Cancer

I have dense breasts. Does that increase my risk of breast cancer?

DEAR DOCTOR K: My doctor says I have dense breasts, and a friend says that means I have an increased risk of breast cancer. I'm hoping you'll tell me that's not so.

DEAR READER: I wish I could fully reassure you, but I can't. A woman who has dense breasts does have a slightly increased risk of breast cancer, although not clearly an increased risk of fatal breast cancer.

Can you discuss hormonal therapy to treat prostate cancer?

DEAR DOCTOR K: My doctor has proposed androgen deprivation therapy to treat my prostate cancer. Can you tell me about this treatment?

DEAR READER: Androgens are the family of male sex hormones that includes testosterone. When prostate cancer develops, testosterone contributes to the growth and spread of the tumor. Androgen deprivation therapy deprives cancer cells of this stimulation. Also known as hormonal therapy, it can be a powerful weapon in the fight against prostate cancer.

Did cancer treatment increase my heart disease risk?

DEAR DOCTOR K: I survived cancer, only to be told that the treatments that saved my life may have increased my risk for cardiovascular disease. What are the risks? And can I minimize them?

DEAR READER: As more people are living longer after a cancer diagnosis, more people are coping with the long-term effects of cancer treatment. Many cancer-suppressing treatments can have undesirable effects, for example, on the heart and blood vessels.

What can elephants teach us about cancer?

DEAR DOCTOR K: I heard on the radio about a new research finding that elephants don't get cancer. If we could figure out why, could we protect ourselves against cancer?

DEAR READER: A recent study found that elephants (and many animals) do, in fact, get cancer, but have lower rates of death from it than humans do. The study also found one possible explanation that, as you suggest, might someday help us deal with cancer.

Does my son need to get the HPV vaccine?

DEAR DOCTOR K: A friend says that my young son should get the vaccine that protects girls against cervical cancer. That doesn't seem to make sense. Can you explain?

DEAR READER: Your friend is right, and here's why. The vaccine is against a virus called human papilloma virus (HPV). There are more than 100 strains of HPV; about 40 of these strains can be transmitted by sexual contact. So-called low-risk strains cause genital warts. High-risk strains can cause cancers of the cervix, anus, penis and throat. I'll call these the HPV-related cancers. Not all of these cancers are caused only by HPV, but the virus is an important cause of each. Most cases of cervical cancer in women in the United States are caused by HPV.

How does sun exposure damage our skin?

DEAR DOCTOR K: You've said many times that the sun can harm our skin and increase the risk for skin cancer. How does it do that?

DEAR READER: As you age, the single biggest cause of damage to skin is sun exposure. This damage is called "photoaging." Over the years, sun exposure causes fine and coarse wrinkles; baggy skin with a yellow, leathery appearance; and dry, scaly skin. It also reduces collagen, a natural chemical that gives strength to tissues and that supports a network of blood vessels in the skin. As a result, the skin bruises more easily.

Do I need to get a Pap test every year?

DEAR DOCTOR K: I've had a Pap test every year for 20 years, since I was about 25. It's always normal. Do I still need one every year?

DEAR READER: The answer used to be yes. The reason was that doing the test often would help catch cancer of the cervix at its earliest and most curable stage. However, studies showed that less frequent Pap tests for younger women caught just as many early cancers. The studies also showed that many older women with repeatedly normal Pap smears (like you) had an extremely low risk of ever getting cancer of the cervix.

What are some of the main causes of cancer?

DEAR DOCTOR K: A while back, you commented on a study that said getting cancer was mainly caused by bad luck. You said you thought the study was wrong. Then recently, I heard that another study agreed with you. Can you explain?

DEAR READER: In April 2015, I responded to a question about a study from a famous cancer researcher. The media had interpreted the study to say that getting cancer was just a matter of "bad luck." In other words, there was not much people could do to protect themselves against getting cancer.

Does radiation therapy for cancer increase heart disease risk?

DEAR DOCTOR K: I had radiation therapy for breast cancer a few years ago. Now I'm reading that radiation therapy might increase my risk for heart disease. Is this true? Can I do anything to decrease my risk?

DEAR READER: Radiation therapy uses high-energy rays to damage or destroy cancer cells. It harms cancer cells primarily by damaging their genes. But the radiation can also damage the genes of healthy non-cancerous cells.

Do all cases of DCIS breast cancer need aggressive treatment?

DEAR DOCTOR K: I have been diagnosed with ductal carcinoma in situ. My doctor wants me to have surgery. But recently I read about a study that said not all women with this type of breast cancer even need to be treated. Can you help clear this up?

DEAR READER: Ductal carcinoma in situ (DCIS) is a type of breast cancer. In DCIS, the cancerous cells are contained within the breast's ducts (which carry milk to the nipple) but have not invaded surrounding tissue.