Please Help!

[Cathy1]

I am so sad. Could you please tell me if you or anyone you know had anything like this? My petscan report said - "a small focus of mildly intense FDG avid uptake is appreciated in the medial aspect of the right posterior iliac bone adjacent to the sacroliac joint with UV of 4.0.The focal nature of this finding should be deemed at least suspicious for malignancy. The catscan of pelvis said- Suggestion of tiny lucent lesion along the posterior and medial aspect of the right iliac bone corresponding with an area of FDG uptake on concurrent petscan. Finding is at least suspicious for metastatic disease. Due to the small size of this area, MRI may or may not be helpful for more complete evaluation.
Is there any treatment for this? Thanks so much and God Bless You All, Cathy

[StephN]

Hi -

This may be something they need to follow for a while to see if the spot changes. Have you had a fall, or any other kind of bruising or possible injury to that area? The PET also picks up areas of healing activity that have to be verified or discounted as disease.

What is the status of your bones? Any evidence of bone loss? If you are not taking a bone strengthener, you may want to ask for Zometa or similar.

Good luck and try to perk up. If it is a met you are catching it early, and if not, thank the good Lord.

[Lani]

There are many kinds of imagine studies which can be done to determine if something is truly a bone met--CTs, PETs or PET/CTs(the CT done simultaneosly with the PET is usually not as exacting as that done in a dedicated unit), MRIs and bone scans. Bone scans inject a different substance than is used in PETS.

CT shows lesions in the hard cortical outer shell better and have higher resolution than MRIs and bone scans often show smaller lesions

MRI shows lesions in the bone marrow better

PET/CT shows areas where glucose uptake indicates there is either fracture trying to heal, infection, or mets

But that is a lot of studies to get when what was seen might be nothing Look at Tom's post on his mother from earlier this summer--she and he had quite a scare from a PET when there was nothing wrong.

I listened to a talk webbroadcast from ASCO this summer where someone from Dana Farber (I believe) highly RECOMMENDED AVOIDING(ie, advised against) getting PETs in patients who had been treated with early breast cancer to follow up and look for mets as they were extremely high numbers of false positives causing "wild goose chases" with lots of expensive and radiation-associated studies.

They recommended PET be done in those with metastasis only and in those patients(those with metastasis) for following the response to treatment only. As they develop different radioactive substances to use with PET (as they are doing with choline based compounds for prostate cancer), the accuracy of the PETs may improve

You do not say if you were having symptoms or why the PET was done.

It sounds as if your lesion is in quite an accessible area (on the back side of
the pelvis and not involving but close to the sacroiliac joint). Perhaps if you are concerned your doctor could send you to an orthopaedic oncologic surgeon--one who treats primary or metastatic bone tumors--for a recommendation of whether this warrants a biopsy Or if you don't live near a major university with such a specialist, any orthopaedic surgeon with experience doing this(hopefully his opinion of whether it is warranted would be equally valid). Hope this helps.

[heblaj01]

Cathy,
PET/CT scans are said to have a 7% rate of false positive when there are multiple detected mets . In such a case this rate will not change the resulting diagnostic as true mets since it is unlikely that all are false positives.
But in the case of a single potential malignant lesion the likelihood of a false positive is greater.
One of the ways to find out if a single detected spot is true or false is to do a second PET/Ct scan 2 to 4 hours after the first one (with of course only one initial FDG18 radioactive injection).
If the second image is the same as the first one the detected spot is a false positive.
If the 2nd image has a higher SUV, it means that the spot has continued to uptake the radioactive glucose & the conclusion is that it is true positive.
I think you should not panic but do further monitoring & testing.

[Lani]

J Nucl Med. 2001 Sep;42(9):1412-7.
Dual time point 18F-FDG PET imaging for differentiating malignant from inflammatory processes.

