Tag: breast cancer

In the last column we asked: Can we prevent breast cancer? The answer is NO! Can we reduce the risk of breast cancer? The answer is YES!

The risk of breast cancer can be reduced by use of medications, surgery and change in lifestyle. Let us first discuss the use of medication – tamoxifen.

The risk of breast cancer is related to levels of hormones present in the body from internal and external sources, says a review article in the New England Journal of Medicine written by Dr. Rowan Chlebowski, Harbor-UCLA Medical Centre, California. Tamoxifen is a medication that blocks the action of oestrogen on tissues. Most breast cancers are oestrogen dependent. And tamoxifen has been found to reduce recurrence of breast cancer in 47 percent of patients who have had breast cancer previously.

Tamoxifen has also been found to reduce the risk of breast cancer in the other breast by 47 percent regardless of the oestrogen dependence of the initial tumour. If this is the case then it was felt that tamoxifen might also reduce the risk of breast cancer in women who have no personal history of the same.

This hypothesis was tried for four years on 13,388 women, with no personal history of breast cancer but with an above average risk. Tamoxifen reduced the overall odds of breast cancer in these women by 50 percent. Unfortunately, the same results were not obtained from the trials in Britain and Italy. Probably, the trials had different designs.

It is not certain whether tamoxifen helps improve mortality, how long should it be used, and once stopped then how long the benefit will last. There is no evidence that more than five years of therapy results in further benefit. Keeping this in mind, the Food and Drug Administration in US has approved the use of tamoxifen for the reduction of breast cancer risk on women at increased risk of this disease.

Use of tamoxifen is not without risk. It is generally very safe but in rare instances can cause cancer of the uterus, blood clots, hot flashes, vaginal discharge etc. Tamoxifen should not be taken for prevention of breast cancer without first discussing with an oncologist.

What about surgery?

Prophylactic removal of both breasts is a reasonable option only for women identified as being at very high risk for breast cancer who are willing to consider its long-term implications, says Dr. Chlebowski. It is an irreversible procedure, there is loss of nipple sensation, and cosmetic and aesthetic results may not always be satisfactory. In one study, removal of both breasts resulted in reducing the calculated odds of breast cancer and associated death by about 90 percent. This is pretty good.

Second surgical option is to have both ovaries removed before menopause. Observational studies have suggested that this may reduce the risk of breast cancer by 22 to 50 percent. But further studies are required to prove that this a good option of premenopausal women at high risk for breast cancer who have decided not to have children or not to have more children, says Dr. Chlebowski.

Finally, lifestyle changes and risk reduction. Increased dietary fat intake, body weight, and alcohol intake and decreased exercise have been associated with increase breast-cancer risk, says Dr. Chlebowski. Improving in all these areas will certainly help in overall improvement of health.

Sometimes medicine has been described as imperfect science. What you read today is a good example. There are no clear-cut answers, but there some options which may help some women. I guess that is better than no options! So discuss this with your doctor or an oncologist before you decide what is good for you.

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Can we prevent breast cancer? Probably not! Prevention implies complete protection from breast cancer. This is not possible. What is possible is to understand the risk factors and then try risk reduction.

What are the risk factors for breast cancer?

Being a woman is a risk factor. Men do get breast cancer. But of all breast cancers, only one percent is in men.

Age of the woman is another risk factor. Incidence of breast cancer has been rising in the North American women probably due to aging population. Breast cancer is uncommon at younger ages.

An article in the New England Journal of Medicine, written by researchers in Toronto, says that a woman entering her 30s has a 1 in 250 chance of breast cancer in the next 10 years. The risk of breast cancer increases with age, so that a woman entering her 40s has a 1 in 77 chance of the disease in the following decade. The risk of breast cancer in any decade of life never exceeds 1 in 34.

The cause of death among women at any age is always more likely to be something other than breast cancer. But proportionately, middle-aged ladies have more deaths due to breast cancer than older ladies, as tumours in younger women are more aggressive than older women.

Here are some interesting numbers on other factors that increase the risk of breast cancer: alcohol (more than 3 drinks/day) – 63 percent increased risk, lack of exercise – 59 percent increased risk, first birth after age 30 – 48 percent increased risk, weight gain (more than 20 kg) – 40 percent increased risk, late menopause – 28 percent increased risk, early menarche (before age 12) – 24 percent increased risk.

