A few updates from AUA

[DoctwoB]

Couple of interesting rad-onc related abstracts from our national meeting.

1. Phase 1 trial of neoadjuvant sbrt before RP in locally advanced high risk PC. Good idea, but sadly failed utterly. High toxicity rates, not great disease control.

2. RT or surgery as option in low volume metastatic PC. One RCT out of China comparing local therapy to no local therapy (most patients got RP) showing HR of 0.5 at 2 years for rPFS. PMortality data still cooking.

Second prospective series out of Belgium where patients with low volume Mets got no local therapy, xrt, or surgery based on patient preference. Surgery and radiation had better 3 year OS and CSS then no local therapy. No difference between surgery and xrt, but fewer mortalities in radiation arm. Significantly better local event free survival in surgery arm compared to radiation. Obvious concerns re:selection bias in treatment, though patients only recruited if good candidates for all 3.

Overall looks promising that like in non metastatic disease, surgery or xrt will both be options in low volume metastatic disease. Still waiting on SWOG trial in this area, which will be higher quality data.

3. A few other retrospective looks at SBRT. One showing pretty good toxicity profile in large prostates over 100gm. Another looking at consolidating met directed therapy in bladder CA, showing a 20% 2 year pfs, which actually isn’t bad for bladder CA

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[ramsesthenice]

Couple of interesting rad-onc related abstracts from our national meeting.

1. Phase 1 trial of neoadjuvant sbrt before RP in locally advanced high risk PC. Good idea, but sadly failed utterly. High toxicity rates, not great disease control.

2. RT or surgery as option in low volume metastatic PC. One RCT out of China comparing local therapy to no local therapy (most patients got RP) showing HR of 0.5 at 2 years for rPFS. PMortality data still cooking.

Second prospective series out of Belgium where patients with low volume Mets got no local therapy, xrt, or surgery based on patient preference. Surgery and radiation had better 3 year OS and CSS then no local therapy. No difference between surgery and xrt, but fewer mortalities in radiation arm. Significantly better local event free survival in surgery arm compared to radiation. Obvious concerns re:selection bias in treatment, though patients only recruited if good candidates for all 3.

Overall looks promising that like in non metastatic disease, surgery or xrt will both be options in low volume metastatic disease. Still waiting on SWOG trial in this area, which will be higher quality data.

3. A few other retrospective looks at SBRT. One showing pretty good toxicity profile in large prostates over 100gm. Another looking at consolidating met directed therapy in bladder CA, showing a 20% 2 year pfs, which actually isn’t bad for bladder CA

Thanks for sharing. From a technical perspective, I have to say that I actually think the concept of preop SBRT was not a particularly good idea. Salvage RT to the prostate bed works (presumably) because we treat can treat larger margins than you can resect. By definition, SBRT employs very tight margins. Presumably preop RT would improve control by effectively "virtually widening" the surgical margins. If so, SBRT is probably not the right approach. Sadly, this is not the only disease site in which we are learning this lesson.

 

[dieABRdie]

Thanks for sharing. From a technical perspective, I have to say that I actually think the concept of preop SBRT was not a particularly good idea. Salvage RT to the prostate bed works (presumably) because we treat can treat larger margins than you can resect. By definition, SBRT employs very tight margins. Presumably preop RT would improve control by effectively "virtually widening" the surgical margins. If so, SBRT is probably not the right approach. Sadly, this is not the only disease site in which we are learning this lesson.

I didn't think it was a great idea from a biologic perspective either. Taking out a prostate and leaving that person with their continence requires a skilled surgeon and adequate healing. Throwing "ablative radiation" on top of that is a recipe for diapers all day. The best place for preop SBRT is before resection of brain metastases.

Thanks DoctwoB

 

[Ray D. Ayshun]

Yes, less toxicity to sbrt the prostate following removal. That'll show it.

 

[evilbooyaa]

Couple of interesting rad-onc related abstracts from our national meeting.

