A soft tissue sarcoma (STS) is a malignant tumor that starts in soft tissue such as muscle, deep skin tissues, cartilage, or fat. It often occurs as a lump in the arm, although it can happen anywhere.
Tumor response assessment by Choi criteria in localized high-risk soft tissue sarcoma (STS) treated with chemotherapy (CT): Update at 10-year follow-up of an exploratory analysis on a phase III trial.