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Posted 9/23/2015 2:26 AM (GMT 0)
SBRT looks to have better published cancer control rates than surgery. ..

How is this possible when surgery actually removes the prostate and SBRT does not?

Common sense suggests that if there is a cancer in any organ, and that organ is removed, then by definition, that should be "as good as can be got".

What am I missing?

Thanks

Post Edited (island time) : 9/22/2015 8:45:18 PM (GMT-6)

Posted 9/23/2015 3:23 AM (GMT 0)

island time said...
SBRT looks to have better published cancer control rates than surgery. ..

How is this possible when surgery actually removes the prostate and SBRT does not?

Common sense suggests that if there is a cancer in any organ, and that organ is removed, then by definition, that should be "as good as can be got".

What am I missing?

Thanks

Maybe that the PC is sometimes, despite what is suspected pre-op, NOT contained(as in my case)? Thus the surgery will leve some behind, while the RT might cover enough area to get it all? Thus better results- I guess- with SBRT?
Posted 9/23/2015 3:26 AM (GMT 0)
Lots. There is a ton of info out there, but it does take time to read it.

With surgery, part of the prostate is left so as to try to preserve penile function. Cancer can recur in the part that's left behind.

Here are some threads to get you up to date:

https://www.inspire.com/groups/us-too-prostate-cancer/discussion/post-rp/

https://www.inspire.com/groups/us-too-prostate-cancer/discussion/is-the-following-criticism-regarding-radical-robotic-prostatectomy-valid/
Posted 9/23/2015 3:58 AM (GMT 0)
I, too, was looking at SBRT. Then I went to a radiation oncologist who recommended HDR monotherapy (and nothing else, much to my surprise as that is his focus). I then researched the heck out of it and discovered that HDR monotherapy appears to be as effective as anything else in preventing recurrence, but has fewer permanent side effects and apparently costs less than most other radiation therapies, which is likely one reason it isn't highly touted. Now I am leaning heavily toward it.

Please keep in mind that HDR monotherapy is not offered in every city, and your radiation oncologist may not offer it as it requires special equipment (like most radiation therapies). HDR has been around since the 1990s, but it didn't start becoming a stand alone treatment (hence "monotherapy") until the mid to late 1990s.

Part of the difficulty in being diagnosed with PCa is figuring out what's available treatment-wise, and what's best for us that because there isn't ONE doc we can visit who will explain all the options, the pros and cons, and the permanent side effect percentages that are associated with each therapy. Frustrating to say the least.

Have a look at this HDR thread in case you aren't yet familiar with it:

https://www.inspire.com/groups/us-too-prostate-cancer/discussion/side-effects-hdr-monotherapy-seems-to-have-the-least/
Posted 9/23/2015 4:01 AM (GMT 0)
Thanks for the links. I'm still reading them but, so far, what I'm reading is that a surgeon can sometimes "tear up" a prostate getting it out. So what would have been a "successful" sbrt outcome could be an unsuccessful surgery?

I've not hear od this before. There should be some kind of medical literature on this somewhere...other than what "someone said".

And i was unaware the fact that, with surgery some of the prostate is intentionally left behind (evidently to spare the nerves)? Is this correct?

Thanks for the links....

BillyBob@388. ..that's what my thing was as well. But...there's mitigating circumstances. ..ie...with sbrt one can have recurrences in the prostate itself due to the prostate not being removed.

Just doesn't "seem like" there should be the kinds differences I'm seeing in the studies.


And, for the purposes of (this) discussion. ..I'm not interested in the side effects side of the equation. Strictly cancer control. Thanks.

Post Edited (island time) : 9/22/2015 10:08:57 PM (GMT-6)

Posted 9/23/2015 4:10 AM (GMT 0)
The main difference in SBRT and surgery is that a margin can be included with the radiation and cannot with surgery. I believe that accounts for the better success rate for SBRT. I studied and studied before making my decision on SBRT or surgery, and it wasn't until I talked to a couple radiation onocologists that the "margin" idea made a lot of sense to me. And SBRT hits it hard and fast which has shown excellent results compared to slow drawn out IMRT.
Posted 9/23/2015 4:27 AM (GMT 0)
SBRT 5 yr. bRFS rates:

Low risk: 95.2%
Intermediate: 84.1%
High risk: 81.2%

Throw in a little ADT and it goes up even higher.

