Case of Concerned or Oversensitive? - 1259318

Size is the gold standard of assessing treatment options. So the stable 1.1cm tumor would be considered stable disease, not progression. It would be difficult to say if no growth with a rising or falling SUV is common or not because lung specialist assess with CT scans so SUVs aren't commonly followed. I can say from my husband's experience, he's been followed by PET/CT and has shown rise in SUV without size change so we didn't do anything differently in treatment planning.

"The role for PET scans in advanced disease to assess response to therapy remains a controversial area. A CT can provide plenty of helpful information for assessing response to therapy once stage has been established, and CT scans are the well studied and validated metric for assessing interval change for cancers with measurable disease. Some people favor getting PET/CTs to clarify response in extreme detail, but there is a real risk of identifying clinically insignificant changes, such as by a minimal increase in the PET uptake of a tumor that remains stable in size, that might lead to a change in management that isn’t clearly necessary." http://cancergrace.org/cancer-101/2010/09/16/cancer-101-faq-assessment-…

You're always welcome. :) Let me contact one of our faculty for input on that.

Hi NJ
I can certainly see why such a "big" change in the SUV - which is something we pay attention to - would make you wonder about cancer growing. However, i would have to agree with Janine, that it's really the size that we care about most of all. SUV is a measure of sugar uptake, so in theory there could be several biological processes that might change the SUV other than cancer becoming active.

i would not change treatment based on an SUV change alone. especially if the treatment she's on is well tolerated (as iressa usually is). of course she needs follow up in the form of CTs (or PETs if that is what is standard where you live).

as i am not a nuclear medicine doctor (these are the ones who read PET scans) i have sent your question to one of my colleagues in case they have any explanations for this change. i'll update this post when i hear back from them.

i hope that helps.

I would also add that we really can't say how common it is or isn't to see changes in metabolic uptake in the absence of size changes, or what exactly this might mean in this setting, because many lung cancer specialists, including Dr. Laskin and myself, don't typically do PET scans regularly to do regular follow-up on ongoing treatment for advanced NSCLC. This is because we find that additional information about SUV in the absence of a change in tumor size is ambiguous and may well lead us to make worse decisions about how best to treat patients, potentially leading us to be tempted to make a change when it really isn't indicated or advisable.

Good luck.

-Dr. West

Hi NJ
i did ask my colleagues who read PET scans - they said that it was hard to explain why the SUV would change but not the size. maybe there were differences in the technique or the timing between the sugar injection and the scan?
in any case, i think repeat imaging in the next 3 months (or so) would be advisable, unless you are going to take some local action with radiation as you described.
best of luck!

Thanks for the clarification.

I would say that RFA of lung lesions has failed to find any clear place in the management of lung cancer and has had more concerns raised about its safety, while SBRT has been studied in a much broader setting and has gained far more traction. There is plenty more written about these subjects if you want to search for them.

Good luck.

The issue of a "flare" of progression is something still debated. Most people just discontinue an EGFR inhibitor in the face of clinically significant progression of disease, and in most cases there isn't a flare of faster disease progression. In the event that there is worsening of symptoms, you would have a clear idea of how to remedy the situation.

Unfortunately, there is no evidence-based answer of a best approach here.

Good luck.

-Dr. West

A short course of radiation (4 or 5 sessions) is most often given for palliative/pain purposes while the longer 30-40 sessions are given in hopes of eradicating all the cancer. The link below describes this, It begins, "For many patients, it comes as a surprise when their radiation oncologist explains a recommendation for a five to seven week course of radiation therapy with daily treatments on a Monday through Friday schedule. The rationale for splitting a prescribed radiation dose into sometimes upwards of 35 or 40 treatments is two-fold: to maximize the good effect of radiation (killing cancer cells), and to minimize any negative effect of radiation (scarring of neighboring normal healthy tissues).", http://cancergrace.org/radiation/2011/02/03/rt-fractionation/

Here's a link to more on radiation, http://cancergrace.org/search-results?q=radiation%20grays

I'm sure you've read this but here goes, http://cancergrace.org/lung/2013/01/23/acquired-resistance-algorithm/

Stereotactic body radiation therapy (SBRT) is typically over 4-5 sessions, and conventional RT is an alternative approach. I think you would need to speak with her radiation oncologist about the reason why he or she favored conventional fractionation (weeks of daily RT) instead of a few days of hypofractionated (4-5 treatments at high dose) along the lines of SBRT.

I would consider a single nodule of progression to represent "oligo-progressive" disease and be inclined to favor continuation of the EGFR inhibitor in this setting, but it's important to note that this isn't an undisputed standard of care: it's just the way that many, though certainly not all, lung cancr specialists approach this situation in an EGFR mutation-positive or ALK-positive patient who is demonstrating mild, limited progression against a background of good disease control.

Good luck.
-Dr. West