Study: Addition of Short-term ADT Fails to Improve Survival over Radiotherapy Alone for Intermediate-Risk PCa

[Revcat]

This is a very interesting large-scale study but it is only one study.

Here's the Scoop:

"The addition of short-term androgen deprivation (STAD) to dose-escalated radiotherapy did not improve overall survival (OS) for patients with intermediate-risk prostate cancer, although the regimen did produce some benefit in metastases rates, prostate cancer death, and prostate-specific antigen (PSA) failures, according to data from the phase 3 NRG Oncology/Radiation Therapy Oncology Group (RTOG) 0815 study (NCT00936390)."

Source: cancernetwork.com/view/stad... (April 30, 2023)

This study only looked at patients diagnosed with intermediate-risk cancer. Reportedly, trials have shown that adding ADT to RT improves survival in men with aggressive prostate cancer. This could result from the ADT making cancer cells more susceptible to radiation or it could result from exposure to ADT at an earlier stage of the disease. I don't know whether there has been any definitive research to establish which of these two paths or a combination of the two is responsible for the increase in OS.

Does this new study shed any light? I look forward to TA putting this all in context for us.

.

[BruceSF]

Well, I think it would be fair to say that after8 years, the study does not yet show a difference in overall survival (OS) between the two arms (RT alone or RT + ST ADT) . The death rates in the two arms at 8 years were 21% (RT alone) and 16% (RT+ ST ADT); this was not statistically significant. Since intermediate prostate cancer is a slowly progressing disease, the difference could easily become significant in a few more years. I would at least wait until 50% of the subjects have passed away, and look at the difference in median survival, before concluding that there was no difference. As they say, “ absence of evidence is not evidence of absence (of an effect).”

[jmarsh]

Agree 100%. My cancer is/was aggressive. My doc didn't hesitate to do ADT prior to radiation and continue for 2 yrs afterward. I'm about 8 months post-radiation and numbers are good. I guess it depends on aggressiveness and your age and other health complications. I'm relatively young for my situation. If your cancer is less aggressive, I guess you could outlive it. But who wants to find out when it's too late that maybe they should have thrown everything possible at it??? Just my thoughts.

[Magnus1964]

Eight years does not seem long enough to get a real evaluation on STAD before radiation.

Magnus

[Blugill]

Everyone pushed my husband to get 3 months of ADT before proton therapy last year. When we asked the radiation oncologist why they recommended this they only said that it was "standard of care" When we pushed further and asked how it worked to improve the outcome we were told that they didn't know...(this was a major teaching hospital as well...how don't they know?) We did a lot of research online and found that it was patients that got the older type of radiation that was not targeted that seemed to benefit from time to recurrence of the cancer, but even they didn't seem to have a longer survival rate. Since my husband had no spread, in the end we decided that the 3 months of misery wasn't really worth it and he declined the treatment.

[Revcat in reply to Blugill]

Your experience at a major teaching hospital underlies my question: what possible mechanisms may account for the survival benefits of adding ADT to radiation found in some patient populations? Is it merely the advantage of hitting the cancer cells with ADT sooner rather than later? Is it merely the advantage of making the cancer cells more susceptible to the radiation? Some combination of the two? Or something else entirely? I haven't found the answer yet, but there may be some study out there that sheds more light on the subject.

[RMontana]

I think the results of this study align with the research I posted on the net differences between short term vs long term ADT (STADT n LTADT) plus low dose radiation therapy (LDRT) post RP...STADT plus LDRT was not as effective in preventing 5 year PCSM (mortality) or DM (MET)...with hazard ratios (OR) nearly double! An OR of 1.0 would mean no effect and those less than one show benefit...STADT did have some benefit, but not nearly that of LTADT...

healthunlocked.com/active-s...

Too bad the effects of LTADT with its destruction of TET production is so wrought with side effects...but it appears to work...Rick