It’s not uncommon for estrogen-positive metastatic breast cancer to shift, to mutate, and to become resistant to hormone therapy. Truthfully, the cancer continues to mutate so as to evade all lines of available treatment at some point, including even the most harsh lines of intravenous chemotherapy. This is a critical, but poorly-understood, area of both research and treatment, and is a huge issue with finding treatments for the breast cancers that are expressing as estrogen-positive, but not actually responsive to the standard hormone-driven therapies. But I’m getting ahead of myself.
Way back in January when I started the clinical trial, I underwent a bone biopsy as part of the trial profiling process. I had a previous bone biopsy in December 2017, which had indicated that my breast cancer was strongly estrogen-receptor positive. These initial results had been the roadmap for my treatment plan and anticipated other treatments available. I had not anticipated any new information would come from the January biopsy results; it was my understanding that the procedure was strictly protocol.
However, because my disease progressed on my first line of treatment (the targeted hormonal therapies Ibrance and letrozole) there was suspicion that my cancer was developing less of a sensitivity to estrogen – and therefore any estrogen-driven drug therapy would create less of a positive response. After the January bone biopsy, the pathology report indicated that my estrogen receptor status had decreased significantly. This drop surprised us all, however, bone pathology is not a particularly reliable sample site for accurate readings for that sort of pathology information. Regardless of this information, my cancer was still categorized as hormone-receptor positive, due to the presence of the hormone receptors, even if they were present in fewer number than before.
As I entered into the clinical trial, I began to feel very nervous about the potential for my cancer to shift, to mutate, and no longer respond to hormone therapy. Should this happen, a significant number of treatment options would suddenly no longer be available for me, and many of the treatment options available would be much harsher and more difficult. After the uncertain results from the January bone biopsy, I felt like I was in a bit of a holding pattern. Part of the research protocol called for a repeat bone biopsy in February, and so we waited for those results. Unfortunately, those results were also not tremendously helpful. They indicated that my cancer was still carrying some level of estrogen receptor, but the degree to which it was was unclear.
At this point, the trial drug seemed to be working – at the very least, I had almost no side effects from it. My cancer was contained in my bones, so there was no other site from which we could take a biopsy sample to get more information, and, also, while I felt uneasy, there was no real indicator that things were going awry. There was no reason to change treatment at that point, only an unsettling suspicion. The clinical trial drug was promising, and, while it was a possibility that I would not respond to it at all, all pathology thus far indicated that I was still a candidate for further hormone therapy. My oncologist wanted to see how long the trial worked for me, and we agreed that it made sense to gather whatever information became available – whether the trial worked for two months or twenty. Several weeks following the February bone biopsy, I had a CT scan of my chest, abdomen, and pelvis, and bone scan after two months on the trial, which came back stable – boringly so. We were thrilled and relieved to find a brief island of respite after all of the frustrations in January and February following the back-to-back bone biopsies.
However, in early March, a number of irregular headaches sent me back for an additional scan – a brain MRI that identified my two brain lesions. We were back in it, once again, and I found myself existing as if I had a set of horse blinders on, driving relentlessly forward to attend to all of the appointments, scans, and procedures needed to address the lesions in my head. Although I had experienced stable scans at the end of February, my oncologist ordered a repeat set of scans for early April. She was concerned that the development of the brain lesions might be an indicator that my cancer had become more aggressive and was trying to move elsewhere. In addition, the only way for me to stay on the clinical trial was a stable scan – proof that I had no progression in any other area of my body. This would tell us whether or not the trial drug was still working, or if the brain lesions were a sign that there was progression elsewhere. (The trial drug does not cross the blood-brain barrier, so that treatment would not have affected the brain lesions in any case.) After I completed stereotactic brain radiation, I had yet another CT and bone scan in early April. These scans indicated that I was stable and had no disease progression, but for a very small (sub-centimeter) lesion that appeared in my liver. We had a sense that the liver spot was metastatic, but it was too early to tell, so my oncologist decided to wait another month and see if it grew.
Last week at my monthly follow-up appointment, I had some right side discomfort and my bloodwork showed an elevated tumor marker. Dr. G ordered a scan for that afternoon, and the following morning, called with the results. I had four liver lesions, all approximately 1 centimeter in diameter, and a small but questionable spot on my left lung. It was clearly progression, and I was off the clinical trial. It has become clear that my cancer is no longer responding to hormone therapy, and is likely being driven by something other than estrogen. This morning, I underwent a biopsy of my liver lesions to obtain more information about what caused this rapid progression. On Sunday, I will start my third line of treatment, an oral chemotherapy drug called Xeloda.
I don’t think I have to put into words how difficult this past week has been. Truthfully, we have been piecing together this information for several months, but the picture has not been clear until very recently, and the picture is pretty frightening. I’m hopeful about the efficacy of this drug, but it does carry some significant side effects (although I won’t lose my hair!). I am also hopeful that the liver biopsy results yield useful information. I’ve been able to spend much of the week with my head down, navigating all of the myriad appointments I have had to leave the clinical trial, start Xeloda, and prepare for the liver biopsy.
I don’t have any more answers, and don’t know what is to come. It’s hard to think that six weeks ago, my disease was isolated to my bones, and has since moved into several other organs. It’s hard to think that only eighteen months ago, our family was sitting with the news of my cancer diagnosis for the first time. It’s hard to think about what any of this might mean – for my treatment options, for my family, and for my ability to continue to function in many of the ways I have been able to over the past year and a half. But the unknown space, for all of its fears and uncertainties, can hold a tremendous amount of hope, and when it’s hard to think of much else, I find myself thinking of that.