IMRT Procedure

Irmaly, if you are on, I am at the point of treatment planning. Do you recall the type of targeted guidance Dr. Lee uses at Duke? Some centers implant gold markers in the prostate while others utilize a CT for each IMRT treatment (process at Seby Jones) which is less efficient. I am very satisfied with Dr. Mack, the RO here, but want to compare process and equipment Dr. Lee uses. I would think Duke would have the most contemporary process.

Also, I know your husband had an MRI done at Wake Baptist but did Dr. Lee do any other scans/tests? I noticed your husband had an undetectable PSA after the IMRT treatment, and virtually no side effects (the first being rare for IMRT). Do you attribute that to the process and equipment Dr. Lee utilizes?

I have decided on IMRT and initially wanted it done here so I don't have to leave my wife alone for most of 7 - 8 weeks. She is still tired from her IMRT. However, if there is a big difference in process etc. here vs. Duke, I may change. I have an email ready to send to Dr. Lee.

  

Thanks,

Robert   

Robert,

There are two ways that prostate motion is tracked inter-fractionally -- only once at the beginning of each session. Often that's done with cone-beam CTs. The other way is intra-fractionally -- continually throughout each treatment. Intra-fractional tracking is more precise and gives fewer SEs. Both of these are called "IGRT" - image guided radiation therapy.

Image guidance is achieved in one of 3 ways:
- tracking the position of gold fiducials with X-rays (cone beam CT or stereo X-rays)
- radio transponders (Calypso)
- continuous CT scanning (Tomotherapy)

I just read that the cone beam CTs can add up to 1 Gy on an 80 Gy treatment. Probably not enough to worry about.

As for your other question about whether combo therapy (BT+IMRT) is better than dose-escalated IMRT for intermediate risk PC...

In a recently completed randomized prospective trial, the only one ever done that I know of, they found in an interim unpublished analysis that there were superior outcomes with combination of EBRT plus brachy boost as compared with EBRT alone.

Retrospective analyses are unclear. At Sloan Kettering they found that an HDR brachy boost+IMRT had better results than ultrahigh dose-escalated (86 Gy) IMRT:
Comparison of PSA relapse-free survival in patients treated with ultra-high-dose IMRT versus combination HDR brachytherapy and IMRT.

However a retrospective analysis from UC Irvine found no difference between HDR brachy boost+IMRT compared to high dose IMRT alone:
Preliminary results in prostate cancer patients treated with high-dose-rate brachytherapy and intensity modulated radiation therapy (IMRT) vs. IMRT alone.

Both HDR brachy and SBRT have been used as monotherapies for intermediate risk with excellent results:
High dose brachytherapy as monotherapy for intermediate risk prostate cancer.
Intermediate-Risk Patients With Organ-Confined Prostate Cancer Have High Cancer-Free Survival Rate After Stereotactic Body Radiation Therapy

It seems like you have several good choices.

- Allen

Here's the info on the randomized prospective trial, called the ASCENDE-RT trial:

Androgen Suppression Combined With Elective Nodal and Dose Escalated Radiation Therapy

and this link has all I know about the results:

www.bccancer.bc.ca/HPI/CancerManagementGuidelines/Genitourinary/Prostate/Brachytherapy.htm

the authors said...

In November of 2002, BCCA opened a randomized control phase II trial (accrued 41), which was further expanded to a randomized phase III trial in October 2004 (accrued 357) (ASCENDE RT), to compare the efficacy and toxicity of dose escalated radiating using EBRT vs. EBRT plus brachytherapy. Eligibility criteria included patients with ≤ Clinical stage (CS) T3a, any Gleason score (GS) and an initial PSA (iPSA) ≤40 ng/mL. All patients received 12 months ADT (8 months neoadjuvant) and elective pelvic nodal irradiation (46Gy/23 fractions 4 field conformal). Randomization was between high dose conformal EBRT (78Gy total dose to prostate) vs. a brachytherapy boost (115Gy, I125 Permanent Prostate Implant)(19). Trial was closed Dec 1, 2011. Results are pending publication. An interim analysis of ASCENDE-RT phases II-III (including all patients started on LHRH injections on or before Aug 31, 2006 N=161 pts) showed superior outcomes with combination of EBRT with brachytherapy boost as compared with an EBRT alone.

