Sarcoma Therapy: Functional outcome and relationship to treatment parameters

Abstract

Purpose: To systematically assess the functional outcome of patients treated with surgery and irradiation for extremity or truncal sarcomas, and to correlate this outcome with a detailed analysis of the radiation dose distribution and surgical technique. Conservative surgery and radiation therapy (RT) are known to provide excellent local control, but the relationship of technique to functional outcome requires further study. Methods and Materials: Forty-one patients were treated for lower extremity (25 patients, 61%), upper extremity (8 patients, 19.5%), and truncal (8, 19.5%) sarcomas from 1983 to 1990. Most patients had malignant fibrous histiocytoma (15), liposarcoma (8), or, aggressive fibromatosis (6). Age ranged from 13 to 85 years (median 54). All patients received RT and 39 (95%) had surgery. The mean total RT dose was 59 Gy (range 55.8–64.8 Gy). A protocol for functional assessment was devised and included a 4 point scale (0–3) for each of seven functional parameters (range of motion, fibrosis, edema, pain, skin changes, muscle strength, gait, or upper extremity performance). An aggregate score was obtained by adding the seven parameter scores and compared with both a patient and physician overall functional rating score (excellent, good, fair, poor). Based on this analysis, aggregate scores were defined as ≤ 3 = excellent, ≤ 8 = good, ≤ 13 = fair, and > 13 = poor, with 21 as the worst possible score. The same orthopaedic surgeon and radiation oncologist independently examined and rated 22 patients. An additional 17 patients were evaluated by record review. The median time from completion of radiation therapy was 30.5 months (range 7–95 months). A computerized radiation therapy dosimetric analysis was performed on 34 patients. Results: Local control was achieved in 39 patients (95%), including 6 with aggressive fibromatosis. The mean functional outcome score was 5.1 with a range of 0–16. 34 patients (83%) had good or excellent functional outcomes. The rating system demonstrated minimal interobserver variability. There was a positive relationship between volume irradiated to ≥ 55 Gy and functional score, strength, fibrosis, and skin changes. Total dose independent of volume was significantly associated with skin changes. Increasing peak dose (hot spot dose) was associated with fibrosis and skin changes. More fibrosis developed as the volume of the peak dose increased. A portion of the joint was treated in 5 33 extremity patients and the entire joint in 24 33 (mean dose 55.8 Gy, range 45–65 Gy). Neither range of motion nor total functional score was correlated with joint dose. Edema and functional score were not related to either the volume or percent of limb spared (receiving ≤ 40 Gy). The physician functional status ratings generally concurred with patient self-assessments. Conclusions: A system for functional assessment has been developed which is easily performed and provides detailed information about patient functional outcome. This system can be used to evaluate the morbidity of combined modality sarcoma therapy. Doses up to 65 Gy, even over joint spaces, are not associated with significant morbidity. Only a small volume treated to ≤ 40 Gy is required to maintain good outcome. The most important parameter appears to be the volume treated to ≥55 Gy.