Salvage after primary radiation: Personal experiences? (This time w/o the survey)

Hello Tall One,

So, that is a guy who had a local failure after radiation but was unable to make further attempts to "salvage" the curative effort because of some idiosyncrasies of his anatomy. And that is rare.

But, my question is this: how common is salvage after radiation of any sort? Several commenters here have told us that salvage after radiation is rare because it is seldom needed since radiation treats the local area as well as the prostate and local recurrences don't happen. I understand the theory but was curious how it aligns with what we have seen. I was trying to get a sense of that by asking for personal experience either by being a recipient of salvage oneself after radiation or knowing someone who had attempted such salvage.

What set me off on this tangent was the latest crop of newly diagnosed who all seemed to quote their surgeon on the radiation-after-surgery-but-no-surgery-after-radiation thing. Among the responses we offer in rebuttal is a list of the possibilities for salvage after radiation... But I didn't remember a lot of guys on the forum who had had salvage of any sort after their radiation. We have a few guys who are trying the Oligometastatic thing which, I suppose might qualify and we did have one guy pipe up that he had surgery after his radiation.

So if it is misleading, as many here believe, for surgeons to claim there is effectively no salvage available should radiation fail, isn't it also misleading to give the impression that radiological failure is routinely salvaged?

The numbers I looked at with my RO were not close to 30%. If they had been, I'd have done something else.

The long term studies I saw were pretty much the same for brachytherapy and surgery. Just a matter of preference on which to choose individually.

Another good question Peter, would be "who has experienced a local recurrence after radiation?" Do we know of people who've had a recurrence where no treatments were available to them?

PDA,
My impression is that local failure after radiation is rare these days (since the realization of what curative doses are), but they do occur. In Dr. Katz's study of SBRT for high risk patients, 31% had biochemical failure within the 6 years of follow up. However, only 22% of those (7) were local failures, and the remaining 78% were distant failures. Since there were only 97 high risk patients, this is a local failure rate of 7%. Among his 477 low and intermediate risk patients tracked for 7 years, he's only had 7 local failures, for a local failure rate of 1.5%.

I know that you're trying to get to a number that reflects the extra cures that one can get from treating a margin beyond the prostate, and this won't tell you that. Even with mpMRI, tiny tumors growing into the prostate bed are impossible to detect, so how many cancers are staged cT2 that are really pT3? And how many pT2s have in reality, already seeded microscopic cancers?All we can judge by is the natural history of PC progression, which usually entails growth in the prostate bed.

- Allen

aul Y. Song, M.D.
Valley Radiotherapy Associates, Inc.
Santa Monica & West Hills CA

Edited from PCRI Insights November, 2008 v 11.4

Recently reported estimates from the Surveillance, Epidemiology, and End Results (SEER) Program indicate that 186,320 men will be diagnosed with prostate cancer in the United States in 2008.1 Up to 80% of these men will present with localized disease, and about 30% will be initially managed with external beam irradiation.2,3 Based on long-term data, up to 13,500 men may be faced with a local recurrence after primary irradiation in the United States alone.1

Lee et al recently reported that of men who have a rising PSA after definitive radiation, approximately 26% will have clinical evidence of a local recurrence, and 47% will develop distant metastases within five years.4 With more and younger patients opting for radiation treatment, the number of patients for potential risk of failure may continue to increase. This, coupled with the stage migration toward early-stage, lower-PSA disease, may result in an increasing population of patients with perhaps more curable recurrent disease. Many of these patients will have local recurrence as the sole component of their disease and might indeed benefit from additional local treatment to their prostate.

Patients most likely to benefit from salvage local therapy after primary radiotherapy are those with the following:

1. Pathologically documented local failure
2. No clinical or radiographic evidence of distant metastases
3. Life expectancy > 5 to 10 years based on age and health
4. Disease-free interval of >2 years
5. PSA < 10 at time of salvage

using these numbers reveal that about 6.2% of primary radiation patients had a local reoccurrence. (55,000 divided into 13,500 = 24.5% total radiation failures X 26% local failures = 6.2%).

igh Dose Rate Brachytherapy

High Dose Rate (HDR) brachytherapy is already a well established and safe treatment for localized prostate cancer.14,15,16 It allows for the precise delivery of very high doses of radiation in a very short treatment time and is more conformal than seeds, protons, or IMRT. Not only does HDR brachytherapy not share these limitations, it also has the advantage of delivering the most conformal dose distribution compared to seeds, protons, and/or IMRT. (See Table 1)

Table 1. HDR Advantages vs. LDR (Summary)) 1. Radiation can be directed very precisely (conformal treatment) to the prostate thereby reducing side effects to the urethra, bladder, and rectum. Symptoms may be less than a permanent implant
2. Treatment is delivered in minutes over a period of days.
3. No permanent radioactivity remains inside the patient.
4. Extracapsular tissues and seminal vesicles can be treated.
5. Greater control of evenly distributed radiation doses throughout the intended target while minimizing exposure to the bladder and rectum.
6. Radiation dose can be modified after catheter insertion and before any radiation is delivered to the patient to insure an optimal implant.
7. Radiobiological advantage to the HDR fractionation and the accelerated treatment course.
8. Absolute knowledge of radiation dose distribution before the treatment is given.
HDR is a completely different method of delivering brachytherapy radiation. Instead of having a large number of uniform intensity seeds permanently inserted into the prostate, HDR uses a single high-intensity Iridium-192 source which is inserted temporarily and can be adjusted and customized to conform to each patient’s individual anatomy. Unlike the permanent seed implant process, which cannot be changed once the seeds have been placed, the ability to adjust and alter the HDR catheter dwell times prevents ever having a suboptimal implant (one that has regions of too much or too little radiation coverage).

HDR provides greater overall accuracy of dosimetry than with LDR brachytherapy without the radiation exposure to hospital staff and family members.17 Recent radiation biology studies suggest that prostate cancer cells may actually be more responsive to large fractions sizes of radiation delivered in fewer overall treatments than conventional radiation regimens.18,19,20

It appears from the LDR literature that the dose-limiting structure with salvage brachytherapy is the urethra and not the rectum. This is not very surprising as the dose to the urethra with a seed implant is usually substantially higher than the prescription dose to the entire prostate. The real potential promise of HDR brachytherapy when compared to LDR brachytherapy in the salvage setting is its unique ability to decrease the dose to the urethra while still maintaining adequate coverage of the prostate and limiting the dose to the bladder and rectum.

Although there have been few reported series of HDR salvage brachytherapy, those few appear to show great promise with better biochemical control and decreased toxicity when compared to LDR brachytherapy and cryotherapy.21 Lee et al reported on a series of 21 patients who were treated with 36 Gy in six fractions.21 With a median follow-up of 18.7 months, their two-year biochemical control after recurrence was 89%. Three patients (14%) developed grade 3 genitourinary toxicity. There was no rectal toxicity noted.

Tharp et al reported a 71% disease-free survival with a median follow-up of 58 months with no significant rectal toxicity, but did report increased urethral strictures requiring dilation in 71% of the patients.

Post Edited (John T) : 1/5/2015 8:29:02 AM (GMT-7)