ORIOLE study and the Oligometastatic therapy

VascodaGama

Some of you that have followed my entries in this forum know that I have been procuring an oligometastatic treatment as my last chance in killing the hidden bandit. Unfortunately I was informed by my doctors (urologist and radiotherapist) that I cannot pursue such a therapy due to several reasons explained in this link; https://csn.cancer.org/node/314326?page=1

This therapy is used to treat recurrence from a main radical (surgery and/or radiation). It conditions the treatment to a fewer number of localized metastasis (maximum 5 spots) and uses high-dose radiation directed to those spots. This is different from the standard IMRT typically used in salvage treatments post failed surgery. Some patients of this forum have gone through oligometastatic therapy with successful results. I hope that they report their story one day for the many interested.

The ORIOLE study done by Johns Hopkins involved 54 patients with various statuses but all under the conditions set for in having a fewer number of metastases. The results are reported in the following link. What made me to publish the matter in this forum is that the conclusions of the study include other aspects that are of interest to us survivors from radical therapies. Apart from the cure possibility, the researchers indicate about other benefits from the procedure, even if the radiation has not treated totally the metastases. It seems that they found a sort of intervention by the immune system in killing the affected cells that were under the radiation. These may have signaling a distress call due to their defective DNA. One could therefore think that radiation doesn’t treat alone but it combines with the immune system to get the perfect kill. Very interesting indeed.
Another aspect found from this study is that patients with some sort of genes may not do well to such a treatment implying a differentiation among the patients when chosen or recommended to the therapy. Those with that enumerated genes would abstain from oligometastatic treatment and pursue a systemic approach.
The only thing missing in the report is the theme related to rads over rads. We know that such prohibits additional radiation but I wonder if at Johns Hopkins they offer to radiate areas that have been radiated previously. I know of at least two cases where the oligometastatic approach involved the areas of previous SRT. Here is the link;

https://www.medscape.com/viewarticle/918509#vp_1

One thing for sure is that this treatment requires that one identifies firstly the number and location of the metastases. This is not done via the traditional MRI or CT. In the study they used PSMA PET scans which exam directly involves PCa at cellular level independently of tumor size.

My experience reported at my above link is for the 18F choline PET/CT (positive exam) and 68Ga PSMA PET/CT (negative exam). The latter is better in PCa cases but both needs to involve experienced PCa nuclear doctors to read the films for a trustful the report. The negative 68Ga PSMA PET in my case was a false negative as I have cancer but the doctor reading the film could not distinguish the cancerous cells at the area of the bladder (prostate bed) leading him to report exclusively what he saw.
I think that the half-life of the isotope and the method used at clinics and the timing of the picture must be reviewed and adapted to the particulars of each individual. The existing PSMA ligands (18F and 68Ga) are the best. However, one manages to be better than the other depending on the area involved. The timing when the image is taken also contributes to errors. The 68 Gallium has a shorter half-life than fluorine 18Fwhich obliges the exam to be done at one hour post injection. This is when the radiopharmaceutical has been already excreted (via the urine) and accumulates at the bladder blurring the vision of the prostate bed. Some physicians suggest taking a picture must earlier for comparison.
In the case of the fluorine 18F (18F PSMA PET/CT),the image is taken at the very beginning of the scan and again two hours later (the half-life is longer).

Economics also play a role in the choice of the exam. The 68Ga PSMA can be produced with a simple generator (easily available at any clinic) while the 18F PSMA requires cyclotron facilities usually procured at close nuclear facilities, therefore more expensive. The isotope needs to be supplied in time for not losing its half-life particularities.

Here are some links comparing PSMA PET exams;

https://www.ncbi.nlm.nih.gov/pubmed/31253741

https://www.ncbi.nlm.nih.gov/pubmed/29269569

https://journals.sagepub.com/doi/full/10.1177/1756287218815793

https://www.thelancet.com/journals/lanonc/article/PIIS1470-2045(19)30415-2/fulltext

Best wishes to all my comrades.

VGama