Cancer

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.

What are the risks and benefits of mammograms?

DEAR READERS: In yesterday's column, I answered a question from a 47-year-old woman who had never had a mammogram and wondered if she should have one. She had heard that one group of experts -- the American Cancer Society (ACS) -- had recently changed its recommendations on this issue.

When should I start getting mammograms?

DEAR DOCTOR K: I'm a 47-year-old woman who has never had a mammogram. Some experts recommend I get one, but others do not. I understand that the American Cancer Society recently updated its recommendations about breast cancer screening. Does it say I should have a mammogram? If so, which experts should I believe?

DEAR READER: I'm surprised when people are bothered by medical experts having different opinions. Expert politicians, expert lawyers, expert architects -- experts of all kinds disagree with each other all the time. Why? Because it is rare for the "truth" of any question to be clear beyond dispute.

Can aspirin really help to prevent cancer?

DEAR DOCTOR K: I read that aspirin might help to prevent cancer. Is there anything to this idea?

DEAR READER: Open any medicine cabinet in America and you're likely to find a bottle of aspirin. Aspirin has been on the market for more than 110 years. It's an old standby for fighting fever, quieting inflammation and reducing pain. For some, it can help prevent a heart attack or stroke. And growing research points to a possible new benefit for this old friend: reducing the risk of dying from cancer.

What is the treatment for melanoma?

DEAR DOCTOR K: My doctor just discovered that I have melanoma, but didn't really explain the treatment. Can you tell me what I'm in for?

DEAR READER: Melanoma is skin cancer that begins in the melanocytes -- cells that give skin its color. Usually these cells first form a precancerous condition called a dysplastic (diss-PLAS-tik) mole. Then the cells turn cancerous and start to reproduce aggressively.

My doctor advised active surveillance for my prostate cancer. What does this mean?

DEAR DOCTOR K: After an abnormal PSA test and biopsy, I have been diagnosed with early-stage, non-aggressive prostate cancer. My doctor advised active surveillance. What does this mean?

DEAR READER: Prostate cancer is the uncontrolled growth of abnormal cells in the prostate. This walnut-sized gland sits below the bladder, in front of the rectum, near the base of the penis. Prostate cancer is common, but it is not always dangerous. People are often surprised to hear "cancer" and "not dangerous" in the same sentence.

What should I look for when I examine my skin for melanoma?

DEAR DOCTOR K: My aunt developed the skin cancer called melanoma, and I hear that this cancer can run in families. What should I look for when I examine my skin for melanoma?

DEAR READER: Skin cancers are the most common cancers in the United States, and skin checks are an important way to identify them. You asked about the deadliest type of skin cancer, melanoma. My Harvard Medical School colleague, dermatologist Dr. Kenneth Arndt, says that more than half of melanomas are identified by patients, either alone or with the help of a partner. That's important because more than 90 percent of cases can be cured with early detection and treatment. Skin carries out many functions that help maintain health. It forms a defensive barrier, protecting inner organs from foreign invaders such as bacteria and viruses.