Outcome of primary soft tissue sarcoma of the knee and elbow

Concern is frequently raised regarding the tolerance of irradiation over a joint space. The purpose of this study was to determine the outcome in terms of relapse and potential complications in patients with knee and elbow soft tissue sarcoma treated with limb-sparing surgery with or without adjuvant radiotherapy (RT).

A review of our prospective database between June 1982 and December 1999 identified 86 adult patients with primary soft tissue sarcoma arising from the knee (n = 65; 76%) or elbow (n = 21; 24%) treated with limb-sparing surgery. Tumors had high-grade histologic features in 72% and were >5 cm in 48% of patients. Adjuvant RT was given to 46 (54%) of 86 patients. The type of RT was postoperative external beam RT in 63% and brachytherapy in 37%. Of the 46 patients who received RT, 85% (n = 39) had deep, 78% (n = 36) high-grade, and 54% (n = 25) >5-cm tumors. Complications were assessed in terms of wound complications requiring repeated surgery, bone fracture, nerve damage, and joint stiffness.

With a median follow-up of 48 months (range 4-175), the 5-year actuarial rate of local control, distant control, and overall survival was 75% (95% confidence interval [CI] 64-85%), 82% (95% CI 73-91%), and 81% (95% CI 71-91%), respectively. The 5-year local control rate for patients who received RT was 80% vs. 71% for those who did not (p = 0.3). The type of RT did not significantly influence the local control rate. Patients treated with external beam RT had a 5-year local control rate of 84% compared with 73% for those treated with brachytherapy (p = 0.4). On multivariate analysis, tumor size >5 cm retained its significance as an independent predictor of poor local control (p = 0.04; relative risk 3; 95% CI 1-6). In addition, high-grade histologic features emerged as an independent predictor of local recurrence (p = 0.02; relative risk 4; 95% CI 1-20). No statistically significant difference was found between the RT and no-RT group in terms of the 5-year actuarial rate of wound reoperation (10% vs. 3%, p = 0.1), bone fracture (3% vs. 5%, p = 0.5), or nerve damage (6% vs. 3%, p = 0.5). Joint stiffness was significantly higher in the RT group (24% vs. 0%, p = 0.001), but this stiffness was severe to moderate in only 2 patients.

On the basis of the findings of this retrospective review, adjuvant RT seems to be relatively well tolerated despite the inclusion of part of the joint space in the irradiation portal. Joint stiffness was seen more frequently with adjuvant RT, but it was moderate to severe in only a small number of patients.