A family history of breast cancer is a well-known risk factor. The risk to a woman with a first-degree relative with breast cancer is generally reported to be two to three times higher than the risk to a woman with a negative family history. This is not something new. Physicians knew the familial occurrence of breast cancer as early as the year 100 A.D.

What about women with lumpy and granular breasts (fibrocystic changes)? Many attempts have been made to evaluate the relation between fibrocystic disease and cancer. There has been no clear cut evidence to suggest that fibrocystic changes in general predisposes to cancer. Once a woman has had a biopsy for benign disease, she is more likely to have a second biopsy, either because there is increased follow-up or there is distortion of tissue due to previous biopsy. Biopsy rate amongst women with fibrocystic changes is five times higher than other women.

When it comes to breast cancer, every woman is a potential target. Breast cancer is the leading cause of premature death in Alberta’s women. So, are there any strategies to reduce the risk of breast cancer?

Yes. In the next column, we will look at the recent research results that suggest that the risk of breast cancer can be reduced. So, stay tuned!

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“Dr. B, is there a pill to prevent breast cancer? You know my sister has had breast cancer and she takes Tamoxifen. Does the pill prevent cancer in women who have had no breast cancer?”

As always, Susan’s questions are right to the point. She has read recent reports about the benefits of Tamoxifen in women with a significantly elevated risk factors. She wants to know where she stands.

Susan, let’s look at the history of Tamoxifen – it’s usage, side effects – and then review the results of recent study undertaken by the Breast Cancer Prevention Trial (BCPT).

Breast cancer is usually hormone (estrogen) dependent. When indicated, women with breast cancer underwent surgery to remove organs which produced estrogen (e.g. ovaries) which helped control or regress the tumor.

Discovery of Tamoxifen reduced the need for these surgical procedures as the drug stopped the binding of estrogen to the tumor. In 1977, Tamoxifen was approved in the U.S. by the Food and Drug Administration for use in breast cancer. Thus began a new era in the treatment of this cancer.

“Dr. B, why did the researchers think that Tamoxifen would help prevent cancer in women who have no personal history of breast cancer?”

Tamoxifen has been used for 21years in the treatment of breast cancer. During this time, it clearly showed that it can reduce the risk of recurrent breast cancer and development of cancer in the other breast. The later finding encouraged researchers to start Breast Cancer Prevention Trial.

“Go on Dr. B, how did they do the study?”

Susan, BCPT enrolled 13,388 women at 300 sites in U.S. and Canada. These women were at a higher risk of developing breast cancer. They were randomly assigned to receive either placebo or Tamoxifen

The study – over 6 years – showed 45 per cent reduction of breast cancer in women who took Tamoxifen compared to the placebo group. It was also observed that these women have lower incidence of osteoporosis and coronary artery disease. Because of this significant finding the trial was discontinued earlier than expected due to ethical reasons.

“Doctor, what are the side-effects of Tamoxifen?”

Susan, some women developed cancer of the uterus, some had deep vein thrombosis (blood clot in the leg), and some had pulmonary embolism (blood clot in the lungs). About 15 percent of women suffer from: hot flushes, irregular menstrual periods, nausea, vomiting, light-headedness and dizziness.

One significant unanswered question is: For how long a woman can take Tamoxifen without increasing the chance of side-effects?

Women with breast cancer have been advised not to take Tamoxifen for more than 5 years as the risk of recurrent cancer and death were higher in women who took Tamoxifen for 10 years. The same cannot be said for women who take this pill for prevention. The study wasn’t long enough.

“So, Dr. B, can a woman take Tamoxifen for prevention if she is not part of a clinical trial?”

Last year, Susan, Editorials in the British Medical Journal and the Canadian Medical Association Journal discouraged women taking Tamoxifen outside clinical trials until further information was available on its risks and benefits.

But the authors, who reported the BCPT results in the Journal of National Cancer Institute said: Despite side effects resulting from administration of Tamoxifen, its use as a breast cancer preventive agent is appropriate in many women at increased risk for the disease.

Susan was keen on exploring the idea further for preventive measures and was referred to a medical oncologist.

(This series of articles explore the health problems of Dave and his family. They are composite characters of a typical family with health problems)

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