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The Link Between Prostate And Breast Cancer

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Dr Greggory Pinto

By DR GREGGORY PINTO

What does prostate cancer have in common with breast cancer?

The answer is the BRCA 1 and 2 gene mutations. The BRCA 1 and 2 genes were first discovered in 1994.

BRCA stands for Breast Cancer associated gene. Women with the inherited BRCA 1 or BRCA 2 gene mutations are at higher risk of developing breast cancer, ovarian cancer, colon/rectal cancer and pancreatic cancer in their lifetimes.

This BRCA 1 and 2 gene mutations or faults aren't just an increased cancer risk for women.

Men can also inherit BRCA gene mutations, which puts them at risk for not just breast cancer, colon/rectal cancer, melanomas and pancreatic cancer, but also prostate cancer.

Every human, men and women, has BRCA 1 and BRCA 2 genes. BRCA genes do not cause breast cancer or prostate cancer or any other cancers.

In fact, BRCA genes play a role in preventing breast cancer and the BRCA 2 gene has an important role in preventing prostate cancer. These genes help repair DNA breaks that could potentially lead to cancer formation; they are tumour suppressor genes.

In certain individuals, these BRCA tumour suppressor genes have mutations and do not function properly in their important role of suppressing or preventing cancer formation.

When a BRCA 2 gene is mutated it is not effective at repairing broken DNA and helping to prevent both prostate cancer, breast cancer and certain other cancers.

Every cell in our body contains DNA and this DNA is continually damaged by various factors.

The cells in our body undergo a daily cycle of DNA damage and repair. The repair mechanisms are controlled by genes such as the BRCA 1 and 2 genes.

BRCA 2 genes play a far more important role in preventing prostate cancer in men than the BRCA 1 genes. The BRCA 2 gene mutation is associated with 8.6-fold increased risk of developing prostate cancer in a lifetime and the BRCA 1 gene mutation a related 3.9 fold increased risk of developing prostate cancer.

Men with the BRCA 2 gene mutation are also 8 times more likely to develop breast cancer before the age of 80 than men without this gene mutation.

It is estimated that one in eight women will develop breast cancer in their lifetime. Approximately 55 percent to 65 percent of women with the BRCA 1 gene mutation will develop breast cancer by the age of 70 years old.

BRCA 1 gene mutations can also lead to a more aggressive form of breast cancer.

An estimated 1 in 300 Caucasian American men have the BRCA 2 gene mutation. Some studies have determined that the incidence of BRCA 2 mutations in African American men is approximately 1 in 100.

Persons of Ashkenazi Jewish ancestry have a 1 in 40 incidence of BRCA 2 gene mutations.

One in six men of African ancestry will develop prostate cancer in their lifetime. Men of African or Caribbean ancestry in the United Kingdom have a one in five lifetime risk of developing prostate cancer.

African ancestry is one of the greatest risk factors for developing prostate cancer.

Men with the BRCA 2 gene mutation are eight times more likely to be diagnosed with prostate cancer and at a younger age, 61 years old age versus an average age of 64 years old for men without the BRCA 2 gene mutation. The BRCA 2 gene mutation can also double the risk of developing a more aggressive form of prostate cancer.

In the Bahamian population there is a disproportionately high number of BRCA 1 and BRCA 2 gene mutations in both men and women, and unfortunately this results in large numbers of women being diagnosed in the Bahamas with an aggressive form of breast cancer at an earlier age and Bahamian men being diagnosed with aggressive forms of prostate cancer at earlier ages than men without the BRCA 2 gene mutation.

A pioneering gene-targeted drug that has been licenced for breast and ovarian cancer treatment has promising benefits for men with prostate cancer and the BRCA 2 gene mutations. The drug Olaparib has shown to have an 80 percent positive treatment response for BRCA 2 gene mutation men with prostate cancer.

Olaparib targets cancer cells that aren't able to repair their damaged DNA due to BRCA 1 or 2 gene mutations. Phase three trials of this promising drug are ongoing and gene targeted prostate cancer treatment may play an important role in prostate cancer management in the near future.

The BRCA 1 or BRCA 2 gene mutation is inherited in an autosomal dominant pattern from a mother or a father.

Each child of a parent with the BRCA gene mutation has a 50 percent (1 in 2) chance of inheriting the gene mutation.

Men having either a BRCA 1 or 2 gene mutation does not necessarily mean that they will develop prostate cancer in their lifetime; it just increases the risk when compared to men without the gene mutation.

BRCA 1 and 2 gene mutation tests are available locally. Some of the available tests look specifically at harmful BRCA 1 or BRCA 2 gene mutations that have already been identified in another member of the family.

Bahamian men with a strong family history of breast and or prostate cancer should be very diligent in obtaining annual prostate cancer screening in the form of a PSA prostate specific antigen blood test every year starting at the age of 40 years old. Men with known BRCA 2 or 1 gene mutations or a strong family history of first degree relatives being diagnosed before the age of 50 years old with prostate cancer, should start prostate cancer screening at the age of 35 years old.

Bahamian men should also consider genetic testing for BRCA 1 and 2 gene mutations so that they are made aware of their increased risk for developing prostate cancer in their lifetime. Men are also at risk of developing breast cancer.

The good news: the prostate cancer specific survival for early detected low risk organ confined prostate cancer at ten years is approximately 99 percent.

Prostate cancer is a very treatable disease, with an excellent potential cure rate when diagnosed early.

Seek comprehensive, confidential and compassionate care for prostate cancer screening and management.

Dr Greggory Pinto is a Bahamian urologist who has trained in South Africa, Germany, France and India. He is a member of the European Association of Urologists. Dr Pinto can be reached at the Urology Care Bahamas at the Surgical Suite, Centreville Medical Centre, Collins Avenue and Sixth Terrace. Call 326 1929; e-mail: welcome@urologycarebahamas.com, or visit www.urologycarebahamas.

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