Other major prognostic factors
Other major prognostic factors are histopathology, and I’ll go over some of these at the end. Lymph node involvement, which is extremely rare, connotes a very poor prognosis. And you can see that with epithelioids, synovial, rhabdo and angio. For the most part though we don’t recommend doing lymph node dissections because for the most part sarcomas do not go to the lymph nodes. Age; those patients under 60 usually do better than over 60. Females, as for most tumors, do a little bit better than males. And then there’s some literature on P-glycoprotein and Ki-67 expression, and aneuploidy. Debatable literature. Ploidy, you can find in both directions, whether it has significance or not. P-glycoprotein is for measurement of MDR and Ki-67 expression, DNA synthesis. Obviously those patients who have a higher DNA synthesis do somewhat worse.
We have two major staging systems for soft tissue sarcoma. One of them is the Enneking system, put together by Dr. Enneking who is sort of the father of orthopedic oncology, who was at the University of Florida. It’s a bi-gradal system; low grade, high grade and then whether the tumor is either intra-compartmental or extra-compartmental, and then if the patient has nodes or metastases they would be stage III. This emphasizes compartmentalization. It is best suited for extremity sarcomas. It’s not good for other areas of the body, and size and depth are not included. It’s the system though that’s probably used the most by orthopedic oncologists. Now our other grading system is the American Joint Cancer Committee system and this again has been changed in 2006 from a tri-grade to a bi-gradal system. Putting well-differentiated and moderately- differentiated in one group, and poorly and un-differentiated in another. But in addition to that, it looks at size – less than or greater than 5 cm – and it also looks as to whether the tumor is superficial or deep. The tumors that specifically we want to look at, that have probably the highest rate of recurrence and where we possibly could look to give adjuvant therapy, would be in the high grades that are somewhat superficial, but more the high grades that are large and that are deep. Those are the ones that have the most potential for recurrence and where we would think possibly of giving adjuvant chemotherapy. Obviously those that do the worst are those who have nodal involvement or metastasis.
Now this is what a typical soft tissue sarcoma looks like, and I put this up to show to you that it’s critically, critically important that you get this patient to a surgeon who knows what they are doing the first time. Many of these tumors, the majority of these tumors, have a pseudo capsule around them and many many a time the patient gets the “oops” procedure. In other words, the surgeon goes in and sees, “Boy that capsule, this is easy. I’m just going to slide it right out” and the tumor is out. Then the pathology comes back and all the margins are positive. And why are the margins positive? Because there are satellite areas of tumor around that pseudo capsule, so you just don’t want to scoop it out. If possible, you want to get a wide excision with at least 1-2 cm of normal tissue around it. When we do a marginal resection, a shell-out, there is about a 90% incidence of local recurrence.
Even with wide excision, there can be about 50% in older series. When we do a radical, it is less than 15%. Sometimes we still have to do an amputation, and this is really based on the biopsy site and the biopsy being done properly, as I said before, whether there is neurovascular or compartmental involvement, the size of the tumor, and what the anticipated function is. If the patient, after the surgery, is left with very poor function then there is no point in doing a limb-sparing procedure. So in terms of surgical treatment, there has been a transition from doing a shelling out, where there is 90% local recurrence, to an amputation, to now limb-sparing surgery plus radiation, where there is about a 5-15% local recurrence rate. In a trial done at NCI comparing limb-sparing surgery plus radiation, versus amputation, there was no difference in survival.