so far it's non invasive dcis, but they won't know for 100% until they go in. If I do a lumpectomy there's radiation in addition to chemo for Her2. Recommendations?
I'm not sure if posting your question in "Mixed Type Breast Cancer" will get you many responses. From the information you've provided, you have DCIS, so maybe post in one of those threads.
Welcome, sorry you have to be here. Do you have DCIS only? Which is Her2+? If so, you would not be needing chemo for the Her2 aspect - that is only given for an invasive component that is Her2+. For your surgical consideration here are some thread topics that lay out decision making criteria that you may find helpful.
Breast Cancer Topic: Considerations: Lumpectomy w/Rads vs. UMX vs. BMX
In addition to the links from Special K, check out the 'search' area. There are lots of threads discussing this exact thing.
Further to SpecialK's post, if your final diagnosis is Stage 0 DCIS, then chemo will not be given, no matter what. DCIS is a localized disease (the breast area) whereas chemo is a systemic treatment (it goes into and treats the whole body), so chemo is not given for DCIS.
However, should your final diagnosis include an invasive cancer that warrants chemo (based on size, aggressiveness or subtype such as HER2+ or ER-/PR-), you will need chemo whether you have a lumpectomy or a mastectomy. Surgery is a localized treatment and therefore the type of surgery does not impact the need for a systemic treatment, should one be recommended.
As for radiation, while usually it is not required after a mastectomy, if there are close surgical margins near the chest wall, even just for DCIS, radiation may be recommended. But if your area of DCIS is not near the chest wall, this shouldn't be a concern.
As an FYI, the risk of a diagnosis upgrade to invasive cancer after a core needle biopsy finding of DCIS is about 20%. So hopefully your final diagnosis remains pure DCIS.