Oligometastatic prostate case

[w00tz]

Guy in his 50s with newly diagnosed prostate cancer. GS 4+5 x 1, GS 4+4 x 3 cores, PSA 47, met to scapula and left ischium.

Wanting to treat prostate and bone mets with radiation. Would you treat the ischium and prostate separately or together? SBRT both? Hypofx both? Hypofx prostate and SBRT ischium?

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[Gfunk6]

I've had analogous situations a couple of times. I would hypofractionate the ischium/prostate simultaneously and SBRT the scapula.

 

[Mandelin Rain]

Yes. I don't know the exact dose I'd do to ischium, assuming you're doing 20 fractions, but I'd definitely do them simultaneously.

I'd probably SIB it a bit lower than 55Gy.

 

[BobbyHeenan]

I've had analogous situations a couple of times. I would hypofractionate the ischium/prostate simultaneously and SBRT the scapula.

I have a very similar case right now. I'm doing 55/20 and including the adjacent bone (R pubic symphysis area) in that PTV. My guy has a R iliac wing (way away from prostate) second bone met, that I'm doing SBRT on.

I'm just billing it as one IMRT course though since he's getting SBRT during his IMRT prostate due to transportation issues.

 

[w00tz]

Awesome, thanks for the input.

 

[ramsesthenice]

I've had analogous situations a couple of times. I would hypofractionate the ischium/prostate simultaneously and SBRT the scapula.

That is my practice as well. If a bone met more or less touches the traditional prostate/nodal contours I pretty much just include it and pretend like its a node. Seems to work fine.

 

[Mandelin Rain]

Would everyone take this particular met to 55Gy, directly touching femoral head?

 

[BobbyHeenan]

Would everyone take this particular met to 55Gy, directly touching femoral head?

I'd probably treat it to 45-50 rather than 55 in 20 (SIB plan). No clue if that matters at all.

RTOG 0534 allowed up to 10% of femoral head to get 50 Gy (though obviously that's at standard frac).

 

[Mandelin Rain]

I'd probably treat it to 45-50 rather than 55 in 20 (SIB plan). No clue if that matters at all.

RTOG 0534 allowed up to 10% of femoral head to get 50 Gy (though obviously that's at standard frac).

That's what I was thinking.

 

[evilbooyaa]

That's what I was thinking.

Would take as much of it to Rx dose as feasible while limiting femoral head point dose to 50Gy leading to some natural underdosing along the antoerlateral aspect of the disease pictured.

 

[deleted1111261]

The 55/20 study also allowed for 6 Gy x 6 delivered weekly for M1 patients. Wouldn’t do in this guy, but have done it in past. Reasonable approach.

 

[w00tz]

Say there are 9mm and 8mm left ext iliac nodes...
Leave them for systemic therapy?
Try to take to 55-60Gy/20fx?
Anyone treating elective nodes in this case?

 

[Ray D. Ayshun]

Say there are 9mm and 8mm left ext iliac nodes...
Leave them for systemic therapy?
Try to take to 55-60Gy/20fx?
Anyone treating elective nodes in this case?

If they're abutting the field maybe. I wouldn't do elective. You're gonna retreat this guy a few times I bet.

 

[evilbooyaa]

Say there are 9mm and 8mm left ext iliac nodes...
Leave them for systemic therapy?
Try to take to 55-60Gy/20fx?
Anyone treating elective nodes in this case?

Generally, for me, size threshold is 1cm or higher with unfavorable morphology, or brightness on say a F18 or PSMA PET.

STAMPEDE did not cover LNs, but I could see an argument for doing 44/20 elective to nodal basin while SIBbing gross nodes to 55-60/20 if you see say multiple suspicious LNs. Your threshold for what is suspicious may be different than mine.

 

[Ray D. Ayshun]

Generally, for me, size threshold is 1cm or higher with unfavorable morphology, or brightness on say a F18 or PSMA PET.

STAMPEDE did not cover LNs, but I could see an argument for doing 44/20 elective to nodal basin while SIBbing gross nodes to 55-60/20 if you see say multiple suspicious LNs. Your threshold for what is suspicious may be different than mine.