Zhuang H et al


The aim of this study was to investigate the difference in the rates of FDG uptake between malignant and inflammatory cells and processes. METHODS: In vitro studies: (18)F-FDG uptake by different tumor cell lines and peripheral blood mononuclear cells isolated from 8 healthy human volunteers was measured 20 and 60 min after FDG was added into growth medium. Animal studies: II45 cells were implanted into the left flank of rats (n = 5) and a focal inflammatory reaction (mechanical irritation) was generated in the right flank. PET images at 45 and 90 min after injection of FDG were obtained and standardized uptake values (SUVs) were determined. Patient studies: Seventy-six patients who had dual time FDG PET scans were retrospectively analyzed. All results were expressed as the percentage change in SUV of the later time image from that of the earlier time (mean +/- SD). RESULTS: In vitro studies: Except for the SKOV3 cell line, which had only minimally increased FDG uptake (+10% +/- 26%; P > 0.3), all other tumor cell lines tested showed significantly increased FDG uptake over time (GM1500, +59% +/- 19%; B18F10, +81% +/- 15%; AB12, 93% +/- 21%; II45, +161% +/- 21%; REN, +198% +/- 48%; P < 0.01 for all). By contrast, FDG uptake in mononuclear cells was decreased in 7 of 8 donors. Animal studies: SUVs of tumors from 90-min images were significantly higher than those from 45-min images (+18% +/- 8%; P < 0.01), whereas the SUVs of inflammatory lesions decreased over time (-17% +/- 13% of the early images; P < 0.05). Clinical studies: The SUVs of delayed images from the known malignant lesions compared with those of earlier scans increased over time (+19.18% +/- 9.58%; n = 31; P < 0.001; 95% confidence interval, 15.8%-22.6%). By contrast, the SUVs of benign lung nodules decreased slightly over time (-6.3% +/- 8.1%; n = 12; P < 0.05; 95% confidence interval, -10.9% to -1.7%). The SUV of inflammatory lesions caused by radiation therapy (+1.16% +/- 7.23%; n = 8; P > 0.05; 95% confidence interval, -3.9%-6.2%) and the lesions of painful lower limb prostheses (+4.03% +/- 11.32%; n = 25; P > 0.05; 95% confidence interval, -0.4%-8.5%) remained stable over time. CONCLUSION: These preliminary data show that dual time imaging appears to be useful in distinguishing malignant from benign lesions.

[Lani]

1: J Nucl Med. 2005 Nov;46(11):1819-24. Links
Potential of dual-time-point imaging to improve breast cancer diagnosis with (18)F-FDG PET.

Kumar R,
Loving VA,
Chauhan A,
Zhuang H,
Mitchell S,
Alavi A.
Division of Nuclear Medicine, Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
The purpose of this study was to assess the utility of dual-time-point imaging for identifying malignant lesions in the breast by (18)F-FDG PET. METHODS: Fifty-four breast cancer patients with 57 breast lesions underwent 2 sequential PET scans (dual-time-point imaging). The average percent change in standardized uptake values (SUVs) between time point 1 and time point 2 was calculated. All PET study results were correlated with follow-up surgical pathology results. RESULTS: Of the 57 breast lesions, 39 were invasive carcinoma and 18 were postbiopsy inflammation. Among the invasive carcinoma lesions, 33 (85%) showed an increase and 6 (15%) showed either no change or a decrease in SUVs over time. The percent change in SUVs from time point 1 to time point 2 (mean +/- SD) was +12.6% +/- 11.4% (P = 0.003). Of the 18 inflammatory lesions, 3 (17%) showed an increase and 15 (83%) showed either no change or a decrease in SUVs. The percent change in SUVs from time point 1 to time point 2 (mean +/- SD) was -10.2% +/- 16.5% (P = 0.03). Of the 57 normal contralateral breasts, 2 (3.5%) showed an increase and 55 (96.5%) showed either no change or a decrease in SUVs. The percent change in SUVs from time point 1 to time point 2 (mean +/- SD) was -15.8% +/- 17% (P = 0.005). CONCLUSION: There is increasing uptake of (18)F-FDG over time in breast malignancies, whereas the uptake of (18)F-FDG in inflammatory lesions and normal breast tissues decreases over time. A percent change of +3.75 or more in SUVs over time is highly sensitive and specific in differentiating inflammatory lesions from malignant lesions.
PMID: 16269595 [PubMed - indexed for MEDLINE]

[Cathy1]

Dear Steph, Lani and Heblaj,

Thank you so much for responding to my post. I did fall about fifteen years ago and I always felt that I hurt something then, I even think I heard something crack, but I never got checked. Nothing had shown up on any test in that area until now. I remember I was moving furniture around the week of my petscan and catscan, so I don't know if I bruised it then.
The reason I was getting the petscan was to follow up because I was NED for awhile and the doctor was checking to see how I was doing.I went off of xeloda and herceptin in June and the petscan was in September and everything was cleared up. I had a mastectomy in 2001 and then a recurrence in 2005- an area between my lungs and also on my collarbone. They cleared up and now this spot showed up. The doctor wants to do an xray and bone scan but it isn't until December 15. Do you think I should get it done sooner? Also, if it is bad news, what would be the treatment for this?Would they be able to take it out or give me chemo, or doesn't chemo work on the bone? Thanks Again! God Bless and Keep You All, Cathy