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Pacing of SBRT treatments

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Posted 4/16/2023 9:17 PM (GMT 0)
I have a friend that will be starting SBRT next month (G7, 3+4 diagnosis). The RO recommended that he have the sessions every other day, as opposed to all 5 sessions all in one week, but the choice is his. For my part, I didn't know that spacing the sessions out was even a thing, but then I'm an IMRT guy. Any thoughts on this? He's in his mid-70s and otherwise healthy.
Posted 4/16/2023 9:33 PM (GMT 0)
I have not heard of many doing SBRT daily. Did find some studies about every other day vs. weekly which is the other direction. My guess is that there is not a clear cut answer to this. Daily may make one more tired than every other day so you end up in the same spot at 10 days.

My wife had 3 SBRT treatments to a rib every other day. That's all I know for sure.
Posted 4/16/2023 11:13 PM (GMT 0)
I quickly scanned some SBRT papers in my file.
Katz and Collins (both SBRT pioneers but at different institutions) describe daily sessions.
I do agree that an every other day protocol is likely to be more convenient for the patient.
Posted 4/17/2023 10:19 AM (GMT 0)
I was also a G7 3+4 that had five sessions of SBRT (7.25 Gy per session). My sessions ( 3 1/2 years ago) were on a Friday, Monday, Wednesday, Friday, and Monday. I have never heard of anyone having SBRT treatment sessions for PC on consecutive days.
Results have been excellent. My last PSA reading a month ago was 0.24.
Posted 4/17/2023 12:30 PM (GMT 0)
When I was treated six years ago with SBRT every other day treatment was the norm. I’ve heard of four day treatments; however, I believe five treatments remain the norm. Either way I believe the data shows SBRT to be safe, effective and very convenient. More low and intermediate risks guys should investigate it as a treatment option.
Posted 4/17/2023 12:36 PM (GMT 0)
Yes, five-session SBRT may be offered on either consecutive or alternate days, for example:

1.5T MR-Guided Daily-Adaptive SBRT for Prostate Cancer: Preliminary Report of Toxicity and Quality of Life of the First 100 Patients (2023, Full Text)

"Abstract
Purpose: The present study reports the preliminary outcomes in terms of adverse events and quality of life in the first 100 patients treated with 1.5T MR-guided daily-adaptive stereotactic body radiotherapy for prostate cancer. Methods: From October 2019 to December 2020, 100 patients, enrolled in a prospective study, received MR-guided SBRT for prostate cancer. Rectal spacer insertion was optional and administered in 37 patients. In total, 32 patients received androgen deprivation therapy in accordance with international guidelines. A prospective collection of data regarding toxicity and quality of life was performed. Results: The median age was 71 years (range, 52–84). The median total dose delivered was 35 Gy (35–36.25 Gy) in five sessions, either on alternate days (n = 25) or consecutive days (n = 75). For acute toxicity, we recorded: seven cases of acute G2 urinary pain and four cases of G2 gastrointestinal events. The median follow-up was 12 months (3–20), recording three late G2 urinary events and one G3 case, consisting of a patient who required a TURP 8 months after the treatment. For gastrointestinal toxicity, we observed 3 G ≥ 2 GI events, including one patient who received argon laser therapy for radiation-induced proctitis. Up to the last follow-up, all patients are alive and with no evidence of biochemical relapse, except for an M1 low-volume patient in distant progression two months after radiotherapy. QoL evaluation reported a substantial resolution of any discomfort within the second follow-up after radiotherapy, with the only exception being sexual items. Notably, after one year, global health items were improved compared to the baseline assessment. Conclusions: This study reports very promising outcomes in terms of adverse events and QoL, supporting the role of 1.5T MR-guided SBRT for prostate cancer. To date, this series is one of the first and largest available in the literature. Long-term results are warranted."
Posted 4/17/2023 3:38 PM (GMT 0)
Thanks all! (And Djin, I was hoping you'd post a link to a relevant study!) Having gone though IMRT as part of my treatment and its daily treatments, I just assumed that the 5 sessions of SBRT were also once a day. But it does make sense that the protocol for SBRT would be different. I'll pass this information and the experiences you've shared to my friend.
Posted 4/18/2023 2:56 PM (GMT 0)
Everyone I have know that used SBRT was alternate day and that continues to be the method used by the radiotherapy clinic I used for HDR-BT and IMRT.
Posted 4/19/2023 5:50 PM (GMT 0)
Had SBRT over a year and half ago and it was alternate days.
My PSA is dropping but after a year I developed strictures.
I had dilation and my flow has returned to normal but I have resumed hematuria off and on. Not sure what that means but strictures can return.
I choose SBRT mainly because I have chronic pain and laying on the table hurt me.


