PET/MRI finds brain(and other) mets in her2+ pts not seen on PET/CT & has less false

[Lani]

positive findings--will it become the new gold standard in imaging (gold standard overall will remain biopsying, of course)?

Will it ever become a screening method for her2+ brain mets (awful expensive for that, although less radioactivity than PET/CT). OF course, "more studies are needed..." to see if finding these additional mets and earlier.. "impacts survival"

You would think so-- some here at her2support have personal experience of brain mets that were found early when they could be successfully treated with cyber or gamma knife. You would think that finding brain mets when they were smaller and less numerous would increase the numbers treatable successfully with SRS.

As usual, additional numbers of patients will be need to participate in trials before suffficient numbers are generated for statistics showing increased survival so a "cost-benefit" analysis can be done.


The following is an abstract for the upcoming asco 2014 Annual Meeting:

Detection of metastases in breast cancer: Is whole body PET/MR better than PET/CT?

Sub-category:
Molecular Diagnostics and Imaging

Category:
Tumor Biology

Meeting:
2014 ASCO Annual Meeting

Abstract No:
11002
Attend this session at the
2014 ASCO Annual Meeting!

Session: Tumor Biology

Type: Oral Abstract Session

Time: Monday June 2, 3:00 PM to 6:00 PM

Location: S100bc
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Author(s): Komal L. Jhaveri, Eleonora Teplinsky, Francisco J. Esteva, Akshat Pujara, Linda Moy, Amy Melsaether; New York University School of Medicine, New York, NY; New York University Cancer Institute, New York, NY; NYU Langone Medical Center and NYU Cancer Institute, New York, NY

Abstract Disclosures

Abstract:

Background: Whole body (WB)PET/CT is commonly utilized in breast cancer (BC) patients (pts). Limitations include assessment of treatment response in bone metastases (mets), high physiologic uptake in brain and liver, and cumulative radiation exposure. The site of mets can have prognostic and therapeutic implications. PET/MR, an exciting new hybrid technology, delivers less radiation than PET/CT. Our aim was to compare the differences in metastatic lesion detection using PET/CT and PET/MR in all BC subtypes. Methods: Pts who had WB PET/CT for staging and assessment of treatment response also had WB PET/MR after a single 18-FDG injection. PET/MR and PET/CT images were each read by a radiologist blinded to prior exams or reports. The number of mets per organ was recorded. 2 experienced radiologists unblinded to imaging and pathology reports served as the gold standard. Clinical data were obtained. Trial accrual is ongoing. Results: 48 pts underwent PET/CT and PET/MR (28 MBC, 5 neoadjuvant & 15 adjuvant setting). Median age was 48; range 31-79 with 31 ER+/HER2-, 9 ER+/HER2+, 2 ER-/HER+, 5 ER-/HER2-, 1 unknown. 11 pts had no evidence of mets. In remaining 37 pts, PET/MR and/or PET/CT detected bone, liver, or brain mets in 23, 9 and 5 pts, respectively; some patients had ≥1 metastatic site. PET/MR accurately detected 1 bone (ER+/HER2), 3 liver (ER+/HER2-) and 5 brain lesions (2 ER+/HER2-, 2ER-/HER2+, 1ER+/HER2+) in 8 unique pts that were not identified on PET/CT. 2 liver and 2 brain mets identified on PET/MR were previously unknown. PET/MR accurately reported treated bone lesions in 10 pts. Per organ system, there were more false neg and false pos with PET/CT (Table). Conclusions: Our preliminary data suggest that PET/MR may be more sensitive and specific than PET/CT in detecting mets in breast cancer. Prospective studies of PET/MR are warranted to determine whether early detection of mets, including occult brain mets in HER2+ pts, impacts survival.
Organ (N)a # Pts with
concordant PET/CT &
PET/MR findings # Pts with
false (+)
on PET/CT # Pts with
false (-)
on PET/CT
Bone (23) b 10 9 2
Lung (5) 2 2 1
Pleura (5) 4 1 0
Nodes (axilla + other) (19) 9 6 4
Liver (9) 5 1 3
Brain (5) 0 0 5

aSome pts had ≥1 metastatic site b In 2 pts, neither modality accurately detected the # lesions.

[Debbie L.]

Thanks as always, Lani. This is interesting, and timely for another thread, Catherine's about standard follow-up and tumor markers, where there's a sub-thread about tumor markers and brain mets.

This study did not, however, compare PET/MRI to simple brain MRI. It was looking at whole body PET/CT vs PET/MRI, right? Is it possible (even likely) that a basic brain MRI could do as well as a PET/MRI, for detecting brain mets?

I'm glad that they are looking at ways to detect brain mets as soon as possible, because as you say, treatment can be less invasive when brain mets are small. But I can't help but wonder where this will take us. Just anecdotally, it seems to me that typical HER2+ brain mets progress quite rapidly. If it was decided, for example, that everyone diagnosed with HER2+ breast cancer should be regularly screened for brain mets -- how often would we have to do that, to make a difference?

I hope that this becomes a moot question. That we find a treatment that, ideally, prevents brain mets, or at least treats them systemically, with fewer toxicities (there is a study in the works using temozolomide for prevention). And I'd have to add that as I've seen it, one of the biggest downsides for some people is the side effects of the steroids, and the weaning from them.

Debbie Laxague