New, overwhelmed: What's microsatellite stable?

Posted by MommaCandy @mommacandy, Aug 9, 2023

My best friend, who i'm a caregiver and driver for, received a positive confirmation of an adenocarcinoma on the tail of the pancreas through a EUS. (we had already been told it was most likely cancer but needed that done to confirm it)...
It said it was "microsatellite stable" (whatever that means), and measures 3.3 cm x 3.6 cm on Aug 2, This means that since the original CT scan when it measured 2 cm x 2.3 cm was done on June 21, it has grown quite a bit...his CA 19-9 was 2462... the doctor who did the EUS at University of Virginia said that it was T2 and did not APPEAR to have spread to the left lobe of the liver. We are meeting with surgeon next week, and oncology medical the week after...
I guess my main question is what is "microsatellite stable" and why is it important? i know it has to do with DNA but beyond that i'm lost.. Any thoughts and help on things i need to learn about would be appreciated...as a 10 year thyroid cancer survivor this one is a bit out of my league and knowledge so i'm doing what i did when i was diagnosed...hitting the support boards to find answers from REAL people who can explain things simply 🙂

Interested in more discussions like this? Go to the Pancreatic Cancer Support Group.

MommaCandy | @mommacandy | Aug 12, 2023

In reply to @gardenlady1116 "Caregivers can suffer from the demands of caregiving. Hope you will find ways to take good..." + (show)

ty i'm trying but its hard atm...i feel ready to run away for a few days but unfortunately that isn't an option right now

granite | @granite | Aug 15, 2023

In reply to @markymarkfl "You're very welcome, and I hope it helps lead to a positive outcome. One thing I..." + (show)

@markymarkfl

You're very welcome, and I hope it helps lead to a positive outcome.

One thing I meant to elaborate on a little more was the neoadjuvant treatment. There was a study (can't find it & don't remember name) showing patients who got chemo before surgery had better outcomes (don't remember the exact outcome criteria either) than those who got surgery first.

Part of it is based on the likelihood that even without evidence of spread, there is often an undetectable "micro-level" spread already to places that surgery would miss, and that surgery with a tough recovery period would delay the start of "adjuvant" chemo to address it, which lets it spread anyway. Their thought process is that surgery in that case just puts the patient through unnecessary agony on the way to the inevitable. With neoadjuvant chemo, they figure a) it gives drugs a chance to target malignant cells that have spread elsewhere; and b) if they do see a spread while the patient was on chemo, then they conclude it was not controllable before surgery and thus would not have been controllable with basic chemo after the surgery. Sort of a patient-screening process to see who really benefits from surgery.

Another level of screening occurs when they do the actual surgery. While the actual procedure may be done "open" or laparoscopically, they typically do a "diagnostic laparoscopy" at the beginning of the procedure. It just means they make the minimal laparoscopic openings, insert some cameras, and look around. If they see evidence of tumors elsewhere, in too many places or a couple bad places, they close up and abort the bigger surgery.

"TNT" (TOTAL NEOadjuvant Therapy) is the approach of doing all chemo before surgery, and none after, on the presumption that if you got a full dose and could tolerate it, that's the best they could do. It was part of the failure in my case (faster spread after recurrence), which is one reason I'm not a fan.

I've attached a paper, with a quote from page 2, "During the last twenty years, it has been well established that all surgical approaches to pancreatic cancer need to be supplemented by adjuvant therapy."

But there are two 10-minute sides of that debate worth watching here:
https://youtu.be/naQ-HlZbEoI (Dr. Jordan Berlin, Vanderbilt, for TNT)
https://youtu.be/nd1l5-GrdVQ (Dr. Matthew Katz, MD Anderson, for surgery first)

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I wish I had seen Dr Matthew Katz’s video 17 months ago. I may have presented it to our oncologist at top cancer center to go on the table immediately after diagnosis (with somatic mutation after presenting with high bilirubin levels.)
He quickly developed pancreatitis so the stent was needed, but it delayed treatment when it became obstructed twice and he had to be hospitalized. These delays may have contributed to the ineffectiveness of the neoadjuvant Folfirinox. What has Katz been presenting lately?

markymarkfl | @markymarkfl | Aug 15, 2023

I haven't kept up with any of Dr. Katz' presentations, but when I met with him for a second-opinion surgical consult last January, his eagle eye spotted a metastasis on CT that his radiologist and the previous institution didn't see.

Unfortunately, he said that ruled me out as a surgical candidate for now, and recommended me for systemic therapy (chemo). Since I've been somewhat stable for almost 6 months on chemo now, I'm going to ask him about HIPEC with CRS (cytoreductive surgery).

Similar to my other treating surgeon, I don't think he does the HIPEC procedure himself, but would be the one removing what's left of my post-Whipple pancreas (and spleen with it), while another surgeon picks out all the "lint" in the rest of my abdomen.

It's a long shot that my medical oncologists are recommending against, but if CRS doesn't work and I survive the procedure, I can still revert to the medical interventions (chemo/immuno/targeted therapies) with a few less tumors lurking in the body.

gamaryanne | @gamaryanne | Aug 16, 2023

In reply to @granite "I wish I had seen Dr Matthew Katz’s video 17 months ago. I may have presented..." + (show)

Just one additional note to this; each case is so different vis a vis stage at diagnosis, where the tumor(s) are located, etc.
the cancer is often silent for a long time and is systemic in nature so if one is staged beyond 2 the likelihood is that there are cells hiding somewhere. Initial systemic therapy to attack those and shrink tumor makes sense to try. Surgery can be curative but “wack a mole” is not a game for the faint of heart and may prove to fail ultimately without adjuvant therapy/radiation. My initial pancreatic tumor is gone-it was necrotic when removed. My metastasis in liver were necrotic too-except one small spot. Liver margins were clear. Yet-I have a small reoccurrence. As much as I would like to just cut it out-I know I need to play the long game and try to clear my system.

gamaryanne | @gamaryanne | Aug 16, 2023

In reply to @mommacandy "Sigh...atm its feeling like the world is revolving around him...i've basically "took care of him" if..." + (show)

You are an amazing person. He is blessed to have your beautiful loving heart.
There are many angles to this disease. It is not a death sentence! (Any more than we all have one-I don’t think any of us are getting out alive!)
Remind him that everyone has something. Encourage him to eat well, get outside as much as possible, and try to stay active. But most of all, take good care of yourself. You are one in a million.

MommaCandy | @mommacandy | Aug 18, 2023

In reply to @gamaryanne "You are an amazing person. He is blessed to have your beautiful loving heart. There are..." + (show)

thank you so much...you have no idea how much i needed to hear that tonight...i've not been online for a couple of days because i'd been to Charlottesville and tbh i struggle with anything on my phone...
Surgeon has said 3 months of chemo, month of "washout" then he'll reevaluate at that time...he COULD do it now but feels it will greatly improve success rates by doing the chemo first....and when my friend told him he trusted his choice, Dr Z said "well if its my decision and you trust it, then we'll start with 3 months of chemo" and got him scheduled to have a port put in next Wed after we meet with oncology...