Glen
Posted 4/29/2023 12:02 AM (GMT 0)
What am I missing. Why doesn't everyone do this treatment. Only 5 sessions and you are finished.
Posted 4/29/2023 5:36 PM (GMT 0)
It is a relatively new technology, been around for about 12-15 years, and has a great track record.
Posted 4/29/2023 7:50 PM (GMT 0)

62gal said...
What am I missing. Why doesn't everyone do this treatment. Only 5 sessions and you are finished.

Pratoman said...
It is a relatively new technology, been around for about 12-15 years, and has a great track record.

AFAIK, SBRT is not used alone for high-grade PCa. Also, because it is a newer technology, we don't have long-term outcomes where it is monotherapy.

"Abstract
Stereotactic body radiotherapy (SBRT) is well accepted for low- and intermediate-favorable risk prostate cancer. Available evidence about the application of SBRT in unfavorable- and high-risk prostate cancer is less solid. During last year's multiple variations in treatment, techniques have been reported making comparisons more complicated. This review's objective is to review current evidence in application of SBRT in intermediate unfavourable and high-risk prostate cancer and to outline variations in SBRT treatment techniques and relevant results." From Overview of the current role of stereotactic body radiotherapy in the treatment of unfavorable intermediate- and high-risk prostate cancer (2023)

Djin
Posted 4/30/2023 3:04 AM (GMT 0)

Pratoman said...
It is a relatively new technology, been around for about 12-15 years, and has a great track record.

Not to be snarky, but how much historical data do we need?

I had SBRT 6 1/2 years ago. At that time, we already had Dr. Katz's 9-year results published, with his 10-year data to shortly follow. (This was enough information for me and for my uro. Others may or may not be comfortable with "only" 9-10 years' data.) These days it seems that by the time we (meaning "some" uro's) have enough historical results data to support a treatment protocol, a new one comes along and disrupts the decision process all over again.

I am afraid that there is still a bit of "we can't do that for you, so maybe it isn't all that good" out there. There are also many urology practice groups still trying to amortize the cost of their IMRT suites. They won't invest in SBRT capabilities until the current equipment has been fully "paid for" in billings.

Of course, there are still many, many communities where there is no nearby SBRT capability. These patients have no choice, unless they are willing and able to travel for a week or two for treatment.

I am not trying to be negative. When my RO and I discussed SBRT before I started treatment, we both agreed that we didn't understand why anyone would NOT choose SBRT, but even now some choose the old "gold standard" treatment protocol.

My treatment protocol was 5 fractions at 7.25 Gy per fraction, on alternate days. We did, at one point, add an extra "off" day to allow for the Thanksgiving holiday, but they then had me come in on a Sunday to make it up.

At the time of my treatment, SBRT was approved by insurance companies for low-risk and favorable intermediate risk patients. Any unfavorable intermediate risk or high-risk patients could only receive SBRT if it was part of a research study.
Posted 4/30/2023 12:09 PM (GMT 0)
Pratoman, try several decades. It was first used in Sweden in 1990 and first used in the US for PCa in 2000. It is not by any means relatively new as it shares about the same development timeline as robotic assisted surgery and no one would dare claim it is relatively new. I do appreciate your comment about it having a great track record. TallAllen was one of the first on the board to use it in around 2010 and at that point his oncologist had formally published seven years of results.

Big reasons for under use in my opinion is financial and training. The radiation clinic makes a similar fee for each faction. So with traditional IMRT being about 45 fractions versus 5 for SBRT, it is much less profitable. Plus, to make less money, the clinic and various people have to be trained (at significant expense) to use it effectively. Basically any linac machine that does IMRT also does SBRT as they are essentially the same from a radiation field control basis, so no new hardware is required.

And as Djin has pointed out, its use is narrowed a bit based on risk, however as practitioners continue to push the envelope I think the use will become more widespread as we have already seen with all types of cancer that employ SBRT. Also it is usually not used when combined with brachytherapy or for salvage radiation after failed surgery as those uses usually mean expanding the radiation field. It has been used for decades for all types of spot tumor radiation when the cancer has spread.

