"It is my hope that precision medicine will help cancer patients live longer and better lives"

How genomics are empowering Rosilene on her journey with metastatic breast cancer

I am Rosilene Kraft. I live in Coquitlam, British Columbia. I am a professional engineer with master's and PhD degrees in engineering. I am married and have a bright 9-year-old daughter. I was diagnosed with breast cancer in 2018, 3 years after seeing my dad pass away with metastatic lung cancer. My mom was diagnosed only months after me, with early-stage breast cancer, but died in 2020 from treatment complications.

My cancer was diagnosed metastatic from the start, meaning that I was never treated with curative intent, but instead I move from treatment to treatment until no option is left.

After receiving a grim prognosis from my oncologist, I went to see the surgeon who had diagnosed me. She referred me to a renowned specialist who confirmed that I was on what was the most current treatment for my type of cancer. She asked for a genetic panel to assess if I had any of the most common germline mutations associated with cancers - I had none. She also asked to test my tumour for the PIK3CA mutation, offered as part of a clinical trial for a drug targeting that mutation. My sample tested positive.

As the treatment with the CDK4/6 inhibitor and aromatase inhibitor for my ER+/HER2- tumour wouldn’t be funded again if I took a break to join the trial, I chose to remain on that treatment until progression. In March 2020, I had a surgery to remove the primary tumour. With a fresh sample, I decided to have a genomic test done. This test confirmed the PIK3CA mutation and identified PTEN loss of function, besides others of unknown significance. PIK3CA is targetable, PTEN is not yet.

Immunohistochemical tests were performed on my sample to see if immunotherapy could be an option for me in the future. As with most hormone receptor positive breast cancers, the tests showed that mine was unlikely to respond to immunotherapy. 

A little later that year, I developed a new bone metastasis, but decided to continue on the same systemic treatment and join a clinical trial that used stereotactic radiotherapy to treat new lesions. The treatment worked. I managed to stay on my first line of treatment for 36 months.

By then, the clinical trial for the PI3K inhibitor had ended and it was approved by Health Canada. However, CADTH did not recommend it for reimbursement, meaning that it is not funded by provinces. I was a little out of luck as the manufacturer had stopped their compassionate access program just days before my CT scan report was out showing disease progression.

I then decided to join a clinical trial for an AKT-inhibitor. There is a cellular pathway involved in cell proliferation called PI3K-AKT-mTOR. The PIK3CA mutation upregulates PI3K in this pathway, leading cells to divide faster.  PTEN is associated with this pathway, working as a tumour suppressor. With the loss of function, it allows the tumour to divide more aggressively. There was a chance that the AKT-inhibitor could perhaps slow this circuit down. 

A genomic test was done as part of the trial. Mine was a liquid biopsy. Curiously but not surprisingly, it did not show the PIK3CA or PTEN mutations. Not showing all mutations is a possibility as tumours are heterogenous and liquid biopsies show what tumours are “shedding” at the time of the sample collection. The test did not show any actionable mutations.

The treatment in the clinical trial worked for around 10 months and I had new disease progression. I learned more recently that PTEN lof can make drugs acting on this pathway less effective and maybe it is why the treatment with the trial drug did not last longer for me?

After that trial, I chose to be on a reduced dose of IV chemotherapy. I will then qualify for an antibody-drug conjugate which has shown to work well for many patients with not only HER2+ breast cancers, but also for many with lower numbers of HER2 receptors, designated as HER2-low, which is my case. This drug has recently received CADTH’s recommendation for reimbursement. It should be my next line of treatment.

Learning about my disease and tests that I could get done, keeping myself informed through newsletters such as those from ASCO, sharing information with peers, and browsing clinical trial websites have helped me to be a better self advocate. It helps me to participate in the decision-making process with my oncologist and other healthcare providers about my treatments. It also helps me to plan which possible treatments I still have available, how to sequence them, and what to avoid in order to try to remain a candidate in future clinical trials and to receive provincial coverage.

I have just completed 5 years of my diagnosis. How we are counted as patients with metastatic breast cancer is a matter of discussion, but in what is known, currently, around 31% of those with metastatic breast cancer will be alive at 5 years. This number has been rising recently due to the new treatments of the last few years, but it is still quite low and I have seen good friends I met along the way not reach that mark.

It is my hope that precision medicine will help cancer patients live longer and better lives and I am excited to learn how the Marathon of Hope Cancer Centres is trying to make it a reality for more patients.

Learning about my disease and tests that I could get done, helps me to participate in the decision-making process with my oncologist and other healthcare providers about my treatments.