Bone Mets or Arthritis?

[Dett]

Hello all,

I’m increasingly confused about how radiologists differentiate between PC bone mets and routine degenerative changes like arthritis. Bear with me...

My husband’s initial CT scan on 8/19 stated “Lytic lesion is seen in T7 as seen on the recent bone scan. A lytic lesion in the right L5 vertebral body is also present.” It also stated that “Degenerative changes are present in the lumbar spine. Indeterminate sclerotic lesion is seen in the left posterior acetabulum and right proximal femur.” The bone scan on the same day showed “Findings suspicious for osseous metastatic disease involving the medial aspect the left iliac bone adjacent to the SI joint, posterior lateral aspect of the right fourth rib and T7 vertebral body.” No mention of L5, the left acetabulum, or of the femur.

A follow-up CT scan 11/19 showed “Sclerotic bony metastases has progressed. For example, a 1.8 cm sclerotic lesion in T7 previously was lytic. A 1.1 cm lesion at the right posterior fourth rib has become more sclerotic. A 1.8 cm sclerotic lesion at the left iliac bone appears new.” No mention of L5 as shown on the initial CT scan, the left acetabulum, or of the femur. A follow-up bone scan 1/20 showed “Decreased size and conspicuity of multiple bone lesions consistent with therapy effect including: Posterior Liliac bone at the SI joint, posterior Rfourth rib, T7” and “Linear activity left L2-3 disc level with corresponding degenerative changes on CT”. No mention of a lytic lesion in L5.

My husband met with a prominent radiation oncologist at another facility and based on his recommendation he decided to have radiation for oligometastatic PC (in addition to ADT). He had an MRI following placement of fiducials 2/20. This showed “Ill-defined nonenhancing left iliac bone lesion, corresponds to sclerotic lesion on CT.” The CT scan on the same date showed “Sclerotic lesion in the posterior left iliac wing. Degenerative disc disease of L3-L4 and L5-S1 is evident. Sclerotic lesion in the posterior left iliac wing raises the question of metastasis in the setting of known prostate cancer.” A CT scan 5/20 showed “T7 sclerotic metastatic lesion with superimposed superior endplate deformity. This was a lytic lesion on the CT from August 15, 2019. Degenerative changes cause severe bilateral foraminal stenosis at L4-L5 and moderate bilateral foraminal stenosis at L2-L3. L5 is partially sacralized.”

Bottom line - the T7 met appears pretty definitive, as is the rib met, with a sclerotic lesion in the left iliac wing. The L5 lytic lesion on the original CT scan appears more like arthritis on the last CT scan. The left acetabulum and the femur from the first CT scan are never mentioned again.

Husband recently completed one week of Cyberknife and five weeks of IMRT to the prostate area, followed by one week of Cyberknife to the T7 met. The RO is not particularly concerned about the iliac bone (which he is not sure is cancerous) or the rib met, but he would like to Cyberknife L4.

What am I missing? Why the discrepancies between the different scans? I’d really like to definitively know how many bone mets my husband has and where they are located (recognizing that this could change over time). Maybe that’s unrealistic. Thanks for any insights that you can provide.

[Tall_Allen]

It really doesn't matter how many he has and where they are - he has a lot. Continuing to playi whack-a-mole when there are so many tumors is fruitless, unless they are causing pain or in danger of fracturing/spinal compression. It made sense to try it when there were few, but not anymore. The ones that have not progressed may still be responding to ADT. More concerning are the lytic lesions. If possible (and on the spine it may not be possible) you may find more productive therapies by having one of the larger lytic lesions biopsied.

The more important question is whether progression has occurred while on his current ADT regime. If so, it may be time to reconsider his medication. Docetaxel, Zytiga, Erleada, and Xtandi are available and all seem to be about equally beneficial for men in his situation. It may increase his survival more to try one of those, rather than to play whack-a-mole anymore.

[Dett in reply to Tall_Allen]

Thanks for your response, Allen. “...so many tumors”...as far as I can tell, husband seems to have one or two on the spine, one in a rib, and one in the left iliac wing. The lytic lesions both seem to have become sclerotic somehow. Why are lytic lesions more concerning? I assume PC is still responding to ADT since his last PSA was .06 and testosterone was 3. Husband has an appointment with his MO at the end of July. I am trying to get him to accelerate it so we can request Zytiga; however, the MO’s assistant advised us that the doctor probably won’t prescribe it since it’s not ‘standard of care’. I thought Zytiga or chemo are standard of care. This is all so confusing.

