What experience has anyone had with the Signatera blood test?

Back @ Mayo today for stool test, blood work, IV hydration and maybe a CT (depends on authorization) due to diarrhea and abdominal pain the past few days. Hopefully a stomach bug (my wife and sons had this through early this week) and not colitis.

Morthstar billed my insurance $7K+. It was denied. Northstar informed me they will not bill me.

Commercial insurance typically does not cover ctdna testing. Medicare does when the cancer is advanced. Fortunately, the DNA companies usually do not charge (Natera) or very little (Billion to One).

Signatera is the standard currently and has been used in many clinical trials for years. Northstar Response is fairly new and unknown to most oncologists. Both companies also provide DNA analysis to detect mutations to target treatments and assess risk of the cancer tissue.

Some oncologists use ctdna to commence further treatments. Others do not (like my oncologist). However, it does influence their decision. Based on my signatera (repeat negative) my oncologist was holding off on opdivo. With northstar coming back very low (close to the detectable limit of 25 at 31) , he agreed with my request to start opdivo. Hopefully, DDMVAC 4 resolved the remaining MRD as the first Northstar was pulled before this cycle. Although my kidneys recovered 100% interestingly my oncologist did not agree with two additional DDMVAC cycles despite my request. The oncology RN also noted that Northstar may have picked up necrotic ctdna from DDMVAC 3 as the first Northstar was pulled a couple of weeks after that cycle. I will know more next week with Northstar 2.

I still have opdivo side effects today. Bad stomach pain that comes and goes. Some back pain that comes and goes. And I was extremely fatigued around noon and had to nap for 90 minutes.

@judilafleur Molecular testing (which is a type of blood testing) for cancer comes in two main types: personalized tests like Natera Signatera and standardized tests like Northstar Response. (There are other companies, too.)

Personalized or "tumor-informed" tests like Natera's Signatera analyze the patient's specific tumor (from tumor tissue taken at the time of the initial biopsy, for example) to create a customized panel of 16 "targets" that looks for those exact mutations in blood samples. Standardized or "tumor-agnostic" tests like Northstar don't require tumor tissue samples and instead look for common cancer-associated genetic changes across many cancer types. >500 genomic loci, according to their website.

Both approaches detect tiny fragments of cancer DNA in the bloodstream, allowing doctors to monitor treatment effectiveness and potential recurrence earlier than imaging, but they differ in their precision (personalized tests are more sensitive for a specific cancer) versus versatility (standardized tests can detect multiple cancer types without needing tumor tissue). Given the increasing body of research demonstrating the tests' effectiveness, insurance companies now will often cover such testing, depending on the initial diagnosis (type of cancer, stage, etc.).

Please explain the purpose of this blood test,etc.

Today I experienced stomach pain. It may have been a Panera salad however. The Northstar ctdna sample was only received today. They told me FedEx was having weather delays.

This morning and yesterday I had to nap. Sudden fatigue sets on. But afterwards it dissipates. I have some joint pain also that comes and goes. But some of that I also had after RC surgery.

I am anxious about the second ctdna results next week. I am hoping/praying ddmvac 4 removed any mrd.

Two days in I have some minor side effects. A slight headache that comes and goes. And some nausea and feeling weird that comes and goes. I also have more energy than after chemo interestingly. I was able to buy 16 24 packs of water at CVS for the first time since August yesterday and do some home repairs yesterday.

First Opdivo around 930AM. No side effects so far. Fatigue but I had to get up at 5AM and I never sleep well when I know I have to get up early.

Both RX’ are to manage nausea when applicable. I still have a lot of OD so I canceled that one.

My bloodwork this morning included Northstar but not Signatera interestingly. I guess my oncologist is looking for a post chemo/pre immunotherapy baseline.

Opdivo at 8AM.

Second generation H1 antihistamines are recommended. So Claritin it is. The oncology RN stated there are no contraindications for Zyrtec and Benadryl. I will drop Zyrtec (seasonal allergies) and add a daily Claritin. The urostomy RN recommended Benadryl against stoma site rash. The oncologist also prescribed odansetron and something else. I am awaiting an explanation.