1. Phase 1 trial of neoadjuvant sbrt before RP in locally advanced high risk PC. Good idea, but sadly failed utterly. High toxicity rates, not great disease control.

2. RT or surgery as option in low volume metastatic PC. One RCT out of China comparing local therapy to no local therapy (most patients got RP) showing HR of 0.5 at 2 years for rPFS. PMortality data still cooking.

Second prospective series out of Belgium where patients with low volume Mets got no local therapy, xrt, or surgery based on patient preference. Surgery and radiation had better 3 year OS and CSS then no local therapy. No difference between surgery and xrt, but fewer mortalities in radiation arm. Significantly better local event free survival in surgery arm compared to radiation. Obvious concerns re:selection bias in treatment, though patients only recruited if good candidates for all 3.

Overall looks promising that like in non metastatic disease, surgery or xrt will both be options in low volume metastatic disease. Still waiting on SWOG trial in this area, which will be higher quality data.

3. A few other retrospective looks at SBRT. One showing pretty good toxicity profile in large prostates over 100gm. Another looking at consolidating met directed therapy in bladder CA, showing a 20% 2 year pfs, which actually isn’t bad for bladder CA

Big wins for Urology if you guys start getting evidence to offer RP off-protocol to low-volume metastatic patients. I do think there will be a subset of patients who actually benefit from this. Treatment preference driving RP vs RT will be a tough thing to overcome and will color any data, as you mentioned.

The question will be, is the potential toxicity of a RP worth it in a non-curative setting? Frequently these patients have big bulky primary prostates as well. RT is done at a lower dose (55Gy in 20 fractions) than it is for conventional treatment (60Gy in 20 fractions).

Whether local event free survival matters on its own would be TBD. Maybe for some patients. Maybe some of these folks can go for RP first and then come back for salvage fossa/LNs afterwards.

Thanks for sharing!

 

[Palex80]

Couple of interesting rad-onc related abstracts from our national meeting.

1. Phase 1 trial of neoadjuvant sbrt before RP in locally advanced high risk PC. Good idea, but sadly failed utterly. High toxicity rates, not great disease control.

Hmmmm... I am not sure why this was seen as a good idea? I mean, what is the problem with locally advanced prostate cancer scheduled to undergo resection? Local control is not the issue, since RP + adjuvant / early salvage RT are very good in that. The problem with locally advanced / high-Gleason disease is rather regional nodal recurrence and systemic disease. Both of these things cannot be countered by neoadjuvant SBRT.
This is not unresectable pancreatic cancer because of vessel involvement, where SBRT MIGHT increase resectability. It's prostate cancer.

2. RT or surgery as option in low volume metastatic PC. One RCT out of China comparing local therapy to no local therapy (most patients got RP) showing HR of 0.5 at 2 years for rPFS. PMortality data still cooking.

Nice, need to await long term follow up.

Second prospective series out of Belgium where patients with low volume Mets got no local therapy, xrt, or surgery based on patient preference. Surgery and radiation had better 3 year OS and CSS then no local therapy. No difference between surgery and xrt, but fewer mortalities in radiation arm. Significantly better local event free survival in surgery arm compared to radiation. Obvious concerns re:selection bias in treatment, though patients only recruited if good candidates for all 3.

Overall looks promising that like in non metastatic disease, surgery or xrt will both be options in low volume metastatic disease. Still waiting on SWOG trial in this area, which will be higher quality data.

Patient preference is a major bias in all prostate cancer trials looking into local therapies.
My last information is that SWOG is hardly recruiting and international collaborationwas seeked out but not achieved.
The next problem is that with STAMPEDE data out, randomizing low-volume metastatic patients to no local therapy is simply unethical.

3. A few other retrospective looks at SBRT. One showing pretty good toxicity profile in large prostates over 100gm. Another looking at consolidating met directed therapy in bladder CA, showing a 20% 2 year pfs, which actually isn’t bad for bladder CA

Oh, single arm SBRT trials. When will we stop doing those?


Sorry for being so negative!