Phyllodes tumor

I had a lump removed 2 weeks ago and it turned out to be a benign phyllodes tumor. My surgeon would like to perform a lumpectomy in one month since no breast tissue was removed durning the first surgery.
I am 32 years old and am planning to be pregant at least one more time. My surgeon advised me that it would be safest to get the lumpectomy done since a pregnancy could trigger a new phyllodes tumor, which could turn malignant. He could not guarantee that I would be able to breastfeed after the lumpectomy. He also said that my breast risks to be deformed because of its small size.
If I decide not to have the lumpectomy, what are the risks of me developping a new phyllodes tumor? What is the % of it becoming malignant? Could the fact that no breast tissue was removed the first time, increase my chances of getting a new tumor? If so, what would the % be?
Thank you in advance for your help.

Veronique

[CCF-RN,MSN-JS]

Dear Veronique, The term phyllodes tumor includes a group of lesions of varying malignant potential ranging from completely benign (non-cancerous) to fully malignant (cancerous) sarcomas.
Approximately 20% of phyllodes tumors will recur locally if removed with no margin or a margin of a few millimeters of normal breast tissue, regardless of whether they are benign or malignant.  A wide excision with a 2cm margin of normal breast tissue is appropriate therapy for benign and borderline phyllodes tumors unless they are so large that this is not cosmetically feasible.  

[mksg]

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