24 gy in 2 fx spine

[radiation]

anybody using this?

Stereotactic body radiotherapy versus conventional external beam radiotherapy in patients with painful spinal metastases: an open-label, multicentre, randomised, controlled, phase 2/3 trial​

---

Members don't see this ad.

 

[TheWallnerus]

anybody using this?

Stereotactic body radiotherapy versus conventional external beam radiotherapy in patients with painful spinal metastases: an open-label, multicentre, randomised, controlled, phase 2/3 trial​

i'm gonna start

 

[Palex80]

Can someone help me out, please? Randomized trials on spine SBRT are confusing.
Why did this trial show a benefit in terms of pain control, while these other two trials came back negative:

RTOG 0631
German Phase II trial

Now, don't get me wrong. I like spine SBRT, I have been doing too every now and then when I felt that durable pain and tumor control were important, but why should I "trust" this trial's results and declare it to a new s.o.c., when others have failed?

 

[Ray D. Ayshun]

Can someone help me out, please? Randomized trials on spine SBRT are confusing.
Why did this trial show a benefit in terms of pain control, while these other two trials came back negative:

RTOG 0631
German Phase II trial

Now, don't get me wrong. I like spine SBRT, I have been doing too every now and then when I felt that durable pain and tumor control were important, but why should I "trust" this trial's results and declare it to a new s.o.c., when others have failed?

On the whole, could argue the German trial was positive based on my quick read of the abstract.

 

[TheWallnerus]

Can someone help me out, please? Randomized trials on spine SBRT are confusing.
Why did this trial show a benefit in terms of pain control, while these other two trials came back negative:

RTOG 0631
German Phase II trial

Now, don't get me wrong. I like spine SBRT, I have been doing too every now and then when I felt that durable pain and tumor control were important, but why should I "trust" this trial's results and declare it to a new s.o.c., when others have failed?

please let us have nice things

 

[Krukenberg]

On the whole, could argue the German trial was positive based on my quick read of the abstract.

Yea I would. It’s a phase 2 and it showed a significant pain improvement at 6 months, with a trend towards improvement at 3 months. Enough signal to justify a real phase 3 like the Canadian trial

 

[deleted969641]

Edit to the above to actually answer the question.

Yes I have treated spine SBRT for palliation multiple times. There is in particular respectable evidence that it makes sense in select patients with cord compression who can't get surgery or have a delay to surgery but are neurologically intact:

Radiosurgical decompression of metastatic epidural compression (wiley.com)

I do 8 Gy x 1 all the time too to the spine. However, in so many cases SBRT makes "sense" whether "common" or not, and unfortunately it is a point of pride among many to reflexively pound fists and yell that a spine met equals AP-PA 8 Gy x 1 (try to debate 3 Gy x 10 let alone SBRT) as much as 2+2=4 (or 5?)

But I didn't complete a palliative RT fellowship so excuse my simple caveman medicoradiotherapist ramblings.

 

[Neuronix]

If tumor is abutting cord I recommend sending to separation surgery, not forcing SBRT.

The NOMS framework: approach to the treatment of spinal metastatic tumors - PubMed

NOMS paradigm provides a decision framework that incorporates sentinel decision points in the treatment of spinal metastases. Consideration of the tumor sensitivity to radiation in conjunction with the extent of epidural extension allows determination of the optimal radiation treatment and the...

pubmed.ncbi.nlm.nih.gov

The tumor fails where you skimp on dose to make cord constraint.

Correlation of local failure with measures of dose insufficiency in the high-dose single-fraction treatment of bony metastases - PubMed

The results indicate that D(min), D(98), and D(95) may be important risk factors for local failure. No local failures in any histology were observed when D(min) was >15 Gy, suggesting that this metric may be an important predictor of local control.

pubmed.ncbi.nlm.nih.gov

Outcomes for Spine Stereotactic Body Radiation Therapy and an Analysis of Predictors of Local Recurrence - PubMed

Stereotactic body radiation therapy offers durable control for spinal metastases, but there is a subset of patients that recur locally. Patients with local relapse had significantly poorer tumor coverage, which was likely attributable to treatment planning directives that prioritized the spinal...

pubmed.ncbi.nlm.nih.gov

If you max your RTOG 0631/TG-101 constraints on the first treatment good luck finding an appropriate dose to re-treat with.

I recommend the opposite--not doing SBRT in cord compression. I often do 20 Gy in 5 fractions in such cases because it is very easy to re-treat 20 Gy in 5 fractions a second time.

Or at the very least you can give cord plus margin 20 Gy in 5 fractions (allowing for a reasonable hot spot in that area) and the surrounding tumor higher dose if you feel you really want to do SBRT for some reason. That way you can come back and re-treat 20 in 5 again later. This is very risky because the tumor will have very little room to grow before the patient has symptomatic cord compression in the future. A separation surgery gives you a little buffer in the future as well if the tumor starts to regrow.

