What criteria do you use in deciding whether or not to treat the pelvis in prostate cancer?

NRG/RTOG 0924 - The end of elective nodal RT in localized prostate cancer?

Top line results:

NRG/RTOG 0924 is a very large phase III randomized trial powered for overall survival (OS) to determine if there is a benefit of the addition of whole pelvic radiotherapy (WPRT) to prostate RT plus ADT. This was a negative trial, period. OS was negative, HR 1.01, 95%CI 0.85-1.20, one-sided p=0.54. DM was negative, HR 1.05, 95%CI 0.73-1.50, one-sided p=0.60. Grasping at straws, a 4% absolute improvement in 10-year BCR in favor of WPRT was shown (HR 0.82, 95%CI 0.65-1.03, 1-sided p=0.045, 2-sided p=0.09) that is technically not even statistically significant, and well below any measure of clinical significance. As expected, lower-grade toxicity was in...

The literature is compelling (as summarized by Dr. @Dr. First Last) that for many high-risk patients, and likely all unfavorable intermediate-risk patients, WPRT is unnecessary.

That said, I will gripe that stating "The end of elective nodal RT in localized prostate cancer" is overselling things a little bit, as patients at the highest risk of nodal involvement were excluded from RTOG 0924. This factor probably explains why POP-RT data are discordant from other WPRT prospective randomized trials (rather than dismissing POP-RT results as single-institution or having small enrollment). POP-RT was looking at a considerably higher-risk population overall.

For example, almost 80% of POP-RT patients were stage T3 or T4 (including 38% with T3b), whe...

There may be no issue in radiation oncology more controversial than elective nodal irradiation (ENI) in prostate cancer. If we knew, we wouldn’t currently have 0924 open, which is the largest study ever attempted by the RTOG, this time powered for 10-year OS (target accrual = 2,580). Since we actually don’t know, any answer to this question will only elicit visceral hypotheses that may lead readers to over- or under-treat patients. That is because no criteria have ever been validated to predict for a benefit with ENI. Meanwhile, the reasons for ENI are obvious. LNs are often involved, perhaps 45-50 Gy may eradicate microscopic disease, and IMRT limits the toxicity of larger pelvic fields (Deville et al., PMID 20171807). However, the argumen...

It’s interesting that in PEACE V, elective nodal volume treatment in nodal recurrence did improve regional recurrence as well as metastasis-free survival compared to INRT. So it may be a function of the risk of microscopic disease in the pelvis. PEACE-2 for very high risk done in the modern era with PET and MRI imaging included, may show if it impacts outcome outside POP-RT data.

Regarding the putative efficacy of ENI, could the nodal template be an issue regarding the trials mentioned? Consider the PSMA/PET patterns of failure by Schiller et al., PMID 32451312.

I always let the patient decide.

I review the accuracy of an MRI, CT, and PET for detecting lymph nodes.

I then review the idea behind the MSKCC nomogram followed by the low pelvic failure rates despite a high prediction rate Zumsteg et al., PMID 26165583.

We then cover the ability to salvage pelvic failures with RT. Yesterday I used the PEACE V-STORM data. Ost et al., PMID 40339593

At this point, if they are on the fence, I may even use the Decipher score. Up until recently all of my patients were enrolled on the NRG-009 and 010 trials.

If they want to be as aggressive as possible they will choose pelvic RT. I have been routinely giving 25 Gy in 5 fractions with SBRT to the prostate.