[LearnAll in reply to Dett]

Its not the number of tumors...but their state which is more important. Treatment dries them and they can still be seen on scans. In fact, after death of cancer cells, these tumors are like shells of fibrous tissue and scar tissue.

Lytic lesions turning into blastic is good. In general, Lytic lesions are more concerning because risk of fracture is higher with them due to severe loss of bony minerals in them causing thin, fragile bone.

PSA 0.3 is excellent. If his ALP is below 100 then, that is even better news. ALP indirectly tells you the extent of live cancer cells in bone mets.

[Tall_Allen in reply to LearnAll]

No, the number is the important variable.

[Dett in reply to LearnAll]

Thanks. PSA is .06. ALP is 88; highest was 102 five months ago.

[Tall_Allen in reply to Dett]

Perhaps I am confused, but didn't you also say that in addition to the ones at L3-L4 and L5-S1, the rib, and the ilium,there were more at T7, the left acetabulum, and the femur? When tumors "disappear" after ADT, it is definitive for prostate metastases.

Lytic lesions are often characteristic of more aggressive forms of prostate cancer. They are sometimes both lytic and sclerotic.

A lot depends upon whether the bone metastases have increased in number and size since he started on ADT. If so, he may be castration resistant in spite of his low PSA. That combination, low PSA and rapid metastatic progression while using ADT, indicates a very aggressive variety.

Zytiga and chemo are standard of care for metastatic hormone-sensitive PC (mHSPC) - Erleada and Xtandi have also been added to that list.

[Dett in reply to Tall_Allen]

“ ...in addition to the ones at L3-L4 and L5-S1”...the only mention of the lumbar spine before the sixth CT/bone scan was in the first CT scan (“A lytic lesion in the right L5 vertebral body is also present.”) The sixth CT scan reports that “Degenerative disc disease of L3-L4 and L5-S1 is evident.” The seventh CT scan reports that “Degenerative changes cause severe bilateral foraminal stenosis at L4-L5 and moderate bilateral foraminal stenosis at L2-L3. L5 is partially sacralized.” I assumed - perhaps incorrectly - that these were benign processes, which I have a hard time reconciling with the first CT scan (lytic lesion L5).

Similarly, the first CT scan showed “Indeterminate sclerotic lesion is seen in the left posterior acetabulum and right proximal femur.” A bone scan done the same day did not say anything re the acetabulum or femur - nor has any scan since.

There has been no reported increase in quantity or size of metastases. In fact, the fourth scan reported “Decreased size and conspicuity of multiple bone lesions consistent with

therapy effect including: Posterior Liliac bone at the SI joint,

posterior Rfourth rib, T7. No new or suspicious areas of abnormal increased or decreased activity in the skeleton to suggest progressive disease”.

The RO said today that husband is doing great. I don’t know if the fact that these scans were done at two different hospitals and read by seven different doctors makes any difference.

[Tall_Allen in reply to Dett]

Lytic bone metastases don't show up on a bone scan because bone scans only detect sclerotic lesions (active bone overgrowth), but they will show up on a CT. It might be a good idea to get an FDG PET/CT.

[LearnAll]

Only an experienced radiologist can identify correctly number and location of bone mets.

Its difficult because 3 different possibilities are there when looking at a bony lesion.

Firstly, it can be a osteoblastic met...which usually show as a mottled area with deeper,thicker bone. Can be easily identified by someone who has seen blastic lesions often.

Then, th ere are lytic mets...lesions which are areas of thinner bone with missing bony architecture. Again, trained eyes can easily recognize these lesions.

Lastly, the lesions are Osteoarthritic...Characteristic feature of these lesions is the "bone spurs" side ward protrusions of margins of the bones.

Unless you have seen these different lesions many times, it can be confusing to sort them out.

.

