Prognosis good for low-grade sarcoma
Q We own two Basset Hounds who are typically in good health. Our vet recently pointed out that one of the dogs had a large, softball-sized growth on the bottom of his chest. It had grown rapidly and was getting raw and scabs on the bottom since the dog is low to the ground, and the mass frequently came in contact with the floor. We had the growth removed, and the vet said it was a malignant soft tissue sarcoma, grade 2. While the pathology report could not specifically say it was completely removed, our vet said she got it all and that it was well contained. Should we be concerned about it? Can it grow back? A Soft tissue sarcomas include several types of subcutaneous tumors, such as nerve sheath tumors, fibrosarcomas and others that are malignant masses emanating from the skin or any one of several types of such tissues as muscle, fat, connective tissue, nerves and more. They can be found in lots of locations on the body and usually are seen to be well encapsulated. However, that can be misleading since metastatic invasion into surrounding areas is often not well visualized and a surgeon can leave cancerous tissue behind that can grow back. I have had great success removing some of these from sites such as the one you describe, but I find the ones on legs near joints, which are usually nerve sheath tumors, are the most challenging. In those cases, a lack of loose skin to close a surgical defect coupled with the invasiveness of the mass often leads to regrowth. Growths like the isolated one you describe often have good outcomes when removed. Another factor is the grading. Your dog has a grade 2 mass, which is intermediate. If the surgeon felt she got it all, then your dog may be cancer free. If any growth comes back, a second surgery may be indicated. Low and intermediate grade STS often have a good prognosis when removed completely. You might want to speak with your veterinarian about following up with an oncologist who might suggest radiation. I’m sure your dog feels a lot better now not having to carry that mass around any longer.