When I had the chest wall/pectoral muscle tumor removed, I was left with a positive margin in the muscle. Like you, just a tiny bit more would have left me with a clear margin. Why cut it sooooo close? And, good question, why didn't they check for clear margins during surgery? I was not at a teaching hospital or cancer center, but the hospital I was at is not rinky dink and is in the top 50 nationally. Hmmm. Definitely, a good question everyone should ask before surgery.