High Dose Brachytherapy

I have a general question or two on this treatment.

I have punched my info into the MSK and JH nomograms.

My PSA is 8.1, Gleason 3+4, 6 of 12 cores pos.

Anyhow the MSK nomogram predicts 33% chance of the cancer being organ contained and 66% of ECE and SVI+ 7%

The John Hopkins predicts 68% organ confined, 28% ECE, SVI+ 4%

My concern is , how well does High Dose Brachy Therapy treat any SVI+ and if the cancer is outside the capsule, how effective is it as mono therapy at treating that? My concern is if I have some ECE, is this therapy a good choice?

I note on the CET page, they make this statement
"•Excellent coverage of possible microscopic extension of cancer "

So is this true or is microscopic extension, not the same a ECE?

Is there a rule of thumb the RO/Physicist use for a margin around the prostate that they can include in the Target volume?


Also what usually dictates them using a combination HDR + IMRT, is it usually higher Gleason Score?

any feedback would be appreciated.

JNF

Thanks, but your treatment included the IMRT, I assume they did the IMRT because of the lymph nodes and nomogram predictions.

But is there a cut off where the RO's switch to combo therapy? I am going to do some consultations on HDR, Surgery and SBRT down in Boston.

The HDR up here is 3 days in the hospital, 4 fractions at 38 Gy.

Also does it matter what type of imaging they use to insert the needles, some use CT and some ultrasound? also some use a fixed grid others a flexible template?

Guess I will get the details once I talk to the RO.

HDR-BT monotherapy (but not LDR-BT monotherapy) can be used to treat ECE and SVI. They can stick the catheters anywhere, whereas seeds are limited to the prostate capsule. SBRT, of course, can be used to treat both ECE and SVI as well. With both HDR-BT and SBRT, they will do a planning MRI/CT that will show with great precision the contours of the prostate (including any extension) and the seminal vesicles. They both add a margin around the contours of the treated areas.

In my case, my treatment margin was 2-3 mm, except near the rectum where it was 0 mm. My seminal vesicles were not treated, except at their base. I'm pretty sure your case would get a similar treatment. I know that for high risk cases, Dr King expands the margin to 5 mm (4 mm posterior), and treats the entire seminal vesicles with no margin. Larger margins increase toxicity. I would expect similar parameters for HDR-BT.

I am T2a.

I think favorable intermediate except for the #cores, 50%, flip a coin.

I see some use a fixed grid for the needle placement versus flexiguide?
Is this so important, I assume all use software to simulate the dosing and amount and margins.

Other than being invasive, is there really a drawback, if they have good quality control as to where the cathoders are, I would assume the dosing they want would be very accurate.





UCLA Guidelines

"*Candidates for HDR monotherapy
•Low risk (T1, PSA < 10, GS 6)
•Intermediate risk (T1-T2, PSA 10-20, GS 6-7)
•Select favorable high risk (T1-T2), PSA < 20, GS 8)
Length of treatment:
•2 implants, 1-2 weeks apart, each implant delivers one treatment, 13.5 Gy x 2 (no overnight stay)
OR
•1 implant, 10.5 Gy x 3 (overnight stay)