I agree that you have to know what to ask, and it helps to speak in their language (Medicalese). Also, a given doctor may not pay a lot of attention to things outside his specialty. The way I have handled some discussions is that I print out (or email in advance, even better) abstracts or articles from peer-reviewed journals. I usually lead off by saying, "You've probably already seen this, but I wanted to get your perspective on this research..." My experience has been that my doctors sometimes haven't seen it and are very interested (I looked for doctors who are research mavens). As long as the source is good, they are happy to talk about it -- they live and breathe this stuff and have devoted their lives to it after all.

- Allen

Hey, Time. Looks like you already got your answers. My husband had the gold markers, and I think his undedectable PSA was because of the lupron.

Allen,

I wouldn't be a candidate for that trial since I am on 6 months HT. The gy's look low? When I was at Duke, Dr. Lee mentioned a trial he was doing on high dose IMRT for 5 weeks but I missed the start and couldn't get in. Regarding Brachy + IMRT, Dr. Lee siad he was concerned about toxicity in my case. I emailed him yesterday, and he again said he still recommended IMRT alone for me.

In your post above, you mentioned: "I just read that the cone beam CTs can add up to 1 Gy on an 80 Gy treatment. Probably not enough to worry about". I don't know if it is cone beam that I will have for guidance. I was told that it involves a CT just before each treatment to make sure beams are correctly placed. So, is that cone beam? I will not have the gold implants like at Duke.

Robert

Yep, just varified mine will be the cone beam so I'll get another Gy. Don't know total Gys yet but will know at planning session next Wed. RO may also do 7 to 8 pelvic lymph nodes to be safe. I asked her about doing them all so she is thinking. There is no indication of LN involvement, but why not play it safe. I can't have a combidex and MRI/CT won't show PC cells.
Robert

Robert,

I'm a little confused...

Robert said...
All I know so far is I will have continuous CT scanning (Tomotherapy) for guidance.

Robert said...
I was told that it involves a CT just before each treatment to make sure beams are correctly placed.

Tomotherapy uses the wasted X-rays of your treatment, the ones not absorbed by your body, to provide continuous CT scanning (not cone beam) throughout the treatment (intra-fractional).

Inter-fractional guidance can be done without fiducials too. They can just do a CT scan (usually cone beam) and adjust the position based on where your bones and tattoos (dots they put on your belly) line up that day. They can put a balloon up your rectum to restrict organ motion -- they do that when they give proton therapy. I had semi-permanent tattoos (they came off with alcohol when I was done) that were sighted by lasers, and that was used to position the bench that I lay on at the start of each treatment.

Allen,

No, I'm the one who is confused. Got a call this morning to schedule planning and the RO's scheduler said I would have a low dose cone beam CT when I mentioned I was concerned about a daily CT before each treatment. Apparently, I used the wrong term -Tommograpy. So, it's a one time CT just before each treatment to line up with the tattoos they will do in planning/simulation.

Sorry for confusion...I'm new at all this particularly radiation. It's done different by doctors and centers, as you know.

The RO mentioned she typically does only 7 - 8 lymph nodes only if needed when I asked about it. She said they do a 2mm slice CT scan in the planning step to look for any swollen nodes. No scan shows cancer cells other than combidex that I have read about. So, guess my point was to hit some close by nodes rather than wait until there is a possible problem. Even though I have a small amount of cancer based only on the needle biopsy, the 4+3=7 acts like an 8. Anyway, I'm going to just let the RO do what needs to be done and try to keep my anxiousness and need for excessive control under control LOL. My wife just recently finished treatments recently for BC so I am overly cautious about all this.

Robert

Robert - ah - that explains it -- the words all sound alike - it is very confusing. I think the marketers at Accuray called their machine Tomotherapy because it uses Computed Tomography (CT). But lots of IGRT machines use CT too.

