No Genetic Mutations

I received the results of my BreastNext test, the full panel of genetic testing - all negative! This wasn't something I was worried about (I strongly feel that I have to be extremely selective about what I worry about these days), but it's always good to get good news.

BreastNext utilizes next generation sequencing to offer a comprehensive testing panel for hereditary breast and/or ovarian cancer. They start by checking for mutations in BRCA1 and BRCA2, which are responsible for 25-50% of hereditary breast cancers. These are the results that I got last month. If the BRCA results are negative, as mine were, they move on to the full panel, which includes fifteen other identified genes (ATM, BARD1, BRIP1, CDH1, CHEK2, MRE11A, MUTYH, NBN, NF1, PALB2, PTEN, RAD50, RAD51C, RAD51D and TP53). According to Ambry Genetics, the maker of the test, studies demonstrate that mutations in the genes on the BreastNext panel can confer an estimated 25-70% lifetime risk for breast cancer.  Some of these genes have also been associated with increased risks for other cancers, such as pancreatic cancer with PALB2, ovarian cancer with RAD51C, and sarcomas with TP53. 

Although many people have a family history of breast cancer, only 5-10% of breast cancers are hereditary. People who carry these inherited genetic mutations are born with them - they do not develop over time. (Interestingly, an additional 20-30% of women who develop breast cancer do have a family history but do not carry an identifiable gene mutation - this type of cancer is described as 'familial' but not 'hereditary'. In these cases, the breast cancer may be caused by a genetic mutation that hasn't yet been identified, shared factors such as environment and lifestyle, or a combination of both. The remaining 60-75% of breast cancers are called 'sporadic', meaning that they are associated with other risk factors - age, reproductive and menstrual history, alcohol, radiation, high body mass index, and benign breast disease - or, as in my case, for no reason at all that we know of.) Understanding if a cancer is due to an inherited mutation can help to clarify future risks and determine screening and treatment choices, as hereditary breast cancers tend to occur earlier in life and are more likely to involve both breasts. 

Because my results were negative, my lifetime risk of recurrence or of developing a whole new breast cancer are the same as the general population - about 12%. While this is certainly preferable to a 25-70% chance, it still is 27 times more than my chance was of getting breast cancer in the first place at this point in my life - but I did. This is why Seth and I decided a while ago not to get to wrapped up in the statistics. For one thing, there's always a glass half-full, half-empty dilemma, and it's too easy to either have a false sense of security if you're a half-full kind of person (which I am), or to have an equally false sense of impending doom if you see the glass as half-empty. For another thing, probability is always trumped by actuality - it really doesn't matter how likely something is to have happened once it happens. But perhaps even more important is the recognition that all of these statistics are backward-facing - that is, based on past patients and past treatments. There are no statistics for my particular type of cancer with my particular type of treatment - so I just choose to believe that my chances are better than they ever would have been before, and try not to worry about the numbers.