resume your sex life varies. It depends on the type of operation and how well you are healing. Your surgeon can tell you when it’s safe to try sexual activity again.
• Some types of cancer, like cancer of the cervix or 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 take care not to rub against the dressing, sex should not cause any problems.
• When you are being treated for cancer, there are often times when your immune system isn’t working as well as it should. This may happen during radiation therapy or chemotherapy. At such times, it may be easier for you to get all kinds of infections. Again, ask your doctor if sexual contact poses too much of a threat for infection. Most doctors say that if you are well enough to be out in public, you’re well enough to have sex. If you’re in the hospital because of weak immunity, ask your doctor’s advice on kissing, cuddling, or sexual touching.
• There are things you can do to try to prevent urinary tract infections. Some of the bacteria that can start an infection in the urinary tract or genital area can be washed away by urinating a few minutes after sex. Some doctors also suggest washing the genital area before sex and drinking extra fluids. If you have urinary tract infections often, your doctor may give you antibiotics to take after sex. This can help prevent infection.
• If you notice any sores, bumps, or warts on your partner’s genitals or a white or greenish-gray fluid (other than semen) in the opening at the tip the penis, you should ask for an explanation of the symptom and decide whether it’s safe to have sex.
• You can greatly reduce your chances of getting a sexually transmitted disease (STD) if your partner wears a condom from start to finish each time you have sex. For women with female partners, plastic film or dental dams can be used for oral sex.
• The sperm-killing chemicals in contraceptives were once thought helpful in fighting bacteria and some viruses. But some studies showed a higher risk of getting HIV infection in women who used nonoxynol-9 (N-9), a popular ingredient in foam and gel contraceptives. Some lubricated condoms also have N-9, so you may want to check the label before you use them. If a woman’s vagina is irritated or dry, contraceptive foams, jellies, or films may make the problem worse and be painful. Water-based lubricants or vaginal moisturizers may be used to help with dryness. (See the section called “Vaginal dryness.”) Talk with your doctor about what methods might best meet your needs for preventing STDs or pregnancy.

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.

What about sex and advanced cancer or at the end of life?

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. Touching, caressing, sharing, and emotional intimacy are always important — even at the end of life.

When cancer is far advanced, a person’s needs for affection, sharing of feelings, and touch may become even stronger. Partners of patients can help by remembering how important physical closeness is, even when intercourse might be too much for the person with cancer.