It's hard to justify doing anything electively in this case in my mind. I'd just strategize on where and how I'll end up treating future sites of progression. IOW, can the nodes you're mentioning be easily SBRT'd in a year if they progress (are even involved), or are they so close it would make sense to go ahead and treat them now?

 

[seper]

Metastatic disease = do no harm

 

[Chartreuse Wombat]

Metastatic disease = do no harm

Save the nodes for later (if needed)

 

[Palex80]

Metastatic disease = do no harm

... to the tumor.

 

[elementaryschooleconomics]

... to the tumor.

Look at this trans-Atlantic sass!

A couple of times I have opted to treat the pelvic nodes in low-metastatic prostate patients, when they had obvious (>>1cm) gross nodal disease in classic (RTOG-consensus) regional nodes. Those patients have done, and continue to do, very will with minimal (acute) toxicity. We'll see how they're doing in 5 years though.

I have a hard time reconciling the STAMPEDE control arm N+M0 benefit (with 80% getting pelvic RT) and the M+ benefit in the main report to conclude that pelvic coverage is not needed in N+M+ patients with obvious gross disease.

But based on the responses in this thread - am I in the minority here? If a patient presents with a single, small bony lesion at L5, and let's say one 2cm node in the left internal iliac chain, and one 2.2cm node in the right internal iliac chain, most of you would opt to treat prostate only with SBRT to the bony met?

Nodal coverage in prostate is in my top 5 least favorite topics.

 

[Ray D. Ayshun]

Look at this trans-Atlantic sass!

A couple of times I have opted to treat the pelvic nodes in low-metastatic prostate patients, when they had obvious (>>1cm) gross nodal disease in classic (RTOG-consensus) regional nodes. Those patients have done, and continue to do, very will with minimal (acute) toxicity. We'll see how they're doing in 5 years though.

I have a hard time reconciling the STAMPEDE control arm N+M0 benefit (with 80% getting pelvic RT) and the M+ benefit in the main report to conclude that pelvic coverage is not needed in N+M+ patients with obvious gross disease.

But based on the responses in this thread - am I in the minority here? If a patient presents with a single, small bony lesion at L5, and let's say one 2cm node in the left internal iliac chain, and one 2.2cm node in the right internal iliac chain, most of you would opt to treat prostate only with SBRT to the bony met?

Nodal coverage in prostate is in my top 5 least favorite topics.

When I say don't treat nodes, I mean elective volumes personally. The nodes mentioned in this case are equivocal at best. If they're abutting the present volume, I'd day treat now if treating in the future would be dangerous. If they're well away, then save for another day. If they're well away and 2 cm, then I'd treat, but I wouldn't necessarily plan on treating a consensus pelvic volume like I would in N+M0 disease, though it's possible. I think it's not hard to argue that not treating a 2 cm node in a patient with limited metastatic disease is doing as much harm as not treating the prostate. If I can safely thin the herd, I'll do it.

 

[evilbooyaa]

Look at this trans-Atlantic sass!

A couple of times I have opted to treat the pelvic nodes in low-metastatic prostate patients, when they had obvious (>>1cm) gross nodal disease in classic (RTOG-consensus) regional nodes. Those patients have done, and continue to do, very will with minimal (acute) toxicity. We'll see how they're doing in 5 years though.

I have a hard time reconciling the STAMPEDE control arm N+M0 benefit (with 80% getting pelvic RT) and the M+ benefit in the main report to conclude that pelvic coverage is not needed in N+M+ patients with obvious gross disease.

But based on the responses in this thread - am I in the minority here? If a patient presents with a single, small bony lesion at L5, and let's say one 2cm node in the left internal iliac chain, and one 2.2cm node in the right internal iliac chain, most of you would opt to treat prostate only with SBRT to the bony met?

Nodal coverage in prostate is in my top 5 least favorite topics.

For me it's the 8mm and 9mm thresholds without PET avidity that favor me against treating.

Your post is nuanced and reasonable.

Some, however, will be purists. M+ received RT to prostate only, didn't matter if they were N0 or N1 IIRC. I think the toxicity of elective nodal RT in prostate is pretty vastly overstated. If the goal is to treat ALL sites of disease (like by treating the oligomet) then I'd also treat nodal sites (assuming gross disease, the threshold for which is different person to person).