First, let me say that I do not want to interfere with your medical care and your relationship with your treating doctors. Your doctors are more familiar with the details of your case and I would be doing you a disservice to pretend otherwise. I defer to their expertise. Please make sure you follow up with your doctor.
My answer below to your question is intended to be for general informational purposes only and not medical advice.
However, generically speaking, I can provide you with a short overview of Phyllodes tumors and some of the more common considerations encountered by patients and physicians when treating these tumors and I hope that this information is helpful to you.
First, Phyllodes tumors are relatively rare. Because of this, we don’t have too many large studies that enable us to fine-tune our evidence based medicine approach. Stated another way, we just don’t have as much experience with them as we do with other tumors. However, there are still a few things that almost everyone agrees upon that should be helpful to you.
In general, Phyllodes tumors (note alternative spellings and various pronunciations are common) can be relatively difficult to diagnose. They often look just like a fibroadenoma on ultrasound and mammogram and even when a biopsy is done, it can still be hard to determine specific characteristics of the tumor under the microscope. This is in part because Phyllodes tumors exhibit a spectrum of behavior from benign to malignant.
One of the most useful characteristics to determine how the tumor is behaving (benign versus malignant) is to look at how quickly the cells are dividing. The quicker the cells are dividing (generally referred to as mitotic rate), the more aggressive the tumor and the more likely it is malignant. Because cells may divide at different rates in different areas, it is useful to examine a larger area of tissue to get a more accurate overall impression. For this reason it is useful to have as much tissue as possible for examination.
However, mitotic rate is not the whole story, there are other very specific tissue characteristics which require special tests to be done on the tissue which can give clues about the tumor’s behavior. For this reason, it is useful to have an expert pathologist familiar with Phyllodes tumors make the diagnosis. Often, even with the best of circumstances, the Phyllodes tumor can only be classified as “middle grade” or somewhere between benign and malignant.
In any event, because of all of these considerations, it is widely agreed upon that the tumor should always be removed regardless of the initial impression from biopsy (whether benign, borderline/intermediate grade, or malignant). This is done by completely removing the tumor along with some surrounding normal breast tissue to ensure removal is as complete as possible (known as wide local excision). A surgeon with experience in removing tumors from the breast should be able to successfully perform the surgery.
After the tumor is removed, all of the tissue will be examined and a final diagnosis will be made about the tumor. About 10-25% of the tumors are determined to be malignant. However, most of the time the removal of the tumor alone is curative. A small percentage of the time the tumor returns and a second surgery is needed. In general, no other therapy other than surgery is recommended to treat Phyllodes tumors. The overwhelming majority of all patients with a diagnosis of Phyllodes tumors on biopsy do remarkably well.
I hope this helps.