DCIS that is ki67+

Do you agree that a mastectomy would be a good idea or would you prefer to stick with the original plan and have a lumpectomy?

I find your BS's recommendation to be rather odd.  Women with aggressive invasive cancer do just fine with a lumpectomy + rads; the survival rate for a lumpectomy + rads is the same as it is for a mastectomy.  So I don't understand why your BS would recommend a mastectomy based on a possibility that you might have some invasive cancer.  Even if your entire tumor were found to be invasive (which is extremely unlikely), most surgeons would say that a lumpectomy + rads is a perfectly reasonable option. 

On average about 20% of women with a biopsy diagnosis of DCIS are ultimately found to have invasive cancer.  This risk is greatest for those who have a large area of DCIS and those who have high grade DCIS and/or comedonecrosis.  It doesn't appear that your biopsy diagnosis meets any of these criteria.  So the risk that there may be some invasive cancer hidden with your DCIS is probably 20% at most.   

If you are not sure that you want the MX or if you know that you would prefer the lumpectomy + rads option, I'd recommend that you get a second opinion. It sounds as though your BS believes in a very aggressive treatment approach.  There are pros and cons to that and it might be helpful to get another perspective.  

As for genetic testing, being 45 you are considered 'young' for a diagnosis of BC although 45 is right at the top of the age limit for most insurance carriers in terms of approving BCRA testing (i.e. they approve testing if the patient is aged 45 or younger at time of diagnosis). The exception is if there is a family history of breast cancer or related cancers (ovarian, prostate and some others), particularly if those family members were diagnosed under the age of 50. Do you have any family history of these types of cancers?

I am over the age of 45. My bc dx was 8 months ago. I wanted to have BRCA testing to know the results so that (1) I could decide whether to consider a hysterectomy and (2) I could find out if my daughter would be affected. I was told that most likely it wouldn't be covered by insurance. I was prepared to pay out of pocket and think of it as an investment. It was important for me to know. I must say I was surprised to find out after testing that it was mostly covered. I ended up paying co-pays which wasnt cheap but, for me, was worth it.

The result was that I didn't have the gene. However, because of bc and infertility meds, I am still seriously considering a hysterectomy.