Genetic testing to determine cancer risk
© Dr. Michael D. Jacobson, D.O. Do not reproduce this article without permission.
From the January 2020 issue of Heartfelt Magazine.
Editor’s note: Genetic testing is ineligible for sharing unless testing is required to determine a current medical condition’s treatment plan. In all such cases, CHM must receive medical records to confirm eligibility. For more information, see CHM Guideline R.7 and the appendix.
Recently, a CHM member wrote:
My father, who is 86 and has prostate cancer, was asked if he wanted to undergo genetic testing for his cancer. He was first diagnosed and treated in his 60s. The cancer has now returned. I went with him for his consultation and was told the testing will not help him, but it might be useful to me and my three siblings.
From what I understand, if he should test positive for this gene mutation, I would have a 50 percent chance of having that same mutation. Apparently, the mutation in females would put me at a much higher risk for breast, ovarian and pancreatic cancer.
Here is some family history that might shed light on why we should or shouldn’t pursue this.
- My paternal grandfather died at 81 from prostate cancer that spread into his bones. He didn’t go to doctors, so we don’t know how long he had the cancer before he passed away.
- My grandfather had five siblings and one of his sisters had breast cancer in her 40s but was treated and survived into her 80s.
- My father has three siblings. His two brothers developed prostate cancer in their 60s.
- My father’s only sister has no history of cancer.
I’d appreciate your thoughts on this. I am 57 with no history of cancer but have had breast surgery three times to remove benign cysts.
Dr. Jacobson’s response: “Cascade testing” is the idea of genetically testing family members of a cancer patient who has a higher genetic cancer risk. The scope of concern is typically limited to first-degree relatives (blood-related parents, children and siblings). As genetic testing is a relatively new science, the research and data available are constantly changing.
After reviewing several resources (which will be referenced at the end of this article series), a few concepts emerge that might be helpful in your decision:
- Because of its newness, genetic testing (generally using a blood or saliva sample) costs vary considerably and depend on what’s being tested. The National Institutes of Health (NIH) states that the cost of genetic testing can vary anywhere from around $100 to over $2,000. I have heard about genetic testing costs that are upwards of $10,000!
- Genetic counselors can be a valuable resource for determining whether the latest research supports the benefit or need for genetic testing. Given their other responsibilities and busy lives, I personally think it’s difficult for most physicians to stay up on the latest information. In answering this question, I spent a considerable amount of time researching and I only scratched the surface of the available material.
After considering the continually growing research and potential benefits, it’s also important to understand the association between males who have had cancer and their female relatives. Does prostate cancer have a possible link to an inherited, increased risk of female cancer? Stay tuned for next month’s issue to find out.