hi guys since we did surgery on a soft tissue sarcoma today I thought it'd be interesting to just quickly review the treatment options for substitution soft tissue sarcomas and what can we can expect as far as outcomes concerned so say for example we've got this soft tissue sarcoma sitting here on the right front leg of a dog we can see that there's a previous biopsy tract sitting here the biopsy results revealed a grade - soft tissue sarcoma so the conversation that I would have with the owners at this point would be I would get a dry rice board and I would say that with soft tissue sarcomas we've got two different issues to be concerned about we've got the primary tumor that we can see and we have the risk of risk of secondary metastasis now as far as secondary metastasis is concerned the best predictor is the grade of the tumor and they're graded one two and three grade one soft tissue sarcomas have somewhere between a five and ten percent chance a secondary spread great twos are somewhere around a ten percent chance the secondary spread Gate 3s are about 50% chance a secondary spread and it's been shown both in humans and in animals that chemotherapy is of no benefit in preventing secondary spread of these tumors the other interesting predictor with soft tissue sarcomas is the location of the tumor and I did a study back in 1996 that showed the tumors on the extremity were significantly less aggressive than tumors on the trunk and more specifically out of several thousand soft tissue sarcomas that I've operated on in the past I've never seen a tumor on the extremity metastasize I have seen a few grade three soft tissue sarcomas but metastases again has never been an issue that being said it's still a good idea to take chest radiographs prior to any kind of treatment just to make sure that it isn't an odd case that has metastasized for that there isn't another primary tumor somewhere else in the body that has spread or you could even have a primary lung chamber that you'd want to pick up before you put a patient through a major surgery now as far as the primary tumor is concerned surgery is the first line of defense now when we do a surgery we check our surgical margins and what that means is that we're making sure that we have completely surrounded the tumor with our surgery to make sure that we haven't left any cancer cells behind now say for example we've got this chamber shown in color here that tumor is represented by purple if we did a surgery represented by the blue marker here marking pen that would be considered an incomplete margin because we've left all of these cancer cells behind and that will almost invariably recur if however we did a surgery which looked like this and completely surrounded the tumor that would be considered a clean margin and would be predictive of no recurrence so again if we review our surgical margins clear margins are predictive of no recurrence and in my study the risk of recurrence was about 5% in five years that's in contrast to having dirty margins where in my study we had a 75% chance of recurrence in five years so what do we do if we have dirty margins let's come down here we have a few different options that we could consider the first one then the best choice would be surgery when you go back and do a surgery with dirty margins and come back and get clear margins that's virtually curative for soft tissue sarcomas as long as you're aggressive enough and I've used this option as my primary choice when I'm dealing with in completely excised tumors the other thing that you could consider doing would be taking a wait-and-see approach recognizing that on the trunk about 75% of tumors are going to recur within five years on the extremity it's been shown that with low and intermediate grade tumors so great one in two tumors the risk of recurrence is only about 30% so if you had particularly an older dog that had an incompletely excised soft tissue sarcoma on the extremity and got a dirty margin or a close margin it wouldn't be a terrible idea to just wait and see what happens that's in contrast to either a really young dog that there's gonna be a lot longer opportunity for recurrence to occur or if you had a larger tumor or a tumor on the trunk that tumor is also more likely to recur so we're gonna want to take a more aggressive approach and wait and see probably wouldn't be appropriate now what if it's in an area that another surgery is not appropriate and you want to do something radiation therapy is very effective at cleaning up in completely excised tumors and so that will drop the recurrence rate from 75 percent down to about 20 percent in five years and that's a great option in anatomically restrictive areas where you don't have the option for another surgery and then the last option would be metronomic chemotherapy and metronomic chemotherapy the word describes what we were doing and so if you think about a metronome that goes tick tick tick tick tick metronomic chemotherapy is applied every other day for the life of the patient and the drugs that we use for that would be her oxygen and cyclophosphamide and most patients tolerate that very well and the severe complication or side effect rate that we see with that protocol is about 8% and it can consist of hemorrhagic cystitis and hemorrhagic cystitis is just as bad as it sounds where you have a really horrendous hemorrhage and it sounds like the worst urinary tract infection I could ever imagine but that hemorrhagic cystitis resolved in almost every case with discontinuation of the medication now note that metronomic chemotherapy is basically as effective as radiation therapy in that it reduces recurrence from 75% down to about 20% in five years so the bottom line here is that soft tissue sarcomas are treatable and honestly the majority of soft tissue sarcomas that come in the front door of our clinic are cured as far as the local disease is concerned in terms of using surgery plus or minus adjuvant therapy recognize that the high-grade tumors the grade three ones still have a chance of secondary spread and so we're definitely going to want to stage the tumor before him by taking at least chest x-rays prior to any kind of treatment and then the other really important thing is that after we do our surgery we're going to want to check our surgical margins to check and see how good a job we did recognizing that clean margins are associated with a very high chance of the local cure and dirty margins are associated with generally fairly high rate of or occurrence particularly on the trunk or when you have a high-grade tumor like a grade three so just to review our principles with surgical oncology the first thing that we want to do is biopsy the tumor and find out what we're dealing with either in the form of a true incisional biopsy which is where we take a sample of this tumor before we go in and try to surgically remove it or at least cytology in the form of a final aspirin after that we're going to do a literature review to find out how this tumor behaves and do we have a chance for surgical cure what are the chances of secondary spread where is secondary spread going to occur you know what kind of staging should we do after we do our literature review the next thing that we're going to want to do is complete staging in the form of at least thoracic radiographs with soft tissue sarcomas and and aspirating the regional lymph nodes is probably not a bad idea either then we're going to do a curative intent surgery and that means that we are going to go in with the idea that we're going to cure this patient and if we can't cure the patient we have to either prepare for doing some kind of adjuvant therapy in the form of radiation therapy I mention on the chemotherapy or we're going to consider maybe trying to send it somewhere that could achieve a surgical cure so curative intent surgery we're gonna check our margins we're going to consider adjuvant therapy and then not with soft tissue sarcomas because chemotherapy is ineffective at preventing secondary spread but with for example mast cell tumor was a grade 3 ml cell tumor chemotherapy is quite effective at preventing secondary spread so please follow our tenants of surgical oncology and your future patients so that we don't miss things and things don't fall for the through the classic cracks I hope you enjoyed this little mini lecture and please message me if you have any questions or comments