Jenn, I am sorry to hear this.
Switzerland offers several excellent options for veterinary oncology treatment, especially at the two universities. Often treatment is a partnership effort between an oncology center and your own vet. Key is that you feel comfortable with your choices.
My dogs have been treated at the Zürich Tierspital, linked in Sigh's post above, and at the Animal Oncology and Imaging Center in Zug.
https://www.anicura.ch/aoi/die-klinik/
Looking at the AOIC website, it seems they have changed management and practice structure. I'm afraid I don't know the current team. The old AIOC was outstanding with my Haifisch's osteosarcoma, but perhaps because my experience is outdated this should be taken as information only.
My most recent experience at the Tierspital was last summer, please consider this a current recommendation. It was a hemangiosarcoma so we started with the cardiology professor, Dr Tony Glaus, and liased with the oncology team. My girl received excellent care, and everyone we saw was very kind. (Over many years and many dogs I've spent a lot of time at the Tierspital, and that has always been my experience.)
I live fairly far from the Tierspital and travel was difficult for my girl. Fortunately, my local clinic also has a skilled oncologist on their team, Dr Katya Reuss, who provided chemo support when we decided it would be best to limit travel.
https://www.marigin.ch/katja-ruess.html
One of the impressive things about Switzerland's veterinary care system is the level of cooperation among different areas of expertise and different providers and clinics, to ensure that my dog has the best care possible. I have always felt in good hands here.
Start with your general practice vet, have them refer you to the experts. You will be seen quickly, and by the right person, with a referral. If you are in Bern, then UniBe - linked by Island Monkey - is the logical choice.
A heads-up: COVID restrictions are still in place, meaning that only one person may accompany the animal at a time during clinic visits. Something to discuss with the family if more than one person wishes to be involved.
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You and your girl will be in my thoughts - here's hoping for the best.
ETA:
Jenn, do I understand that you are in the process of moving here? Was the diagnosis made by a vet outside of Switzerland? If so, please bring copies of all tests, imaging, and treatment notes with you.