"Too busy, under-resourced and overcrowded"

I underwent two surgeries after I detected a rare breast tumor called phyllodes during a self-examination in January. After the second surgery, the surgeon told me (about the tumor) "It can come back, but benign". This has left me feeling anxious because the standard treatment for a phyllodes tumor involves removing a safe margin of healthy tissue to prevent recurrence completely, since it is aggressive and prone to return to begin with. Moreover, it can return as borderline or malignant. The first surgery was for removal of the tumor (initially diagnosed as a fibroadenoma) and the second one for removal of a margin (rim) of healthy tissue in the place where the tumor was, to prevent recurrence. Throughout the surgeon was a bit flippant, dismissing my fears and anxieties as childish. I was not explained why "it can come back". The final aim of the second surgery should have been to completely prevent recurrence. The surgeon explained to me the width of the margins obtained at the biggest and narrowest point. I gather the narrowest point is under the skin, but did the surgeon remove some skin as well? Why is the surgeon saying it can come back? Not enough information left me feeling anxious. I got the impression they are a bit overworked and the breast department a bit under-resourced. I understand it's not their fault, but patient care suffers as a result of this.