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Egfr exon 21 tagrisso


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My mom was diagnosed with nsclc adenocarcinoma egfr exon 21 mutation stage 4 ( probably 4b from what I've read) with a small brain met and a different bone met in her hip. I had to drag it out of her oncologist as to what mutation it was as he seemed to think it was irrelevant to the conversation, so I'm not sure if that's a deletion or really what that means what I do know is I can find a lot of information on exon 18,20 etc but not 21. I really want to know what the pfs is on tagrisso with this is and what her next lines of treatment would be considering she has the 21 mutation which I'm thinking is less common since I can't find a lot of reading material on it. The only few things I did find looked like it didn't respond as well to a lot of the drugs that are available. Does anyone have any information on this? She's been on tagrisso for about 1 year now she got gamma ray knife on a small brain met . The two spots they saw mets in her body have completely disappeared and her lung tumor has halved in size and now remained constant about half way through this treatment. I feel like they means this could stop working any day now considering pfs with a lot of other patients. I just want to make a plan but it's hard to talk with her oncologist when she's there since I know she doesn't want to have the tough conversations and I try and respect that decision to just live day by day. I on the other hand as her caregiver take care of all the hard stuff and I don't want to be blindsided. I want to be calm and prepared with what questions I need to ask and what we need to do, so she doesn't have to worry about it. If this stops working or I guess, when it does, what are the options for this particular mutation? What does this particular mutation even mean in contrast to the other similar sounding ones? Does anyone else have any information about it? And another thing. Why if the signs of cancer in the rest of her body have all disappeared, can she not have her stage reclassified. Why is she still inoperable? The oncologist won't even go down this road with me. He just says no she does not have that option. Ok, Thank you❤️❤️❤️

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Welcome here and very sorry to learn of your mom's diagnosis.

You've posed some pretty tough questions. Before attempting an answer, I'd like you to consider that studies citing progression free survival (PFS) are of small populations and while projections based on small populations may be sufficient to foster approval of a new therapy, they are generally not representative of the PFS your mother may actually experience. Why? Predictive statistics generate a mean or median value, but there are always outliers in the analysis and statistics as a scientific method focuses narrowly on the mean or median. A noted professor, Stephen Jay Gould, published an essay called the "Median is not the Message", and you can listen to it here. (See the link in the last paragraph of my blog).

I was once projected with an extinction probability of about 6 months and yet I've lived longer than 17 years. Is was (am) an outlier, an input variable that is clearly within the framework of a diagnosed lung cancer patient, but with characteristics that cause me to be excluded from a statistical projection. What would be those characteristics? I wouldn't know. The relevant fact is that statistics is a projection, not an absolute outcome. If you are googling PFS survival for adenocarcinoma EGFR with exon 21 (L858R), be careful to read recent studies (say 2019 through the present) and pay attention to the accuracy factor in the study--the "P value". As a general rule of thumb, a P value greater than .01 indicates inaccuracy and thus the predictive value should be discounted. For example, consider this study. It is a current study but look at the cited P values of all the predictions (P = .0189; .0186; .5572; .3466; .0209; .0208). A P value statisticians would consider accurate might be P = .0001. And then, there is the frank admission at the end of the abstract: "Overall survival data were immature at the time of cutoff,...."

So, let's move beyond statistics (know this is hard for me to do because as an engineer, I love predictive statistics when I can control input variables). First, let's accentuate the positive. Your mom's tumor burden is waning. Gama Knife precision radiation will almost certainly eradicate the brain met. These two good news items tell me your mom's treatment is working. Indeed that is cause for celebration.

Second, there are other ways of treating adenocarcinoma EGFR exon 21 (L858R). Here are some. And, research is discovering new targeted treatments and immunotherapy treatments at a rapid pace. You asked what EFGR exon 21 (L858R) was. Here is an answer. As far as stage classification, once diagnosed, the stage of diagnosis becomes a matter of record. One may be "restaged" for treatment, but the original diagnostic stage stays with the patient for life. I was diagnosed with stage IIIB non small cell squamous cell carcinoma. I progressed to stage IV in the course of my treatment but my diagnostic stage will remain IIIB. But, with lung cancer, staging is not an important consideration. Treatment and response are far more important. You mom indeed may achieve our desired end state of "no evidence of disease" or NED. But, she will always carry a diagnostic stage of IV.

Here is something you might want to share with your mother. It is wonderful that you are accompanying your mom to her oncology sessions. My wife's "second set of ears" and terribly preceptive questions saved my life.

Stay the course.


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