Early salvage study - counterintuitive result question

[Spaceman210]

cancernetwork.com/prostate-...

For ESRT: "Pathological T stage, surgical Gleason score, nodal radiotherapy, and postoperative ADT were also significantly associated with biochemical failure."

Is there a reason why inclusion of nodal therapy and postoperative ADT could be more associated with failure? Counterintuitive and contrary to other studies.

Jeff

[GP24]

I think nodal radiotherapy was done when metastases were determined with CT. Trials show that there is a significant recurrence percentage after nodal RT. So these patients did have biochemical failure, just later than it would be the case without RT.

Adjuvant RT is reported in the study as beneficial! However, they do not report the PSA value when early salvage RT was done. If it was above 0.5 ng/ml for a certain percentage of the patients in this group the benefit of the RT is limited and no wonder they had a worse outcome compared to adjuvant RT. Probably the files they worked with did not have this PSA value for salvage RT.

[tango65 in reply to GP24]

In the early salvage RT group the median PSA pre RT was 0.3 and the IQR was 02-0.4.

[GP24 in reply to tango65]

So I was not correct with my guess. However, the authors mention:

Another important limitation is that, although all patients in the ESRT group had recurrent disease by definition, an unknown subset of patients in the ART group may never have developed recurrence, which may overestimate the benefit of ART.

jamanetwork.com/journals/ja...

This subset is quite substantial. In the following phase III study researching ART, the subset of patients without recurrence who were (over)treated with ART was 35%.

europeanurology.com/article...

"At 10 yr, PFS was 56% for ART and 35% for WS[=wait-and-see] (p < 0.0001)."

So I think this large subset influenced the result of the study mentioned in cancernetwork.

Also, if the benefit for ART in the study I mentioned is 21% compared with a wait-and-see policy, I do not understand that the study mentioned in cancernetwork shows a 26% benefit for ART compared with early salvage radiation (69% with ART and 43% with ESRT). ESRT should have a benefit when compared with wait-and-see and not result in a worse outcome.

[Tall_Allen]

Any factor that makes your cancer more risky is associated with BCR - that's why they are risk factors.

[Spaceman210 in reply to Tall_Allen]

Sorry I'm not understanding. Why are nodal RT and ADT considered risk factors here when, for example, in the SPPORT trial they are beneficial?

[Tall_Allen in reply to Spaceman210]

Because men who receive nodal RT and ADT get those therapies because their risk of recurrence is higher. Nodal RT and ADT are beneficial in curing higher risk men.

[Break60 in reply to Tall_Allen]

That’s my situation: very high risk ( gl9, SVI, EPE, positive margin) however low volume (2 cores, 10%, 40%) . I had IMRT to all pelvic lymph nodes at very high dose (75grays in 50 fractions) and have had no recurrence there at least.