Thursday, June 23, 2016

Peptide Receptor Radionuclide Therapy (PRRT) Did Not Work for Me

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.  

3 comments:

  1. Beth, I appreciate you sharing these statistics on overall success of PRRT. I really had no idea they were that low. I'm disappointed for you and hope the embolization works well.

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    1. Thanks for the well wishes. I'll be reporting back after my embolization.

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  2. Beth, thank you for sharing this. I too didn't realize response rates were that low. Yes it works for some and not others. I hope your embolization is over with and that it went well!

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