It doesn't make sense that a G8 or G9 should have those kinds of numbers.

Unbelievable. There's got to be an explanation for this disparity vs. Surgery. Gotta be..

I understand the pos. Margins deal, but...my gosh. Can PSM be all there is that's causing this?

Post Edited (island time) : 9/22/2015 10:37:08 PM (GMT-6)

Posted 9/23/2015 4:45 AM (GMT 0)
island time-

SBRT treats a margin of tissue outside of the prostate capsule that surgery can't reach. For favorable risk patients, both give approximately equal and excellent control. For unfavorable risk patients, SBRT has the advantage because of the wider treatment area.

Check out the two links in my signature. Katz will be delivering his 9-yr update next month at ASTRO - I don't expect it will be much different.

There's actually quite a lot of literature on SBRT- I've read most of it.

HDR brachy is radiologically identical to SBRT - SBRT was, in fact, designed to mimic it in almost every way. The dose to the prostate, to the margin treated outside the prostate, and to all organs at risk are exactly the same. The one difference is in the dose homogeneity. SBRT typically delivers a smooth dose throughout the prostate, whereas HDR brachy delivers higher doses where the catheters are placed. There is a clinical trial of such heterogeneous dosing delivered by SBRT (it is programmable to within less than a millimeter so any dose distribution can be simulated). So far, the urinary SEs are a bit higher with such heterogeneous dosing, but not by that much. For acute urinary toxicity, Demanes (HDR) reported 10% Grade 2 urinary frequency/urgency and 3% Grade 3 urinary retention. Katz (SBRT) reported 4% Grade 2 urinary toxicity and none more than that. In both cases, the toxicities were transient. For acute rectal toxicity, Demanes reported <1%, Katz reported 4%. Late term Grade 3 urinary toxicity was 5% for HDR, 2% for SBRT. Potency preservation was similar. There's good radiobiological reason why the results are similar and so good for both of these. Buy me a beer, and I'll explain.
Posted 9/23/2015 3:29 PM (GMT 0)
island time,

It appears to me that your are influenced by the common myth that "gone is better than dead".

While radiation doesn't technically remove the cancer, what cancer, if any, that survives the ablation is unable to multiply and spread because the radiation has altered the DNA and the cancer can not heal itself. Eventually most all the cells die (process of apoptosis), but so long as they don't multiply and spread, they will do no harm.

As other have said, it is difficult and often impossible to remove all the cells during surgery. Look at the very significant number of men that must have salvage radiation therapy after failed surgery.
Posted 9/23/2015 3:48 PM (GMT 0)
It is a common belief that surgery removes the entire prostate, in fact there is some prostate tissue around the nerves and in the apex that is left, 50% of all positive margins occur in the apex.
The rates of positive margins is also skill related, at MSK the best surgeons have an 11% rate and the worst 32% with a 21% average. Radiation treats 5 mm into the prostate bed and up to 15mm if ECE is suspected. it also treats all the tissue around the nerves. These reasons explain the difference in reoccurrance rates between surgery and any form of radiation.
Basically if the cancer is not around the nerves and not protruding into the prostate bed and you have a skilled surgeon the cure rates for surgery and radiation should be equal.
The differences in cure rates using different forms of radiation is insignificant as long as the equivalent dose is above 81gy. Some forms of radiation are slightly better in terms of side effects because of the differences in accuracy and the time period in which the dose is delivered. As with surgery the more skilled radiologists have better results than the less skilled, especially with side effects.
Posted 9/23/2015 8:23 PM (GMT 0)
As always there are different opinions and conclusion.
www.bmj.com/content/348/bmj.g1502
This large observational study with follow-up to 15 years suggests that for most men with non-metastatic prostate cancer, surgery leads to better survival than does radiotherapy. Younger men and those with less comorbidity who have intermediate or high risk localised prostate cancer might have a greater benefit from surgery.

