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Wednesday, July 22, 2015

Cancer: Genetic Testing

The instructions I received before (free) genetic counseling (and my insurance covered the testing) was that there would be no drinking water, eating anything or chewing gum during the hour to hour and a half appointment? What?  I mean, first off, would you NEED to eat and drink during an hour and a half?  And second, WHY NOT?

One also has to fill out an extensive family history form. I left a lot of blanks. My folks didn't report to children about causes of death much, even if they knew them. I thought my form was sparse, but the counselor said it was pretty good. What I particularly noted was that while there wasn't a ton of cancer in my family, people were dropping like flies from heart attacks! All that tasty pastrami, liver pate and tongue took their toll.

The reason my doctors strongly recommended genetic testing is that I am of Ashkenazi (eastern European Jewish) decent. One in 40 Ashkenazi Jews carry the BRAC 1 or BRAC 2 (breast cancer) marker. This figure is somewhat higher than the general population.  Okay, I took notes as fast as I could, but the exact percentage difference fell through the cracks.  Gimme a break!  

The counselor noticed on my family history is that we don’t have a lot of girls which may be the reason why we don’t have a lot of breast cancer.. The other thing was that breast cancer in the 30s and 40s tends to indicate presence of breast cancer genes.  Our instances of breast cancer had later onset.  One mark for me on the positive side of the ledger.  (Or, hmmm, the negative side, depending on how you read it.  Oh, never mind!)  

While BRAC 1 and BRAC 2 are the most common genes, there are a total of 24 genetic markers!    Yikes!  They’re not really genes, though, they’re genetic mutations, and they’re discovering more all the time!  Is this a Darwinian way of winnowing the human herd?  That seems harsh.  

Should I have one of the high risk cancer genes, my direct blood relatives would each have a 50% chance of being carriers.  Along with breast cancer, these genes indicate a higher risk of ovarian (but not cervical) cancer. Not many males get breast cancer, but they would be at a 20%-50% higher risk of prostate cancer.  

A lot of research has been done on the four highest-risk cancer genes. Less is known about the others. Whether you choose to be tested for any or all, it's done at the same time with the same sample, no further fuss for you. I choose to be tested for only the top four:

             Gene                                            Associated Cancer

BRAC 1 and BRAC 2          45%-87% increase in breast, ovarian, pancreatic, prostate and                                               male breast cancer

CDH1 breast,                       39%-52% increase in breast, gastric and colorectal

PTEN                                   Up to 50% increase in breast, thyroid, uterine, colorectal, kidney

TP53                                    no % assigned, significant increase in breast, sarcoma, brain (!),                                              adrenocortical, and others (and OTHERS?!!) 

The most surprising thing I learned during counseling was that even if you carry the BRAC 1 and 2 genes, there are two methods of treatment with EQUAL OUTCOMES. Yes, if you are young and want to be sure you don’t have a lifetime of worry ahead of you, you may opt for a mastectomy. That removes absolutely all risk of breast cancer and, obviously, metastasis. However, you can also opt for twice-a-year mammograms, MRIs and clinical exams, keeping on top of the beginning of any cancer. The outcome to your health and life-expectancy are the same. Wow, I did not know that.  I was surprised at what a relief that was.

You will receive one of three possible results.

Guess what? Testing is not about blood at all. Now my veins like to play roll-away from a needle, and no blood flows out. Sometimes the needle hits the vein wall which hurts, and no blood flows out. If I’m pretty well hydrated, a skilled phlebotomist with a pediatric needle can zoop right in there, but otherwise, I’m in for a prolonged, multi-stick session. Score! They don’t take blood for genetic testing.

They don’t take a cheek swab either. This is not a crime show. Nope, instead the counselor opened up a compact case to reveal two small tubes with mouth pieces. You have to fill each one with spit. At least now the no-gum/water/food rule makes sense: they don’t want anything to taint the results.

You spit and you spit and you spit. Although I’m sure this would be quite a treat for the counselor to watch, she turned to her computer. My job is to fill about a ¼ inch space in each tube with saliva. It takes a while, and it’s messy. The box of Kleenex I thought was for weepy patients (and it might well be) was what I used to keep spittle from running down my chin. Not much did, though. The task was daunting enough for me to make sure that no drop is wasted.

The first line is just above the white label area.
You have to fill it to the black line.  

The counselor showed me how to seal each tube as it was completed. Now I wait.

There are three possible results.
          Positive: a clear genetic mutation with associated cancer risk.
          Negative and winner of the prize: no genetic mutation.
          Variant (under 10% of the results, and the one most likely to make you crazy): This is           not the basis for a movie plot. It means they found some weird genetic change,  
          something they’ve never seen before and don’t know what it means. I have already
          decided that if I get a Variant result, I am totally blowing it off.

And wait.

Still waiting -- for two to three weeks.

But I am not going to make you wait because that’s just the kind of person I am. In any case, my results came in early, and I only had to wait two weeks.  I am not a mutant 

Most of my relief is that I don’t have cancer-related genes. The rest of my relief is that I won’t have 50 million more medical appointments to deal with! Yay!

Have I been bored in the weeks between completing radiation and getting my genetic test results? Oh, no, I have not been bored. During that time a very dear friend, one for whom I hold Powers of Attorney, climbed up on the railing of the Good Ship Sanity and fell overboard into the sea of massive infection and mental confusion. You know, just so I don’t run out of material to blog about. Oh, yeah, that’ll be next.