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Is whole pelvic radiation needed for primary treatment of Gleason 9/10?

Tall_Allen
Tall_Allen

When it is not obvious that there are cancerous pelvic lymph nodes, it may nonetheless improve outcomes to treat the whole pelvic area with radiation. The decision of whether to treat it or not is often made based on the "Roach formula":

% pelvic LN risk = PSA * 2/3 + ((Gleason score – 6) * 10) ≥ 15%

Based on that formula, all men with Gleason scores of 8-10 should have whole pelvic radiation (WPRT). But even men newly diagnosed with Gleason 9 or 10 may not have any metastases in pelvic lymph nodes. WPRT may be over-treatment for some. This article discusses the evidence that patients and their radiation oncologists should consider.

pcnrv.blogspot.com/2019/05/...

15 Replies
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I had proton for my small contained G 4+5, they also treated my pelvic LN's.

I do not understand the Roach formula. Could you provide a sample calculation?

Sure. Let's say you were newly diagnosed with a PSA of 6, and a Gleason score of 9. So, substituting into the Roach formula:

% pelvic LN risk = 6 * 2/3 + ((9 – 6) * 10) ≥ 15%

% pelvic LN risk = 4 + ((3) * 10) ≥ 15%

% pelvic LN risk = 4 + (30) ≥ 15%

% pelvic LN risk = 34 ≥ 15%

So, your % pelvic risk is 34%, which is greater than 15%

Thx for the post. Very informative. Any thoughts on Combidex Scans to local lymph node cancer? I've heard mixed reviews.

It's only available in the Netherlands. Jelle Berentz claims it can detect lymph nodes as small as 2 mm, which is about half the size limit of our best PET/CT scans. It's still not everything, though.

Thank u

How does WPRT differ from the proton radiation I had where they designed a pattern where the cancer was located on the mri. Are you talking broader than the prostate area.

Tall_Allen
Tall_Allen in reply to carlo8686

Yes, it's the entire pelvic area

Hi TA

You frequently mention that node positive within the pelvic region still has a chance for cure

Any trials/studies you can provide insight from?

It would be nice to better understand the percentage of success (cure)

Thx

You mean as salvage therapy?

pcnrv.blogspot.com/2017/12/...

Thank u. I’ll review

Our Mo was selective around the pelvic area targeting mets but trying to spare unaffected area to preserve bone marrow.

Tall_Allen
Tall_Allen in reply to The_Don5

I don't think it's a good idea to target specific mets, except as a boost to a broad treatment of the entire area. You have no idea what is really affected by cancer. To be detectably metastatic with today's best imaging technology, a clump of tumor cells must be at least 4 mm long. The cancer cell may be about 10 μm, so there are at least 200,000,000 of them before the smallest metastasis becomes detectable. All of those cancer cells are constantly shedding and forming new daughter metastases elsewhere. So cancer cells may be circulating, clumping, and growing for a long time before they form a big enough clump to be detectable. The hope is that they are slowed down by the lymph.

Bone marrow recovers from the relatively low doses used. Much of our blood cell production occurs in long bones, rather than the bony structures of the pelvis and spine.

The_Don5
The_Don5 in reply to Tall_Allen

Interesting. The radiotherapy used in our instance was a one off condensed blast versus five weeks of smaller doses. Think Mo targeted a specific proliferation or cluster in the hemi pelvis on the last one. It didn't actually work- no symptomatic pain relief to date some 4 weeks after. Saying that the Lu-177 is slow to pick up on the bone mets also- two doses to date and no remarkable change in pain or mobility . The radiotherapy was delivered in between doses.

Just to be clear, we are talking about pelvic lymph nodes, not bone mets in the pelvis.

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