Breast cancer

DOCTOR’S CORNER

BREAST cancer is the commonest form of cancer to affect women in the Western world. There are 24 000 new cases in the UK every year and it is directly responsible for 19 percent of all cancer-related deaths in women.

The statistics for Lesotho are not readily available, but breast cancer is known to affect the population significantly. It is suspected to be on the increase.

In the Western world, the probabilities of developing the disease were estimated at 1:13 in 1970, 1:11 in 1980 and 1:9 in 1992. In general, the less industrialised nations tend to have lower rates of breast cancer, but this difference is diminishing.

Breast cancer is rare under the age of 35, and increases with age. A family history of breast cancer and sometimes related cancers such as cancer of the intestines and the womb are risk factors. The risk is even more when there are one or more first or second-degree relatives with breast cancer.

Women who undergo early menarche — ie start their menstrual periods at an earlier age than usual — and late menopause are at a higher risk of breast cancer.

A woman who has a child before the age of 18 years has one-third the risk of developing breast cancer than a woman with one child (primiparity) and is over the age of 35.

Infertility and nulli-parity (having no children) confer a higher probability/risk of developing the disease and a first full-term pregnancy after the age of 30 makes the risk greater than that for a woman with no children (nulli-parous).

Breast-feeding for a total time of greater than 36 months during a woman’s reproductive years was thought to protect against the development of breast cancer. However, repeated observations have shown this to be untrue.

Dietary fat has been suggested as a risk factor although its exact role remains controversial. The different amounts of saturated and unsaturated fat available within specific diets may be important. In fact, the number of new cases in Japan has doubled and has been attributed to the adoption of a westernised diet.

The information available from the researches on diet and breast cancer is further complicated by the fact that obesity is a definite risk factor in its own right. In post-menopausal women (women who are no longer having their periods), obesity directly correlates with an increase in breast cancer risk of up to twofold. However, these women tend to come from the more affluent Western societies where saturated animal fats in the diet are common.

Exogenous hormones, which are hormones that are introduced from outside the body, may introduce a slight risk of developing breast cancer such as if a high dose of estrogen oral contraceptive has been taken for a prolonged time at an early age or before the first full-term pregnancy. This form of contraception is no longer in use and the risk from the low dose oral contraceptive pill, which is “the pill” used now, is considered negligible.

Estrogen-containing hormone replacement therapy (HRT) may slightly increase the risk in post-menopausal women, especially those with pre-existing benign disease such as those non-cancerous breast problems that we have been discussing in the last two articles.

As we mentioned, there are some benign breast conditions that may put you at risk of developing a cancer, so it is important to inform your doctor of any previous breast problems that you may have had.

The risk of a second cancer is reported to be up to five times the general risk and is inversely related to age at presentation of the first. In other words, if you have had a breast cancer before, including some of the benign conditions, then there are five times more chances of developing breast cancer in the future, and the risk is even higher if the patient had the initial breast condition at an earlier age.

A second cancer on the same side/breast is more common in women with a family history of breast cancer. In general, about 0.5 percent of women with a previous history of breast cancer will be expected to develop a second cancer each year for the next 15 years.

Women with a previous history of ovarian or womb cancer are also at an increased risk, although probably less than twice that of the general population.

Exposure to radiation increases the risk. The effect is accumulative and the number of new cases has been shown to be higher in survivors of nuclear weapon detonation and in women who have undergone multiple chest X-rays.

Pregnancy has been thought to be associated with a particularly aggressive form of breast cancer, but the evidence for this is not conclusive at the moment.

There are many other possible risk factors that have been related to breast cancer, but have subsequently been disproved although they remain a source of potential confusion.

For example, smoking is not a risk factor, but because it is related to early menopause, it has a popular but undeserved reputation as a protective factor. The balance of evidence supports neither a causative nor a protective role.

Other such controversial factors in breast cancer are emotional stress, trauma to the breast, keeping money (notes), cellphones or other things in the bra as well as the use of drugs such as valium.