 

[RADONC4285]

Can someone help me out, please? Randomized trials on spine SBRT are confusing.
Why did this trial show a benefit in terms of pain control, while these other two trials came back negative:

RTOG 0631
German Phase II trial

Now, don't get me wrong. I like spine SBRT, I have been doing too every now and then when I felt that durable pain and tumor control were important, but why should I "trust" this trial's results and declare it to a new s.o.c., when others have failed?

There were imbalances in the RTOG 0631 trial. the SBRT arm had higher SINS scores and pain scores. Also, while the BED of RTOG doses and 24/2 is similar, maybe there is something in the biology that makes 2 fraction SBRT more effective. I still think if the patient has poor prognosis SBRT doesn't make a difference. The benefit is more long term. I plan to do 24/2 for patients with a decent PS who are not oligometastatic. If oligometastatic then need higher BED for "cure". I agree with above, wouldn't do SBRT if very close to the cord. Highly consider separation surgery, then post op SBRT, which is under utilized IMHO

 

[Neuronix]

then post op SBRT, which is under utilized IMHO

Post-op SBRT is very challenging to contour depending on whether hardware is placed in surgery and the quality of the imaging you have. Dedicated MRI simulator helps me a lot for these cases.

I do a lot of single fraction SBRT/SRS, but maybe that isn't the right answer? The 24/2 is making me question all the various spine regimens. Like is there some magic of a particular fractionation in the 1-5 regime? There seems to be a sweet spot between disease control and compression fracture risk that probably exists in all these fractionations. It makes you wonder if there's a temporal dependence when fractionating as well.

 

[RADONC4285]

Post-op SBRT is very challenging to contour depending on whether hardware is placed in surgery and the quality of the imaging you have. Dedicated MRI simulator helps me a lot for these cases.

I do a lot of single fraction SBRT/SRS, but maybe that isn't the right answer? The 24/2 is making me question all the various spine regimens. Like is there some magic of a particular fractionation in the 1-5 regime? There seems to be a sweet spot between disease control and compression fracture risk that probably exists in all these fractionations. It makes you wonder if there's a temporal dependence when fractionating as well.

I agree post op SBRT is challenging to contour, but a CT myelogram is usually helpful and gives you enough to have a good CTV at least. MRI actually can have considerable geometric distortion with metal in the field. the alternative is to do SBRT without surgery, but then you know you're under-dosing.

At this point, i do not plan to do any single fraction spine SBRT. we have clinical and preclinical data showing it leads to higher fracture rates. If you're going for "cure", then probably need 24 Gy x 1, which is what MSK does, but that's very risky IMO. I prefer 3-5 fx for definitive cases, and 24/2 in durable palliative cases

 

[Neuronix]

I agree post op SBRT is challenging to contour, but a CT myelogram is usually helpful and gives you enough to have a good CTV at least. MRI actually can have considerable geometric distortion with metal in the field. the alternative is to do SBRT without surgery, but then you know you're under-dosing.

This is a good point. CT myelogram is also a good option. I've gotten so much streak artifact from the metal at times that it's also not 100%.

We mostly use our Viewray system for this. The low field MRI reduces the artifacts and distortion significantly because of the low field strength and the distortion resistant sequence used. Siemens/Varian is releasing a 0.55T wide bore MRI system that they seem to be pushing as an MRI simulator as well, probably also going to be good for this.

At this point, i do not plan to do any single fraction spine SBRT. we have clinical and preclinical data showing it leads to higher fracture rates. If you're going for "cure", then probably need 24 Gy x 1, which is what MSK does, but that's very risky IMO. I prefer 3-5 fx for definitive cases, and 24/2 in durable palliative cases

I've done 24 Gy in 1 fraction in some cases to limited disease. I'm usually in the 16-20 Gy range for single fraction. Compression fracture risk goes up above 20 Gy. I wonder what MSK is doing in practice given compression fracture risk? Maybe 24 Gy to GTV and 16-18 Gy to CTV? Do they not believe the JCO paper? Anyone around from there who would comment?

 

[Palex80]

We know that single-fraction SBRT for spine lesions is associated with more bone complications than fractionated treatments.

Single fraction radiosurgery, fractionated radiosurgery, and conventional radiotherapy for spinal oligometastasis (SAFFRON): A systematic review and meta-analysis - PubMed

SF-SRS resulted in superior LC with a roughly 5% LC benefit for every 10 Gy₁₀ increase in BED₁₀ with higher VCF rates compared to MF-SRS. If LC is the goal of treatment, then SRS may be a preferred treatment modality. However, these results are hypothesis-generating, and...

pubmed.ncbi.nlm.nih.gov

Perhaps the difference in pain scores has to with that as well?

 

[RADONC4285]

This is a good point. CT myelogram is also a good option. I've gotten so much streak artifact from the metal at times that it's also not 100%.

We mostly use our Viewray system for this. The low field MRI reduces the artifacts and distortion significantly because of the low field strength and the distortion resistant sequence used. Siemens/Varian is releasing a 0.55T wide bore MRI system that they seem to be pushing as an MRI simulator as well, probably also going to be good for this.



