Question about IMRT on multiple targets simultaneously

[EdMiller]

I was diagnosed with Stage 4 M1b prostate cancer nearly 4 years with a Gleason score of 9 and a PSA doubling time of 2 months. My prostate and seminal vesicles were removed 3 years ago. I have gone through Lupron, Zytiga, and Xtandi. I take Xgeva for the bone metastases and for the last 18 months they do not show up on bone scans nor do I have any bone pain. About a month ago, I had a PET scan specific for prostate cancer performed. The PET scan results showed that I have 3 cancerous lymph nodes but did not show any other metastases. Given the above, my oncologist and radiation oncologist have decided to use IMRT on the 3 cancerous lymph nodes. Question: Are there any good articles or other info that give a good explanation for how IMRT can target the 3 separate lymph nodes but miss the tissue in between them? Thanks.

[Thinus]

Hallo Ed, I am learning from your post. I was diagnosed 18 months ago with T4 tubular prostate cancer. Received 4 Lucrin injections, PSA went down to 0.23 in March 2017, but are back now 6.38. They are going to do the first MRI now. There was a black spot on the pelvis, but that is gone. I will follow your post.

[Sisira]

New imaging tools can provide radiation oncologists with accurate maps to guide the extent of the delivery of high-dose conformal radiation to a precise target while minimizing radiation toxicity to non targeted normal tissues. Availability of IMRT and IGRT makes the above procedure usable in treating metastatic PCa decease in the lymph nodes. Since radiation is a focal therapy, the targets should be accessible by the beamlets in the first place. However, there can be chances of missing the microscopic decease in nodes by the radiologists. It is also postulated that radiotherapy is more effective when combined with hormone therapy for synergistic curative effects.

Hope your learned oncologist and radio oncologist have taken into consideration the forgoing facts at least in their decision making. An effective treatment is always a challenge for Stage 4 M, GS9 PCa.

Thank you for joining us in our forward march.

Sisira

[EdMiller in reply to Sisira]

Thank you very much, Sisira. I will be discussing what you have shared with my oncologist.

[Hidden]

A gnats ass, funny.

[Break60]

I had suspicious two iliac lymph nodes located by MRI with contrast back in September 2015. Being Gleason 9 with a high risk for micro metastasis, it was decided to have imrt to all pelvic lymph nodes with a total of 75 grays over 50 fractions. It would have made little sense to zap just the two bad guys. I've had no recurrence in that area since then. On the other hand a ctpet scan with axumin recently found one met on femur. I decided to have SBRT in 3 fractions at 30 grays total.

The choice of what type of radiation and how many fractions was based on the possible collateral damage due to proximity to other vital or previously radiated organs. I had SRT to prostate bed before the lymph node mets surfaced so there was concern about high dose radiation in the adjacent area.

Your RO will be knowledgeable about risks and rewards.

Bob

[EdMiller in reply to Break60]

Thanks Bob!

[Break60 in reply to EdMiller]

Ed

It's worth noting that the RO who did my lymph nodes suggested low dose imrt in 30 fractions ; but he does not yet have the equipment to do high dose. He's very meticulous and treats only PCa but the thought of another 30 fractions and having to live in Sarasota again for six weeks was unappealing when I could get the job done in three days here near home.

Bob

[EdMiller in reply to Break60]

Interesting.

[Sisira in reply to Break60]

Very useful inputs indeed with real life experience.

Thanks Bob.

Sisira