Redwing57 - I was treated on a RapidArc machine too, but it was rigged up with stereoscopic X-rays that they used to line up my fiducials with the plan MRI/CT image. They did that before each of the four half arcs, and the entire treatment took only 5 minutes, including the realignment time. Varian's new TrueBeam machine is twice as fast! You're right - not much time for much movement with that. My treatment was SBRT -- only 5 treatments at about 8 Gy each. SBRT is more typically done with Accuray's CyberKnife machine. When they're delivering that kind of radiation intensity, they have to be extremely accurate and account for intra-fractional motion. When they're only delivering 2 Gy per treatment, there is less of a need to be that precise.

Only about 100 men in the US with high risk PC have been treated with SBRT. My RO, Dr.King, is just starting to expand to high risk patients. So far, the early results look very promising. They are treating a wider margin (except near the rectum) and are increasing the dose to anyplace where imaging suggests there is more cancer. I'm happy to see all these innovations occurring.

- Allen

Robert,
I'm not sure that there's any advantage to one machine over another for IMRT (other than speed), especially with the wide spray you seem to be getting. There was a report recently that IMRT had no real advantage over 3DCRT, an older technique.

The important part is the treatment plan -- making sure you get an adequate dose to the treatment area, and that you don't get too much dose to organs at risk. As I said, SBRT uses very intense dosing so that tracking intra-fractional motion becomes very important. On the CyberKnife version, a free-moving robot moves around the patient, constantly checking position before every beam. My friend in Florida just had it done, and each treatment took about 50 minutes. With IMRT, interfractional tracking may be adequate.

Maybe you will feel more confident if you can ask your RO to go over the treatment plan with you. I found it interesting to see the "isodose curves" (a contour map connecting the points that get the same dose) and the "dose-volume histogram" (showing what percent of each organ-at-risk (e.g., bladder, rectum, penile bulb) gets what dose).

After the initial positioning, you will be getting the radiation. I don't know how the multileaf collimator on your machine works. It's the device that shapes the beam to the shape of your prostate. On some machines the X-rays stop while it re-adjusts. There's usually a mold you lie in that keeps you in position, and there's probably something that pauses everything if you move too much. You can ask your RO what kind of controls are in place for that particular machine.

Robert,
The combination of androgen deprivation and radiation over a wide area can be bad for erectile function. I hope she avoids the penile bulb as much as possible. Low dose Viagra taken for 6 months starting at the beginning of IMRT helped prevent ED in a recent study. However, that was not with androgen deprivation as well. She is right that the problem with radiation is damage and subsequent fibrosis of blood vessels (especially the penile artery that connects by way of the prostate) rather than the nerve damage caused by surgery.

If ED meds don't work, there's always injections. Sometimes hyperbaric oxygen therapy can reverse the fibrosis if it sets in.

The best thing I know of to prevent the damage to blood vessels and all healthy tissues is exercise - plenty of it. It helps fight fatigue that may occur with IMRT. And it actually helps the radiation kill more cancer cells.

- Allen

Robert,

I was going to sit this one out since the conversation has passed my level of expertise and I am in learning mode here. But since you sent me an email asking me to comment, a few thoughts.

I had my ART treatment at the Cancer Centers of North Carolina in Raleigh. I am not sure of the exact model of IMRT machine they use. They used CT scans and xrays for planning and weekly xrays and daily ultrasound to make fine adjustments. They made a mold of my feet from the knees down which was used to position me on the table and they lined me up with laser lines and tattoos and then verified the location of my prostate bed with an ultrasound device that communicated with the room's 3-D positioning system. Since I was doing ART and not primary treatment the dose was slightly lower (66.6 gy total) and since I no longer had a prostate there was nothing in particular to aim at -- although there were things to avoid. They were radiating the general area around the surgical margin and no phenomenal accuracy was required.

Tall probably has some numbers for this but my impression is that the differences between the options you are looking at are small in terms of the percentages of negative outcomes. The reality is that the difference in the risks are small compared to the risk themselves and you can probably allow yourself the luxury of considering such things as convenience. Pulling numbers out of the air here, if your chances of developing ED as a result of treatment are 36 percent in Boone but only 34 percent in Durham then it is seventeen times as important to be lucky as it is to make the right choice.

You've done your homework. You've done the extra credit exercise. It's time to kiss your lucky rabbits foot, decide on an option, and get 'er done.

My Advice, for what it's worth.