Question about being Stage 4 and Primary Tumor to Remove or Not..

[Lala]

My original dx 6 months ago was stage 4 her2+ er/pr+.
I have been thinking about removing my primary breast tumor or at least having another biopsy done all to be frozen for future testing. I am also wondering about the survival possibilities too. I did see the previously posted article from Lani. I found that article very interesting but still had this question.

My question is:
Has anyone had their primary tumor removed or biopsies after treatments began or between the changing of treatments?

Thanks in advance for reading this.