Clearly, all candidates considering EBRT should always get an assessment for SBRT as it is far superior from a patient convenience factor.
Posted 4/30/2023 6:42 PM (GMT 0)
I stand corrected.

I recall that for Prostate Cancer, at the time of my diagnosis, in 2015, Dr Katz et al had 6-7 years of track record. That wasn't quite enough for me.
Today, 8 years later, if i was diagnosed, i would considerit m uch more seriously
Posted 4/30/2023 7:37 PM (GMT 0)
SBRT for PCa as a primary treatment seems to have stalled out a bit which is a shame. Cyberknife was a driver of their system and they are nowhere to be found around here anymore (MN). All the other places seem to have moved to hypofractionated IMRT at 20-28 treatments as the compromise position. SBRT for anything else seems to be common but not so much with PCa.

The RO's still hold to the limitations on staging and any complexities to the PCa for considering SBRT. A friend I recommended SBRT to even had Mayo say no to SBRT for his particular PCa case so he got the same local IMRT treatment @ 25 sessions vs. the 80 mile drive and back.

The last I heard, a dosage of 40Gy over 5 treatments is preferred now for optimum results so it seems like the studies go on and on. Always hard to knock the incumbents out of office without local proponents of the technology it seems.
Posted 4/30/2023 8:41 PM (GMT 0)
I share in Paxton’s comments earlier in this thread. I can’t understand why SBRT has not already passed other treatments for low and intermediate risks guy recently diagnosed. It’s much more convenient and arguably safer and more effective than other forms of beam radiation. It’s also significantly less expensive. The cynical side of me says SBRT simply doesn’t pay enough for RO’s and their teams to invest in training for the treatment of PCa. We live in Pittsburgh where the equipment capable of delivering SBRT is readily available. But, we traveled to Cleveland Clinic for treatment since the skill to deliver that treatment was not available in Pittsburgh. Maybe we should have gotten a ‘thank you’ letter from our insurance provider for saving them $10,000 over the cost of IMRT?
Posted 4/30/2023 9:22 PM (GMT 0)

Mumbo said...
...
The last I heard, a dosage of 40Gy over 5 treatments is preferred now for optimum results so it seems like the studies go on and on. Always hard to knock the incumbents out of office without local proponents of the technology it seems.

Yes, the optimal regime (total dose and fractionization schedule) is still being worked out. Longer-term studies are indeed needed to have a full picture. For example, does the number of fractions, schedule, or dosage affect the rate of secondary primary tumors (bladder and bowel) or the recurrence rate among Gleason 7 men?

We should also remember that some men who are assumed to be low- or intermediate-risk based on their biopsy are, in fact, high-risk (men who would have been upgraded to high-risk post RP).

Here is a recent review comparing SBRT with Brachy:

Stereotactic Radiation Therapy versus Brachytherapy: Relative Strengths of Two Highly Efficient Options for the Treatment of Localized Prostate Cancer (2022, Full Text)
Posted 4/30/2023 11:31 PM (GMT 0)
I know I've mentioned this already but I think the convenience factor is important.
Many of us have issues that make being in certain positions for long periods very uncomfortable. In my case I'd say very painful to stay in position to have 55 sessions of IMRT.
I was able to get past 7 sessions but getting the side effect of retention gave me the opportunity to reassess my treatment options and I choose SBRT.
I only opted for IMRT because my RO suggested it.
So far my PSA is dropping so it looks good.

Glen
Posted 5/1/2023 2:05 AM (GMT 0)

DjinTonic said...
Yes, five-session SBRT may be offered on either consecutive or alternate days, for example:

1.5T MR-Guided Daily-Adaptive SBRT for Prostate Cancer: Preliminary Report of Toxicity and Quality of Life of the First 100 Patients (2023, Full Text)


A maybe subtle point with this paper is that they are specifically talking about the Viewray system that does the radiation while in an MRI. Much more accurate.

If you aren’t so accurate, then spreading the radiation over 20-40 doses helps ensure you will cover the whole prostate, as the spread in targeting errors hopefully average out. If you are dosing just a few times, you can’t afford that inaccuracy. I’m thinking that might be even more true if you go 5 days straight?

The treatment sessions are also a lot longer. You are getting an MRI each visit.

The results from the MRI-guided radiation are really promising, though.
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