Bone met scenario

[Grubbe-a-dub-dub]

Here's a scenario I need help with:

70ish yo M with castrate-resistant stage IV prostate cancer. PSMA PET showed a mid femur met along with other small bone lesions, the patient was asymptomatic. I radiated the mid femur met 30 Gy in 10 fractions hoping to prevent a fracture (based on the data presented at ASTRO).

PSA goes down (patient is on xtandi btw). Med onc orders restaging bone scan and he still has uptake in the right mid femur (very bright, same spot I radiated), no other uptake. The patient is still asymptomatic.

Worth re-irradiating? If so how? Other options?

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[Ray D. Ayshun]

Here's a scenario I need help with:

70ish yo M with castrate-resistant stage IV prostate cancer. PSMA PET showed a mid femur met along with other small bone lesions, the patient was asymptomatic. I radiated the mid femur met 30 Gy in 10 fractions hoping to prevent a fracture (based on the data presented at ASTRO).

PSA goes down (patient is on xtandi btw). Med onc orders restaging bone scan and he still has uptake in the right mid femur (very bright, same spot I radiated), no other uptake. The patient is still asymptomatic.

Worth re-irradiating? If so how? Other options?

I'd say no. Also, remember that after definitive rt, the low point in the psa happens like 1-1.5 years later. I suspect this is dead and dying cancer. I also suspect 60 gy to the femur is more likely to cause a fracture than an asymptomatic met.

 

[RadOncDoc21]

IR Ablation +biopsy?

 

[RickyScott]

Here's a scenario I need help with:

70ish yo M with castrate-resistant stage IV prostate cancer. PSMA PET showed a mid femur met along with other small bone lesions, the patient was asymptomatic. I radiated the mid femur met 30 Gy in 10 fractions hoping to prevent a fracture (based on the data presented at ASTRO).

PSA goes down (patient is on xtandi btw). Med onc orders restaging bone scan and he still has uptake in the right mid femur (very bright, same spot I radiated), no other uptake. The patient is still asymptomatic.

Worth re-irradiating? If so how? Other options?

I dont think that the bone scan reflects presence of disease in this case- tracer is taken up by bone not cancer cells. I have often found it positive long after radiation even with SBRT. It just reflects remodeling bone

 

[OTN]

Leave 'er be

 

[Palex80]

I would observe.

 

[TheWallnerus]

Can’t fix what ain’t broken. In this case quite literally.

 

[Palex80]

Can’t fix what ain’t broken. In this case quite literally.

 

[deleted1111261]

+1

 

[salubalu]

Femurectomy

 

[Fpg1245]

Femurectomy

Sounds like a complete note written by an ortho HPI/PE/A/P all in one word

 

[taserlaser]

Femurectomy

You joke, but my colleague did a case of extracorporeal radiation not too long ago. I believe it was a femur to 100 Gy, if I recall correctly. One of the non-rad onc MDs asked if that dose burned out the linac haha.

 

[TheWallnerus]

You joke, but my colleague did a case of extracorporeal radiation not too long ago. I believe it was a femur to 100 Gy, if I recall correctly. One of the non-rad onc MDs asked if that dose burned out the linac haha.

Even 50 Gy in one fraction won’t sterilize 100% of the cancer cells in 100% of the patients…

 

[sirspamalot]

If only all of radiation could be extracorporeal.. we'd have a real winner.

 

[evilbooyaa]

Would not re-treat based on bone scan uptake alone

If PSA goes down and stays down, why is med onc ordering restaging imaging? If restaging imaging is being ordered, why would it ever be a bone scan in this situation vs a PSMA PET?

 

[Ray D. Ayshun]

Oops. I thought they ordered a PSMA PET. Yeah, BS useless here. When the PSA is going down, the correct imaging is with you eyes.

 

[Grubbe-a-dub-dub]

Would not re-treat based on bone scan uptake alone

If PSA goes down and stays down, why is med onc ordering restaging imaging? If restaging imaging is being ordered, why would it ever be a bone scan in this situation vs a PSMA PET?

I had the same question. I noticed it on other stage IV prostate patients - this physician frequently orders re-staging imaging. This causes all sorts of anxiety about how to interpret the results.

 

[evilbooyaa]

If like undifferentiated pCA with low PSA at baseline with Gleason 9 or 10 disease or concern for a dedifferentiated component, I get it. But if PSA is appropriately responsive, patient is not worsening symptomatically despite low PSA then doesn't make sense

 

[Palex80]

If PSA goes down and stays down, why is med onc ordering restaging imaging? If restaging imaging is being ordered, why would it ever be a bone scan in this situation vs a PSMA PET?

In mHSPC, it is recommended to undergo restaging periodically, regardless of PSA response.
The exact period is not well defined in the guidelines, in contrast to mCRPC. I rescan yearly if a patient stays with me (mostly oligo-M1).
If this was not oligo-M1, rescanning with bone scan & CT is s.o.c.
PSMA-PET-CT is not considered as standard for poly-M1 restaging on ADT. PSMA-PET-CT is good for ADT-naive patients or in mCRPC patients progressing, when you would like to evaluate for PSMA-Lutetium treatment or in the seldom case of oligo-progression, where you may SBRT something.

 

[sirspamalot]

And you know we gunna SBRT somethin'