Repeated stereotactic body radiotherapy for oligometastatic prostate cancer recurrence

Wow, that is amazing! 100% local control in 2 years with all 50 patients. That is almost sounds too good to be true!?

Jerry L and Farmerboy,

We need all the good news we can get.

Best wishes to all the brothers and there family's.

Gerry

This is an outstanding example of where the treatment for our disease is headed, in my opinion. In the past, primary treatment failure meant a limited chance of secondary treatment success. That has now been extended with protocols such as this one. I think anyone with progressive disease and distant metastases would consider resetting his clock on his disease as a wonderful opportunity. I certainly did/do.
I expect to see more articles such as this in the near future. I also hope more men will expect their treatment professionals to consider such a protocol.

Hi Jerry L and Lupronjim

I read it as:

median PFS- 19 (13-25) months

median ADT-FS 25 (20-30) months

There was a few months after PFS till they started ADT.

Psa doubling time as usual was a factor for PFS and ADT-FS

best wishes

Gerry

Jerry L,

That is exactly how I read it. Most had been treated previously with surgery and salvage RT. They used a maximum of 3 mets to define "oligometastatic" (others use 5 mets) but 3/4 had only 1 met. Although they used a very high dose of SBRT, there was very little toxicity from the treatment. Most were treated with only moderate hypofractionation with a month of ADT, but as understanding of SBRT progressed, they increased the hypofractionation and eliminated the ADT.

After a median of 2 years, 18 of the 50 (36%) were progression-free. They used initiation of ADT treatment as a surrogate endpoint for PC survival.

- Allen

Sorry, I accidentally posted to wrong thread. I deleted the offending post. If TA can delete his comment I will complete the cycle by deleting this that I posted here just to give TA's comment some context, after offending thread was deleted.

LupronJim

I meet periodically with my radiation oncologist...always considered him a key player on my team. I'm going to have to ask him specifically what dose of radiation was given for my spot radiation. I only had one zap per spot...in this study it looks like multiple times to the same spot....similar to my adj. radiation.

Jerry L,

The single zap is palliative. They found that one zap is as good for that as a longer course of treatment. Sometimes they have to follow up with a second zap if that doesn't stop its growth.

In this study, they were trying to see if curative therapy is possible if they kept chasing down a small number of mets as they popped up. It is at most curative in 36% after 2 years of picking them off, but as the data matures, we expect that number will decline. It seems that there are often micromets waiting to take root and it seldom stays at an oligometastatic stage.

- Allen

Jerry,

I wish I could answer that question. I don't think anyone can. The natural history of progression is incredibly diverse. I don't think there's any way to predict that with current technology.

They can biopsy the bone, but what would be the point? Usually the differential diagnosis is that if hormone therapy controls it, at least until castrate resistance sets in, then it was prostate cancer.

- Allen

The limit has to do with the radiation exposure of healthy tissue in organs at risk. At some point, healthy tissue loses its ability to self-repair. Bowel tissue is particularly sensitive to late term effects. One RO I met with believes that the risk goes down over time, and he was comfortable re-irradiating my friend who'd been treated 5 years earlier.

A lot depends on where it is. I doubt any RO would hesitate to treat a met on, say, a rib that is completely out of field of a previous treatment to the prostate. Stereotactic linacs decrease the risk because the radiation is so precisely targeted that there is very little out-of-field dose. Hypofractionation opens up more possibilities - the biologically effective dose (at destroying the tumor) is much higher than what can be achieved by traditional IMRT, while the dose to healthy tissue is only the nominal dose, which is much lower. In this study, they stereotactically applied 3 doses at 10 Gy each to the mets. That is biologically equivalent in tumor killing power to 99 Gy (huge!) if it were delivered like IMRT; however, nearby healthy tissue were only exposed to 30 Gy.

- Allen

Allen,

Off subject a bit....do we know the average time most guys on IHT get to take a HT vacation?

Thanks,
Jerry

Jerry L. said...
Allen,
Guess there are pros and cons to a single zap. I'm always worried about getting too much radiation...seeing that I may need it down the road...

yet I still have 2 very small spots on pelvic bone that show up every 6 months on F18...has been consistently there for well over 2 years...makes a guy wonder, is this cancer? is this a healed lesion? was it ever cancer? so little facts on such important things...

At what point after being on HT and spot radiation do micromets rear their ugly head on scan or PSA?

Jerry

Jerry - that's the exact question I have on my alleged Oligomets. I am not in denial, just don't have much confidence in small town Imaging firm where I live in Florida.

Dr. Fabio Almeida at AZ Molecular Imaging is going to review all my prior scans, MRI's, bone density test etc with me and give his opinion, plus give me the results of the prior day F-18 more high powered scan.

My radiation onco in FL who I do have confidence in was never convinced the spots on thoracic spine were mets, even after an MRI but did declare the spot on he right sacral ala as classic prostate cancer metastatic to bone as result of pelvic MRI.

The MRI to thoracic spine did confirm that the brightest spots at T7-T8 were a benign herniated disc with spinal compression, but court is still out on the spots at T4 & T9. Never knew I had the herniated disc since I have not had any back pain, knock on wood,

Of course were it not for the Lupron Since 3-28-13, maybe I could get some wood:}

LupronJim