I've done 24 Gy in 1 fraction in some cases to limitedView them? disease. I'm usually in the 16-20 Gy range for single fraction. Compression fracture risk goes up above 20 Gy. I wonder what MSK is doing in practice given compression fracture risk? Maybe 24 Gy to GTV and 16-18 Gy to CTV? Do they not believe the JCO paper? Anyone around from there who would comment?

This RCT, which included a lot of patients tx at MSK claims a very low fracture rate with 24 Gy x 1, but with all due respect to the MSK, I don't believe it. Plenty of evidence showing high fracture rates with 24 Gy. It's a really good trial though and shows that a high BED is needed for long term control

Phase 3 Multi-Center, Prospective, Randomized Trial Comparing Single-Dose 24 Gy Radiation Therapy to a 3-Fraction SBRT Regimen in the Treatment of Oligometastatic Cancer - PubMed

The study confirms SDRT as a superior ablative treatment, indicating that effective ablation of oligometastatic lesions is associated with significant mitigation of distant metastatic progression.

pubmed.ncbi.nlm.nih.gov

 

[Neuronix]

We know that single-fraction SBRT for spine lesions is associated with more bone complications than fractionated treatments.

Single fraction radiosurgery, fractionated radiosurgery, and conventional radiotherapy for spinal oligometastasis (SAFFRON): A systematic review and meta-analysis - PubMed

SF-SRS resulted in superior LC with a roughly 5% LC benefit for every 10 Gy₁₀ increase in BED₁₀ with higher VCF rates compared to MF-SRS. If LC is the goal of treatment, then SRS may be a preferred treatment modality. However, these results are hypothesis-generating, and...

pubmed.ncbi.nlm.nih.gov

Perhaps the difference in pain scores has to with that as well?

This is confounded because single fraction SBRT used more aggressive dose-fractionation regimens when BED corrected (especially if you think about BED2 for late toxicity). The single fraction SBRT also had higher control. There's always a trade off between control and toxicity.

This RCT, which included a lot of patients tx at MSK claims a very low fracture rate with 24 Gy x 1, but with all due respect to the MSK, I don't believe it. Plenty of evidence showing high fracture rates with 24 Gy. It's a really good trial though and shows that a high BED is needed for long term control

Phase 3 Multi-Center, Prospective, Randomized Trial Comparing Single-Dose 24 Gy Radiation Therapy to a 3-Fraction SBRT Regimen in the Treatment of Oligometastatic Cancer - PubMed

The study confirms SDRT as a superior ablative treatment, indicating that effective ablation of oligometastatic lesions is associated with significant mitigation of distant metastatic progression.

pubmed.ncbi.nlm.nih.gov

This is part of the issue with SBRT in general. Everyone prescribes differently. Is it dose to a volume? Normalized to what volume? Is it dose to Dmax? It's like the wild west out there. You have to account for this when comparing studies and series, which can be very hard to do.

 

[TheWallnerus]

Post-op SBRT is very challenging to contour depending on whether hardware is placed in surgery and the quality of the imaging you have. Dedicated MRI simulator helps me a lot for these cases.

I do a lot of single fraction SBRT/SRS, but maybe that isn't the right answer? The 24/2 is making me question all the various spine regimens. Like is there some magic of a particular fractionation in the 1-5 regime? There seems to be a sweet spot between disease control and compression fracture risk that probably exists in all these fractionations. It makes you wonder if there's a temporal dependence when fractionating as well.

As we know, there are known knowns. There are things we know we know.
We also know there are known unknowns. That is to say: we know there are some things we do not know.
But there are also unknown unknowns: things we don't know we don't know.

- Donald Rumsfeld

 

[Krukenberg]

This is a good point. CT myelogram is also a good option. I've gotten so much streak artifact from the metal at times that it's also not 100%.

We mostly use our Viewray system for this. The low field MRI reduces the artifacts and distortion significantly because of the low field strength and the distortion resistant sequence used. Siemens/Varian is releasing a 0.55T wide bore MRI system that they seem to be pushing as an MRI simulator as well, probably also going to be good for this.



I've done 24 Gy in 1 fraction in some cases to limited disease. I'm usually in the 16-20 Gy range for single fraction. Compression fracture risk goes up above 20 Gy. I wonder what MSK is doing in practice given compression fracture risk? Maybe 24 Gy to GTV and 16-18 Gy to CTV? Do they not believe the JCO paper? Anyone around from there who would comment?

Someone can correct me if I’m wrong, but I heard that when they treat to that dose, they send to IR for prophylactic kypho. They’ve set the whole spine program up so that everyone gets some action

 

[RADONC4285]

Someone can correct me if I’m wrong, but I heard that when they treat to that dose, they send to IR for prophylactic kypho. They’ve set the whole spine program up so that everyone gets some action

I know they usually do a CT myelogram on the day of treatment but not sure they do a kypho