The One Where I Try to Teach Science

Yesterday was my big appointment with the oncologist, where I hoped to find out the results of the genomic sequencing and biopsy they had done on February 3. It was also the day I hoped to find out my next course of treatment, either Piqray (if the sequencing uncovered a PIK3 mutation) or Aromasin (if it did not). Instead, we decided to go another route entirely.

The results of the biopsy had come back but not the results of the genomic sequencing. Still, the biopsy showed that my cancer has become significantly less sensitive to estrogen and therefore might respond better to a different plan of attack altogether. Since I have the BRCA2 genetic mutation (in my DNA, not the cancer's), I'm a candidate for a category of drugs called PARP inhibitors. 

Ready for a science lesson? I think I've got these concepts worked out enough to explain them. Here goes...

In human DNA, the BRCA gene is found on chromosome 13 and keeps damaged cells from proliferating.  In people with a mutation of the BRCA gene, like me, this mechanism is basically broken, and damaged cells are allowed to replicate and form cancer. This is why women with the BRCA mutation are much more likely to develop cancer and to develop it at younger ages than the rest of the population. 

Another way that cells get repaired is by the activation of the PARP enzyme. But because my cells have cancer, we don't want them to be repaired and keep multiplying. So we're going to try turning off the PARP enzyme with a drug called a PARP inhibitor. The thought is that if the PARP enzyme is deactivated (inhibited), the cancer cells can't repair themselves and will therefore die off. (I think I got all that straight, but I'm no expert.)

Photo by National Cancer Institute on Unsplash

So I will be starting a PARP inhibitor called Talzenna as soon as my insurance approves it and the specialty pharmacy can fill it for me. It's another oral chemo that I'll take at home daily. The side effects mainly involve issues with my blood counts - anemia, low platelets, low white blood cells - but also fatigue, nausea, hair loss, headache, and others. I'm optimistic that my body will handle the drug well.

While I was writing this post, my oncologist actually called with the results of the genome sequencing. I do not have the PIK3 mutation, so Piqray wouldn't have worked for me anyway. And with my decreased estrogen receptivity, the decision we made to go with Talzenna has been validated. I actually only have one mutation, RB1, and this mutation signals that I may be resistant to the CDK 4/6 inhibitors, like Ibrance and drugs that function similarly. So, while we might have circled back to try that class of drug again in the future, we probably won't now that we know my genes suggest resistance. 

Whew! That was a bear of a post to write. I hope it's helpful to those of you who like to understand all the details of my care and treatment. My current prayer needs are for Talzenna to be approved quickly by my insurance company, for the financial assistance to be worked out, and for the drug to get to me so I can start taking it! Oh yeah, and also that it works and the side effects are manageable. :) Thank you, friends!