[Dett in reply to LearnAll]

Thanks for the explanation re characteristics of different bone lesions. What I don’t understand is why there seem to be inconsistencies among the findings of the different CT and bone scans that my husband has had. For example, L5 was identified as a lytic lesion in the first CT scan. There is no further mention of L5 at all until the last two CT scans, where the lumbar area is characterized as ‘degenerative disc disease’ (which I assume is in contrast to bone cancer). What am I missing? Why was an ‘indeterminate sclerotic lesion’ reported in a femur in the first scan but not in the subsequent six CT and bone scans?

[LearnAll in reply to Dett]

Inconsistent reading of scans and tests are not uncommon. Haste and inexperience of the reader causes lot of confusion.

In my own case, my first pathologist in USA gave Gleason score 3+4 . A second opinion on the slide from an ivory tower famous cancer center in Houston gave 4+4 and 4+5 and then , a radiologist in England gave Gleason 3+4 and finally a radiologist in India also gave 3+4. (exact same slides)

So expect incorrect readings.

Your husband's doctor may be satisfied that just Lupron is doing such a fantastic job and nothing more is needed at this time. The bone mets seem mostly inactive and just scar tissue. Aggressive variants don't have Just one lytic lesion..( and that might in reality probably misread)

IMO...He is responding beautifully to Lupron and the proof is his PSA is 0.06 and ALP 88.

Adding too many testosterone killers have their problems...besides adding more side effects the greatest risk is conversion to androgen resistant cancer cells ..and early castration resistance requiring excessive and more toxic treatments. Talk to your doctor and ask why he thinks additional meds are not needed at this point.

[Dett in reply to LearnAll]

Thanks.

[Hidden]

I can address your questions directly. I can only write as one who from 2003 until 2012 had 24 nuclear bone and soft tissue CT scans plus a last set in 2016.

The key is base line. Each treating physician will want to establish a baseline of their own to mark degenerative arthritis and new hot spots and then the reduction of those hot spots based on the tests. It is the best way to mark progression and success. And, it is a solid indicator along blood work.

In 2004, I entered a six month chemotherapy plus hormone therapy clinical trial. The results of that trial indicate that systemic treatment with chemotherapy with, say, Lupron/Eligard is very positive and has been added to the standard of care possible treatments. I know very little about new drugs developed since.

Your husband has metastatic prostate cancer. You might want to discuss the various treatments available in systemic disease. You might want to discuss micro-metastasis and how it interplays with disease spread or control.

I am a proponent of early treatment with chemotherapy and ADT while the body is strong and the tumor burden minimal with no co-morbity. So, I am biased. It worked for me and two distant bone mets to my spine 16 years ago.

I wish the best.

Gourd Dancer

[Dett in reply to Hidden]

Thanks for your input. Your story is inspiring.

[TheTopBanana in reply to Hidden]

I agree with the other post saying that your story is inspiring! Did the tumors disappear?

[Hidden in reply to TheTopBanana]

Blue, in my case mets were resolved at the conclusion of the trial. They have been replaced with new bone growth. I hit it hard and very early upon discovery. For six months prior to discovery I had monthly PSAs. In other words, closely monitored after my primary treatment.

Good luck.

GD

[TheTopBanana in reply to Hidden]

That’s sound wonderful. Did you have an aggressive cancer?

[Hidden in reply to TheTopBanana]

Thanks. I don’t know..... I had a PSA that jumped from 4.0 to 6.8 in a year. Biopsid. Gleason 7(4+3). Scans clean. Brachytherapy scans clean and 25 sessions of IMRT. Scans clear. PSA never really came down.six months after primary treatment, PSA 12. Scans clear. Next month PSA 32, scab showed mets at T2 and L3 of spine. Took a shot of Lupron and Six weeks chemo hormone trial.

I was aggressive. Basically 16 months after initial DX, I started the trial.

[gleason9guy]

Great topic. My oncologist seemed to blow off my concerns about bone pain. Although he did his due diligence by ordering scans, his response was pretty much no more than "you're getting older." And as I understand that prostate cancer will commonly metastasize to the bones, it's a reasonable question.

[j-o-h-n in reply to gleason9guy]

"You're getting older" "and no thanks to you doctor"........

Good Luck, Good Health and Good Humor.

j-o-h-n Wednesday 06/03/2020 6:20 PM DST

[Dett in reply to gleason9guy]

At least our RO waited until he’d seen the knarly scans to say “you’re getting older”.