One advantage for surgery is the obvious that removing the prostate enables a full pathological assessment of the tumor characteristics and thus a better estimation of the risk of recurrence.
Posted 9/23/2015 8:48 PM (GMT 0)

Island Time said...
SBRT 5 yr. bRFS rates:

Low risk: 95.2%
Intermediate: 84.1%
High risk: 81.2%

Throw in a little ADT and it goes up even higher.

It doesn't make sense that a G8 or G9 should have those kinds of numbers.

Unbelievable. There's got to be an explanation for this disparity vs. Surgery. Gotta be..

I understand the pos. Margins deal, but...my gosh. Can PSM be all there is that's causing this?

Gemlin said...
As always there are different opinions and conclusion.
www.bmj.com/content/348/bmj.g1502
This large observational study with follow-up to 15 years suggests that for most men with non-metastatic prostate cancer, surgery leads to better survival than does radiotherapy. Younger men and those with less comorbidity who have intermediate or high risk localised prostate cancer might have a greater benefit from surgery.

One advantage for surgery is the obvious that removing the prostate enables a full pathological assessment of the tumor characteristics and thus a better estimation of the risk of recurrence.

Right, there always seems to be another study. Which does not always confirm the other studies. In this one, the over all survival and PC specific survival is looked at, which is a whole lot different than just looking at BCR. BCR by no means = death or even suffering from PC 5 or 10 years after BCR. But the real kicker about this study is not only is it 30,000+ men and ALL high risk, it looks out 15 -25 years. Do any of these RT studies have that kind of long term data available yet? If so, is survival actually superior? Is it even equal? Don't know actually, just asking. Oh, and of course, trying to make myself feel better about that dang surgery I submitted to. wink
www.renalandurologynews.com/prostate-cancer/study-supports-surgery-for-high-risk-prostate-cancer/article/338483/

Somebody said...
In a study of 30,379 men (mean age 62.5 years) who underwent RP for Gleason 8-10 non-metastatic PCa, Naveen Pokala, MD, and colleagues at the University of Missouri-Columbia School of Medicine in Columbia found that the overall survival rates at 5, 10, 15, 20, and 25 years were 92.8%, 78.6%, 59.5%, 38.6%, and 20.0%, respectively. Cancer-specific survival rates were 96.4%, 89.5%, 82.0%, 72.9%, and 68.8%, respectively, the researchers reported online ahead of print in the World Journal of Urology.

“This is the first study to demonstrate excellent 20-year cancer-specific survival of men with Gleason 8-10 prostate cancer,” the authors wrote.

A total of 52.8% of patients had T2 disease, 73% had node-negative disease, 80.2% underwent lymph node dissection, and 12.9% had adjuvant radiation therapy. The study showed that pelvic lymph node dissection did not significantly affect overall survival.

Dr. Pokala's group noted that some urologists are reluctant to offer RP as a treatment for high-risk disease because of the higher incidence of lymph node metastasis, local and systemic recurrence, and poor survival. They cited an investigation from the Cancer of the Prostate Strategic Urological Research Endeavor disease registry showing that patients with Gleason 8-10 PCa were nearly twice as likely to have external beam radiation treatment and four times as likely to receive primary androgen deprivation therapy as they were to undergo surgery.

The researchers cited previous studies showing that, for patients with Gleason 8-10 disease, RP is associated with a significantly lower risk of cancer-specific death compared with conservative management or radiotherapy.

With regard to study limitations, Dr. Pokala and colleagues noted that they analyzed data from a cancer database representing many institutions, so there was no standardization with regard to how pathologic specimens were interpreted.

Posted 9/23/2015 8:59 PM (GMT 0)
Gemlin, that's a very interesting study.

Not being a statistician, I'm not sure what the actual difference is among the risk groups. Hopefully someone will chime in.

For instance, in low risk patients, if the difference in survival at 15 years is like 90% surgery vs 85% RT, I'm not concerned. If it's 90% vs 70%, that's a another matter......

