Ugh, after one round of PRRT with Lu-177-dota-JR11, my existing tumors
progressed in the liver and there was also a new tumor seen there. This is my first new tumor since my diagnosis
in 2010. Given this information, I was
removed from the clinical trial since the treatment did not work as expected for
me. The tumors in the lymph nodes were
stable or slightly smaller but the growth of the liver tumors and the new
1.4x1.3 cm tumor in the liver was what disqualified me.
I was under the impression, wrongly, I guess, that if my Ga-68
scan “lit up like a Christmas tree” that I would be a good candidate for PRRT. In reality, the objective response rates, as
shown by multicenter reports from Europe are seen in 15% - 35% of patients (see
this article http://www.ncbi.nlm.nih.gov/pubmed/25117465). This is much lower than I thought given the information
about PRRT that I have seen and heard through my experience. In reality, I do not read a lot of scientific
papers and depend on my doctors to give me information. Dr. Reidy-Lagunes said that she feels bad
when she recommends patients for PRRT in Europe because they are paying a lot
of money out of pocket for results that are great if it works for them but the
chances of a complete response, meaning tumors are gone or have shrunk 50% are
less than 35%.
I asked Dr. Weber, the head of nuclear medicine at Sloan
Kettering, if he thought that I would respond more positively to other radiolabeled
agents such as Y-90 or other peptides such as dotatate or dotatoc and he said “It
is hard to predict if other forms of PRRT will potentially be effective. All the clinically used PRRTs target the
somatostatin receptor (as does JR11). Therefore
the limited effect of JR11 on the liver metastases also decreases the
likelihood of a response to other PRRT agents.”
So, unfortunately my PRRT experience was not
successful. I’m still glad I entered
this trial and I would have even if I had known that my probability of
objective response was 15% - 35%. This
is not to say it will be unsuccessful for others as I know of one other
participant in this PRRT clinical trial that has had 50% reduction in tumor
size after one round. I think it is
important to understand that although PRRT is a great new treatment that is
going to be available soon in the US, it does not always work, even if you have
the proper receptors.
Dr. Reidy-Lagunes and Dr. Chan both said that a liver
embolization is the next treatment I should consider. I am meeting with an interventional
radiologist tomorrow to discuss this procedure.
