Tuesday, 26 November 2013

Preventing Breast Cancer

By: Altaf Patel
 
 

Breast cancer generally occurs as a result of mutations in the genes, but not all tumours are cancerous.

The gurus tell us that most women are unhappy with their breasts. Consider the media hype with buxom women adorning the pages of newspapers, this is not surprising. Nevertheless, more women these days are worried about breast cancer. Whenever a woman is diagnosed with breast cancer; her relatives and friends march into doctors' offices worrying that they are also afflicted.

Ever since the BRCA1 gene was found in 1990, several articles linked it with cancer in the mutated sate. The purpose of this gene is to repair damaged DNAs. But if the gene itself is damaged then it increases the risk of breast cancer. The methods of diagnosis of these mutated gene was initially patented by Myriad Genetics and Laboratories. In June, 2013, the Association for Molecular Pathology filed a law suit against Myriad Genetics in the US Supreme Court. The court ruled that a DNA segment is a product of nature and therefore not patent eligible. Myriad Genetics'patent on BRCA1 and 2 were invalidated.

The BRCA 1 and 2 genes are tumour suppressors and ensure stability of the DNA. Researches have identified several hundred mutations of both BRCA 1 and 2. Many of these are associated with an increased risk of cancer. Women with abnormal BRCA 1 and 2 genes have an 85% risk of developing breast cancer by the time they are 90. The risk of developing ovarian cancer is about 55% for women with BRCA1 mutation and 25% for women with BRCA 2 mutations. However, not all such mutations of the gene are harmful.

Some mutations can, in fact, be beneficial, while others neutral. Some studies show that mutations in the BRCA1 gene increases a women's risk of uterine, colonic and pancreatic cancer as well. BRCA 2 mutations increase the risk of stomach, gall bladder, pancreatic cancer and skin cancer (melanoma). That is not to say that these genes are exclusively in the female species. In a male, BRCA mutations increase the risk of prostrate cancer, testicular cancer, breast cancer, and pancreatic cancer. Male breast cancer, prostratic and pancreatic cancer appear to be more strongly related to the BRCA 2 mutation. Other genetic mutations such as TP53, PTEN, STK11/LK B1 are also carcinogenic but the majority of breast cancers are linked to BRCA1 and 2.

Researches estimate that 12% of women develop breast cancers if they have such genetic mutations. Similarly 1.4% of the population develop ovarian cancer as compared to 15% and 40% with these genetic mutations. These mutations are more common in certain races.

The Ashkenazi Jewish populations have 5 times these genetic mutations as compared to the general public. Norwegians, Dutch and Icelanders too have higher proportion of BRCA1 and BRCA2 genetic mutations. There are at present no guidelines on who should be tested but if you have breast cancer diagnosed in a more than two first degree relatives then you have the increased risk of having cancer. Similarly, if you have a combination of 2 or more 1st or 2nd degree relatives diagnosed with ovarian cancer, then you are at increased risk of ovarian cancer.

If you are of Ashkenazi Jewish descent then if you have any first degree relative diagnosed with breast or ovarian cancer, and two second degree relative on the same side of the family diagnosed with breast or ovarian cancer then you are at increased risk for cancer.

There are other risk factors besides genetic in the development of breast and ovarian cancers. A family history is already stated, and history of having breast cancer once is at an increases risk of developing breast or new ovarian cancer.

Studies suggest that women on birth control pills have chances of getting breast cancer. There is however a decrease in ovarian cancer in such women and this protective effect is enhanced by the duration of use of birth control pills. Such pills also reduce the risk of developing ovarian cancer in women with the BRCA1 and BRCA2 mutation. The use of hormone replacement therapy still remains the hot topic of discussion.

Data show the HRT with estrogen and progestin increase the risk of not only breast cancer but heart attacks and stroke as well. The impact of use of estrogen on breast cancer is uncertain but there is an increased risk of heart attack and stroke as well. Breast cancer can be also associated with increased fat diet, alcohol consumption and obesity. Studies have documented the decrease in cancer with physical activity.

In essence, surveillance is important. This may be done with mammography and MRIs. For ovarian cancer, transvaginal ultrasound and the monitoring of antigens must be done. Ever since Angelina Jolie created had her breasts removed, more people are inquiring about this. Prophylactic surgery tries to remove the tissue at risk. Bilateral removal of healthy breasts do help, but it is not a guarantor against developing breast cancer. Chemoprevention with Tamoxifen has been shown to reduce the risk of developing breast cancer. Raloxifene also helps to reduce the risk in post menopausal women of breast cancer. These approaches are less drastic and more logical.

Self examination recommended for prevention of breast cancer. One should look for puckering of skin, a nipple that has changed position, redness, soreness or swelling. Look for fluid or discharge from the breasts.

Certain studies show that the diagnostic yield from mammography done was 53% but jumped to 82% when sonography was added. Recommendation for such screening change from time to time, but it makes sense to have annual screenings. Not all tumours are cancerous and these decisions are best left to your doctors. Reasonable care shall go a long way in preventing or diagnosing early the big C

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