Er+ Pr + Her2+ T1 grade 3. Small tumor, no lymph node or metastasis.

I was a few years younger and was (PR-) but very similar. But there are new drugs out there today to treat her2+ cancer. They really have gotten a handle on it that they didn’t have when I was diagnosed. My tumor was larger but no nodes or metastasis at diagnosis.
Surgical biopsy, due to ambivalent imaging reports. Lumpectomy, and node dissection (not sentinel node) followed two weeks later. Then port implantation for chemo. Taxol, Adriamycin, Cytoxin, for six treatments. Then came the oopherectomy, since I had already had a partial hysterectomy. Then came six weeks of radiation.
This was followed by endocrine therapy.
I really believe if they had the drugs then that they have now, that would have been the end of it. This was nearly twenty years ago and things were different. I believe you will have an easier time of it.
If I have any advice, I would say find the best cancer center you can, even if it means some travel. Educate yourself as much as you can, and be your own advocate. You got this❣️

Neoadjuvant treatment before surgery may be recommended, to shrink the tumor before mastectomy or lumpectomy. But neo-adjuvant therapy is usually for node-positive, tumor size over 2 cm, inflammatory or locally advanced HER2+ cancer.

Adjuvant treatment is after surgery and would include Herceptin and Perjeta for one year (18 cycles) along with chemo. There is also a drug called Phesgo that combines Herceptin and Perjeta. The chemo is taken for less time than these drugs. If you look up Phesgo there is a chart comparing the time on chemo and the time on Phesgo.

There is a new drug on trial btw https://www.curetoday.com/view/fda-lifts-hold-on-trial-investigating-novel-drug-in-patients-with-high-risk-breast-cancer

When I was diagnosed with cancer in 2015, Perjeta was new. A lot of advances have taken place in treatment of HER2+. My HER2 tests were confusing. I was told I was HER2+ after biopsy and got an Rx for a wig. Then after surgery it was equivocal at three different labs, and negative with further testing. I had a mixed ductal/lobular tumor. The ductal part of my cancer was positive (the biopsy probably targeted this) and the lobular part was negative, I was told. I still worry whether it should have been treated but I just did hormonal treatment and have made it 7 years.

The site breastcancer.org may be helpful.

Here is a thread on HER2+ treatment: https://www.breastcancer.org/treatment/targeted-therapy/what-are-anti-her2-therapies

There are many different medicines that are used to treat HER2-positive breast cancer by targeting HER2 receptors. Many HER2 inhibitors are given in combination with other treatments. Some anti-HER2 medicines called “antibody-drug conjugates” are made with HER2 inhibitors and have other medicines attached to them.

Some of these anti-HER2 medicines also carry chemotherapy directly to the HER2-positive cancer cells, which helps protect healthy cells from the toxic effects of chemotherapy medicines.

This information is provided by Breastcancer.org.

Thank you. Any input on side effects. The heart and lung issues look very serious. The thought of surviving cancer to live in restriction with a bad heart isn’t very encouraging.

Thank you.

The key word is "surviving." I would talk to your doctor. Not everyone gets those side effects and I am sure you will be monitored.

pbnew: I don't know about lung effects, but the heart effect is well known and the heart is carefully monitored. Patients receive a cardiac echo every 3 months. If ejection fraction goes down, treatment is stopped until it comes back up. The cardiologist I saw told me in 11 years of her job (cardiac oncologist), no patients on Herceptin had had heart effects from it. But it could be possible. That's why they monitor it.