Also, I found this language interesting, too:

"Information on radiotherapy dosing or type, or surgical technique was not available and thus we do not know how comparable these evaluated treatments are to contemporary practice, especially with the advent of intensity modulated radiotherapy, dose escalation programmes, high dose brachytherapy, and robotic assisted radical prostatectomy.

For instance, it is not known whether radiotherapy dosing levels over this period in Sweden reached the acceptable contemporary standard of 74 Gy or more for low risk disease and 78 Gy for intermediate and high risk cases. This might have affected the results, and is likely to be a much more important confounder than advances in surgical practice over the years captured in this study.

However, we did a further sensitivity analysis evaluating comparisons stratified by year of diagnosis (see appendix 1 on bmj.com) and found no temporal trend in results, suggesting that a presumed increase in radiotherapy dosing with time did not significantly confound our findings.

No information is also available from PCBaSe as to whether secondary treatments were applied, and it might be that a greater proportion of men in the surgery arm underwent multimodality therapy than in the radiotherapy arm, because giving radiotherapy after surgery is more often done than performing surgery after radiotherapy. This would again bias our findings in favour of surgery."

Still, I'm not inclined for surgery at this point given the side effects. If I opt for some form of RT, hopefully there will be new and effective treatments down the road should there be a recurrence.
Posted 9/23/2015 9:17 PM (GMT 0)
I found some comments authored by various docs which may explain the disparity:

"Patients selecting radical prostatectomy are likely to be more healthy and be harbouring earlier tumour stages. It is conceivable that even within the same risk category the worst cases were assigned to external beam radiotherapy due to selection and self-selection. Thus, beside overt imbalance in the risk distribution between surgery and radiotherapy , there were probably further hidden biases putting surgery at an advantage . These biases may not be eliminated completely even by advanced statistics. Only randomized trials are able to prove superiority of any treatment option for early prostate cancer."

"In conclusion, it is undeniable that for the intrinsic major biases affecting the population treated with EBRT in the study by Sooriakumaran and colleagues, unfortunately their data could not be a benchmark to take clinical decision in the daily clinical practice and radiation therapy should be still considered a valid and efficacious alternative to RP in all the stages of PCa. Considering the important recent developments in radiation oncology both in terms of treatment planning and delivery, its clinically efficacy needs to be fully, prospectively validated and compared to the results of modern RP a randomized, well designed trials."

"Despite a rather short median follow-up time of 5 years, a clear survival benefit was observed between radiotherapy and prostatectomy even in the low risk group. This further increases our concerns about the results from this study keeping in mind that prostatectomy has not shown better cancer specific mortality compared with watchful waiting in two large randomized trials for the low risk category, with much longer median follow up times of 10 and 13.4 years, respectively (2, 3). The reason for this discrepancy is unknown but raises concerns about the treatment comparisons made, given the known efficacy of radiotherapy in prostate cancer treatment (4, 5)."

http://www.bmj.com/content/348/bmj.g1502/rapid-responses
Posted 9/23/2015 10:39 PM (GMT 0)
Holy biochemical recurrence Batman...

There's an awful lot of information here!
Posted 9/23/2015 10:47 PM (GMT 0)
One must factor in the possibility of secondary cancers caused by radiation, which is dependent on age. The younger one is having radiotherapy the more likely another cancer will form.
Posted 9/23/2015 11:00 PM (GMT 0)
One has to be very careful about the studies one looks at to be sure that apples to apples are being compared. The study that Gemlin cited is completely irrelevant to any of us looking at radiation today. There are no 15 year data on IMRT at dosage levels now considered curative, nor on SBRT, of course. Dose escalation made a major impact in the curative power of IMRT. The longest running IMRT study is 10 years at MSKCC; the longest running SBRT study is 7 years by Katz (see links in my signature).
Posted 9/23/2015 11:16 PM (GMT 0)
lapilot - secondary cancers due to radiation are on the order of 3-5 per 1000. Probably similar to the mortality rate of prostatectomy. If you're a pilot, I'd be much more concerned about the chronic radiation exposure from being at high altitudes.

