Darkness falls earlier and the leaves are turning. Already bursts of color litter the forest floor; soon it will be an almost fantastical carpet of yellow, pink, red, orange and purple. I have begun my daily treks, camera in hand, attempting to capture…
I feel as if some seasonal change is taking place for me as well.
This is not easy to acknowledge, but I had, beyond merely hope, almost an expectation in regard to this current clinical trial. I visualized myself having a rapid response and returning, once again, to a period of good health. While on crizotinib, my lung cancer had seemingly melted away. This time, a model of my new mutation had been tested in the lab and shown great sensitivity to LDK378.
On Friday I had a PET scan to assess my progress thus far. The report read:
Overall mild decrease in size of intensity of uptake in opacities in the bilateral, left greater than right, lungs. No abnormal foci of uptake are identified in the mediastinum. No other abnormal foci of uptake are identified.
Mild interval decrease in bilateral lung tumor burden.
It is not a negative report. Nor does it indicate any sort of rapid response to the trial drug.
First, an explanation of what a PET scan is and does. PET is an acronym for positive emission tomography, and, as defined by Wikipedia:
“Positron emission tomography (PET) is a nuclear medicine imaging technique that produces a three-dimensional image or picture of functional processes in the body. The system detects pairs of gamma rays emitted indirectly by a positron-emittingradionuclide (tracer), which is introduced into the body on a biologically active molecule. Three-dimensional images of tracer concentration within the body are then constructed by computer analysis.”
“If the biologically active molecule chosen for PET is FDG, an analogue of glucose, the concentrations of tracer imaged then give tissue metabolic activity, in terms of regional glucose uptake.”
My PET scan before I started the trial was somewhat ‘hot’, meaning my lungs showed an ‘avidity’ (uptake of) the FDG-PET (2-deoxy-2[F-18]fluoro-D-glucose positron emission tomography).
The histology of my lung cancer is BAC, which generally shows only mild FDG avidity.
So what is going on here? There are several possible answers. A PET scan essentially measures metabolic activity, the theory being that a highly metabolic area shows a greater avidity (or eagerness) for glucose. Neoplasms tend to be highly metabolic. However, several sources of inflammation could also produce these ‘hot’ spots. Perhaps I have an unresolved pneumonia which is showing partial resistance to the levaquin. I did feel much better when I was taking the antibiotics.
It may be that my cancer itself has ‘heated up’ or become more metabolic and therefore more aggressive, potentially transitioning away from pure BAC to a histology more in line with adenocarcinoma. Or, despite the early promise, LDK378 may be working, but potentially not as well as we’d hoped.
A passage from the archives of GRACE (an excellent online resource):
“Dr. West: In the metastatic setting for lung cancer specifically, clinical trials include CT scans to assess response or progression. Do you believe that the PET scan adds significantly to that or can we do as well with CT scans basically showing shrinkage or enlargement of known disease?
Dr. Djang: Definitely the PET scan has been proven to be more accurate in the setting of metastatic disease. I think what it comes down to is that if the treatment is working, if the chemotherapy, chemoradiation therapy is working, the first change that you’re going to see is a decrease in the metabolic activity of the tumor cells. That can only be measured with a PET scan and that change will come first. The CT can only measure response to therapy by looking at tumor size. That takes time. It takes time, at least some time for a tumor to grow or to shrink if the therapy is successful. If you have a car that has stopped running, the engine will become cool long before the body of the car starts to degrade. So in the same concept, the metastatic deposit will cool off on the PET scan before it shrinks.
Dr. West: So a PET scan may be especially valuable in getting some early feedback about whether your treatment is likely to be helpful or not?
Dr. Djang: Early and more accurate, yes.”
It has not been an easy time to stay hopeful. I have several friends who are struggling with their disease and I don’t know what the hell is going on with mine. Some weeks ago a post I had written for my online support group regarding battle fatigue was republished on e-patients.net. I concluded it on a strong note.
I started on levaquin again yesterday; just so that I can feel better. Tomorrow, after my labs, I’m heading to NYC for a few days with my dear W & C. Next Monday I am scheduled for a bronchoscopy. Not only will the surgeon ‘harvest’ some fluid for a culture, an enlarged lymph node might be biopsied. And then on Thursday I will have a chest CT scan, which is an anatomic versus metabolic view of my disease.
My desire to think positive is sometimes subjugated to my need to think possible; as in all possible outcomes. To prepare myself for whatever comes. But if you spend too much trying to see what lies ahead, you may miss the very moment.