Risk for radiation-induced second primary cancer (RTSPC) is low and may differ by radiation technique

- Allen
Posted 9/24/2015 2:07 AM (GMT 0)
Plus radiation induced cancers don't show up for 10-15 years....dying on the table is rather immediate. If it came down to that risk factor I would clearly take the radiation risk.
Posted 9/24/2015 4:55 PM (GMT 0)

Tall Allen said...
One has to be very careful about the studies one looks at to be sure that apples to apples are being compared. The study that Gemlin cited is completely irrelevant to any of us looking at radiation today. There are no 15 year data on IMRT at dosage levels now considered curative, nor on SBRT, of course. Dose escalation made a major impact in the curative power of IMRT. The longest running IMRT study is 10 years at MSKCC; the longest running SBRT study is 7 years by Katz (see links in my signature).

Allen,
"Apples to apples". Isn't it fair to assume that both radical prostatectomy and radiotherapy both improves over time? We can not compare radiation treatment of today with surgery treatment 15 years ago. It could be that a similar S vs. R study in 15 years will have the same comparative result, or the opposite. Who knows?
Anyway, both treatments can cure and both will be offered men with our disease. It is up to each of us to be well informed and make a decision.
Posted 9/24/2015 6:17 PM (GMT 0)
Certainly, results improve slowly in both surgery and radiation as clinicians move up the learning curve. But that's not what we're talking about here. Actually, the surgical techniques have not changed all that much since nerve sparing in the 1990s and the oncological results have not changed very much comparing a doctor who has equal experience. Even robotic surgery, introduced in 2000, hasn't measurably improved oncological results. On the other hand, radiation techniques have changed dramatically. Dose escalation and high-precision linacs and imaging techniques have changed results to the point that men treated 15 years ago are not at all comparable. For LDR brachy, high-tech intraoperative planning has changed results dramatically as well. HDR brachy and SBRT were quantum breakthroughs using new discoveries in radiobiology and image guidance. We've come to expect this rapid pace of change in all of our computer-driven technologies. There has been nothing comparable in surgery.

- Allen
Posted 9/24/2015 6:57 PM (GMT 0)
Following the conversation above, I followed a few links and came to this may be relevant here. "Second primary cancers after radiation for prostate cancer: A systematic review of the clinical data and impact of treatment technique", a 2014 survey of research on secondary cancers published in Radiotherapy Oncology concludes with these two sentences,

"As PCa survival improves, the risk of second malignancy becomes more relevant, especially when treating younger patients. Second primary cancer risks must therefore be borne in mind when considering which patients to irradiate and which techniques to employ."
Posted 9/24/2015 7:00 PM (GMT 0)
Wilderness, you may want to read my more comprehensive 2015 review of the subject given in the link above. There was new data from NIH this year.

- Allen

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Posted 9/24/2015 10:44 PM (GMT 0)
Allen

I see you had your SBRT at UCLA, which undoubtedly is one of the best in the nation, if the not THE best. Question: How important is the experience level of the radiologist doing the SBRT, is it as important as a surgeon doing a RRP?
Posted 9/24/2015 11:52 PM (GMT 0)
onthefence-

It's true that Dr King (then at Stanford) was the first to use SBRT (CyberKnife then) against prostate cancer in 2003, so he has a lot of experience. Others do as well. My impression is that the learning curve isn't anywhere near as steep as for surgery or LDR brachy. Some have pointed to some improvement in outcomes in recent years compared to early years as evidence that there is a learning curve. It is a highly automated and computer-driven process. In fact, my RO was never around during the actual treatments - his main work was done in the planning phase. One CyberKnife RO said he thinks 100, or even less, is plenty to learn the ropes and deal with variations. That said, I've read reports where ROs screwed it up by not using intra-fractional tracking, poor imaging, setting margins too wide, using too-high doses, not using sufficiently tight organ-at-risk dose constraints, or failing to assure the bladder was filled. It gave me a lot of confidence seeing the isodose plan and the dose-volume histogram before treatment. It's as close as radiation patients get to a pathology report, but it takes some work to understand them.
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